U.S. patent application number 17/345873 was filed with the patent office on 2021-10-07 for apparatus for transmitting broadcast signals, apparatus for receiving broadcast signals, method for transmitting broadcast signals and method for receiving broadcast signals.
This patent application is currently assigned to LG ELECTRONICS INC.. The applicant listed for this patent is LG ELECTRONICS INC.. Invention is credited to Sungryong HONG, Woosuk KO, Minsung KWAK, Woosuk KWON, Kyoungsoo MOON.
Application Number | 20210314076 17/345873 |
Document ID | / |
Family ID | 1000005649830 |
Filed Date | 2021-10-07 |
United States Patent
Application |
20210314076 |
Kind Code |
A1 |
KWAK; Minsung ; et
al. |
October 7, 2021 |
APPARATUS FOR TRANSMITTING BROADCAST SIGNALS, APPARATUS FOR
RECEIVING BROADCAST SIGNALS, METHOD FOR TRANSMITTING BROADCAST
SIGNALS AND METHOD FOR RECEIVING BROADCAST SIGNALS
Abstract
A method of processing a broadcast signal includes physical
layer processing a plurality of packets into a plurality of data
pipes to form a signal frame of the broadcast signal. Further, a
packet includes an emergency alert message for an emergency alert
service so that a data pipe carries the emergency alert massage,
the emergency alert message including a message identifier (ID) for
identifying the emergency alert message and a service ID
identifying a service related to the emergency alert message. The
physical layer processing further includes encoding data in each
data pipe; bit interleaving the encoded data in each data pipe; and
time interleaving the bit interleaved data in each data pipe
according to a first mode or a second mode, the first mode
represents that the time interleaving is performed based on
convolutional interleaving operation, the second mode represents
that the time interleaving is performed based on a combination of
block interleaving operation and convolutional interleaving
operation; and transmitting the broadcast signal. In addition, the
broadcast signal further includes physical layer signaling
information, the physical layer signaling information including a
signaling information representing that the data pipe carries the
emergency alert message and time interleaving signaling information
related to the first mode and the second mode.
Inventors: |
KWAK; Minsung; (Seoul,
KR) ; MOON; Kyoungsoo; (Seoul, KR) ; KWON;
Woosuk; (Seoul, KR) ; KO; Woosuk; (Seoul,
KR) ; HONG; Sungryong; (Seoul, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
LG ELECTRONICS INC. |
Seoul |
|
KR |
|
|
Assignee: |
LG ELECTRONICS INC.
Seoul
KR
|
Family ID: |
1000005649830 |
Appl. No.: |
17/345873 |
Filed: |
June 11, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16569860 |
Sep 13, 2019 |
11075705 |
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17345873 |
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15307734 |
Oct 28, 2016 |
10454602 |
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PCT/KR2016/000058 |
Jan 5, 2016 |
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16569860 |
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62119262 |
Feb 22, 2015 |
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62100081 |
Jan 6, 2015 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04N 21/6112 20130101;
H04W 4/06 20130101; H04N 7/08 20130101; H04N 21/814 20130101; H04N
21/478 20130101; H04W 4/90 20180201; H04H 20/59 20130101 |
International
Class: |
H04H 20/59 20060101
H04H020/59; H04N 21/478 20060101 H04N021/478; H04N 7/08 20060101
H04N007/08; H04N 21/81 20060101 H04N021/81; H04N 21/61 20060101
H04N021/61; H04W 4/90 20060101 H04W004/90; H04W 4/06 20060101
H04W004/06 |
Claims
1. A method of processing a broadcast signal, comprising: physical
layer processing a plurality of data pipes, wherein: a data pipe
carries an emergency alert message, the emergency alert message
including a message identifier (ID) for identifying the emergency
alert message, a service ID identifying a service related to the
emergency alert message and information for identifying an issuer
of the emergency alert message, the physical layer processing
further includes: encoding data in each data pipe; bit interleaving
the encoded data in each data pipe; time interleaving the bit
interleaved data in each data pipe according to a first mode or a
second mode, the first mode represents that the time interleaving
is performed based on a convolutional interleaving operation, the
second mode represents that the time interleaving is performed
based on a block interleaving operation and a convolutional
interleaving operation; building a signal frame carrying the time
interleaved data; and performing frequency interleaving operation
on an OFDM symbol in the signal frame; and transmitting the
broadcast signal, wherein: the broadcast signal includes physical
layer signaling information, the physical layer signaling
information including signaling information for the data pipe
carrying the emergency alert message and time interleaving
signaling information related to the first mode or the second
mode.
2. The method of claim 1, wherein the emergency alert message is
carried in an IP (Internet Protocol) packet.
3. A device of processing a broadcast signal, comprising: a
physical layer processor configured to process a plurality of data
pipes, wherein: a data pipe carries an emergency alert message, the
emergency alert message including a message identifier (ID) for
identifying the emergency alert message, a service ID identifying a
service related to the emergency alert message and information for
identifying an issuer of the emergency alert message, the physical
layer processor is further configured to: encode data in each data
pipe; bit interleave the encoded data in each data pipe; time
interleave the bit interleaved data in each data pipe according to
a first mode or a second mode, the first mode represents that the
time interleaving is performed based on a convolutional
interleaving operation, the second mode represents that the time
interleaving is performed based on a block interleaving operation
and a convolutional interleaving operation; build a signal frame
carrying the time interleaved data; and perform frequency
interleaving operation on an OFDM symbol in the signal frame; and a
transmitter configured to transmit the broadcast signal, wherein:
the physical layer signaling information includes signaling
information for the data pipe carrying the emergency alert message
and time interleaving signaling information related to the first
mode or the second mode.
4. The device of claim 3, wherein the emergency alert message is
carried in an IP(Internet Protocol) packet.
5. A method of processing a broadcast signal, comprising: receiving
the broadcast signal carrying a signal frame, the signal frame
including a plurality of data pipes and physical layer signaling
information; and physical layer processing the broadcast signal,
the physical layer processing including: frequency deinterleaving
the broadcast signal; decoding the physical layer signaling
information of the frequency deinterleaved broadcast signal,
wherein: the physical layer signaling information include signaling
information for a data pipe carrying an emergency alert message for
an emergency service, time interleaving signaling information
related to a first mode or a second mode of time interleaving
operation, the first mode represents that the time interleaving
operation includes a convolutional interleaving operation, and the
second mode represents that the time interleaving operation
includes a convolutional interleaving operation and a block
interleaving operation; processing data in the data pipe based on
the signaling information in order to output the emergency alert
message, the processing including: time deinterleaving the data in
the data pipe of the frequency deinterleaved broadcast signal based
on the time interleaving signaling information; bit deinterleaving
the time deinterleaved data in the data pipe; and decoding the bit
deinterleaved data in the data pipe, wherein: the emergency alert
message includes a message identifier (ID) for identifying the
emergency alert message, a service ID identifying a service related
to the emergency alert message and information for identifying an
issuer of the emergency alert message.
6. The method of claim 5, wherein the emergency alert message is
carried in an IP(Internet Protocol) packet.
7. A device of processing a broadcast signal, comprising: a tuner
configured to receive the broadcast signal carrying a signal frame,
the signal frame including a plurality of data pipes and physical
layer signaling information; and a physical layer processor
configured to perform processing the broadcast signal, processing
including: frequency deinterleaving the broadcast signal; decoding
the physical layer signaling information of the frequency
deinterleaved broadcast signal, wherein: the physical layer
signaling information include signaling information for a data pipe
carrying an emergency alert message for an emergency service, time
interleaving signaling information related to a first mode or a
second mode of time interleaving operation, the first mode
represents that the time interleaving operation includes a
convolutional interleaving operation, and the second mode
represents that the time interleaving operation includes a
convolutional interleaving operation and a block interleaving
operation; wherein the physical layer processor is further
configured to perform processing data in the data pipe based on the
signaling information in order to output the emergency alert
message, the processing including: time deinterleaving the data in
the data pipe of the frequency deinterleaved broadcast signal based
on the time interleaving signaling information; bit deinterleaving
the time deinterleaved data in the data pipe; and decoding the bit
deinterleaved data in the data pipe, wherein: the emergency alert
message includes a message identifier (ID) for identifying the
emergency alert message, a service ID identifying a service related
to the emergency alert message and information for identifying an
issuer of the emergency alert message.
8. The device of claim 7, wherein the emergency alert message is
carried in an IP (Internet Protocol) packet.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Continuation of co-pending U.S. patent
application Ser. No. 16/569,860 filed on Sep. 13, 2019, which is a
Continuation U.S. patent application Ser. No. 15/307,734 filed on
Oct. 28, 2016 (now U.S. Pat. No. 10,454,602 issued on Oct. 22,
2019), which is the National Phase of PCT International Application
No. PCT/KR2016/000058 filed on Jan. 5, 2016, which claims the
priority benefit under 35 U.S.C. .sctn. 119(e) to U.S. Provisional
Application Nos. 62/119,262 filed on Feb. 22, 2015 and 62/100,081
filed on Jan. 6, 2015, all of which are hereby expressly
incorporated by reference into the present application.
BACKGROUND OF THE INVENTION
Field of the Invention
[0002] The present invention relates to an apparatus for
transmitting a broadcast signal, an apparatus for receiving a
broadcast signal and methods for transmitting and receiving a
broadcast signal.
Discussion of the Related Art
[0003] As analog broadcast signal transmission comes to an end,
various technologies for transmitting/receiving digital broadcast
signals are being developed. A digital broadcast signal may include
a larger amount of video/audio data than an analog broadcast signal
and further include various types of additional data in addition to
the video/audio data.
SUMMARY OF THE INVENTION
[0004] That is, a digital broadcast system can provide HD (high
definition) images, multichannel audio and various additional
services. However, data transmission efficiency for transmission of
large amounts of data, robustness of transmission/reception
networks and network flexibility in consideration of mobile
reception equipment need to be improved for digital broadcast.
[0005] The present invention provides a system capable of
effectively supporting future broadcast services in an environment
supporting future hybrid broadcasting using terrestrial broadcast
networks and the Internet and related signaling methods.
Advantageous Effects
[0006] The present invention can control quality of service (QoS)
with respect to services or service components by processing data
on the basis of service characteristics, thereby providing various
broadcast services.
[0007] The present invention can achieve transmission flexibility
by transmitting various broadcast services through the same radio
frequency (RF) signal bandwidth.
[0008] The present invention can provide methods and apparatuses
for transmitting and receiving broadcast signals, which enable
digital broadcast signals to be received without error even w % ben
a mobile reception device is used or even in an indoor
environment.
[0009] The present invention can effectively support future
broadcast services in an environment supporting future hybrid
broadcasting using terrestrial broadcast networks and the
Internet.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The accompanying drawings, which are included to provide a
further understanding of the invention and are incorporated in and
constitute a part of this application, illustrate embodiment(s) of
the invention and together with the description serve to explain
the principle of the invention. In the drawings:
[0011] FIG. 1 illustrates a receiver protocol stack according to an
embodiment of the present invention.
[0012] FIG. 2 illustrates a relation between an SLT and service
layer signaling (SLS) according to an embodiment of the present
invention.
[0013] FIG. 3 illustrates an SLT according to an embodiment of the
present invention.
[0014] FIG. 4 illustrates SLS bootstrapping and a service discovery
process according to an embodiment of the present invention.
[0015] FIG. 5 illustrates a USBD fragment for ROUTEDASH according
to an embodiment of the present invention.
[0016] FIG. 6 illustrates an S-TSID fragment for ROUTE/DASH
according to an embodiment of the present invention.
[0017] FIG. 7 illustrates a USBD/USD fragment for MMT according to
an embodiment of the present invention.
[0018] FIG. 8 illustrates a link layer protocol architecture
according to an embodiment of the present invention.
[0019] FIG. 9 illustrates a structure of a base header of a link
layer packet according to an embodiment of the present
invention.
[0020] FIG. 10 illustrates a structure of an additional header of a
link layer packet according to an embodiment of the present
invention.
[0021] FIG. 11 illustrates a structure of an additional header of a
link layer packet according to another embodiment of the present
invention.
[0022] FIG. 12 illustrates a header structure of a link layer
packet for an MPEG-2 TS packet and an encapsulation process thereof
according to an embodiment of the present invention.
[0023] FIG. 13 illustrates an example of adaptation modes in IP
header compression according to an embodiment of the present
invention (transmitting side).
[0024] FIG. 14 illustrates a link mapping table (LMT) and an RoHC-U
description table according to an embodiment of the present
invention.
[0025] FIG. 15 illustrates a structure of a link layer on a
transmitter side according to an embodiment of the present
invention.
[0026] FIG. 16 illustrates a structure of a link layer on a
receiver side according to an embodiment of the present
invention.
[0027] FIG. 17 illustrates a configuration of signaling
transmission through a link layer according to an embodiment of the
present invention (transmitting/receiving sides).
[0028] FIG. 18 is a block diagram illustrating a configuration of a
broadcast signal transmission apparatus for future broadcast
services according to an embodiment of the present invention.
[0029] FIG. 19 is a block diagram illustrating a bit interleaved
coding & modulation (BICM) block according to an embodiment of
the present invention.
[0030] FIG. 20 is a block diagram illustrating a BICM block
according to another embodiment of the present invention.
[0031] FIG. 21 illustrates a bit interleaving process of physical
layer signaling (PLS) according to an embodiment of the present
invention.
[0032] FIG. 22 is a block diagram illustrating a configuration of a
broadcast signal reception apparatus for future broadcast services
according to an embodiment of the present invention.
[0033] FIG. 23 illustrates a signaling hierarchy structure of a
frame according to an embodiment of the present invention.
[0034] FIG. 24 is a table illustrating PLS1 data according to an
embodiment of the present invention.
[0035] FIG. 25 is a table illustrating PLS2 data according to an
embodiment of the present invention.
[0036] FIG. 26 is a table illustrating PLS2 data according to
another embodiment of the present invention.
[0037] FIG. 27 illustrates a logical structure of a frame according
to an embodiment of the present invention.
[0038] FIG. 28 illustrates PLS mapping according to an embodiment
of the present invention.
[0039] FIG. 29 illustrates time interleaving according to an
embodiment of the present invention.
[0040] FIG. 30 illustrates a basic operation of a twisted
row-column block interleaver according to an embodiment of the
present invention.
[0041] FIG. 31 illustrates an operation of a twisted row-column
block interleaver according to another embodiment of the present
invention.
[0042] FIG. 32 is a block diagram illustrating an interleaving
address generator including a main pseudo-random binary sequence
(PRBS) generator and a sub-PRBS generator according to each FFT
mode according to an embodiment of the present invention.
[0043] FIG. 33 illustrates a main PRBS used for all FFT modes
according to an embodiment of the present invention.
[0044] FIG. 34 illustrates a sub-PRBS used for FFT modes and an
interleaving address for frequency interleaving according to an
embodiment of the present invention.
[0045] FIG. 35 illustrates a write operation of a time interleaver
according to an embodiment of the present invention.
[0046] FIG. 36 is a table illustrating an interleaving type applied
according to the number of PLPs.
[0047] FIG. 37 is a block diagram including a first example of a
structure of a hybrid time interleaver.
[0048] FIG. 38 is a block diagram including a second example of the
structure of the hybrid time interleaver.
[0049] FIG. 39 is a block diagram including a first example of a
structure of a hybrid time deinterleaver.
[0050] FIG. 40 is a block diagram including a second example of the
structure of the hybrid time deinterleaver.
[0051] FIG. 41 is a diagram illustrating an example of a protocol
stack for supporting a broadcast service according to the present
invention.
[0052] FIG. 42 is a diagram illustrating another example of the
protocol stack for supporting the broadcast service according to
the present invention.
[0053] FIG. 43 is a diagram illustrating an example of a transport
layer of the broadcast service according to the present
invention.
[0054] FIG. 44 is a block diagram illustrating the whole
configuration of the emergency alert system according to an
embodiment of the present invention.
[0055] FIG. 45 illustrates syntax of EAT information according to
an embodiment of the present invention.
[0056] FIG. 46 illustrates syntax of an emergency alert message
according to an embodiment of the present invention.
[0057] FIG. 47 illustrates syntax for automatic channel tuning
information according to an embodiment of the present
invention.
[0058] FIG. 48 illustrates syntax for NRT service information
according to an embodiment of the present invention.
[0059] FIG. 49 illustrates embodiments of syntax of a section table
for transmitting an emergency alert message according to the
present invention.
[0060] FIG. 50 illustrates embodiments of syntax of a section table
for transmitting an emergency alert message according to the
present invention.
[0061] FIG. 51 illustrates an embodiment of configuring a packet to
transmit an EAT without changing the form according to the present
invention.
[0062] FIG. 52 illustrates an embodiment of configuring a packet to
transmit an emergency alert message in the form of separate
information rather than a section table according to the present
invention.
[0063] FIG. 53 is a block diagram illustrating another embodiment
of the emergency alert system for transmitting/receiving the
emergency alert information according to the present invention.
[0064] FIG. 54 is a block diagram illustrating another embodiment
of the emergency alert system for transmitting/receiving the
emergency alert information according to the present invention.
[0065] FIG. 55 is a block diagram illustrating another embodiment
of the emergency alert system for transmitting/receiving the
emergency alert information according to the present invention.
[0066] FIG. 56 is a block diagram illustrating another embodiment
of the emergency alert system for transmitting/receiving the
emergency alert information according to the present invention.
[0067] FIG. 57 illustrates an embodiment of syntax of an emergency
alert message transmitted through a signaling channel.
[0068] FIG. 58 is a block diagram illustrating another embodiment
of the emergency alert system for transmitting/receiving the
emergency alert information according to the present invention.
[0069] FIG. 59 illustrates an embodiment of syntax for signaling an
emergency alert transmitted through a signaling channel.
[0070] FIG. 60 is a flowchart illustrating an operation method of a
broadcast transmitter according to an embodiment of the present
invention.
[0071] FIG. 61 is a flowchart illustrating an operation method of a
broadcast receiver according to an embodiment of the present
invention.
[0072] FIG. 62 illustrates a conceptual view of a link layer packet
according to the present invention.
[0073] FIG. 63 is a diagram illustrating examples of respective
fields included in a fixed header and an extended header of a link
layer packet.
[0074] FIG. 64 illustrates the fixed header and the extended header
in the form of syntax.
[0075] FIG. 65 is a diagram illustrating definition of values
assigned to a signaling_class field of a link layer packet header
in the form of a table according to the present invention.
[0076] FIG. 66 is a diagram illustrating definition of values
assigned to an information_type field of the link layer packet
header in the form of a table according to the present
invention.
[0077] FIG. 67 illustrates an example of syntax of a payload a
packet for an emergency alert when a link layer packet is the
packet and an emergency alert message is transmitted using the
payload of the packet.
[0078] FIG. 68 is a flowchart illustrating one embodiment of a
method of receiving and processing an emergency alert packet in a
broadcast receiver according to the present invention.
[0079] FIG. 69 illustrates an example of syntax of a payload a
packet for an emergency alert when a link layer packet is the
packet and connection (or link) information of an emergency alert
message is transmitted using the payload of the packet.
[0080] FIG. 70 is a flowchart illustrating an embodiment of a
method for receiving and processing a link layer packet in a
broadcast receiver according to the present invention.
[0081] FIG. 71 illustrates an example of syntax of a payload a
packet for an emergency alert when a link layer packet is the
packet and automatic tuning information related to the emergency
alert is transmitted using the payload of the packet.
[0082] FIG. 72 is a flowchart illustrating an embodiment of a
method for receiving and processing a link layer packet in the
broadcast receiver according to the present invention.
[0083] FIG. 73 illustrates an example of syntax of a payload a
packet for an emergency alert when a link layer packet is the
packet and NRT service information related to the emergency alert
is transmitted using the payload of the packet.
[0084] FIG. 74 is a flowchart illustrating an embodiment of a
method for receiving and processing a link layer packet in the
broadcast receiver according to the present invention.
[0085] FIG. 75 is a block diagram illustrating an embodiment of the
broadcast receiver for supporting an emergency alert service
according to the present invention.
[0086] FIG. 76 is a block diagram illustrating another embodiment
of the broadcast receiver for supporting the emergency alert
service according to the present invention.
[0087] FIG. 77 is a block diagram illustrating another embodiment
of the broadcast receiver for supporting the emergency alert
service according to the present invention.
[0088] FIG. 78 is a diagram illustrating an FIC according to an
embodiment of the present invention.
[0089] FIG. 79 is a diagram illustrating a service category
according to an embodiment of the present invention.
[0090] FIG. 80 is a diagram illustrating a form in which one
frequency is shared by two broadcasters according to an embodiment
of the present invention.
[0091] FIG. 81 is a diagram illustrating Emergency_Alert_Table( )
according to an embodiment of the present invention.
[0092] FIG. 82 is a diagram illustrating a flow of a broadcast
receiver according to an embodiment of the present invention.
[0093] FIG. 83 is a diagram illustrating a flow of a broadcast
receiver according to an embodiment of the present invention.
[0094] FIG. 84 is a diagram illustrating syntax related to an EAC
added to PLS according to an embodiment of the present
invention.
[0095] FIG. 85 is a diagram illustrating a form in which only the
WARN message is transmitted through the EAC according to an
embodiment of the present invention.
[0096] FIG. 86 is a diagram illustrating a form in which a WARN
message and a CAP message are transmitted through an EAC according
to an embodiment of the present invention.
[0097] FIG. 87 is a diagram illustrating a link layer header
according to an embodiment of the present invention.
[0098] FIG. 88 is a diagram illustrating a signaling_class field
according to an embodiment of the present invention.
[0099] FIG. 89 is a diagram illustrating an information_type field
according to an embodiment of the present invention.
[0100] FIG. 90 is a diagram illustrating syntax related to a WARN
message added to PLS according to an embodiment of the present
invention.
[0101] FIG. 91 is a diagram illustrating a form in which a WARN
message is transmitted through LLS according to an embodiment of
the present invention.
[0102] FIG. 92 is a diagram illustrating PLS in a case in which
signaling information for a WARN message is transmitted through an
EAC according to an embodiment of the present invention.
[0103] FIG. 93 is a diagram illustrating an EAT that includes
signaling information for a WARN message according to an embodiment
of the present invention.
[0104] FIG. 94 is a diagram illustrating a form in which signaling
information for a WARN message is transmitted through an EAC
according to an embodiment of the present invention.
[0105] FIG. 95 is a diagram illustrating PLS that includes
signaling information for a WARN message according to an embodiment
of the present invention.
[0106] FIG. 96 is a diagram illustrating a form in which a WARN
message is transmitted through an LCT session according to an
embodiment of the present invention.
[0107] FIG. 97 is a diagram illustrating an EAT in a case in which
signaling information for a WARN message is transmitted through an
EAC according to an embodiment of the present invention.
[0108] FIG. 98 is a diagram illustrating a form in which signaling
information for a WARN message is transmitted through an EAC
according to an embodiment of the present invention.
[0109] FIG. 99 is a diagram illustrating a form in which a WARN
message is transmitted through a dedicated PLP or a dedicated LCT
session according to an embodiment of the present invention.
[0110] FIG. 100 is a diagram illustrating a broadcast transmission
method according to an embodiment of the present invention.
[0111] FIG. 101 is a diagram illustrating a broadcast reception
method according to an embodiment of the present invention.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0112] Reference will now be made in detail to the preferred
embodiments of the present invention, examples of which are
illustrated in the accompanying drawings. The detailed description,
which will be given below with reference to the accompanying
drawings, is intended to explain exemplary embodiments of the
present invention, rather than to show the only embodiments that
can be implemented according to the present invention. The
following detailed description includes specific details in order
to provide a thorough understanding of the present invention.
However, it will be apparent to those skilled in the art that the
present invention may be practiced without such specific
details.
[0113] Although the terms used in the present invention are
selected from generally known and used terms, some of the terms
mentioned in the description of the present invention have been
selected by the applicant at his or her discretion, the detailed
meanings of which are described in relevant parts of the
description herein. Furthermore, it is required that the present
invention is understood, not simply by the actual terms used but by
the meanings of each term lying within.
[0114] The present invention provides apparatuses and methods for
transmitting and receiving broadcast signals for future broadcast
services. Future broadcast services according to an embodiment of
the present invention include a terrestrial broadcast service, a
mobile broadcast service, an ultra high definition television
(UHDTV) service, etc. The present invention may process broadcast
signals for the future broadcast services through non-MIMO
(Multiple Input Multiple Output) or MIMO according to one
embodiment. A non-MIMO scheme according to an embodiment of the
present invention may include a MISO (Multiple Input Single Output)
scheme, a SISO (Single Input Single Output) scheme, etc.
[0115] FIG. 1 illustrates a receiver protocol stack according to an
embodiment of the present invention.
[0116] Two schemes may be used in broadcast service delivery
through a broadcast network.
[0117] In a first scheme, media processing units (MPUs) are
transmitted using an MMT protocol (MMTP) based on MPEG media
transport (MMT). In a second scheme, dynamic adaptive streaming
over HTTP (DASH) segments may be transmitted using real time object
delivery over unidirectional transport (ROUTE) based on MPEG
DASH.
[0118] Non-timed content including NRT media. EPG data, and other
files is delivered with ROUTE. Signaling may be delivered over MMTP
and/or ROUTE, while bootstrap signaling information is provided by
the means of the Service List Table (SLT).
[0119] In hybrid service delivery, MPEG DASH over HTTP/TCP/IP is
used on the broadband side. Media files in ISO Base Media File
Format (BMFF) are used as the delivery, media encapsulation and
synchronization format for both broadcast and broadband delivery.
Here, hybrid service delivery may refer to a case in which one or
more program elements are delivered through a broadband path.
[0120] Services are delivered using three functional layers. These
are the physical layer, the delivery layer and the service
management layer. The physical layer provides the mechanism by
which signaling, service announcement and IP packet streams are
transported over the broadcast physical layer and/or broadband
physical layer. The delivery layer provides object and object flow
transport functionality. It is enabled by the MMTP or the ROUTE
protocol, operating on a UDP/IP multicast over the broadcast
physical layer, and enabled by the HTTP protocol on a TCP/IP
unicast over the broadband physical layer. The service management
layer enables any type of service, such as linear TV or HTML5
application service, to be carried by the underlying delivery and
physical layers.
[0121] In this figure, a protocol stack part on a broadcast side
may be divided into a part transmitted through the SLT and the
MMTP, and a part transmitted through ROUTE.
[0122] The SLT may be encapsulated through UDP and IP layers. Here,
the SLT will be described below. The MMTP may transmit data
formatted in an MPU format defined in MMT, and signaling
information according to the MMTP. The data may be encapsulated
through the UDP and IP layers. ROUTE may transmit data formatted in
a DASH segment form, signaling information, and non-timed data such
as NRT data, etc. The data may be encapsulated through the UDP and
IP layers. According to a given embodiment, some or all processing
according to the UDP and IP layers may be omitted. Here, the
illustrated signaling information may be signaling information
related to a service.
[0123] The part transmitted through the SLT and the MMTP and the
part transmitted through ROUTE may be processed in the UDP and IP
layers, and then encapsulated again in a data link layer. The link
layer will be described below. Broadcast data processed in the link
layer may be multicast as a broadcast signal through processes such
as encoding/interleaving, etc. in the physical layer.
[0124] In this figure, a protocol stack part on a broadband side
may be transmitted through HTTP as described above. Data formatted
in a DASH segment form, signaling information, NRT information,
etc. may be transmitted through HTTP. Here, the illustrated
signaling information may be signaling information related to a
service. The data may be processed through the TCP layer and the IP
layer, and then encapsulated into the link layer. According to a
given embodiment, some or all of the TCP, the IP, and the link
layer may be omitted. Broadband data processed thereafter may be
transmitted by unicast in the broadband through a process for
transmission in the physical layer.
[0125] Service can be a collection of media components presented to
the user in aggregate; components can be of multiple media types; a
Service can be either continuous or intermittent; a Service can be
Real Time or Non-Real Time; Real Time Service can consist of a
sequence of TV programs.
[0126] FIG. 2 illustrates a relation between the SLT and SLS
according to an embodiment of the present invention.
[0127] Service signaling provides service discovery and description
information, and comprises two functional components: Bootstrap
signaling via the Service List Table (SLT) and the Service Layer
Signaling (SLS). These represent the information which is necessary
to discover and acquire user services. The SLT enables the receiver
to build a basic service list, and bootstrap the discovery of the
SLS for each service.
[0128] The SLT can enable very rapid acquisition of basic service
information. The SLS enables the receiver to discover and access
services and their content components. Details of the SLT and SLS
will be described below.
[0129] As described in the foregoing, the SLT may be transmitted
through UDP/IP. In this instance, according to a given embodiment,
data corresponding to the SLT may be delivered through the most
robust scheme in this transmission.
[0130] The SLT may have access information for accessing SLS
delivered by the ROUTE protocol. In other words, the SLT may be
bootstrapped into SLS according to the ROUTE protocol. The SLS is
signaling information positioned in an upper layer of ROUTE in the
above-described protocol stack, and may be delivered through
ROUTE/UDP/IP. The SLS may be transmitted through one of LCT
sessions included in a ROUTE session. It is possible to access a
service component corresponding to a desired service using the
SLS.
[0131] In addition, the SLT may have access information for
accessing an MMT signaling component delivered by MMTP. In other
words, the SLT may be bootstrapped into SLS according to the MMTP.
The SLS may be delivered by an MMTP signaling message defined in
MMT. It is possible to access a streaming service component (MPU)
corresponding to a desired service using the SLS. As described in
the foregoing, in the present invention, an NRT service component
is delivered through the ROUTE protocol, and the SLS according to
the MMTP may include information for accessing the ROUTE protocol.
In broadband delivery, the SLS is carried over HTTP(S)/TCP/IP.
[0132] FIG. 3 illustrates an SLT according to an embodiment of the
present invention.
[0133] First, a description will be given of a relation among
respective logical entities of service management, delivery, and a
physical layer.
[0134] Services may be signaled as being one of two basic types.
First type is a linear audio/video or audio-only service that may
have an app-based enhancement. Second type is a service whose
presentation and composition is controlled by a downloaded
application that is executed upon acquisition of the service. The
latter can be called an "app-based" service.
[0135] The rules regarding presence of ROUTE/LCT sessions and/or
MMTP sessions for carrying the content components of a service may
be as follows.
[0136] For broadcast delivery of a linear service without app-based
enhancement, the service's content components can be carried by
either (but not both): (1) one or more ROUTE/LCT sessions, or (2)
one or more MMTP sessions.
[0137] For broadcast delivery of a linear service with app-based
enhancement, the service's content components can be carried by:
(1) one or more ROUTE/LCT sessions, and (2) zero or more MMTP
sessions.
[0138] In certain embodiments, use of both MMTP and ROUTE for
streaming media components in the same service may not be
allowed.
[0139] For broadcast delivery of an app-based service, the
service's content components can be carried by one or more
ROUTE/LCT sessions.
[0140] Each ROUTE session comprises one or more LCT sessions which
carry as a whole, or in part, the content components that make up
the service. In streaming services delivery, an LCT session may
carry an individual component of a user service such as an audio,
video or closed caption stream. Streaming media is formatted as
DASH Segments.
[0141] Each MMTP session comprises one or more MMTP packet flows
which carry MMT signaling messages or as a whole, or in part, the
content component. An MMTP packet flow may carry MMT signaling
messages or components formatted as MPUs.
[0142] For the delivery of NRT User Services or system metadata, an
LCT session carries file-based content items. These content files
may consist of continuous (time-based) or discrete (non-time-based)
media components of an NRT service, or metadata such as Service
Signaling or ESG fragments. Delivery of system metadata such as
service signaling or ESG fragments may also be achieved through the
signaling message mode of MMTP.
[0143] A broadcast stream is the abstraction for an RF channel,
which is defined in terms of a carrier frequency centered within a
specified bandwidth. It is identified by the pair [geographic area,
frequency]. A physical layer pipe (PLP) corresponds to a portion of
the RF channel. Each PLP has certain modulation and coding
parameters. It is identified by a PLP identifier (PLPID), which is
unique within the broadcast stream it belongs to. Here, PLP can be
referred to as DP (data pipe).
[0144] Each service is identified by two forms of service
identifier: a compact form that is used in the SLT and is unique
only within the broadcast area and a globally unique form that is
used in the SLS and the ESG. A ROUTE session is identified by a
source IP address, destination IP address and destination port
number. An LCT session (associated with the service component(s) it
carries) is identified by a transport session identifier (TSI)
which is unique within the scope of the parent ROUTE session.
Properties common to the LCT sessions, and certain properties
unique to individual LCT sessions, are given in a ROUTE signaling
structure called a service-based transport session instance
description (S-TSID), which is part of the service layer signaling.
Each LCT session is carried over a single physical layer pipe.
According to a given embodiment, one LCT session may be transmitted
through a plurality of PLPs. Different LCT sessions of a ROUTE
session may or may not be contained in different physical layer
pipes. Here, the ROUTE session may be delivered through a plurality
of PLPs. The properties described in the S-TSID include the TSI
value and PLPID for each LCT session, descriptors for the delivery
objects/files, and application layer FEC parameters.
[0145] A MMTP session is identified by destination IP address and
destination port number. An MMTP packet flow (associated with the
service component(s) it carries) is identified by a packet_id which
is unique within the scope of the parent MMTP session. Properties
common to each MMTP packet flow, and certain properties of MMTP
packet flows, are given in the SLT. Properties for each MMTP
session are given by MMT signaling messages, which may be carried
within the MMTP session. Different MMTP packet flows of a MMTP
session may or may not be contained in different physical layer
pipes. Here, the MMTP session may be delivered through a plurality
of PLPs. The properties described in the MMT signaling messages
include the packet_id value and PLPID for each MMTP packet flow.
Here, the MMT signaling messages may have a form defined in MMT, or
have a deformed form according to embodiments to be described
below.
[0146] Hereinafter, a description will be given of low level
signaling (LLS).
[0147] Signaling information which is carried in the payload of IP
packets with a well-known address/port dedicated to this function
is referred to as low level signaling (LLS). The IP address and the
port number may be differently configured depending on embodiments.
In one embodiment, LLS can be transported in IP packets with
address 224.0.23.60 and destination port 4937/udp. LLS may be
positioned in a portion expressed by "SLT" on the above-described
protocol stack. However, according to a given embodiment, the LLS
may be transmitted through a separate physical channel (dedicated
channel) in a signal frame without being subjected to processing of
the UDP/IP layer.
[0148] UDP/IP packets that deliver LLS data may be formatted in a
form referred to as an LLS table. A first byte of each UDP/IP
packet that delivers the LLS data may correspond to a start of the
LLS table. The maximum length of any LLS table is limited by the
largest IP packet that can be delivered from the PHY layer, 65,507
bytes.
[0149] The LLS table may include an LLS table ID field that
identifies a type of the LLS table, and an LLS table version field
that identifies a version of the LLS table. According to a value
indicated by the LLS table ID field, the LLS table may include the
above-described SLT or a rating region table (RRT). The RRT may
have information about content advisory rating.
[0150] Hereinafter, the SLT will be described. LLS can be signaling
information which supports rapid channel scans and bootstrapping of
service acquisition by the receiver, and SLT can be a table of
signaling information which is used to build a basic service
listing and provide bootstrap discovery of SLS.
[0151] The function of the SLT is similar to that of the program
association table (PAT) in MPEG-2 Systems, and the fast information
channel (FIC) found in ATSC Systems. For a receiver first
encountering the broadcast emission, this is the place to start.
SLT supports a rapid channel scan which allows a receiver to build
a list of all the services it can receive, with their channel name,
channel number, etc., and SLT provides bootstrap information that
allows a receiver to discover the SLS for each service. For
ROUTE/DASH-delivered services, the bootstrap information includes
the destination IP address and destination port of the LCT session
that carries the SLS. For MMT/MPU-delivered services, the bootstrap
information includes the destination IP address and destination
port of the MMTP session carrying the SLS.
[0152] The SLT supports rapid channel scans and service acquisition
by including the following information about each service in the
broadcast stream. First, the SLT can include information necessary
to allow the presentation of a service list that is meaningful to
viewers and that can support initial service selection via channel
number or up/down selection. Second, the SLT can include
information necessary to locate the service layer signaling for
each service listed. That is, the SLT may include access
information related to a location at which the SLS is
delivered.
[0153] The illustrated SLT according to the present embodiment is
expressed as an XML document having an SLT root element. According
to a given embodiment, the SLT may be expressed in a binary format
or an XML document.
[0154] The SLT root element of the SLT illustrated in the figure
may include @bsid, @sltSectionVersion, @sltSectionNumber,
@totalSltSectionNumbers, @language, @capabilities, InetSigLoc
and/or Service. According to a given embodiment, the SLT root
element may further include @providerId. According to a given
embodiment, the SLT root element may not include @language.
[0155] The service element may include @serviceId,
@SLTserviceSeqNumber, @protected, @majorChannelNo, @minorChannelNo,
@serviceCategory, @shortServiceName, @hidden, @slsProtocolType,
BroadcastSignaling, @slsPlpId, @slsDestinationIpAddress,
@slsDestinationUdpPort, @slsSourceIpAddress,
@slsMajorProtocolVersion, @SlsMinorProtocolVersion,
@serviceLanguage, @broadbandAccessRequired, @capabilities and/or
InetSigLoc.
[0156] According to a given embodiment, an attribute or an element
of the SLT may be added/changed/deleted. Each element included in
the SLT may additionally have a separate attribute or element, and
some attribute or elements according to the present embodiment may
be omitted. Here, a field which is marked with @ may correspond to
an attribute, and a field which is not marked with @ may correspond
to an element.
[0157] @bsid is an identifier of the whole broadcast stream. The
value of BSID may be unique on a regional level.
[0158] @providerId can be an index of broadcaster that is using
part or all of this broadcast stream. This is an optional
attribute. When it's not present, it means that this broadcast
stream is being used by one broadcaster. @providerId is not
illustrated in the figure.
[0159] @sltSectionVersion can be a version number of the SLT
section. The sltSectionVersion can be incremented by 1 when a
change in the information carried within the sit occurs. When it
reaches maximum value, it wraps around to 0.
[0160] @sltSectionNumber can be the number, counting from 1, of
this section of the SLT. In other words, @sltSectionNumber may
correspond to a section number of the SLT section. When this field
is not used, @sltSectionNumber may be set to a default value of
1.
[0161] @totalSltSectionNumbers can be the total number of sections
(that is, the section with the highest sltSectionNumber) of the SLT
of which this section is part. sltSectionNumber and
totalSltSectionNumbers together can be considered to indicate "Part
M of N" of one portion of the SLT when it is sent in fragments. In
other words, when the SLT is transmitted, transmission through
fragmentation may be supported. When this field is not used,
@totalSltSectionNumbers may be set to a default value of 1. A case
in which this field is not used may correspond to a case in which
the SLT is not transmitted by being fragmented.
[0162] @language can indicate primary language of the services
included in this slt instance. According to a given embodiment, a
value of this field may have a three-character language code
defined in the ISO. This field may be omitted.
[0163] @capabilities can indicate required capabilities for
decoding and meaningfully presenting the content for all the
services in this sit instance.
[0164] InetSigLoc can provide a URL telling the receiver where it
can acquire any requested type of data from external server(s) via
broadband. This element may include @urlType as a lower field.
According to a value of the @urlType field, a type of a URL
provided by InetSigLoc may be indicated. According to a given
embodiment, when the @urlType field has a value of 0, InetSigLoc
may provide a URL of a signaling server. When the @urlType field
has a value of 1, InetSigLoc may provide a URL of an ESG server.
When the @urlType field has other values, the field may be reserved
for future use.
[0165] The service field is an element having information about
each service, and may correspond to a service entry. Service
element fields corresponding to the number of services indicated by
the SLT may be present. Hereinafter, a description will be given of
a lower attribute/element of the service field.
[0166] @serviceId can be an integer number that uniquely identify
this service within the scope of this broadcast area. According to
a given embodiment, a scope of @aserviceId may be changed.
@SLTserviceSeqNumber can be an integer number that indicates the
sequence number of the SLT service information with service ID
equal to the serviceId attribute above. SLTserviceSeqNumber value
can start at 0 for each service and can be incremented by 1 every
time any attribute in this service element is changed. If no
attribute values are changed compared to the previous Service
element with a particular value of ServiceID then
SLTserviceSeqNumber would not be incremented. The
SLTserviceSeqNumber field wraps back to 0 after reaching the
maximum value.
[0167] @protected is flag information which may indicate whether
one or more components for significant reproduction of the service
are in a protected state. When set to "1" (true), that one or more
components necessary for meaningful presentation is protected. When
set to "0" (false), this flag indicates that no components
necessary for meaningful presentation of the service are protected.
Default value is false.
[0168] @majorChannelNo is an integer number representing the
"major" channel number of the service. An example of the field may
have a range of 1 to 999.
[0169] @minorChannelNo is an integer number representing the
"minor" channel number of the service. An example of the field may
have a range of 1 to 999.
[0170] @serviceCategory can indicate the category of this service.
This field may indicate a type that varies depending on
embodiments. According to a given embodiment, when this field has
values of 1, 2, and 3, the values may correspond to a linear A/V
service, a linear audio only service, and an app-based service,
respectively. When this field has a value of 0, the value may
correspond to a service of an undefined category. When this field
has other values except for 1, 2, and 3, the field may be reserved
for future use. @shortServiceName can be a short string name of the
Service.
[0171] @hidden can be boolean value that w % ben present and set to
"true" indicates that the service is intended for testing or
proprietary use, and is not to be selected by ordinary TV
receivers. The default value is "false" when not present.
[0172] @slsProtocolType can be an attribute indicating the type of
protocol of Service Layer Signaling used by this service. This
field may indicate a type that varies depending on embodiments.
According to a given embodiment, when this field has values of 1
and 2, protocols of SLS used by respective corresponding services
may be ROUTE and MMTP, respectively. When this field has other
values except for 0, the field may be reserved for future use. This
field may be referred to as @slsProtocol.
[0173] BroadcastSignaling and lower attributes/elements thereof may
provide information related to broadcast signaling. When the
BroadcastSignaling element is not present, the child element
InetSigLoc of the parent service element can be present and its
attribute urlType includes URL_type 0x00 (URL to signaling server).
In this case attribute url supports the query parameter
svc=<service_id> where service_id corresponds to the
serviceId attribute for the parent service element.
[0174] Alternatively when the BroadcastSignaling element is not
present, the element InetSigLoc can be present as a child element
of the sit root element and the attribute urlType of that
InetSigLoc element includes URL_type 0x00 (URL to signaling
server). In this case, attribute url for URL_type 0x00 supports the
query parameter svc=<service_id> where service_id corresponds
to the serviceId attribute for the parent Service element.
[0175] @slsPlpId can be a string representing an integer number
indicating the PLP ID of the physical layer pipe carrying the SLS
for this service.
[0176] @slsDestinationIpAddress can be a string containing the
dotted-IPv4 destination address of the packets carrying SLS data
for this service.
[0177] @slsDestinationUdpPort can be a string containing the port
number of the packets carrying SLS data for this service. As
described in the foregoing, SLS bootstrapping may be performed by
destination IP/UDP information.
[0178] @slsSourceIpAddress can be a string containing the
dotted-IPv4 source address of the packets carrying SLS data for
this service.
[0179] @slsMajorProtocolVersion can be major version number of the
protocol used to deliver the service layer signaling for this
service. Default value is 1.
[0180] @SlsMinorProtocolVersion can be minor version number of the
protocol used to deliver the service layer signaling for this
service. Default value is 0.
[0181] @serviceLanguage can be a three-character language code
indicating the primary language of the service. A value of this
field may have a form that varies depending on embodiments.
[0182] @broadbandAccessRequired can be a Boolean indicating that
broadband access is required for a receiver to make a meaningful
presentation of the service. Default value is false. When this
field has a value of True, the receiver needs to access a broadband
for significant service reproduction, which may correspond to a
case of hybrid service delivery.
[0183] @capabilities can represent required capabilities for
decoding and meaningfully presenting the content for the service
with service ID equal to the service Id attribute above.
[0184] InetSigLoc can provide a URL for access to signaling or
announcement information via broadband, if available. Its data type
can be an extension of the any URL data type, adding an @urlType
attribute that indicates what the URL gives access to. An @urlType
field of this field may indicate the same meaning as that of the
@urlType field of InetSigLoc described above. When an InetSigLoc
element of attribute URL_type 0x00 is present as an element of the
SLT, it can be used to make HTTP requests for signaling metadata.
The HTTP POST message body may include a service term. When the
InetSigLoc element appears at the section level, the service term
is used to indicate the service to which the requested signaling
metadata objects apply. If the service term is not present, then
the signaling metadata objects for all services in the section are
requested. When the InetSigLoc appears at the service level, then
no service term is needed to designate the desired service. When an
InetSigLoc element of attribute URL type 0x01 is provided, it can
be used to retrieve ESG data via broadband. If the element appears
as a child element of the service element, then the URL can be used
to retrieve ESG data for that service. If the element appears as a
child element of the SLT element, then the URL can be used to
retrieve ESG data for all services in that section.
[0185] In another example of the SLT, @sltSectionVersion,
@sltSectionNumber, @totalSltSectionNumbers and/or @language fields
of the SLT may be omitted.
[0186] In addition, the above-described InetSigLoc field may be
replaced by @sltInetSigUri and/or @sltInetEsgUri field. The two
fields may include the URI of the signaling server and URI
information of the ESG server, respectively. The InetSigLoc field
corresponding to a lower field of the SLT and the InetSigLoc field
corresponding to a lower field of the service field may be replaced
in a similar manner.
[0187] The suggested default values may vary depending on
embodiments. An illustrated "use" column relates to the respective
fields. Here, "1" may indicate that a corresponding field is an
essential field, and "0 . . . 1" may indicate that a corresponding
field is an optional field.
[0188] FIG. 4 illustrates SLS bootstrapping and a service discovery
process according to an embodiment of the present invention.
[0189] Hereinafter, SLS will be described.
[0190] SLS can be signaling which provides information for
discovery and acquisition of services and their content
components.
[0191] For ROUTE/DASH, the SLS for each service describes
characteristics of the service, such as a list of its components
and where to acquire them, and the receiver capabilities required
to make a meaningful presentation of the service. In the ROUTE/DASH
system, the SLS includes the user service bundle description
(USBD), the S-TSID and the DASH media presentation description
(MPD). Here, USBD or user service description (USD) is one of SLS
XML fragments, and may function as a signaling herb that describes
specific descriptive information. USBD/USD may be extended beyond
3GPP MBMS. Details of USBD/USD will be described below.
[0192] The service signaling focuses on basic attributes of the
service itself, especially those attributes needed to acquire the
service. Properties of the service and programming that are
intended for viewers appear as service announcement, or ESG
data.
[0193] Having separate Service Signaling for each service permits a
receiver to acquire the appropriate SLS for a service of interest
without the need to parse the entire SLS carried within a broadcast
stream.
[0194] For optional broadband delivery of Service Signaling, the
SLT can include HTTP URLs where the Service Signaling files can be
obtained, as described above.
[0195] LLS is used for bootstrapping SLS acquisition, and
subsequently, the SLS is used to acquire service components
delivered on either ROUTE sessions or MMTP sessions. The described
figure illustrates the following signaling sequences. Receiver
starts acquiring the SLT described above. Each service identified
by service_id delivered over ROUTE sessions provides SLS
bootstrapping information: PLPID(#1), source IP address (sIP1),
destination IP address (dIP1), and destination port number
(dPort1). Each service identified by service_id delivered over MMTP
sessions provides SLS bootstrapping information: PLPID(#2),
destination IP address (dIP2), and destination port number
(dPort2).
[0196] For streaming services delivery using ROUTE, the receiver
can acquire SLS fragments carried over the IP/UDP/LCT session and
PLP; whereas for streaming services delivery using MMTP, the
receiver can acquire SLS fragments carried over an MMTP session and
PLP. For service delivery using ROUTE, these SLS fragments include
USBD/USD fragments, S-TSID fragments, and MPD fragments. They are
relevant to one service. USBD/USD fragments describe service layer
properties and provide URI references to S-TSID fragments and URI
references to MPD fragments. In other words, the USBD/USD may refer
to S-TSID and MPD. For service delivery using MMTP, the USBD
references the MMT signaling's MPT message, the MP Table of which
provides identification of package ID and location information for
assets belonging to the service. Here, an asset is a multimedia
data entity, and may refer to a data entity which is combined into
one unique ID and is used to generate one multimedia presentation.
The asset may correspond to a service component included in one
service. The MPT message is a message having the MP table of MMT.
Here, the MP table may be an MMT package table having information
about content and an MMT asset. Details may be similar to a
definition in MMT. Here, media presentation may correspond to a
collection of data that establishes bounded/unbounded presentation
of media content.
[0197] The S-TSID fragment provides component acquisition
information associated with one service and mapping between DASH
Representations found in the MPD and in the TSI corresponding to
the component of the service. The S-TSID can provide component
acquisition information in the form of a TSI and the associated
DASH representation identifier, and PLPID carrying DASH segments
associated with the DASH representation. By the PLPID and TSI
values, the receiver collects the audio/video components from the
service and begins buffering DASH media segments then applies the
appropriate decoding processes.
[0198] For USBD listing service components delivered on MMTP
sessions, as illustrated by "Service #2" in the described figure,
the receiver also acquires an MPT message with matching
MMT_package_id to complete the SLS. An MPT message provides the
full list of service components comprising a service and the
acquisition information for each component. Component acquisition
information includes MMTP session information, the PLPID carrying
the session and the packet_id within that session.
[0199] According to a given embodiment, for example, in ROUTE, two
or more S-TSID fragments may be used. Each fragment may provide
access information related to LCT sessions delivering content of
each service.
[0200] In ROUTE, S-TSID, USBD/USD, MPD, or an LCT session
delivering S-TSID, USBD/USD or MPD may be referred to as a service
signaling channel. In MMTP, USBD/UD, an MMT signaling message, or a
packet flow delivering the MMTP or USBD/UD may be referred to as a
service signaling channel.
[0201] Unlike the illustrated example, one ROUTE or MMTP session
may be delivered through a plurality of PLPs. In other words, one
service may be delivered through one or more PLPs. As described in
the foregoing, one LCT session may be delivered through one PLP.
Unlike the figure, according to a given embodiment, components
included in one service may be delivered through different ROUTE
sessions. In addition, according to a given embodiment, components
included in one service may be delivered through different MMTP
sessions. According to a given embodiment, components included in
one service may be delivered separately through a ROUTE session and
an MMTP session. Although not illustrated, components included in
one service may be delivered via broadband (hybrid delivery).
[0202] FIG. 5 illustrates a USBD fragment for ROUTE/DASH according
to an embodiment of the present invention.
[0203] Hereinafter, a description will be given of SLS in delivery
based on ROUTE.
[0204] SLS provides detailed technical information to the receiver
to enable the discovery and access of services and their content
components. It can include a set of XML-encoded metadata fragments
carried over a dedicated LCT session. That LCT session can be
acquired using the bootstrap information contained in the SLT as
described above. The SLS is defined on a per-service level, and it
describes the characteristics and access information of the
service, such as a list of its content components and how to
acquire them, and the receiver capabilities required to make a
meaningful presentation of the service. In the ROUTE/DASH system,
for linear services delivery, the SLS consists of the following
metadata fragments: USBD, S-TSID and the DASH MPD. The SLS
fragments can be delivered on a dedicated LCT transport session
with TSI=0. According to a given embodiment, a TSI of a particular
LCT session (dedicated LCT session) in which an SLS fragment is
delivered may have a different value. According to a given
embodiment, an LCT session in which an SLS fragment is delivered
may be signaled using the SLT or another scheme.
[0205] ROUTE/DASH SLS can include the user service bundle
description (USBD) and service-based transport session instance
description (S-TSID) metadata fragments. These service signaling
fragments are applicable to both linear and application-based
services. The USBD fragment contains service identification, device
capabilities information, references to other SLS fragments
required to access the service and constituent media components,
and metadata to enable the receiver to determine the transport mode
(broadcast and/or broadband) of service components. The S-TSID
fragment, referenced by the USBD, provides transport session
descriptions for the one or more ROUTE/LCT sessions in which the
media content components of a service are delivered, and
descriptions of the delivery objects carried in those LCT sessions.
The USBD and S-TSID will be described below.
[0206] In streaming content signaling in ROUTE-based delivery, a
streaming content signaling component of SLS corresponds to an MPD
fragment. The MPD is typically associated with linear services for
the delivery of DASH Segments as streaming content. The MPD
provides the resource identifiers for individual media components
of the linear/streaming service in the form of Segment URLs, and
the context of the identified resources within the Media
Presentation. Details of the MPD will be described below.
[0207] In app-based enhancement signaling in ROUTE-based delivery,
app-based enhancement signaling pertains to the delivery of
app-based enhancement components, such as an application logic
file, locally-cached media files, network content items, or a
notification stream. An application can also retrieve
locally-cached data over a broadband connection when available.
[0208] Hereinafter, a description will be given of details of
USBD/USD illustrated in the figure.
[0209] The top level or entry point SLS fragment is the USBD
fragment. An illustrated USBD fragment is an example of the present
invention, basic fields of the USBD fragment not illustrated in the
figure may be additionally provided according to a given
embodiment. As described in the foregoing, the illustrated USBD
fragment has an extended form, and may have fields added to a basic
configuration.
[0210] The illustrated USBD may have a bundleDescription root
element. The bundleDescription root element may have a
userServiceDescription element. The userServiceDescription element
may correspond to an instance for one service.
[0211] The userServiceDescription element may include @serviceId,
@atsc:serviceId, @atsc:serviceStatus, @atsc:fullMPDUri,
@atsc:sTSIDUri, name, serviceLanguage, atsc:capabilityCode and/or
deliveryMethod.
[0212] @serviceId can be a globally unique URI that identifies a
service, unique within the scope of the BSID. This parameter can be
used to link to ESG data (Service@globalServiceID).
[0213] @atsc:serviceId is a reference to corresponding service
entry in LLS(SLT). The value of this attribute is the same value of
serviceId assigned to the entry.
[0214] @atsc:serviceStatus can specify the status of this service.
The value indicates whether this service is active or inactive.
When set to "1" (true), that indicates service is active. When this
field is not used, @atsc:serviceStatus may be set to a default
value of 1.
[0215] @atsc:fullMPDUri can reference an MPD fragment which
contains descriptions for contents components of the service
delivered over broadcast and optionally, also over broadband.
[0216] @ atsc:sTSIDUri can reference the S-TSID fragment which
provides access related parameters to the Transport sessions
carrying contents of this service.
[0217] name can indicate name of the service as given by the lang
attribute. name element can include lang attribute, which
indicating language of the service name. The language can be
specified according to XML data types.
[0218] serviceLanguage can represent available languages of the
service. The language can be specified according to XML data
types.
[0219] atsc:capabilityCode can specify the capabilities required in
the receiver to be able to create a meaningful presentation of the
content of this service. According to a given embodiment, this
field may specify a predefined capability group. Here, the
capability group may be a group of capability attribute values for
significant presentation. This field may be omitted according to a
given embodiment.
[0220] deliveryMethod can be a container of transport related
information pertaining to the contents of the service over
broadcast and (optionally) broadband modes of access. Referring to
data included in the service, when the number of the data is N,
delivery schemes for respective data may be described by this
element. The deliveryMethod may include an r12:broadcastAppService
element and an r12:unicastAppService element. Each lower element
may include a basePattern element as a lower element.
[0221] r12:broadcastAppService can be a DASH Representation
delivered over broadcast, in multiplexed or non-multiplexed form,
containing the corresponding media component(s) belonging to the
service, across all Periods of the affiliated media presentation.
In other words, each of the fields may indicate DASH representation
delivered through the broadcast network.
[0222] r12:unicastAppService can be a DASH Representation delivered
over broadband, in multiplexed or non-multiplexed form, containing
the constituent media content component(s) belonging to the
service, across all periods of the affiliated media presentation.
In other words, each of the fields may indicate DASH representation
delivered via broadband.
[0223] basePattern can be a character pattern for use by the
receiver to match against any portion of the segment URL used by
the DASH client to request media segments of a parent
representation under its containing period. A match implies that
the corresponding requested media segment is carried over broadcast
transport. In a URL address for receiving DASH representation
expressed by each of the r12:broadcastAppService element and the
r12:unicastAppService element, a part of the URL, etc. may have a
particular pattern. The pattern may be described by this field.
Some data may be distinguished using this information. The proposed
default values may vary depending on embodiments. The "use" column
illustrated in the figure relates to each field. Here, M may denote
an essential field, O may denote an optional field, OD may denote
an optional field having a default value, and CM may denote a
conditional essential field. 0 . . . 1 to 0 . . . N may indicate
the number of available fields.
[0224] FIG. 6 illustrates an S-TSID fragment for ROUTE/DASH
according to an embodiment of the present invention.
[0225] Hereinafter, a description will be given of the S-TSID
illustrated in the figure in detail.
[0226] S-TSID can be an SLS XML fragment which provides the overall
session description information for transport session(s) which
carry the content components of a service. The S-TSID is the SLS
metadata fragment that contains the overall transport session
description information for the zero or more ROUTE sessions and
constituent LCT sessions in which the media content components of a
service are delivered. The S-TSID also includes file metadata for
the delivery object or object flow carried in the LCT sessions of
the service, as well as additional information on the payload
formats and content components carried in those LCT sessions.
[0227] Each instance of the S-TSID fragment is referenced in the
USBD fragment by the @aatsc:sTSIDUri attribute of the
userServiceDescription element. The illustrated S-TSID according to
the present embodiment is expressed as an XML document. According
to a given embodiment, the S-TSID may be expressed in a binary
format or as an XML document.
[0228] The illustrated S-TSID may have an S-TSID root element. The
S-TSID root element may include @serviceId and/or RS.
[0229] @serviceID can be a reference corresponding service element
in the USD. The value of this attribute can reference a service
with a corresponding value of service_id.
[0230] The RS element may have information about a ROUTE session
for delivering the service data. Service data or service components
may be delivered through a plurality of ROUTE sessions, and thus
the number of RS elements may be 1 to N.
[0231] The RS element may include @bsid, @sIpAddr, @dIpAddr,
@dport, @PLPID and/or LS.
[0232] @bsid can be an identifier of the broadcast stream within
which the content component(s) of the broadcastAppService are
carried. When this attribute is absent, the default broadcast
stream is the one whose PLPs carry SLS fragments for this service.
Its value can be identical to that of the broadcast_stream_id in
the SLT.
[0233] @sIpAddr can indicate source IP address. Here, the source IP
address may be a source IP address of a ROUTE session for
delivering a service component included in the service. As
described in the foregoing, service components of one service may
be delivered through a plurality of ROUTE sessions. Thus, the
service components may be transmitted using another ROUTE session
other than the ROUTE session for delivering the S-TSID. Therefore,
this field may be used to indicate the source IP address of the
ROUTE session. A default value of this field may be a source IP
address of a current ROUTE session. When a service component is
delivered through another ROUTE session, and thus the ROUTE session
needs to be indicated, a value of this field may be a value of a
source IP address of the ROUTE session. In this case, this field
may correspond to M, that is, an essential field.
[0234] @dIpAddr can indicate destination IP address. Here, a
destination IP address may be a destination IP address of a ROUTE
session that delivers a service component included in a service.
For a similar case to the above description of @sIpAddr, this field
may indicate a destination IP address of a ROUTE session that
delivers a service component. A default value of this field may be
a destination IP address of a current ROUTE session. When a service
component is delivered through another ROUTE session, and thus the
ROUTE session needs to be indicated, a value of this field may be a
value of a destination IP address of the ROUTE session. In this
case, this field may correspond to M, that is, an essential
field.
[0235] @dport can indicate destination port. Here, a destination
port may be a destination port of a ROUTE session that delivers a
service component included in a service. For a similar case to the
above description of @sIpAddr, this field may indicate a
destination port of a ROUTE session that delivers a service
component. A default value of this field may be a destination port
number of a current ROUTE session. When a service component is
delivered through another ROUTE session, and thus the ROUTE session
needs to be indicated, a value of this field may be a destination
port number value of the ROUTE session. In this case, this field
may correspond to M, that is, an essential field.
[0236] @PLPID may be an ID of a PLP for a ROUTE session expressed
by an RS. A default value may be an ID of a PLP of an LCT session
including a current S-TSID. According to a given embodiment, this
field may have an ID value of a PLP for an LCT session for
delivering an S-TSID in the ROUTE session, and may have ID values
of all PLPs for the ROUTE session.
[0237] An LS element may have information about an LCT session for
delivering a service data. Service data or service components may
be delivered through a plurality of LCT sessions, and thus the
number of LS elements may be 1 to N.
[0238] The LS element may include @tsi, @PLPID, @bw, @startTime,
@endTime, SrcFlow and/or RprFlow.
[0239] @tsi may indicate a TSI value of an LCT session for
delivering a service component of a service.
[0240] @PLPID may have ID information of a PLP for the LCT session.
This value may be overwritten on a basic ROUTE session value.
[0241] @bw may indicate a maximum bandwidth value. @startTime may
indicate a start time of the LCT session. @endTime may indicate an
end time of the LCT session. A SrcFlow element may describe a
source flow of ROUTE. A RprFlow element may describe a repair flow
of ROUTE.
[0242] The proposed default values may be varied according to an
embodiment. The "use" column illustrated in the figure relates to
each field. Here, M may denote an essential field, O may denote an
optional field, OD may denote an optional field having a default
value, and CM may denote a conditional essential field. 0 . . . 1
to 0 . . . N may indicate the number of available fields.
[0243] Hereinafter, a description will be given of MPD for
ROUTE/DASH.
[0244] The MPD is an SLS metadata fragment which contains a
formalized description of a DASH Media Presentation, corresponding
to a linear service of a given duration defined by the broadcaster
(for example a single TV program, or the set of contiguous linear
TV programs over a period of time). The contents of the MPD provide
the resource identifiers for Segments and the context for the
identified resources within the Media Presentation. The data
structure and semantics of the MPD fragment can be according to the
MPD defined by MPEG DASH.
[0245] One or more of the DASH Representations conveyed in the MPD
can be carried over broadcast. The MPD may describe additional
Representations delivered over broadband, e.g. in the case of a
hybrid service, or to support service continuity in handoff from
broadcast to broadcast due to broadcast signal degradation (e.g.
driving through a tunnel).
[0246] FIG. 7 illustrates a USBD/USD fragment for MMT according to
an embodiment of the present invention.
[0247] MMT SLS for linear services comprises the USBD fragment and
the MMT Package (MP) table. The MP table is as described above. The
USBD fragment contains service identification, device capabilities
information, references to other SLS information required to access
the service and constituent media components, and the metadata to
enable the receiver to determine the transport mode (broadcast
and/or broadband) of the service components. The MP table for MPU
components, referenced by the USBD, provides transport session
descriptions for the MMTP sessions in which the media content
components of a service are delivered and the descriptions of the
Assets carried in those MMTP sessions.
[0248] The streaming content signaling component of the SLS for MPU
components corresponds to the MP table defined in MMT. The MP table
provides a list of MMT assets where each asset corresponds to a
single service component and the description of the location
information for this component.
[0249] USBD fragments may also contain references to the S-TSID and
the MPD as described above, for service components delivered by the
ROUTE protocol and the broadband, respectively. According to a
given embodiment, in delivery through MMT, a service component
delivered through the ROUTE protocol is NRT data, etc. Thus, in
this case, MPD may be unnecessary. In addition, in delivery through
MMT, information about an LCT session for delivering a service
component, which is delivered via broadband, is unnecessary, and
thus an S-TSID may be unnecessary. Here, an MMT package may be a
logical collection of media data delivered using MMT. Here, an MMTP
packet may refer to a formatted unit of media data delivered using
MMT. An MPU may refer to a generic container of independently
decodable timed/non-timed data. Here, data in the MPU is media
codec agnostic.
[0250] Hereinafter, a description will be given of details of the
USBD/USD illustrated in the figure.
[0251] The illustrated USBD fragment is an example of the present
invention, and basic fields of the USBD fragment may be
additionally provided according to an embodiment. As described in
the foregoing, the illustrated USBD fragment has an extended form,
and may have fields added to a basic structure.
[0252] The illustrated USBD according to an embodiment of the
present invention is expressed as an XML document. According to a
given embodiment, the USBD may be expressed in a binary format or
as an XML document.
[0253] The illustrated USBD may have a bundleDescription root
element. The bundleDescription root element may have a
userServiceDescription element. The userServiceDescription element
may be an instance for one service.
[0254] The userServiceDescription element may include @serviceId,
@atsc:serviceId, name, serviceLanguage, atsc:capabilityCode,
atsc:Channel, atsc:mpuComponent, atsc:routeComponent,
atsc:broadbandComponent and/or atsc:ComponentInfo.
[0255] Here, @serviceId, @atsc:serviceId, name, serviceLanguage,
and atsc:capabilityCode may be as described above. The lang field
below the name field may be as described above. atsc:capabilityCode
may be omitted according to a given embodiment.
[0256] The userServiceDescription element may further include an
atsc:contentAdvisoryRating element according to an embodiment. This
element may be an optional element. atsc:contentAdvisoryRating can
specify the content advisory rating. This field is not illustrated
in the figure.
[0257] atsc:Channel may have information about a channel of a
service. The atsc:Channel element may include @atsc:majorChannelNo,
@datsc:minorChannelNo, @atsc:serviceLang, @atsc:serviceGenre,
@atsc:serviceIcon and/or atsc:ServiceDescription.
@atsc:majorChannelNo, @atsc:minorChannelNo, and @atsc:serviceLang
may be omitted according to a given embodiment.
[0258] @atsc:majorChannelNo is an attribute that indicates the
major channel number of the service.
[0259] @atsc:minorChannelNo is an attribute that indicates the
minor channel number of the service.
[0260] @atsc:serviceLang is an attribute that indicates the primary
language used in the service.
[0261] @atsc:serviceGenre is an attribute that indicates primary
genre of the service.
[0262] @atsc:serviceIcon is an attribute that indicates the Uniform
Resource Locator (URL) for the icon used to represent this
service.
[0263] atsc:ServiceDescription includes service description,
possibly in multiple languages. atsc:ServiceDescription includes
can include @atsc:serviceDescrText and/or
@atsc:serviceDescrLang.
[0264] @atsc:serviceDescrText is an attribute that indicates
description of the service.
[0265] @atsc:serviceDescrLang is an attribute that indicates the
language of the serviceDescrText attribute above.
[0266] atsc:mpuComponent may have information about a content
component of a service delivered in a form of an MPU.
atsc:mpuComponent may include @atsc:mmtPackageId and/or
@atsc:nextMmtPackageId.
[0267] @atsc:mmtPackageId can reference a MMT Package for content
components of the service delivered as MPUs.
[0268] @atsc:nextMmtPackageId can reference a MMT Package to be
used after the one referenced by @atsc:mmtPackageId in time for
content components of the service delivered as MPUs.
[0269] atsc:routeComponent may have information about a content
component of a service delivered through ROUTE. atsc:routeComponent
may include @atsc:sTSIDUri, @sTSIDPlpId,
@sTSIDDestinationIpAddress, @sTSIDDestinationUdpPort,
@sTSIDSourceIpAddress, @sTSIDMajorProtocolVersion and/or
@sTSIDMinorProtocolVersion.
[0270] @atsc:sTSIDUri can be a reference to the S-TSID fragment
which provides access related parameters to the Transport sessions
carrying contents of this service. This field may be the same as a
URI for referring to an S-TSID in USBD for ROUTE described above.
As described in the foregoing, in service delivery by the MMTP,
service components, which are delivered through NRT, etc., may be
delivered by ROUTE. This field may be used to refer to the S-TSID
therefor.
[0271] @sTSIDPlpId can be a string representing an integer number
indicating the PLP ID of the physical layer pipe carrying the
S-TSID for this service. (default: current physical layer
pipe).
[0272] @sTSIDDestinationIpAddress can be a string containing the
dotted-IPv4 destination address of the packets carrying S-TSID for
this service. (default: current MMTP session's source IP
address).
[0273] @dsTSIDDestinationUdpPort can be a string containing the
port number of the packets carrying S-TSID for this service.
[0274] @sTSIDSourceIpAddress can be a string containing the
dotted-IPv4 source address of the packets carrying S-TSID for this
service.
[0275] @sTSIDMajorProtocolVersion can indicate major version number
of the protocol used to deliver the S-TSID for this service.
Default value is 1.
[0276] @sTSIDMinorProtocolVersion can indicate minor version number
of the protocol used to deliver the S-TSID for this service.
Default value is 0.
[0277] atsc:broadbandComponent may have information about a content
component of a service delivered via broadband. In other words,
atsc:broadbandComponent may be a field on the assumption of hybrid
delivery. atsc:broadbandComponent may further include
@atsc:fullfMPDUri.
[0278] @atsc:fullfMPDUri can be a reference to an MPD fragment
which contains descriptions for contents components of the service
delivered over broadband.
[0279] An atsc:ComponentInfo field may have information about an
available component of a service. The atsc:ComponentInfo field may
have information about a type, a role, a name, etc. of each
component. The number of atsc:ComponentInfo fields may correspond
to the number (N) of respective components. The atsc:ComponentInfo
field may include @atsc:componentType, @atsc:componentRole,
@atsc:componentProtectedFlag, @atsc:componentId and/or
@atsc:componentName.
[0280] @datsc:componentType is an attribute that indicates the type
of this component. Value of 0 indicates an audio component. Value
of 1 indicates a video component. Value of 2 indicated a closed
caption component. Value of 3 indicates an application component.
Values 4 to 7 are reserved. A meaning of a value of this field may
be differently set depending on embodiments.
[0281] @atsc:componentRole is an attribute that indicates the role
or kind of this component.
[0282] For audio (when componentType attribute above is equal to
0): values of componentRole attribute are as follows: 0=Complete
main, 1=Music and Effects, 2=Dialog, 3=Commentary, 4=Visually
Impaired, 5=Hearing Impaired, 6=Voice-Over, 7-254=reserved,
255=unknown.
[0283] For video (when componentType attribute above is equal to 1)
values of componentRole attribute are as follows: 0=Primary video,
1=Alternative camera view, 2=Other alternative video component,
3=Sign language inset, 4=Follow subject video, 5=3D video left
view, 6=3D video right view, 7=3D video depth information, 8=Part
of video array <x,v> of <n,m>, 9=Follow-Subject
metadata, 10-254=reserved, 255=unknown.
[0284] For Closed Caption component (when componentType attribute
above is equal to 2) values of componentRole attribute are as
follows: 0=Normal, 1=Easy reader, 2-254=reserved, 255=unknown.
[0285] When componentType attribute above is between 3 to 7,
inclusive, the componentRole can be equal to 255. A meaning of a
value of this field may be differently set depending on
embodiments.
[0286] @atsc:componentProtectedFlag is an attribute that indicates
if this component is protected (e.g. encrypted). When this flag is
set to a value of 1 this component is protected (e.g. encrypted).
When this flag is set to a value of 0 this component is not
protected (e.g. encrypted). When not present the value of
componentProtectedFlag attribute is inferred to be equal to 0. A
meaning of a value of this field may be differently set depending
on embodiments.
[0287] @atsc:componentId is an attribute that indicates the
identifier of this component. The value of this attribute can be
the same as the asset_id in the MP table corresponding to this
component.
[0288] @atsc:componentName is an attribute that indicates the human
readable name of this component.
[0289] The proposed default values may vary depending on
embodiments. The "use" column illustrated in the figure relates to
each field. Here, M may denote an essential field, O may denote an
optional field, OD may denote an optional field having a default
value, and CM may denote a conditional essential field. 0 . . . 1
to 0 . . . N may indicate the number of available fields.
[0290] Hereinafter, a description will be given of MPD for MMT.
[0291] The Media Presentation Description is an SLS metadata
fragment corresponding to a linear service of a given duration
defined by the broadcaster (for example a single TV program, or the
set of contiguous linear TV programs over a period of time). The
contents of the MPD provide the resource identifiers for segments
and the context for the identified resources within the media
presentation. The data structure and semantics of the MPD can be
according to the MPD defined by MPEG DASH.
[0292] In the present embodiment, an MPD delivered by an MMTP
session describes Representations delivered over broadband, e.g. in
the case of a hybrid service, or to support service continuity in
handoff from broadcast to broadband due to broadcast signal
degradation (e.g. driving under a mountain or through a
tunnel).
[0293] Hereinafter, a description will be given of an MMT signaling
message for MMT.
[0294] When MMTP sessions are used to carry a streaming service,
MMT signaling messages defined by MMT are delivered by MMTP packets
according to signaling message mode defined by MMT. The value of
the packet_id field of MMTP packets carrying service layer
signaling is set to `00` except for MMTP packets carrying MMT
signaling messages specific to an asset, which can be set to the
same packet_id value as the MMTP packets carrying the asset.
Identifiers referencing the appropriate package for each service
are signaled by the USBD fragment as described above. MMT Package
Table (MPT) messages with matching MMT_package_id can be delivered
on the MMTP session signaled in the SLT. Each MMTP session carries
MMT signaling messages specific to its session or each asset
delivered by the MMTP session.
[0295] In other words, it is possible to access USBD of the MMTP
session by specifying an IP destination address/port number, etc.
of a packet having the SLS for a particular service in the SLT. As
described in the foregoing, a packet ID of an MMTP packet carrying
the SLS may be designated as a particular value such as 00, etc. It
is possible to access an MPT message having a matched packet ID
using the above-described package IP information of USBD. As
described below, the MPT message may be used to access each service
component/asset.
[0296] The following MMTP messages can be delivered by the MMTP
session signaled in the SLT.
[0297] MMT Package Table (MPT) message: This message carries an MP
(MMT Package) table which contains the list of all Assets and their
location information as defined by MMT. If an Asset is delivered by
a PLP different from the current PLP delivering the MP table, the
identifier of the PLP carrying the asset can be provided in the MP
table using physical layer pipe identifier descriptor. The physical
layer pipe identifier descriptor will be described below.
[0298] MMT ATSC3 (MA3) message mmt_atsc3_message( ): This message
carries system metadata specific for services including service
layer signaling as described above. mmt_atsc3_message( ) will be
described below.
[0299] The following MMTP messages can be delivered by the MMTP
session signaled in the SLT, if required.
[0300] Media Presentation Information (MPI) message: This message
carries an MPI table which contains the whole document or a subset
of a document of presentation information. An MP table associated
with the MPI table also can be delivered by this message.
[0301] Clock Relation Information (CRI) message: This message
carries a CRI table which contains clock related information for
the mapping between the NTP timestamp and the MPEG-2 STC. According
to a given embodiment, the CRI message may not be delivered through
the MMTP session.
[0302] The following MMTP messages can be delivered by each MMTP
session carrying streaming content.
[0303] Hypothetical Receiver Buffer Model message: This message
carries information required by the receiver to manage its
buffer.
[0304] Hypothetical Receiver Buffer Model Removal message: This
message carries information required by the receiver to manage its
MMT de-capsulation buffer.
[0305] Hereinafter, a description will be given of
mmt_atsc3_message( ) corresponding to one of MMT signaling
messages. An MMT Signaling message mmt_atsc3_message( ) is defined
to deliver information specific to services according to the
present invention described above. The signaling message may
include message ID, version, and/or length fields corresponding to
basic fields of the MMT signaling message. A payload of the
signaling message may include service ID information, content type
information, content version information, content compression
information and/or URI information. The content type information
may indicate a type of data included in the payload of the
signaling message. The content version information may indicate a
version of data included in the payload, and the content
compression information may indicate a type of compression applied
to the data. The URI information may have URI information related
to content delivered by the message.
[0306] Hereinafter, a description will be given of the physical
layer pipe identifier descriptor.
[0307] The physical layer pipe identifier descriptor is a
descriptor that can be used as one of descriptors of the MP table
described above. The physical layer pipe identifier descriptor
provides information about the PLP carrying an asset. If an asset
is delivered by a PLP different from the current PLP delivering the
MP table, the physical layer pipe identifier descriptor can be used
as an asset descriptor in the associated MP table to identify the
PLP carrying the asset. The physical layer pipe identifier
descriptor may further include BSID information in addition to PLP
ID information. The BSID may be an ID of a broadcast stream that
delivers an MMTP packet for an asset described by the
descriptor.
[0308] FIG. 8 illustrates a link layer protocol architecture
according to an embodiment of the present invention.
[0309] Hereinafter, a link layer will be described.
[0310] The link layer is the layer between the physical layer and
the network layer, and transports the data from the network layer
to the physical layer at the sending side and transports the data
from the physical layer to the network layer at the receiving side.
The purpose of the link layer includes abstracting all input packet
types into a single format for processing by the physical layer,
ensuring flexibility and future extensibility for as yet undefined
input types. In addition, processing within the link layer ensures
that the input data can be transmitted in an efficient manner, for
example by providing options to compress redundant information in
the headers of input packets. The operations of encapsulation,
compression and so on are referred to as the link layer protocol
and packets created using this protocol are called link layer
packets. The link layer may perform functions such as packet
encapsulation, overhead reduction and/or signaling transmission,
etc.
[0311] Hereinafter, packet encapsulation will be described. Link
layer protocol allows encapsulation of any type of packet,
including ones such as IP packets and MPEG-2 TS. Using link layer
protocol, the physical layer need only process one single packet
format, independent of the network layer protocol type (here we
consider MPEG-2 TS packet as a kind of network layer packet.) Each
network layer packet or input packet is transformed into the
payload of a generic link layer packet. Additionally, concatenation
and segmentation can be performed in order to use the physical
layer resources efficiently when the input packet sizes are
particularly small or large.
[0312] As described in the foregoing, segmentation may be used in
packet encapsulation. When the network layer packet is too large to
process easily in the physical layer, the network layer packet is
divided into two or more segments. The link layer packet header
includes protocol fields to perform segmentation on the sending
side and reassembly on the receiving side. When the network layer
packet is segmented, each segment can be encapsulated to link layer
packet in the same order as original position in the network layer
packet. Also each link layer packet which includes a segment of
network layer packet can be transported to PHY layer
consequently.
[0313] As described in the foregoing, concatenation may be used in
packet encapsulation. When the network layer packet is small enough
for the payload of a link layer packet to include several network
layer packets, the link layer packet header includes protocol
fields to perform concatenation. The concatenation is combining of
multiple small sized network layer packets into one payload. When
the network layer packets are concatenated, each network layer
packet can be concatenated to payload of link layer packet in the
same order as original input order. Also each packet which
constructs a payload of link layer packet can be whole packet, not
a segment of packet.
[0314] Hereinafter, overhead reduction will be described. Use of
the link layer protocol can result in significant reduction in
overhead for transport of data on the physical layer. The link
layer protocol according to the present invention may provide IP
overhead reduction and/or MPEG-2 TS overhead reduction. In IP
overhead reduction, IP packets have a fixed header format, however
some of the information which is needed in a communication
environment may be redundant in a broadcast environment. Link layer
protocol provides mechanisms to reduce the broadcast overhead by
compressing headers of IP packets. In MPEG-2 TS overhead reduction,
link layer protocol provides sync byte removal, null packet
deletion and/or common header removal (compression). First, sync
byte removal provides an overhead reduction of one byte per TS
packet, secondly a null packet deletion mechanism removes the 188
byte null TS packets in a manner that they can be re-inserted at
the receiver and finally a common header removal mechanism.
[0315] For signaling transmission, in the link layer protocol. a
particular format for the signaling packet may be provided for link
layer signaling, which will be described below.
[0316] In the illustrated link layer protocol architecture
according to an embodiment of the present invention, link layer
protocol takes as input network layer packets such as IPv4. MPEG-2
TS and so on as input packets. Future extension indicates other
packet types and protocol which is also possible to be input in
link layer. Link layer protocol also specifies the format and
signaling for any link layer signaling, including information about
mapping to specific channel to the physical layer. Figure also
shows how ALP incorporates mechanisms to improve the efficiency of
transmission, via various header compression and deletion
algorithms. In addition, the link layer protocol may basically
encapsulate input packets.
[0317] FIG. 9 illustrates a structure of a base header of a link
layer packet according to an embodiment of the present invention.
Hereinafter, the structure of the header will be described.
[0318] A link layer packet can include a header followed by the
data payload. The header of a link layer packet can include a base
header, and may include an additional header depending on the
control fields of the base header. The presence of an optional
header is indicated from flag fields of the additional header.
According to a given embodiment, a field indicating the presence of
an additional header and an optional header may be positioned in
the base header.
[0319] Hereinafter, the structure of the base header will be
described. The base header for link layer packet encapsulation has
a hierarchical structure. The base header can be two bytes in
length and is the minimum length of the link layer packet
header.
[0320] The illustrated base header according to the present
embodiment may include a Packet_Type field, a PC field and/or a
length field. According to a given embodiment, the base header may
further include an HM field or an S/C field.
[0321] Packet_Type field can be a 3-bit field that indicates the
original protocol or packet type of the input data before
encapsulation into a link layer packet. An IPv4 packet, a
compressed IP packet, a link layer signaling packet, and other
types of packets may have the base header structure and may be
encapsulated. However, according to a given embodiment, the MPEG-2
TS packet may have a different particular structure, and may be
encapsulated. When the value of Packet_Type is "000", "001" "100"
or "111", that is the original data type of an ALP packet is one of
an IPv4 packet, a compressed IP packet, link layer signaling or
extension packet. When the MPEG-2 TS packet is encapsulated, the
value of Packet_Type can be "010". Other values of the Packet_Type
field may be reserved for future use.
[0322] Payload_Configuration (PC) field can be a 1-bit field that
indicates the configuration of the payload. A value of 0 can
indicate that the link layer packet carries a single, whole input
packet and the following field is the Header_Mode field. A value of
1 can indicate that the link layer packet carries more than one
input packet (concatenation) or a part of a large input packet
(segmentation) and the following field is the
Segmentation_Concatenation field.
[0323] Header_Mode (HM) field can be a 1-bit field, when set to 0,
that can indicate there is no additional header, and that the
length of the payload of the link layer packet is less than 2048
bytes. This value may be varied depending on embodiments. A value
of 1 can indicate that an additional header for single packet
defined below is present following the Length field. In this case,
the length of the payload is larger than 2047 bytes and/or optional
features can be used (sub stream identification, header extension,
etc.). This value may be varied depending on embodiments. This
field can be present only when Payload_Configuration field of the
link layer packet has a value of 0.
[0324] Segmentation_Concatenation (S/C) field can be a 1-bit field,
when set to 0, that can indicate that the payload carries a segment
of an input packet and an additional header for segmentation
defined below is present following the Length field. A value of 1
can indicate that the payload carries more than one complete input
packet and an additional header for concatenation defined below is
present following the Length field. This field can be present only
when the value of Payload_Configuration field of the ALP packet is
1.
[0325] Length field can be an 11-bit field that indicates the 11
least significant bits (LSBs) of the length in bytes of payload
carried by the link layer packet. When there is a Length_MSB field
in the following additional header, the length field is
concatenated with the Length_MSB field, and is the LSB to provide
the actual total length of the payload. The number of bits of the
length field may be changed to another value rather than 11
bits.
[0326] Following types of packet configuration are thus possible: a
single packet without any additional header, a single packet with
an additional header, a segmented packet and a concatenated packet.
According to a given embodiment, more packet configurations may be
made through a combination of each additional header, an optional
header, an additional header for signaling information to be
described below, and an additional header for time extension.
[0327] FIG. 10 illustrates a structure of an additional header of a
link layer packet according to an embodiment of the present
invention.
[0328] Various types of additional headers may be present.
Hereinafter, a description will be given of an additional header
for a single packet.
[0329] This additional header for single packet can be present when
Header_Mode (HM)="1". The Header_Mode (HM) can be set to 1 when the
length of the payload of the link layer packet is larger than 2047
bytes or when the optional fields are used. The additional header
for single packet is shown in Figure (tsib10010).
[0330] Length_MSB field can be a 5-bit field that can indicate the
most significant bits (MSBs) of the total payload length in bytes
in the current link layer packet, and is concatenated with the
Length field containing the 11 least significant bits (LSBs) to
obtain the total payload length. The maximum length of the payload
that can be signaled is therefore 65535 bytes. The number of bits
of the length field may be changed to another value rather than 11
bits. In addition, the number of bits of the Length_MSB field may
be changed, and thus a maximum expressible payload length may be
changed. According to a given embodiment, each length field may
indicate a length of a whole link layer packet rather than a
payload.
[0331] SIF (Sub stream Identifier Flag) field can be a 1-bit field
that can indicate whether the sub stream ID (SID) is present after
the HEF field or not. When there is no SID in this link layer
packet, SIF field can be set to 0. When there is a SID after HEF
field in the link layer packet, SIF can be set to 1. The detail of
SID is described below.
[0332] HEF (Header Extension Flag) field can be a 1-bit field that
can indicate, when set to 1 additional header is present for future
extension. A value of 0 can indicate that this extension header is
not present.
[0333] Hereinafter, a description will be given of an additional
header when segmentation is used.
[0334] This additional header (tsib10020) can be present when
Segmentation_Concatenation (S/C)="0". Segment_Sequence_Number can
be a 5-bit unsigned integer that can indicate the order of the
corresponding segment carried by the link layer packet. For the
link layer packet which carries the first segment of an input
packet, the value of this field can be set to 0x0. This field can
be incremented by one with each additional segment belonging to the
segmented input packet.
[0335] Last_Segment_Indicator (LSI) can be a 1-bit field that can
indicate, when set to 1, that the segment in this payload is the
last one of input packet. A value of 0, can indicate that it is not
last segment.
[0336] SIF (Sub stream Identifier Flag) can be a 1-bit field that
can indicate whether the SID is present after the HEF field or not.
When there is no SID in the link layer packet, SIF field can be set
to 0. When there is a SID after the HEF field in the link layer
packet, SIF can be set to 1.
[0337] HEF (Header Extension Flag) can be a This 1-bit field that
can indicate, when set to 1, that the optional header extension is
present after the additional header for future extensions of the
link layer header. A value of 0 can indicate that optional header
extension is not present.
[0338] According to a given embodiment, a packet ID field may be
additionally provided to indicate that each segment is generated
from the same input packet. This field may be unnecessary and thus
be omitted when segments are transmitted in order.
[0339] Hereinafter, a description will be given of an additional
header when concatenation is used.
[0340] This additional header (tsib10030) can be present when
Segmentation_Concatenation (S/C)="1".
[0341] Length_MSB can be a 4-bit field that can indicate MSB bits
of the payload length in bytes in this link layer packet. The
maximum length of the payload is 32767 bytes for concatenation. As
described in the foregoing, a specific numeric value may be
changed.
[0342] Count can be a field that can indicate the number of the
packets included in the link layer packet. The number of the
packets included in the link layer packet, 2 can be set to this
field. So, its maximum value of concatenated packets in a link
layer packet is 9. A scheme in which the count field indicates the
number may be varied depending on embodiments. That is, the numbers
from 1 to 8 may be indicated.
[0343] HEF (Header Extension Flag) can be a 1-bit field that can
indicate, when set to 1 the optional header extension is present
after the additional header for future extensions of the link layer
header. A value of 0, can indicate extension header is not
present.
[0344] Component_Length can be a 12-bit length field that can
indicate the length in byte of each packet. Component_Length fields
are included in the same order as the packets present in the
payload except last component packet. The number of length field
can be indicated by (Count+1). According to a given embodiment,
length fields, the number of which is the same as a value of the
count field, may be present. When a link layer header consists of
an odd number of Component_Length, four stuffing bits can follow
after the last Component_Length field. These bits can be set to 0.
According to a given embodiment, a Component_length field
indicating a length of a last concatenated input packet may not be
present. In this case, the length of the last concatenated input
packet may correspond to a length obtained by subtracting a sum of
values indicated by respective Component_length fields from a whole
payload length.
[0345] Hereinafter, the optional header will be described.
[0346] As described in the foregoing, the optional header may be
added to a rear of the additional header. The optional header field
can contain SID and/or header extension. The SID is used to filter
out specific packet stream in the link layer level. One example of
SID is the role of service identifier in a link layer stream
carrying multiple services. The mapping information between a
service and the SID value corresponding to the service can be
provided in the SLT, if applicable. The header extension contains
extended field for future use. Receivers can ignore any header
extensions which they do not understand.
[0347] SID (Sub stream Identifier) can be an 8-bit field that can
indicate the sub stream identifier for the link layer packet. If
there is optional header extension, SID present between additional
header and optional header extension.
[0348] Header_Extension( ) can include the fields defined
below.
[0349] Extension_Type can be an 8-bit field that can indicate the
type of the Header_Extension ( ).
[0350] Extension_Length can be an 8-bit field that can indicate the
length of the Header Extension ( ) in bytes counting from the next
byte to the last byte of the Header_Extension( ).
[0351] Extension_Byte can be a byte representing the value of the
Header_Extension( ).
[0352] FIG. 11 illustrates a structure of an additional header of a
link layer packet according to another embodiment of the present
invention.
[0353] Hereinafter, a description will be given of an additional
header for signaling information.
[0354] How link layer signaling is incorporated into link layer
packets are as follows. Signaling packets are identified by when
the Packet_Type field of the base header is equal to 100.
[0355] Figure (tsib11010) shows the structure of the link layer
packets containing additional header for signaling information. In
addition to the link layer header, the link layer packet can
consist of two additional parts, additional header for signaling
information and the actual signaling data itself. The total length
of the link layer signaling packet is shown in the link layer
packet header.
[0356] The additional header for signaling information can include
following fields. According to a given embodiment, some fields may
be omitted.
[0357] Signaling_Type can be an 8-bit field that can indicate the
type of signaling.
[0358] Signaling_Type_Extension can be a 16-bit filed that can
indicate the attribute of the signaling. Detail of this field can
be defined in signaling specification.
[0359] Signaling_Version can be an 8-bit field that can indicate
the version of signaling.
[0360] Signaling_Format can be a 2-bit field that can indicate the
data format of the signaling data. Here, a signaling format may
refer to a data format such as a binary format, an XML format,
etc.
[0361] Signaling_Encoding can be a 2-bit field that can specify the
encoding/compression format. This field may indicate whether
compression is not performed and which type of compression is
performed.
[0362] Hereinafter, a description will be given of an additional
header for packet type extension.
[0363] In order to provide a mechanism to allow an almost unlimited
number of additional protocol and packet types to be carried by
link layer in the future, the additional header is defined. Packet
type extension can be used when Packet_type is 111 in the base
header as described above. Figure (tsib11020) shows the structure
of the link layer packets containing additional header for type
extension.
[0364] The additional header for type extension can include
following fields. According to a given embodiment, some fields may
be omitted.
[0365] extended_type can be a 16-bit field that can indicate the
protocol or packet type of the input encapsulated in the link layer
packet as payload. This field cannot be used for any protocol or
packet type already defined by Packet_Type field.
[0366] FIG. 12 illustrates a header structure of a link layer
packet for an MPEG-2 TS packet and an encapsulation process thereof
according to an embodiment of the present invention.
[0367] Hereinafter, a description will be given of a format of the
link layer packet when the MPEG-2 TS packet is input as an input
packet.
[0368] In this case, the Packet_Type field of the base header is
equal to 010. Multiple TS packets can be encapsulated within each
link layer packet. The number of TS packets is signaled via the
NUMTS field. In this case, as described in the foregoing, a
particular link layer packet header format may be used.
[0369] Link layer provides overhead reduction mechanisms for MPEG-2
TS to enhance the transmission efficiency. The sync byte (0x47) of
each TS packet can be deleted. The option to delete NULL packets
and similar TS headers is also provided.
[0370] In order to avoid unnecessary transmission overhead, TS null
packets (PID=0x1FFF) may be removed. Deleted null packets can be
recovered in receiver side using DNP field. The DNP field indicates
the count of deleted null packets. Null packet deletion mechanism
using DNP field is described below.
[0371] In order to achieve more transmission efficiency, similar
header of MPEG-2 TS packets can be removed. When two or more
successive TS packets have sequentially increased continuity
counter fields and other header fields are the same, the header is
sent once at the first packet and the other headers are deleted.
HDM field can indicate whether the header deletion is performed or
not. Detailed procedure of common TS header deletion is described
below.
[0372] When all three overhead reduction mechanisms are performed,
overhead reduction can be performed in sequence of sync removal,
null packet deletion, and common header deletion. According to a
given embodiment, a performance order of respective mechanisms may
be changed. In addition, some mechanisms may be omitted according
to a given embodiment.
[0373] The overall structure of the link layer packet header when
using MPEG-2 TS packet encapsulation is depicted in Figure
(tsib12010).
[0374] Hereinafter, a description will be given of each illustrated
field. Packet Type can be a 3-bit field that can indicate the
protocol type of input packet as describe above. For MPEG-2 TS
packet encapsulation, this field can always be set to 010.
[0375] NUMTS (Number of TS packets) can be a 4-bit field that can
indicate the number of TS packets in the payload of this link layer
packet. A maximum of 16 TS packets can be supported in one link
layer packet. The value of NUMTS=0 can indicate that 16 TS packets
are carried by the payload of the link layer packet. For all other
values of NUMTS, the same number of TS packets are recognized. e.g.
NUMTS=0001 means one TS packet is carried.
[0376] AHF (Additional Header Flag) can be a field that can
indicate whether the additional header is present of not. A value
of 0 indicates that there is no additional header. A value of 1
indicates that an additional header of length 1-byte is present
following the base header. If null TS packets are deleted or TS
header compression is applied this field can be set to 1. The
additional header for TS packet encapsulation consists of the
following two fields and is present only when the value of AHF in
this link layer packet is set to 1.
[0377] HDM (Header Deletion Mode) can be a 1-bit field that
indicates whether TS header deletion can be applied to this link
layer packet. A value of 1 indicates that TS header deletion can be
applied. A value of "0" indicates that the TS header deletion
method is not applied to this link layer packet.
[0378] DNP (Deleted Null Packets) can be a 7-bit field that
indicates the number of deleted null TS packets prior to this link
layer packet. A maximum of 128 null TS packets can be deleted. When
HDM=0 the value of DNP=0 can indicate that 128 null packets are
deleted. When HDM=1 the value of DNP=0 can indicate that no null
packets are deleted. For all other values of DNP, the same number
of null packets are recognized, e.g. DNP=5 means 5 null packets are
deleted.
[0379] The number of bits of each field described above may be
changed. According to the changed number of bits, a minimum/maximum
value of a value indicated by the field may be changed. These
numbers may be changed by a designer.
[0380] Hereinafter, SYNC byte removal will be described.
[0381] When encapsulating TS packets into the payload of a link
layer packet, the SYNC byte (0x47) from the start of each TS packet
can be deleted. Hence the length of the MPEG2-TS packet
encapsulated in the payload of the link layer packet is always of
length 187 bytes (instead of 188 bytes originally).
[0382] Hereinafter, null packet deletion will be described.
[0383] Transport Stream rules require that bit rates at the output
of a transmitter's multiplexer and at the input of the receiver's
de-multiplexer are constant in time and the end-to-end delay is
also constant. For some Transport Stream input signals, null
packets may be present in order to accommodate variable bitrate
services in a constant bitrate stream. In this case, in order to
avoid unnecessary transmission overhead, TS null packets (that is
TS packets with PID=0x1FFF) may be removed. The process is
carried-out in a way that the removed null packets can be
re-inserted in the receiver in the exact place where they were
originally, thus guaranteeing constant bitrate and avoiding the
need for PCR time stamp updating.
[0384] Before generation of a link layer packet, a counter called
DNP (Deleted Null-Packets) can first be reset to zero and then
incremented for each deleted null packet preceding the first
non-null TS packet to be encapsulated into the payload of the
current link layer packet. Then a group of consecutive useful TS
packets is encapsulated into the payload of the current link layer
packet and the value of each field in its header can be determined.
After the generated link layer packet is injected to the physical
layer, the DNP is reset to zero. When DNP reaches its maximum
allowed value, if the next packet is also a null packet, this null
packet is kept as a useful packet and encapsulated into the payload
of the next link layer packet. Each link layer packet can contain
at least one useful TS packet in its payload.
[0385] Hereinafter, TS packet header deletion will be described. TS
packet header deletion may be referred to as TS packet header
compression.
[0386] When two or more successive TS packets have sequentially
increased continuity counter fields and other header fields are the
same, the header is sent once at the first packet and the other
headers are deleted. When the duplicated MPEG-2 TS packets are
included in two or more successive TS packets, header deletion
cannot be applied in transmitter side. HDM field can indicate
whether the header deletion is performed or not. When TS header
deletion is performed, HDM can be set to 1. In the receiver side,
using the first packet header, the deleted packet headers are
recovered, and the continuity counter is restored by increasing it
in order from that of the first header.
[0387] An example tsib12020 illustrated in the figure is an example
of a process in which an input stream of a TS packet is
encapsulated into a link layer packet. First, a TS stream including
TS packets having SYNC byte (0x47) may be input. First, sync bytes
may be deleted through a sync byte deletion process. In this
example, it is presumed that null packet deletion is not
performed.
[0388] Here, it is presumed that packet headers of eight TS packets
have the same field values except for CC, that is, a continuity
counter field value. In this case, TS packet deletion/compression
may be performed. Seven remaining TS packet headers are deleted
except for a first TS packet header corresponding to CC=1. The
processed TS packets may be encapsulated into a payload of the link
layer packet.
[0389] In a completed link layer packet, a Packet_Type field
corresponds to a case in which TS packets are input, and thus may
have a value of 010. A NUMTS field may indicate the number of
encapsulated TS packets. An AHF field may be set to 1 to indicate
the presence of an additional header since packet header deletion
is performed. An HDM field may be set to 1 since header deletion is
performed. DNP may be set to 0 since null packet deletion is not
performed.
[0390] FIG. 13 illustrates an example of adaptation modes in IP
header compression according to an embodiment of the present
invention (transmitting side).
[0391] Hereinafter, IP header compression will be described.
[0392] In the link layer, IP header compression/decompression
scheme can be provided. IP header compression can include two
parts: header compressor/decompressor and adaptation module. The
header compression scheme can be based on the Robust Header
Compression (RoHC). In addition, for broadcasting usage, adaptation
function is added.
[0393] In the transmitter side, ROHC compressor reduces the size of
header for each packet. Then, adaptation module extracts context
information and builds signaling information from each packet
stream. In the receiver side, adaptation module parses the
signaling information associated with the received packet stream
and attaches context information to the received packet stream.
ROHC decompressor reconstructs the original IP packet by recovering
the packet header.
[0394] The header compression scheme can be based on the RoHC as
described above. In particular, in the present system, an RoHC
framework can operate in a unidirectional mode (U mode) of the
RoHC. In addition, in the present system, it is possible to use an
RoHC UDP header compression profile which is identified by a
profile identifier of 0x0002.
[0395] Hereinafter, adaptation will be described.
[0396] In case of transmission through the unidirectional link, if
a receiver has no information of context, decompressor cannot
recover the received packet header until receiving full context.
This may cause channel change delay and turn on delay. For this
reason, context information and configuration parameters between
compressor and decompressor can be always sent with packet
flow.
[0397] The Adaptation function provides out-of-band transmission of
the configuration parameters and context information. Out-of-band
transmission can be done through the link layer signaling.
Therefore, the adaptation function is used to reduce the channel
change delay and decompression error due to loss of context
information.
[0398] Hereinafter, extraction of context information will be
described.
[0399] Context information may be extracted using various schemes
according to adaptation mode. In the present invention, three
examples will be described below. The scope of the present
invention is not restricted to the examples of the adaptation mode
to be described below. Here, the adaptation mode may be referred to
as a context extraction mode.
[0400] Adaptation Mode 1 (not illustrated) may be a mode in which
no additional operation is applied to a basic RoHC packet stream.
In other words, the adaptation module may operate as a buffer in
this mode. Therefore, in this mode, context information may not be
included in link layer signaling.
[0401] In Adaptation Mode 2 (tsib13010). the adaptation module can
detect the IR packet from ROHC packet flow and extract the context
information (static chain). After extracting the context
information, each IR packet can be converted to an IR-DYN packet.
The converted IR-DYN packet can be included and transmitted inside
the ROHC packet flow in the same order as IR packet, replacing the
original packet.
[0402] In Adaptation Mode 3 (tsib13020), the adaptation module can
detect the IR and IR-DYN packet from ROHC packet flow and extract
the context information. The static chain and dynamic chain can be
extracted from IR packet and dynamic chain can be extracted from
IR-DYN packet. After extracting the context information, each IR
and IR-DYN packet can be converted to a compressed packet. The
compressed packet format can be the same with the next packet of IR
or IR-DYN packet. The converted compressed packet can be included
and transmitted inside the ROHC packet flow in the same order as IR
or IR-DYN packet, replacing the original packet.
[0403] Signaling (context) information can be encapsulated based on
transmission structure. For example, context information can be
encapsulated to the link layer signaling. In this case, the packet
type value can be set to "100".
[0404] In the above-described Adaptation Modes 2 and 3, a link
layer packet for context information may have a packet type field
value of 100. In addition, a link layer packet for compressed IP
packets may have a packet type field value of 001. The values
indicate that each of the signaling information and the compressed
IP packets are included in the link layer packet as described
above.
[0405] Hereinafter, a description will be given of a method of
transmitting the extracted context information.
[0406] The extracted context information can be transmitted
separately from ROHC packet flow, with signaling data through
specific physical data path. The transmission of context depends on
the configuration of the physical layer path. The context
information can be sent with other link layer signaling through the
signaling data pipe.
[0407] In other words, the link layer packet having the context
information may be transmitted through a signaling PLP together
with link layer packets having other link layer signaling
information (Packet_Type=100). Compressed IP packets from which
context information is extracted may be transmitted through a
general PLP (Packet_Type=001). Here, depending on embodiments, the
signaling PLP may refer to an L1 signaling path. In addition.
depending on embodiments, the signaling PLP may not be separated
from the general PLP, and may refer to a particular and general PLP
through which the signaling information is transmitted.
[0408] At a receiving side, prior to reception of a packet stream,
a receiver may need to acquire signaling information. When receiver
decodes initial PLP to acquire the signaling information, the
context signaling can be also received. After the signaling
acquisition is done, the PLP to receive packet stream can be
selected. In other words, the receiver may acquire the signaling
information including the context information by selecting the
initial PLP. Here, the initial PLP may be the above-described
signaling PLP. Thereafter, the receiver may select a PLP for
acquiring a packet stream. In this way, the context information may
be acquired prior to reception of the packet stream.
[0409] After the PLP for acquiring the packet stream is selected,
the adaptation module can detect IR-DYN packet form received packet
flow. Then, the adaptation module parses the static chain from the
context information in the signaling data. This is similar to
receiving the IR packet. For the same context identifier, IR-DYN
packet can be recovered to IR packet. Recovered ROHC packet flow
can be sent to ROHC decompressor. Thereafter, decompression may be
started.
[0410] FIG. 14 illustrates a link mapping table (LMT) and an RoHC-U
description table according to an embodiment of the present
invention.
[0411] Hereinafter, link layer signaling will be described.
[0412] Generally, link layer signaling is operates under IP level.
At the receiver side, link layer signaling can be obtained earlier
than IP level signaling such as Service List Table (SLT) and
Service Layer Signaling (SLS). Therefore, link layer signaling can
be obtained before session establishment.
[0413] For link layer signaling, there can be two kinds of
signaling according input path: internal link layer signaling and
external link layer signaling. The internal link layer signaling is
generated in link layer at transmitter side. And the link layer
takes the signaling from external module or protocol. This kind of
signaling information is considered as external link layer
signaling. If some signaling need to be obtained prior to IP level
signaling, external signaling is transmitted in format of link
layer packet.
[0414] The link layer signaling can be encapsulated into link layer
packet as described above. The link layer packets can carry any
format of link layer signaling, including binary and XML. The same
signaling information may not be transmitted in different formats
for the link layer signaling.
[0415] Internal link layer signaling may include signaling
information for link mapping. The Link Mapping Table (LMT) provides
a list of upper layer sessions carried in a PLP. The LMT also
provides addition information for processing the link layer packets
carrying the upper layer sessions in the link layer.
[0416] An example of the LMT (tsib14010) according to the present
invention is illustrated.
[0417] signaling_type can be an 8-bit unsigned integer field that
indicates the type of signaling carried by this table. The value of
signaling_type field for Link Mapping Table (LMT) can be set to
0x01.
[0418] PLP_ID can be an 8-bit field that indicates the PLP
corresponding to this table.
[0419] num_session can be an 8-bit unsigned integer field that
provides the number of upper layer sessions carried in the PLP
identified by the above PLP_ID field. When the value of
signaling_type field is 0x01, this field can indicate the number of
UDP/IP sessions in the PLP.
[0420] src_IP_add can be a 32-bit unsigned integer field that
contains the source IP address of an upper layer session carried in
the PLP identified by the PLP_ID field.
[0421] dst_IP_add can be a 32-bit unsigned integer field that
contains the destination IP address of an upper layer session
carried in the PLP identified by the PLP_ID field.
[0422] src_UDP_port can be a 16-bit unsigned integer field that
represents the source UDP port number of an upper layer session
carried in the PLP identified by the PLP_ID field.
[0423] dst_UDP_port can be a 16-bit unsigned integer field that
represents the destination UDP port number of an upper layer
session carried in the PLP identified by the PLP_ID field.
[0424] SID_flag can be a 1-bit Boolean field that indicates whether
the link layer packet carrying the upper layer session identified
by above 4 fields, Src_IP_add, Dst_IP_add, Src_UDP_Port and
Dst_UDP_Port, has an SID field in its optional header. When the
value of this field is set to 0, the link layer packet carrying the
upper layer session may not have an SID field in its optional
header. When the value of this field is set to 1, the link layer
packet carrying the upper layer session can have an SID field in
its optional header and the value the SID field can be same as the
following SID field in this table.
[0425] compressed_flag can be a 1-bit Boolean field that indicates
whether the header compression is applied the link layer packets
carrying the upper layer session identified by above 4 fields,
Src_IP_add, Dst_IP_add, Src_UDP_Port and Dst_UDP_Port. When the
value of this field is set to 0, the link layer packet carrying the
upper layer session may have a value of 0x00 of Packet_Type field
in its base header. When the value of this field is set to 1, the
link layer packet carrying the upper layer session may have a value
of 0x01 of Packet_Type field in its base header and the Context_ID
field can be present.
[0426] SID can be an 8-bit unsigned integer field that indicates
sub stream identifier for the link layer packets carrying the upper
layer session identified by above 4 fields. Src_IP_add, Dst_IP_add,
Src_UDP_Port and Dst_UDP_Port. This field can be present when the
value of SID_flag is equal to 1.
[0427] context_id can be an 8-bit field that provides a reference
for the context id (CID) provided in the ROHC-U description table.
This field can be present when the value of compressed_flag is
equal to 1.
[0428] An example of the RoHC-U description table (tsib14020)
according to the present invention is illustrated. As described in
the foregoing, the RoHC-U adaptation module may generate
information related to header compression.
[0429] signaling_type can be an 8-bit field that indicates the type
of signaling carried by this table. The value of signaling_type
field for ROHC-U description table (RDT) can be set to "0x02".
[0430] PLP_ID can be an 8-bit field that indicates the PLP
corresponding to this table.
[0431] context_id can be an 8-bit field that indicates the context
id (CID) of the compressed IP stream. In this system, 8-bit CID can
be used for large CID.
[0432] context_profile can be an 8-bit field that indicates the
range of protocols used to compress the stream. This field can be
omitted.
[0433] adaptation_mode can be a 2-bit field that indicates the mode
of adaptation module in this PLP. Adaptation modes have been
described above.
[0434] context_config can be a 2-bit field that indicates the
combination of the context information. If there is no context
information in this table, this field may be set to "0x0". If the
static_chain( ) or dynamic_chain( ) byte is included in this table,
this field may be set to "0x01" or "0x02" respectively. If both of
the static_chain( ) and dynamic_chain( ) byte are included in this
table, this field may be set to "0x03".
[0435] context_length can be an 8-bit field that indicates the
length of the static chain byte sequence. This field can be
omitted.
[0436] static_chain_byte( ) can be a field that conveys the static
information used to initialize the ROHC-U decompressor. The size
and structure of this field depend on the context profile.
[0437] dynamic_chain_byte( ) can be a field that conveys the
dynamic information used to initialize the ROHC-U decompressor. The
size and structure of this field depend on the context profile.
[0438] The static_chain_byte can be defined as sub-header
information of IR packet. The dynamic_chain_byte can be defined as
sub-header information of IR packet and IR-DYN packet.
[0439] FIG. 15 illustrates a structure of a link layer on a
transmitter side according to an embodiment of the present
invention.
[0440] The present embodiment presumes that an IP packet is
processed. From a functional point of view, the link layer on the
transmitter side may broadly include a link layer signaling part in
which signaling information is processed, an overhead reduction
part, and/or an encapsulation part. In addition, the link layer on
the transmitter side may include a scheduler for controlling and
scheduling an overall operation of the link layer and/or input and
output parts of the link layer.
[0441] First, signaling information of an upper layer and/or a
system parameter tsib15010 may be delivered to the link layer. In
addition, an IP stream including IP packets may be delivered to the
link layer from an IP layer tsib15110.
[0442] As described above, the scheduler tsib15020 may determine
and control operations of several modules included in the link
layer. The delivered signaling information and/or system parameter
tsib15010 may be filterer or used by the scheduler tsib15020.
Information, which corresponds to a part of the delivered signaling
information and/or system parameter tsib15010, necessary for a
receiver may be delivered to the link layer signaling part. In
addition, information, which corresponds to a part of the signaling
information, necessary for an operation of the link layer may be
delivered to an overhead reduction controller tsib15120 or an
encapsulation controller tsib15180.
[0443] The link layer signaling part may collect information to be
transmitted as a signal in a physical layer, and convert/configure
the information in a form suitable for transmission. The link layer
signaling part may include a signaling manager tsib15030, a
signaling formatter tsib15040, and/or a buffer for channels
tsib15050.
[0444] The signaling manager tsib15030 may receive signaling
information delivered from the scheduler tsib15020 and/or signaling
(and/or context) information delivered from the overhead reduction
part. The signaling manager tsib15030 may determine a path for
transmission of the signaling information for delivered data. The
signaling information may be delivered through the path determined
by the signaling manager tsib15030. As described in the foregoing.
signaling information to be transmitted through a divided channel
such as the FIC, the EAS. etc. may be delivered to the signaling
formatter tsib15040, and other signaling information may be
delivered to an encapsulation buffer tsib15070.
[0445] The signaling formatter tsib15040 may format related
signaling information in a form suitable for each divided channel
such that signaling information may be transmitted through a
separately divided channel. As described in the foregoing, the
physical layer may include separate physically/logically divided
channels. The divided channels may be used to transmit FIC
signaling information or EAS-related information. The FIC or
EAS-related information may be sorted by the signaling manager
tsib15030, and input to the signaling formatter tsib15040. The
signaling formatter tsib15040 may format the information based on
each separate channel. When the physical layer is designed to
transmit particular signaling information through a separately
divided channel other than the FIC and the EAS, a signaling
formatter for the particular signaling information may be
additionally provided. Through this scheme, the link layer may be
compatible with various physical layers.
[0446] The buffer for channels tsib15050 may deliver the signaling
information received from the signaling formatter tsib15040 to
separate dedicated channels tsib15060. The number and content of
the separate channels may vary depending on embodiments.
[0447] As described in the foregoing, the signaling manager
tsib15030 may deliver signaling information, which is not delivered
to a particular channel, to the encapsulation buffer tsib15070. The
encapsulation buffer tsib15070 may function as a buffer that
receives the signaling information which is not delivered to the
particular channel.
[0448] An encapsulation block for signaling information tsib15080
may encapsulate the signaling information which is not delivered to
the particular channel. A transmission buffer tsib15090 may
function as a buffer that delivers the encapsulated signaling
information to a DP for signaling information tsib15100. Here, the
DP for signaling information tsib15100 may refer to the
above-described PLS region.
[0449] The overhead reduction part may allow efficient transmission
by removing overhead of packets delivered to the link layer. It is
possible to configure overhead reduction parts corresponding to the
number of IP streams input to the link layer.
[0450] An overhead reduction buffer tsib15130 may receive an IP
packet delivered from an upper layer. The received IP packet may be
input to the overhead reduction part through the overhead reduction
buffer tsib15130.
[0451] An overhead reduction controller tsib15120 may determine
whether to perform overhead reduction on a packet stream input to
the overhead reduction buffer tsib15130. The overhead reduction
controller tsib15120 may determine whether to perform overhead
reduction for each packet stream. When overhead reduction is
performed on a packet stream, packets may be delivered to a robust
header compression (RoHC) compressor tsib15140 to perform overhead
reduction. When overhead reduction is not performed on a packet
stream, packets may be delivered to the encapsulation part to
perform encapsulation without overhead reduction. Whether to
perform overhead reduction of packets may be determined based on
the signaling information tsib15010 delivered to the link layer.
The signaling information may be delivered to the encapsulation
controller tsib15180 by the scheduler tsib15020.
[0452] The RoHC compressor tsib15140 may perform overhead reduction
on a packet stream. The RoHC compressor tsib15140 may perform an
operation of compressing a header of a packet. Various schemes may
be used for overhead reduction. Overhead reduction may be performed
using a scheme proposed by the present invention. The present
invention presumes an IP stream, and thus an expression "RoHC
compressor" is used. However, the name may be changed depending on
embodiments. The operation is not restricted to compression of the
IP stream, and overhead reduction of all types of packets may be
performed by the RoHC compressor tsib15140.
[0453] A packet stream configuration block tsib15150 may separate
information to be transmitted to a signaling region and information
to be transmitted to a packet stream from IP packets having
compressed headers. The information to be transmitted to the packet
stream may refer to information to be transmitted to a DP region.
The information to be transmitted to the signaling region may be
delivered to a signaling and/or context controller tsib15160. The
information to be transmitted to the packet stream may be
transmitted to the encapsulation part.
[0454] The signaling and/or context controller tsib15160 may
collect signaling and/or context information and deliver the
signaling and/or context information to the signaling manager in
order to transmit the signaling and/or context information to the
signaling region.
[0455] The encapsulation part may perform an operation of
encapsulating packets in a form suitable for a delivery to the
physical layer. It is possible to configure encapsulation parts
corresponding to the number of IP streams.
[0456] An encapsulation buffer tsib15170 may receive a packet
stream for encapsulation. Packets subjected to overhead reduction
may be received when overhead reduction is performed, and an input
IP packet may be received without change when overhead reduction is
not performed.
[0457] An encapsulation controller tsib15180 may determine whether
to encapsulate an input packet stream. When encapsulation is
performed, the packet stream may be delivered to a
segmentation/concatenation block tsib15190. When encapsulation is
not performed, the packet stream may be delivered to a transmission
buffer tsib15230. Whether to encapsulate packets may be determined
based on the signaling information tsib15010 delivered to the link
layer. The signaling information may be delivered to the
encapsulation controller tsib15180 by the scheduler tsib15020.
[0458] In the segmentation/concatenation block tsib15190, the
above-described segmentation or concatenation operation may be
performed on packets. In other words, when an input IP packet is
longer than a link layer packet corresponding to an output of the
link layer, one IP packet may be segmented into several segments to
configure a plurality of link layer packet payloads. On the other
hand, w % ben an input IP packet is shorter than a link layer
packet corresponding to an output of the link layer, several IP
packets may be concatenated to configure one link layer packet
payload.
[0459] A packet configuration table tsib15200 may have
configuration information of a segmented and/or concatenated link
layer packet. A transmitter and a receiver may have the same
information in the packet configuration table tsib15200. The
transmitter and the receiver may refer to the information of the
packet configuration table tsib15200. An index value of the
information of the packet configuration table tsib15200 may be
included in a header of the link layer packet.
[0460] A link layer header information block tsib15210 may collect
header information generated in an encapsulation process. In
addition, the link layer header information block tsib15210 may
collect header information included in the packet configuration
table tsib15200. The link layer header information block tsib15210
may configure header information according to a header structure of
the link layer packet.
[0461] A header attachment block tsib15220 may add a header to a
payload of a segmented and/or concatenated link layer packet. The
transmission buffer tsib15230 may function as a buffer to deliver
the link layer packet to a DP tsib15240 of the physical layer.
[0462] The respective blocks, modules, or parts may be configured
as one module/protocol or a plurality of modules/protocols in the
link layer.
[0463] FIG. 16 illustrates a structure of a link layer on a
receiver side according to an embodiment of the present
invention.
[0464] The present embodiment presumes that an IP packet is
processed. From a functional point of view, the link layer on the
receiver side may broadly include a link layer signaling part in
which signaling information is processed, an overhead processing
part, and/or a decapsulation part. In addition, the link layer on
the receiver side may include a scheduler for controlling and
scheduling overall operation of the link layer and/or input and
output parts of the link layer.
[0465] First, information received through a physical layer may be
delivered to the link layer. The link layer may process the
information, restore an original state before being processed at a
transmitter side, and then deliver the information to an upper
layer. In the present embodiment, the upper layer may be an IP
layer.
[0466] Information, which is separated in the physical layer and
delivered through a particular channel tsib16030. may be delivered
to a link layer signaling part. The link layer signaling part may
determine signaling information received from the physical layer,
and deliver the determined signaling information to each part of
the link layer.
[0467] A buffer for channels tsib16040 may function as a buffer
that receives signaling information transmitted through particular
channels. As described in the foregoing, when physically/logically
divided separate channels are present in the physical layer, it is
possible to receive signaling information transmitted through the
channels. When the information received from the separate channels
is segmented, the segmented information may be stored until
complete information is configured.
[0468] A signaling decoder/parser tsib16050 may verify a format of
the signaling information received through the particular channel,
and extract information to be used in the link layer. When the
signaling information received through the particular channel is
encoded, decoding may be performed. In addition, according to a
given embodiment, it is possible to verify integrity, etc. of the
signaling information.
[0469] A signaling manager tsib16060 may integrate signaling
information received through several paths. Signaling information
received through a DP for signaling tsib16070 to be described below
may be integrated in the signaling manager tsib16060. The signaling
manager tsib16060 may deliver signaling information necessary for
each part in the link layer. For example, the signaling manager
tsib16060 may deliver context information, etc. for recovery of a
packet to the overhead processing part. In addition, the signaling
manager tsib16060 may deliver signaling information for control to
a scheduler tsib16020.
[0470] General signaling information, which is not received through
a separate particular channel, may be received through the DP for
signaling tsib16070. Here, the DP for signaling may refer to PLS,
L1, etc. Here, the DP may be referred to as a PLP. A reception
buffer tsib16080 may function as a buffer that receives signaling
information delivered from the DP for signaling. In a decapsulation
block for signaling information tsib16090, the received signaling
information may be decapsulated. The decapsulated signaling
information may be delivered to the signaling manager tsib16060
through a decapsulation buffer tsib16100. As described in the
foregoing, the signaling manager tsib16060 may collate signaling
information, and deliver the collated signaling information to a
necessary part in the link layer.
[0471] The scheduler tsib16020 may determine and control operations
of several modules included in the link layer. The scheduler
tsib16020 may control each part of the link layer using receiver
information tsib16010 and/or information delivered from the
signaling manager tsib16060. In addition, the scheduler tsib16020
may determine an operation mode, etc. of each part. Here, the
receiver information tsib16010 may refer to information previously
stored in the receiver. The scheduler tsib16020 may use information
changed by a user such as channel switching, etc. to perform a
control operation.
[0472] The decapsulation part may filter a packet received from a
DP tsib16110 of the physical layer, and separate a packet according
to a type of the packet. It is possible to configure decapsulation
parts corresponding to the number of DPs that can be simultaneously
decoded in the physical layer.
[0473] The decapsulation buffer tsib16100 may function as a buffer
that receives a packet stream from the physical layer to perform
decapsulation. A decapsulation controller tsib16130 may determine
whether to decapsulate an input packet stream. When decapsulation
is performed, the packet stream may be delivered to a link layer
header parser tsib16140. When decapsulation is not performed, the
packet stream may be delivered to an output buffer tsib16220. The
signaling information received from the scheduler tsib16020 may be
used to determine whether to perform decapsulation.
[0474] The link layer header parser tsib16140 may identify a header
of the delivered link layer packet. It is possible to identify a
configuration of an IP packet included in a payload of the link
layer packet by identifying the header. For example, the IP packet
may be segmented or concatenated.
[0475] A packet configuration table tsib16150 may include payload
information of segmented and/or concatenated link layer packets.
The transmitter and the receiver may have the same information in
the packet configuration table tsib16150. The transmitter and the
receiver may refer to the information of the packet configuration
table tsib16150. It is possible to find a value necessary for
reassembly based on index information included in the link layer
packet.
[0476] A reassembly block tsib16160 may configure payloads of the
segmented and/or concatenated link layer packets as packets of an
original IP stream. Segments may be collected and reconfigured as
one IP packet, or concatenated packets may be separated and
reconfigured as a plurality of IP packet streams. Recombined IP
packets may be delivered to the overhead processing part.
[0477] The overhead processing part may perform an operation of
restoring a packet subjected to overhead reduction to an original
packet as a reverse operation of overhead reduction performed in
the transmitter. This operation may be referred to as overhead
processing. It is possible to configure overhead processing parts
corresponding to the number of DPs that can be simultaneously
decoded in the physical layer.
[0478] A packet recovery buffer tsib16170 may function as a buffer
that receives a decapsulated RoHC packet or IP packet to perform
overhead processing.
[0479] An overhead controller tsib16180 may determine whether to
recover and/or decompress the decapsulated packet. When recovery
and/or decompression are performed, the packet may be delivered to
a packet stream recovery block tsib16190. When recovery and/or
decompression are not performed, the packet may be delivered to the
output buffer tsib16220. Whether to perform recovery and/or
decompression may be determined based on the signaling information
delivered by the scheduler tsib16020.
[0480] The packet stream recovery block tsib16190 may perform an
operation of integrating a packet stream separated from the
transmitter with context information of the packet stream. This
operation may be a process of restoring a packet stream such that
an RoHC decompressor tsib16210 can perform processing. In this
process, it is possible to receive signaling information and/or
context information from a signaling and/or context controller
tsib16200. The signaling and/or context controller tsib16200 may
determine signaling information delivered from the transmitter, and
deliver the signaling information to the packet stream recovery
block tsib16190 such that the signaling information may be mapped
to a stream corresponding to a context ID.
[0481] The RoHC decompressor tsib16210 may restore headers of
packets of the packet stream. The packets of the packet stream may
be restored to forms of original IP packets through restoration of
the headers. In other words, the RoHC decompressor tsib16210 may
perform overhead processing.
[0482] The output buffer tsib16220 may function as a buffer before
an output stream is delivered to an IP layer tsib16230.
[0483] The link layers of the transmitter and the receiver proposed
in the present invention may include the blocks or modules
described above. In this way, the link layer may independently
operate irrespective of an upper layer and a lower layer, overhead
reduction may be efficiently performed, and a supportable function
according to an upper/lower layer may be easily
defined/added/deleted.
[0484] FIG. 17 illustrates a configuration of signaling
transmission through a link layer according to an embodiment of the
present invention (transmitting/receiving sides).
[0485] In the present invention, a plurality of service providers
(broadcasters) may provide services within one frequency band. In
addition, a service provider may provide a plurality of services,
and one service may include one or more components. It can be
considered that the user receives content using a service as a
unit.
[0486] The present invention presumes that a transmission protocol
based on a plurality of sessions is used to support an IP hybrid
broadcast. Signaling information delivered through a signaling path
may be determined based on a transmission configuration of each
protocol. Various names may be applied to respective protocols
according to a given embodiment.
[0487] In the illustrated data configuration tsib17010 on the
transmitting side, service providers (broadcasters) may provide a
plurality of services (Service #1, #2, . . . ). In general, a
signal for a service may be transmitted through a general
transmission session (signaling C). However. the signal may be
transmitted through a particular session (dedicated session)
according to a given embodiment (signaling B).
[0488] Service data and service signaling information may be
encapsulated according to a transmission protocol. According to a
given embodiment, an IP/UDP layer may be used. According to a given
embodiment, a signal in the IP/UDP layer (signaling A) may be
additionally provided. This signaling may be omitted.
[0489] Data processed using the IP/UDP may be input to the link
layer. As described in the foregoing, overhead reduction and/or
encapsulation may be performed in the link layer. Here, link layer
signaling may be additionally provided. Link layer signaling may
include a system parameter, etc. Link layer signaling has been
described above.
[0490] The service data and the signaling information subjected to
the above process may be processed through PLPs in a physical
layer. Here, a PLP may be referred to as a DP. The example
illustrated in the figure presumes a case in which a base DP/PLP is
used. However, depending on embodiments, transmission may be
performed using only a general DP/PLP without the base DP/PLP.
[0491] In the example illustrated in the figure, a particular
channel (dedicated channel) such as an FIC, an EAC, etc. is used. A
signal delivered through the FIC may be referred to as a fast
information table (FIT), and a signal delivered through the EAC may
be referred to as an emergency alert table (EAT). The FIT may be
identical to the above-described SLT. The particular channels may
not be used depending on embodiments. When the particular channel
(dedicated channel) is not configured, the FIT and the EAT may be
transmitted using a general link layer signaling transmission
scheme, or transmitted using a PLP via the IP/UDP as other service
data.
[0492] According to a given embodiment, system parameters may
include a transmitter-related parameter, a service provider-related
parameter, etc. Link layer signaling may include IP header
compression-related context information and/or identification
information of data to which the context is applied. Signaling of
an upper layer may include an IP address, a UDP number,
service/component information, emergency alert-related information,
an IP/UDP address for service signaling, a session ID, etc.
Detailed examples thereof have been described above.
[0493] In the illustrated data configuration tsib17020 on the
receiving side, the receiver may decode only a PLP for a
corresponding service using signaling information without having to
decode all PLPs.
[0494] First, when the user selects or changes a service desired to
be received, the receiver may be tuned to a corresponding frequency
and may read receiver information related to a corresponding
channel stored in a DB, etc. The information stored in the DB, etc.
of the receiver may be configured by reading an SLT at the time of
initial channel scan.
[0495] After receiving the SLT and the information about the
corresponding channel, information previously stored in the DB is
updated, and information about a transmission path of the service
selected by the user and information about a path, through which
component information is acquired or a signal necessary to acquire
the information is transmitted, are acquired. When the information
is not determined to be changed using version information of the
SLT, decoding or parsing may be omitted.
[0496] The receiver may verify whether SLT information is included
in a PLP by parsing physical signaling of the PLP in a
corresponding broadcast stream (not illustrated), which may be
indicated through a particular field of physical signaling. It is
possible to access a position at which a service layer signal of a
particular service is transmitted by accessing the SLT information.
The service layer signal may be encapsulated into the IP/UDP and
delivered through a transmission session. It is possible to acquire
information about a component included in the service using this
service layer signaling. A specific SLT-SLS configuration is as
described above.
[0497] In other words, it is possible to acquire transmission path
information, for receiving upper layer signaling information
(service signaling information) necessary to receive the service,
corresponding to one of several packet streams and PLPs currently
transmitted on a channel using the SLT. The transmission path
information may include an IP address, a UDP port number, a session
ID, a PLP ID, etc. Here, depending on embodiments, a value
previously designated by the IANA or a system may be used as an
IP/UDP address. The information may be acquired using a scheme of
accessing a DB or a shared memory. etc.
[0498] When the link layer signal and service data are transmitted
through the same PLP, or only one PLP is operated, service data
delivered through the PLP may be temporarily stored in a device
such as a buffer, etc. while the link layer signal is decoded.
[0499] It is possible to acquire information about a path through
which the service is actually transmitted using service signaling
information of a service to be received. In addition, a received
packet stream may be subjected to decapsulation and header recovery
using information such as overhead reduction for a PLP to be
received, etc.
[0500] In the illustrated example (tsib17020), the FIC and the EAC
are used, and a concept of the base DP/PLP is presumed. As
described in the foregoing, concepts of the FIC, the EAC. and the
base DP/PLP may not be used.
[0501] While MISO or MIMO uses two antennas in the following for
convenience of description, the present invention is applicable to
systems using two or more antennas. The present invention proposes
a physical profile (or system) optimized to minimize receiver
complexity while attaining the performance required for a
particular use case. Physical (PHY) profiles (base, handheld and
advanced profiles) according to an embodiment of the present
invention are subsets of all configurations that a corresponding
receiver should implement. The PHY profiles share most of the
functional blocks but differ slightly in specific blocks and/or
parameters. For the system evolution, future profiles may also be
multiplexed with existing profiles in a single radio frequency (RF)
channel through a future extension frame (FEF). The base profile
and the handheld profile according to the embodiment of the present
invention refer to profiles to which MIMO is not applied, and the
advanced profile refers to a profile to which MIMO is applied. The
base profile may be used as a profile for both the terrestrial
broadcast service and the mobile broadcast service. That is, the
base profile may be used to define a concept of a profile which
includes the mobile profile. In addition, the advanced profile may
be divided into an advanced profile for a base profile with MIMO
and an advanced profile for a handheld profile with MIMO. Moreover,
the profiles may be changed according to intention of the
designer.
[0502] The following terms and definitions may be applied to the
present invention. The following terms and definitions may be
changed according to design.
[0503] Auxiliary stream: sequence of cells carrying data of as yet
undefined modulation and coding, which may be used for future
extensions or as required by broadcasters or network operators.
[0504] Base data pipe: data pipe that carries service signaling
data.
[0505] Baseband frame (or BBFRAME): set of Kbch bits which form the
input to one FEC encoding process (BCH and LDPC encoding).
[0506] Cell: modulation value that is carried by one carrier of
orthogonal frequency division multiplexing (OFDM) transmission.
[0507] Coded block: LDPC-encoded block of PLS1 data or one of the
LDPC-encoded blocks of PLS2 data.
[0508] Data pipe: logical channel in the physical layer that
carries service data or related metadata, which may carry one or a
plurality of service(s) or service component(s).
[0509] Data pipe unit (DPU): a basic unit for allocating data cells
to a DP in a frame.
[0510] Data symbol: OFDM symbol in a frame which is not a preamble
symbol (the data symbol encompasses the frame signaling symbol and
frame edge symbol).
[0511] DP_ID: this 8-bit field identifies uniquely a DP within the
system identified by the SYSTEM_ID.
[0512] Dummy cell: cell carrying a pseudo-random value used to fill
the remaining capacity not used for PLS signaling, DPs or auxiliary
streams.
[0513] Emergency alert channel (EAC): part of a frame that carries
EAS information data.
[0514] Frame: physical layer time slot that starts with a preamble
and ends with a frame edge symbol.
[0515] Frame repetition unit: a set of frames belonging to the same
or different physical layer profiles including an FEF, which is
repeated eight times in a superframe.
[0516] Fast information channel (FIC): a logical channel in a frame
that carries mapping information between a service and the
corresponding base DP.
[0517] FECBLOCK: set of LDPC-encoded bits of DP data.
[0518] FFT size: nominal FFT size used for a particular mode, equal
to the active symbol period Ts expressed in cycles of an elementary
period T.
[0519] Frame signaling symbol: OFDM symbol with higher pilot
density used at the start of a frame in certain combinations of FFT
size, guard interval and scattered pilot pattern, which carries a
part of the PLS data.
[0520] Frame edge symbol: OFDM symbol with higher pilot density
used at the end of a frame in certain combinations of FFT size,
guard interval and scattered pilot pattern.
[0521] Frame group: the set of all frames having the same PHY
profile type in a superframe.
[0522] Future extension frame: physical layer time slot within the
superframe that may be used for future extension, which starts with
a preamble.
[0523] Futurecast UTB system: proposed physical layer broadcast
system, the input of which is one or more MPEG2-TS, IP or general
stream(s) and the output of which is an RF signal.
[0524] Input stream: a stream of data for an ensemble of services
delivered to the end users by the system.
[0525] Normal data symbol: data symbol excluding the frame
signaling symbol and the frame edge symbol.
[0526] PHY profile: subset of all configurations that a
corresponding receiver should implement.
[0527] PLS: physical layer signaling data including PLS1 and
PLS2.
[0528] PLS1: a first set of PLS data carried in a frame signaling
symbol (FSS) having a fixed size, coding and modulation, which
carries basic information about a system as well as parameters
needed to decode PLS2.
[0529] NOTE: PLS1 data remains constant for the duration of a frame
group.
[0530] PLS2: a second set of PLS data transmitted in the FSS, which
carries more detailed PLS data about the system and the DPs.
[0531] PLS2 dynamic data: PLS2 data that dynamically changes
frame-by-frame.
[0532] PLS2 static data: PLS2 data that remains static for the
duration of a frame group.
[0533] Preamble signaling data-signaling data carried by the
preamble symbol and used to identify the basic mode of the
system.
[0534] Preamble symbol: fixed-length pilot symbol that carries
basic PLS data and is located at the beginning of a frame.
[0535] The preamble symbol is mainly used for fast initial band
scan to detect the system signal, timing thereof, frequency offset,
and FFT size.
[0536] Reserved for future use: not defined by the present document
but may be defined in future.
[0537] Superframe: set of eight frame repetition units.
[0538] Time interleaving block (TI block): set of cells within
which time interleaving is carried out, corresponding to one use of
a time interleaver memory.
[0539] TI group: unit over which dynamic capacity allocation for a
particular DP is carried out, made up of an integer, dynamically
varying number of XFECBLOCKs.
[0540] NOTE: The TI group may be mapped directly to one frame or
may be mapped to a plurality of frames. The TI group may contain
one or more TI blocks.
[0541] Type 1 DP: DP of a frame where all DPs are mapped to the
frame in time division multiplexing (TDM) scheme.
[0542] Type 2 DP: DP of a frame where all DPs are mapped to the
frame in frequency division multiplexing (FDM) scheme.
[0543] XFECBLOCK: set of Ncells cells carrying all the bits of one
LDPC FECBLOCK.
[0544] FIG. 18 illustrates a configuration of a broadcast signal
transmission apparatus for future broadcast services according to
an embodiment of the present invention.
[0545] The broadcast signal transmission apparatus for future
broadcast services according to the present embodiment may include
an input formatting block 1000, a bit interleaved coding &
modulation (BICM) block 1010, a frame building block 1020, an OFDM
generation block 1030 and a signaling generation block 1040.
Description will be given of an operation of each block of the
broadcast signal transmission apparatus.
[0546] In input data according to an embodiment of the present
invention, IP stream/packets and MPEG2-TS may be main input
formats, and other stream types are handled as general streams. In
addition to these data inputs, management information is input to
control scheduling and allocation of the corresponding bandwidth
for each input stream. In addition, the present invention allows
simultaneous input of one or a plurality of TS streams. IP
stream(s) and/or a general stream(s).
[0547] The input formatting block 1000 may demultiplex each input
stream into one or a plurality of data pipes, to each of which
independent coding and modulation are applied. A DP is the basic
unit for robustness control, which affects QoS. One or a plurality
of services or service components may be carried by one DP. The DP
is a logical channel in a physical layer for delivering service
data or related metadata capable of carrying one or a plurality of
services or service components.
[0548] In addition, a DPU is a basic unit for allocating data cells
to a DP in one frame.
[0549] An input to the physical layer may include one or a
plurality of data streams. Each of the data streams is delivered by
one DP. The input formatting block 1000 may covert a data stream
input through one or more physical paths (or DPs) into a baseband
frame (BBF). In this case, the input formatting block 1000 may
perform null packet deletion or header compression on input data (a
TS or IP input stream) in order to enhance transmission efficiency.
A receiver may have a priori information for a particular part of a
header, and thus this known information may be deleted from a
transmitter. A null packet deletion block 3030 may be used only for
a TS input stream.
[0550] In the BICM block 1010, parity data is added for error
correction and encoded bit streams are mapped to complex-value
constellation symbols. The symbols are interleaved across a
specific interleaving depth that is used for the corresponding DP.
For the advanced profile, MIMO encoding is performed in the BICM
block 1010 and an additional data path is added at the output for
MIMO transmission.
[0551] The frame building block 1020 may map the data cells of the
input DPs into the OFDM symbols within a frame, and perform
frequency interleaving for frequency-domain diversity. especially
to combat frequency-selective fading channels. The frame building
block 1020 may include a delay compensation block, a cell mapper
and a frequency interleaver.
[0552] The delay compensation block may adjust timing between DPs
and corresponding PLS data to ensure that the DPs and the
corresponding PLS data are co-timed at a transmitter side. The PLS
data is delayed by the same amount as the data pipes by addressing
the delays of data pipes caused by the input formatting block and
BICM block. The delay of the BICM block is mainly due to the time
interleaver. In-band signaling data carries information of the next
TI group so that the information is carried one frame ahead of the
DPs to be signaled. The delay compensation block delays in-band
signaling data accordingly.
[0553] The cell mapper may map PLS, DPs, auxiliary streams, dummy
cells, etc. to active carriers of the OFDM symbols in the frame.
The basic function of the cell mapper 7010 is to map data cells
produced by the TIs for each of the DPs, PLS cells, and EAC/FIC
cells, if any, into arrays of active OFDM cells corresponding to
each of the OFDM symbols within a frame. A basic function of the
cell mapper is to map a data cell generated by time interleaving
for each DP and PLS cell to an array of active OFDM cells (if
present) corresponding to respective OFDM symbols in one frame.
Service signaling data (such as program specific information
(PSI)/SI) may be separately gathered and sent by a DP. The cell
mapper operates according to dynamic information produced by a
scheduler and the configuration of a frame structure. The frequency
interleaver may randomly interleave data cells received from the
cell mapper to provide frequency diversity. In addition, the
frequency interleaver may operate on an OFDM symbol pair including
two sequential OFDM symbols using a different interleaving-seed
order to obtain maximum interleaving gain in a single frame.
[0554] The OFDM generation block 1030 modulates OFDM carriers by
cells produced by the frame building block, inserts pilots, and
produces a time domain signal for transmission. In addition, this
block subsequently inserts guard intervals, and applies
peak-to-average power ratio (PAPR) reduction processing to produce
a final RF signal.
[0555] Specifically, after inserting a preamble at the beginning of
each frame, the OFDM generation block 1030 may apply conventional
OFDM modulation having a cyclic prefix as a guard interval. For
antenna space diversity, a distributed MISO scheme is applied
across transmitters. In addition, a PAPR scheme is performed in the
time domain. For flexible network planning, the present invention
provides a set of various FFT sizes, guard interval lengths and
corresponding pilot patterns.
[0556] In addition, the present invention may multiplex signals of
a plurality of broadcast transmission/reception systems in the time
domain such that data of two or more different broadcast
transmission/reception systems providing broadcast services may be
simultaneously transmitted in the same RF signal bandwidth. In this
case, the two or more different broadcast transmission/reception
systems refer to systems providing different broadcast services.
The different broadcast services may refer to a terrestrial
broadcast service, mobile broadcast service, etc.
[0557] The signaling generation block 1040 may create physical
layer signaling information used for an operation of each
functional block. This signaling information is also transmitted so
that services of interest are properly recovered at a receiver
side. Signaling information according to an embodiment of the
present invention may include PLS data. PLS provides the receiver
with a means to access physical layer DPs. The PLS data includes
PLS1 data and PLS2 data.
[0558] The PLS1 data is a first set of PLS data carried in an FSS
symbol in a frame having a fixed size, coding and modulation, which
carries basic information about the system in addition to the
parameters needed to decode the PLS2 data. The PLS1 data provides
basic transmission parameters including parameters required to
enable reception and decoding of the PLS2 data. In addition, the
PLS1 data remains constant for the duration of a frame group.
[0559] The PLS2 data is a second set of PLS data transmitted in an
FSS symbol, which carries more detailed PLS data about the system
and the DPs. The PLS2 contains parameters that provide sufficient
information for the receiver to decode a desired DP. The PLS2
signaling further includes two types of parameters, PLS2 static
data (PLS2-STAT data) and PLS2 dynamic data (PLS2-DYN data). The
PLS2 static data is PLS2 data that remains static for the duration
of a frame group and the PLS2 dynamic data is PLS2 data that
dynamically changes frame by frame. Details of the PLS data will be
described later.
[0560] The above-described blocks may be omitted or replaced by
blocks having similar or identical functions.
[0561] FIG. 19 illustrates a BICM block according to an embodiment
of the present invention.
[0562] The BICM block illustrated in FIG. 19 corresponds to an
embodiment of the BICM block 1010 described with reference to FIG.
18.
[0563] As described above, the broadcast signal transmission
apparatus for future broadcast services according to the embodiment
of the present invention may provide a terrestrial broadcast
service, mobile broadcast service, UHDTV service, etc.
[0564] Since QoS depends on characteristics of a service provided
by the broadcast signal transmission apparatus for future broadcast
services according to the embodiment of the present invention, data
corresponding to respective services needs to be processed using
different schemes. Accordingly. the BICM block according to the
embodiment of the present invention may independently process
respective DPs by independently applying SISO, MISO and MIMO
schemes to data pipes respectively corresponding to data paths.
Consequently, the broadcast signal transmission apparatus for
future broadcast services according to the embodiment of the
present invention may control QoS for each service or service
component transmitted through each DP.
[0565] (a) shows a BICM block applied to a profile (or system) to
which MIMO is not applied, and (b) shows a BICM block of a profile
(or system) to which MIMO is applied.
[0566] The BICM block to which MIMO is not applied and the BICM
block to which MIMO is applied may include a plurality of
processing blocks for processing each DP.
[0567] Description will be given of each processing block of the
BICM block to which MIMO is not applied and the BICM block to which
MIMO is applied.
[0568] A processing block 5000 of the BICM block to which MIMO is
not applied may include a data FEC encoder 5010, a bit interleaver
5020, a constellation mapper 5030, a signal space diversity (SSD)
encoding block 5040 and a time interleaver 5050.
[0569] The data FEC encoder 5010 performs FEC encoding on an input
BBF to generate FECBLOCK procedure using outer coding (BCH) and
inner coding (LDPC). The outer coding (BCH) is optional coding
method. A detailed operation of the data FEC encoder 5010 will be
described later.
[0570] The bit interleaver 5020 may interleave outputs of the data
FEC encoder 5010 to achieve optimized performance with a
combination of LDPC codes and a modulation scheme while providing
an efficiently implementable structure. A detailed operation of the
bit interleaver 5020 will be described later.
[0571] The constellation mapper 5030 may modulate each cell word
from the bit interleaver 5020 in the base and the handheld
profiles, or each cell word from the cell-word demultiplexer 5010-1
in the advanced profile using either QPSK, QAM-16, non-uniform QAM
(NUQ-64, NUQ-256, or NUQ-1024) or non-uniform constellation
(NUC-16, NUC-64, NUC-256, or NUC-1024) mapping to give a
power-normalized constellation point, el. This constellation
mapping is applied only for DPs. It is observed that QAM-16 and
NUQs are square shaped, while NUCs have arbitrary shapes. When each
constellation is rotated by any multiple of 90 degrees, the rotated
constellation exactly overlaps with its original one. This
"rotation-sense" symmetric property makes the capacities and the
average powers of the real and imaginary components equal to each
other. Both NUQs and NUCs are defined specifically for each code
rate and the particular one used is signaled by the parameter
DP_MOD filed in the PLS2 data.
[0572] The time interleaver 5050 may operates at a DP level.
Parameters of time interleaving (TI) may be set differently for
each DP. A detailed operation of the time interleaver 5050 will be
described later.
[0573] A processing block 5000-1 of the BICM block to which MIMO is
applied may include the data FEC encoder, the bit interleaver, the
constellation mapper, and the time interleaver.
[0574] However, the processing block 5000-1 is distinguished from
the processing block 5000 of the BICM block to which MIMO is not
applied in that the processing block 5000-1 further includes a
cell-word demultiplexer 5010-1 and a MIMO encoding block
5020-1.
[0575] In addition, operations of the data FEC encoder, the bit
interleaver, the constellation mapper, and the time interleaver in
the processing block 5000-1 correspond to those of the data FEC
encoder 5010. the bit interleaver 5020, the constellation mapper
5030, and the time interleaver 5050 described above, and thus
description thereof is omitted.
[0576] The cell-word demultiplexer 5010-1 is used for a DP of the
advanced profile to divide a single cell-word stream into dual
cell-word streams for MIMO processing.
[0577] The MIMO encoding block 5020-1 may process an output of the
cell-word demultiplexer 5010-1 using a MIMO encoding scheme. The
MIMO encoding scheme is optimized for broadcast signal
transmission. MIMO technology is a promising way to obtain a
capacity increase but depends on channel characteristics.
Especially for broadcasting, a strong LOS component of a channel or
a difference in received signal power between two antennas caused
by different signal propagation characteristics makes it difficult
to obtain capacity gain from MIMO. The proposed MIMO encoding
scheme overcomes this problem using rotation-based precoding and
phase randomization of one of MIMO output signals.
[0578] MIMO encoding is intended for a 2.times.2 MIMO system
requiring at least two antennas at both the transmitter and the
receiver. A MIMO encoding mode of the present invention may be
defined as full-rate spatial multiplexing (FR-SM). FR-SM encoding
may provide capacity increase with relatively small complexity
increase at the receiver side. In addition, the MIMO encoding
scheme of the present invention has no restriction on an antenna
polarity configuration.
[0579] MIMO processing is applied at the DP level. NUQ (e1,i and
e2,i) corresponding to a pair of constellation mapper outputs is
fed to an input of a MIMO encoder. Paired MIMO encoder output (g1,i
and g2,i) is transmitted by the same carrier k and OFDM symbol 1 of
respective TX antennas thereof.
[0580] The above-described blocks may be omitted or replaced by
blocks having similar or identical functions.
[0581] FIG. 20 illustrates a BICM block according to another
embodiment of the present invention.
[0582] The BICM block illustrated in FIG. 20 corresponds to another
embodiment of the BICM block 1010 described with reference to FIG.
18.
[0583] FIG. 20 illustrates a BICM block for protection of physical
layer signaling (PLS), an emergency alert channel (EAC) and a fast
information channel (FIC). The EAC is a part of a frame that
carries EAS information data, and the FIC is a logical channel in a
frame that carries mapping information between a service and a
corresponding base DP. Details of the EAC and FIC will be described
later.
[0584] Referring to FIG. 20, the BICM block for protection of the
PLS, the EAC and the FIC may include a PLS FEC encoder 6000, a bit
interleaver 6010 and a constellation mapper 6020.
[0585] In addition, the PLS FEC encoder 6000 may include a
scrambler, a BCH encoding/zero insertion block, an LDPC encoding
block and an LDPC parity puncturing block. Description will be
given of each block of the BICM block.
[0586] The PLS FEC encoder 6000 may encode scrambled PLS 1/2 data,
EAC and FIC sections.
[0587] The scrambler may scramble PLS1 data and PLS2 data before
BCH encoding and shortened and punctured LDPC encoding.
[0588] The BCH encoding/zero insertion block may perform outer
encoding on the scrambled PLS 1/2 data using a shortened BCH code
for PLS protection, and insert zero bits after BCH encoding. For
PLS1 data only, output bits of zero insertion may be permutted
before LDPC encoding.
[0589] The LDPC encoding block may encode an output of the BCH
encoding/zero insertion block using an LDPC code. To generate a
complete coded block, Cldpc and parity bits Pldpc are encoded
systematically from each zero-inserted PLS information block Ildpc
and appended thereto.
C ldpc = [ I ldpc P ldpc ] = [ i 0 , i 1 , .times. .times. , i K
ldpc - 1 , p 0 , p 1 , .times. , p N ldpc - K ldpc - 1 ] [ Equation
.times. .times. 1 ] ##EQU00001##
[0590] The LDPC parity puncturing block may perform puncturing on
the PLS1 data and the PLS2 data.
[0591] When shortening is applied to PLS1 data protection. some
LDPC parity bits are punctured after LDPC encoding. In addition,
for PLS2 data protection, LDPC parity bits of PLS2 are punctured
after LDPC encoding. These punctured bits are not transmitted.
[0592] The bit interleaver 6010 may interleave each of shortened
and punctured PLS 1 data and PLS2 data.
[0593] The constellation mapper 6020 may map the bit-interleaved
PLS1 data and PLS2 data to constellations.
[0594] The above-described blocks may be omitted or replaced by
blocks having similar or identical functions.
[0595] FIG. 21 illustrates a bit interleaving process of PLS
according to an embodiment of the present invention.
[0596] Each shortened and punctured PLS1 and PLS2 coded block is
interleaved bit-by-bit as described in FIG. 22. Each block of
additional parity bits is interleaved with the same block
interleaving structure but separately.
[0597] In the case of BPSK, there are two branches for bit
interleaving to duplicate FEC coded bits in the real and imaginary
parts. Each coded block is written to the upper branch first. The
bits are mapped to the lower branch by applying modulo NFEC
addition with cyclic shifting value floor(NFEC/2), where NFEC is
the length of each LDPC coded block after shortening and
puncturing.
[0598] In other modulation cases, such as QSPK, QAM-16 and NUQ-64,
FEC coded bits are written serially into the interleaver
column-wise, where the number of columns is the same as the
modulation order.
[0599] In the read operation, the bits for one constellation symbol
are read out sequentially row-wise and fed into the bit
demultiplexer block. These operations are continued until the end
of the column.
[0600] Each bit interleaved group is demultiplexed bit-by-bit in a
group before constellation mapping. Depending on modulation order,
there are two mapping rules. In the case of BPSK and QPSK, the
reliability of bits in a symbol is equal. Therefore, the bit group
read out from the bit interleaving block is mapped to a QAM symbol
without any operation.
[0601] In the cases of QAM-16 and NUQ-64 mapped to a QAM symbol,
the rule of operation is described in FIG. 23(a). As shown in FIG.
23(a), i is bit group index corresponding to column index in bit
interleaving.
[0602] FIG. 21 shows the bit demultiplexing rule for QAM-16. This
operation continues until all bit groups are read from the bit
interleaving block.
[0603] FIG. 22 illustrates a configuration of a broadcast signal
reception apparatus for future broadcast services according to an
embodiment of the present invention.
[0604] The broadcast signal reception apparatus for future
broadcast services according to the embodiment of the present
invention may correspond to the broadcast signal transmission
apparatus for future broadcast services described with reference to
FIG. 18.
[0605] The broadcast signal reception apparatus for future
broadcast services according to the embodiment of the present
invention may include a synchronization & demodulation module
9000, a frame parsing module 9010, a demapping & decoding
module 9020, an output processor 9030 and a signaling decoding
module 9040. A description will be given of operation of each
module of the broadcast signal reception apparatus.
[0606] The synchronization & demodulation module 9000 may
receive input signals through m Rx antennas, perform signal
detection and synchronization with respect to a system
corresponding to the broadcast signal reception apparatus. and
carry out demodulation corresponding to a reverse procedure of a
procedure performed by the broadcast signal transmission
apparatus.
[0607] The frame parsing module 9010 may parse input signal frames
and extract data through which a service selected by a user is
transmitted. If the broadcast signal transmission apparatus
performs interleaving, the frame parsing module 9010 may carry out
deinterleaving corresponding to a reverse procedure of
interleaving. In this case, positions of a signal and data that
need to be extracted may be obtained by decoding data output from
the signaling decoding module 9040 to restore scheduling
information generated by the broadcast signal transmission
apparatus.
[0608] The demapping & decoding module 9020 may convert input
signals into bit domain data and then deinterleave the same as
necessary. The demapping & decoding module 9020 may perform
demapping of mapping applied for transmission efficiency and
correct an error generated on a transmission channel through
decoding. In this case, the demapping & decoding module 9020
may obtain transmission parameters necessary for demapping and
decoding by decoding data output from the signaling decoding module
9040.
[0609] The output processor 9030 may perform reverse procedures of
various compression/signal processing procedures which are applied
by the broadcast signal transmission apparatus to improve
transmission efficiency. In this case, the output processor 9030
may acquire necessary control information from data output from the
signaling decoding module 9040. An output of the output processor
9030 corresponds to a signal input to the broadcast signal
transmission apparatus and may be MPEG-TSs, IP streams (v4 or v6)
and generic streams.
[0610] The signaling decoding module 9040 may obtain PLS
information from a signal demodulated by the synchronization &
demodulation module 9000. As described above, the frame parsing
module 9010, the demapping & decoding module 9020 and the
output processor 9030 may execute functions thereof using data
output from the signaling decoding module 9040.
[0611] A frame according to an embodiment of the present invention
is further divided into a number of OFDM symbols and a preamble. As
shown in (d), the frame includes a preamble, one or more frame
signaling symbols (FSSs), normal data symbols and a frame edge
symbol (FES).
[0612] The preamble is a special symbol that enables fast
futurecast UTB system signal detection and provides a set of basic
transmission parameters for efficient transmission and reception of
a signal. Details of the preamble will be described later.
[0613] A main purpose of the FSS is to carry PLS data. For fast
synchronization and channel estimation, and hence fast decoding of
PLS data, the FSS has a dense pilot pattern than a normal data
symbol. The FES has exactly the same pilots as the FSS. which
enables frequency-only interpolation within the FES and temporal
interpolation, without extrapolation, for symbols immediately
preceding the FES.
[0614] FIG. 23 illustrates a signaling hierarchy structure of a
frame according to an embodiment of the present invention.
[0615] FIG. 23 illustrates the signaling hierarchy structure, which
is split into three main parts corresponding to preamble signaling
data 11000, PLS1 data 11010 and PLS2 data 11020. A purpose of a
preamble, which is carried by a preamble symbol in every frame, is
to indicate a transmission type and basic transmission parameters
of the frame. PLS1 enables the receiver to access and decode the
PLS2 data, which contains the parameters to access a DP of
interest. PLS2 is carried in every frame and split into two main
parts corresponding to PLS2-STAT data and PLS2-DYN data Static and
dynamic portions of PLS2 data are followed by padding, if
necessary.
[0616] Preamble signaling data according to an embodiment of the
present invention carries 21 bits of information that are needed to
enable the receiver to access PLS data and trace DPs within the
frame structure. Details of the preamble signaling data are as
follows.
[0617] FFT_SIZE: This 2-bit field indicates an FFT size of a
current frame within a frame group as described in the following
Table 1.
TABLE-US-00001 TABLE 1 Value FFT size 00 8K FFT 01 16K FFT 10 32K
FFT 11 Reserved
[0618] GI_FRACTION. This 3-bit field indicates a guard interval
fraction value in a current superframe as described in the
following Table 2.
TABLE-US-00002 TABLE 2 Value GI_FRACTION 000 1/5 001 1/10 010 1/20
011 1/40 100 1/80 101 1/160 110 to 111 Reserved
[0619] EAC_FLAU: This 1-bit field indicates whether the EAC is
provided in a current frame. If this field is set to `1`, an
emergency alert service (EAS) is provided in the current frame. If
this field set to `0`, the EAS is not carried in the current frame.
This field may be switched dynamically within a superframe.
[0620] PILOT_MODE: This 1-bit field indicates whether a pilot mode
is a mobile mode or a fixed mode for a current frame in a current
frame group. If this field is set to `0`, the mobile pilot mode is
used. If the field is set to `1`, the fixed pilot mode is used.
[0621] PAPR_FLAG: This 1-bit field indicates whether PAPR reduction
is used for a current frame in a current frame group. If this field
is set to a value of `1`, tone reservation is used for PAPR
reduction. If this field is set to a value of `0`, PAPR reduction
is not used.
[0622] RESERVED: This 7-bit field is reserved for future use.
[0623] FIG. 24 illustrates PLS1 data according to an embodiment of
the present invention.
[0624] PLS1 data provides basic transmission parameters including
parameters required to enable reception and decoding of PLS2. As
mentioned above, the PLS1 data remain unchanged for the entire
duration of one frame group. A detailed definition of the signaling
fields of the PLS 1 data is as follows.
[0625] PREAMBLE_DATA: This 20-bit field is a copy of preamble
signaling data excluding EAC_FLAG.
[0626] NUM_FRAME_FRU: This 2-bit field indicates the number of the
frames per FRU.
[0627] PAYLOAD_TYPE: This 3-bit field indicates a format of payload
data carried in a frame group. PAYLOAD TYPE is signaled as shown in
Table 3.
TABLE-US-00003 TABLE 3 Value Payload type 1XX TS is transmitted.
X1X IP stream is transmitted. XX1 GS is transmitted.
[0628] NUM_FSS: This 2-bit field indicates the number of FSSs in a
current frame.
[0629] SYSTEM_VERSION: This 8-bit field indicates a version of a
transmitted signal format. SYSTEM_VERSION is divided into two 4-bit
fields: a major version and a minor version.
[0630] Major version: The MSB corresponding to four bits of the
SYSTEM_VERSION field indicates major version information. A change
in the major version field indicates a non-backward-compatible
change. A default value is `0000`. For a version described in this
standard, a value is set to `0000`.
[0631] Minor version: The LSB corresponding to four bits of
SYSTEM_VERSION field indicates minor version information. A change
in the minor version field is backwards compatible.
[0632] CELL_ID: This is a 16-bit field which uniquely identifies a
geographic cell in an ATSC network. An ATSC cell coverage area may
include one or more frequencies depending on the number of
frequencies used per futurecast UTB system. If a value of CELL_ID
is not known or unspecified, this field is set to `0`.
[0633] NETWORK_ID: This is a 16-bit field which uniquely identifies
a current ATSC network.
[0634] SYSTEM_ID: This 16-bit field uniquely identifies the
futurecast UTB system within the ATSC network. The futurecast UTB
system is a terrestrial broadcast system whose input is one or more
input streams (TS, IP, GS) and whose output is an RF signal. The
futurecast UTB system carries one or more PHY profiles and FEF, if
any. The same futurecast UTB system may carry different input
streams and use different RFs in different geographical areas,
allowing local service insertion. The frame structure and
scheduling are controlled in one place and are identical for all
transmissions within the futurecast UTB system. One or more
futurecast UTB systems may have the same SYSTEM_ID meaning that
they all have the same physical layer structure and
configuration.
[0635] The following loop includes FRU_PHY_PROFILE,
FRU_FRAME_LENGTH, FRU_GI_FRACTION, and RESERVED which are used to
indicate an FRU configuration and a length of each frame type. A
loop size is fixed so that four PHY profiles (including an FEF) are
signaled within the FRU. If NUM_FRAME_FRU is less than 4, unused
fields are filled with zeros.
[0636] FRU_PHY_PROFILE: This 3-bit field indicates a PHY profile
type of an (i+1)th (i is a loop index) frame of an associated FRU.
This field uses the same signaling format as shown in Table 8.
[0637] FRU_FRAME_LENGTH: This 2-bit field indicates a length of an
(i+1)th frame of an associated FRU. Using FRU_FRAME_LENGTH together
with FRU_GI_FRACTION, an exact value of a frame duration may be
obtained.
[0638] FRU_GI_FRACTION: This 3-bit field indicates a guard interval
fraction value of an (i+1)th frame of an associated FRU.
FRU_GI_FRACTION is signaled according to Table 7.
[0639] RESERVED: This 4-bit field is reserved for future use.
[0640] The following fields provide parameters for decoding the
PLS2 data.
[0641] PLS2_FEC_TYPE: This 2-bit field indicates an FEC type used
by PLS2 protection. The FEC type is signaled according to Table 4.
Details of LDPC codes will be described later.
TABLE-US-00004 TABLE 4 Content PLS2 FEC type 00 4K-1/4 and 7K-3/10
LDPC codes 01 to 11 Reserved
[0642] PLS2_MOD: This 3-bit field indicates a modulation type used
by PLS2. The modulation type is signaled according to Table 5.
TABLE-US-00005 TABLE 5 Value PLS2_MODE 000 BPSK 001 QPSK 010 QAM-16
011 NUQ-64 100 to 111 Reserved
[0643] PLS2_SIZE_CELL: This 15-bit field indicates
C.sub.total_partial_block, a size (specified as the number of QAM
cells) of the collection of full coded blocks for PLS2 that is
carried in a current frame group. This value is constant during the
entire duration of the current frame group.
[0644] PLS2_STAT_SIZE_BIT: This 14-bit field indicates a size, in
bits, of PLS2-STAT for a current frame group. This value is
constant during the entire duration of the current frame group.
[0645] PLS2_DYN_SIZE_BIT: This 14-bit field indicates a size, in
bits, of PLS2-DYN for a current frame group. This value is constant
during the entire duration of the current frame group.
[0646] PLS2_REP_FLAG: This 1-bit flag indicates whether a PLS2
repetition mode is used in a current frame group. When this field
is set to a value of `1`, the PLS2 repetition mode is activated.
When this field is set to a value of `0`, the PLS2 repetition mode
is deactivated.
[0647] PLS2_REP_SIZE_CELL: This 15-bit field indicates
C.sub.total_partial_bock, a size (specified as the number of QAM
cells) of the collection of partial coded blocks for PLS2 carried
in every frame of a current frame group, when PLS2 repetition is
used. If repetition is not used, a value of this field is equal to
0. This value is constant during the entire duration of the current
frame group.
[0648] PLS2_NEXT_FEC_TYPE: This 2-bit field indicates an FEC type
used for PLS2 that is carried in every frame of a next frame group.
The FEC type is signaled according to Table 10.
[0649] PLS2_NEXT_MOD: This 3-bit field indicates a modulation type
used for PLS2 that is carried in every frame of a next frame group.
The modulation type is signaled according to Table 11.
[0650] PLS2_NEXT_REP_FLAG: This 1-bit flag indicates whether the
PLS2 repetition mode is used in a next frame group. When this field
is set to a value of `1`, the PLS2 repetition mode is activated.
When this field is set to a value of `0`. the PLS2 repetition mode
is deactivated.
[0651] PLS2_NEXT_REP_SIZE_CELL: This 15-bit field indicates
C.sub.total_full_block, a size (specified as the number of QAM
cells) of the collection of full coded blocks for PLS2 that is
carried in every frame of a next frame group, when PLS2 repetition
is used. If repetition is not used in the next frame group, a value
of this field is equal to 0. This value is constant during the
entire duration of a current frame group.
[0652] PLS2_NEXT_REP_STAT_SIZE_BIT: This 14-bit field indicates a
size, in bits, of PLS2-STAT for a next frame group. This value is
constant in a current frame group.
[0653] PLS2_NEXT_REP_DYN_SIZE_BIT: This 14-bit field indicates the
size, in bits, of the PLS2-DYN for a next frame group. This value
is constant in a current frame group.
[0654] PLS2_AP_MODE: This 2-bit field indicates whether additional
parity is provided for PLS2 in a current frame group. This value is
constant during the entire duration of the current frame group.
Table 6 below provides values of this field. When this field is set
to a value of `00`, additional parity is not used for the PLS2 in
the current frame group.
TABLE-US-00006 TABLE 6 Value PLS2-AP mode 00 AP is not provided 01
AP1 mode 10 to 11 Reserved
[0655] PLS2_AP_SIZE_CELL: This 15-bit field indicates a size
(specified as the number of QAM cells) of additional parity bits of
PLS2. This value is constant during the entire duration of a
current frame group.
[0656] PLS2_NEXT_AP_MODE: This 2-bit field indicates whether
additional parity is provided for PLS2 signaling in every frame of
a next frame group. This value is constant during the entire
duration of a current frame group. Table 12 defines values of this
field.
[0657] PLS2_NEXT_AP_SIZE_CELL: This 15-bit field indicates a size
(specified as the number of QAM cells) of additional parity bits of
PLS2 in every frame of a next frame group. This value is constant
during the entire duration of a current frame group.
[0658] RESERVED: This 32-bit field is reserved for future use.
[0659] CRC_32: A 32-bit error detection code, which is applied to
all PLS1 signaling.
[0660] FIG. 25 illustrates PLS2 data according to an embodiment of
the present invention.
[0661] FIG. 25 illustrates PLS2-STAT data of the PLS2 data. The
PLS2-STAT data is the same within a frame group. while PLS2-DYN
data provides information that is specific for a current frame.
[0662] Details of fields of the PLS2-STAT data are described
below.
[0663] FIC_FLAG: This 1-bit field indicates whether the FIC is used
in a current frame group. If this field is set to `1`. the FIC is
provided in the current frame. If this field set to `0`, the FIC is
not carried in the current frame. This value is constant during the
entire duration of a current frame group.
[0664] AUX_FLAG: This 1-bit field indicates whether an auxiliary
stream is used in a current frame group. If this field is set to
`1`, the auxiliary stream is provided in a current frame. If this
field set to `0`. the auxiliary stream is not carried in the
current frame. This value is constant during the entire duration of
current frame group.
[0665] NUM_DP: This 6-bit field indicates the number of DPs carried
within a current frame. A value of this field ranges from 1 to 64,
and the number of DPs is NUM_DP+1.
[0666] DP_ID: This 6-bit field identifies uniquely a DP within a
PHY profile.
[0667] DP_TYPE: This 3-bit field indicates a type of a DP. This is
signaled according to the following Table 7.
TABLE-US-00007 TABLE 7 Value DP Type 000 DP Type 1 001 DP Type 2
010 to 111 Reserved
[0668] DP_GROUP_ID: This 8-bit field identifies a DP group with
which a current DP is associated. This may be used by the receiver
to access DPs of service components associated with a particular
service having the same DP_GROUP_ID.
[0669] BASE_DP_ID: This 6-bit field indicates a DP carrying service
signaling data (such as PSI/SI) used in a management layer. The DP
indicated by BASE_DP_ID may be either a normal DP carrying the
service signaling data along with service data or a dedicated DP
carrying only the service signaling data.
[0670] DP_FEC_TYPE: This 2-bit field indicates an FEC type used by
an associated DP. The FEC type is signaled according to the
following Table 8.
TABLE-US-00008 TABLE 8 Value FEC_TYPE 00 16K LDPC 01 64K LDPC 10 to
11 Reserved
[0671] DP_COD: This 4-bit field indicates a code rate used by an
associated DP. The code rate is signaled according to the following
Table 9.
TABLE-US-00009 TABLE 9 Value Code rate 0000 5/15 0001 6/15 0010
7/15 0011 8/15 0100 9/15 0101 10/15 0110 11/15 0111 12/15 1000
13/15 1001 to 1111 Reserved
[0672] DP_MOD: This 4-bit field indicates modulation used by an
associated DP. The modulation is signaled according to the
following Table 10.
TABLE-US-00010 TABLE 10 Value Modulation 0000 QPSK 0001 QAM-16 0010
NUQ-64 0011 NUQ-256 0100 NUQ-1024 0101 NUC-16 0110 NUC-64 0111
NUC-256 1000 NUC-1024 1001 to 1111 Reserved
[0673] DP_SSD_FLAG: This 1-bit field indicates whether an SSD mode
is used in an associated DP. If this field is set to a value of
`1`, SSD is used. If this field is set to a value of `0`, SSD is
not used.
[0674] The following field appears only if PHY_PROFILE is equal to
`010`, which indicates the advanced profile:
[0675] DP_MIMO: This 3-bit field indicates which type of MIMO
encoding process is applied to an associated DP. A type of MIMO
encoding process is signaled according to the following Table
11.
TABLE-US-00011 TABLE 11 Value MIMO encoding 000 FR-SM 001 FRFD-SM
010 to 111 Reserved
[0676] DP_TI_TYPE: This 1-bit field indicates a type of time
interleaving. A value of `0` indicates that one TI group
corresponds to one frame and contains one or more TI blocks. A
value of `1` indicates that one TI group is carried in more than
one frame and contains only one TI block.
[0677] DP_TI_LENGTH: The use of this 2-bit field (allowed values
are only 1, 2, 4, and 8) is determined by values set within the
DP_TI_TYPE field as follows.
[0678] If DP_TI_TYPE is set to a value of `1`, this field indicates
PI, the number of frames to which each TI group is mapped, and one
TI block is present per TI group (NTI=1). Allowed values of PI with
the 2-bit field are defined in Table 12 below.
[0679] If DP_TI_TYPE is set to a value of `0`, this field indicates
the number of TI blocks NTI per TI group, and one TI group is
present per frame (PI=1). Allowed values of PI with the 2-bit field
are defined in the following Table 12.
TABLE-US-00012 TABLE 12 2-bit field P.sub.1 N.sub.T1 00 1 1 01 2 7
10 4 3 11 8 4
[0680] DP_FRAME_INTERVAL: This 2-bit field indicates a frame
interval (IJUMP) within a frame group for an associated DP and
allowed values are 1, 2, 4, and 8 (the corresponding 2-bit field is
`00`, `01`, `10`, or `11`, respectively). For DPs that do not
appear every frame of the frame group, a value of this field is
equal to an interval between successive frames. For example, if a
DP appears on frames 1, 5, 9, 13, etc., this field is set to a
value of `4`. For DPs that appear in every frame, this field is set
to a value of `1`.
[0681] DP_TI_BYPASS: This 1-bit field determines availability of
the time interleaver 5050. If time interleaving is not used for a
DP, a value of this field is set to `1`. If time interleaving is
used, the value is set to `0`.
[0682] DP_FIRST_FRAME_IDX: This 5-bit field indicates an index of a
first frame of a superframe in which a current DP occurs. A value
of DP_FIRST_FRAME_IDX ranges from 0 to 31.
[0683] DP_NUM_BLOCK_MAX: This 10-bit field indicates a maximum
value of DP_NUM_BLOCKS for this DP. A value of this field has the
same range as DP_NUM_BLOCKS.
[0684] DP_PAYLOAD_TYPE: This 2-bit field indicates a type of
payload data carried by a given DP, DP_PAYLOAD_TYPE is signaled
according to the following Table 13.
TABLE-US-00013 TABLE 13 Value Payload type 00 TS 01 IP 10 GS 11
Reserved
[0685] DP_INBAND_MODE: This 2-bit field indicates whether a current
DP carries in-band signaling information. An in-band signaling type
is signaled according to the following Table 14.
TABLE-US-00014 TABLE 14 Value In-band mode 00 In-band signaling is
not carried. 01 INBAND-PLS is carried 10 INBAND-ISSY is carried 11
INBAND-PLS and INBAND-ISSY are carried
[0686] DP_PROTOCOL_TYPE: This 2-bit field indicates a protocol type
of a payload carried by a given DP. The protocol type is signaled
according to Table 15 below when input payload types are
selected.
TABLE-US-00015 TABLE 15 If If If DP_PAYLOAD_ DP_ PAYLOAD_ DP_
PAYLOAD_ TYPE TYPE TYPE Value is TS is IP is GS 00 MPEG2-TS IPv4
(Note) 01 Reserved IPv6 Reserved 10 Reserved Reserved Reserved 11
Reserved Reserved Reserved
[0687] DP_CRC_MODE: This 2-bit field indicates whether CRC encoding
is used in an input formatting block. A CRC mode is signaled
according to the following Table 16.
TABLE-US-00016 TABLE 16 Value CRC mode 00 Not used 01 CRC-8 10
CRC-16 11 CRC-32
[0688] DNP_MODE: This 2-bit field indicates a null-packet deletion
mode used by an associated DP when DP_PAYLOAD_TYPE is set to TS
(`00`). DNP_MODE is signaled according to Table 17 below. If
DP_PAYLOAD_TYPE is not TS (`00`), DNP_MODE is set to a value of
`00`.
TABLE-US-00017 TABLE 17 Value Null-packet deletion mode 00 Not used
01 DNP-NORMAL 10 DNP-OFFSET 11 Reserved
[0689] ISSY_MODE: This 2-bit field indicates an ISSY mode used by
an associated DP when DP_PAYLOAD_TYPE is set to TS (`00`).
ISSY_MODE is signaled according to Table 18 below. If
DP_PAYLOAD_TYPE is not TS (`00`), ISSY MODE is set to the value of
`00`.
TABLE-US-00018 TABLE 18 Value ISSY mode 00 Not used 01 ISSY-UP 10
ISSY-BBF 11 Reserved
[0690] HC_MODE_TS: This 2-bit field indicates a TS header
compression mode used by an associated DP when DP_PAYLOAD_TYPE is
set to TS (`00`). HC_MODE_TS is signaled according to the following
Table 19.
TABLE-US-00019 TABLE 19 Value Header compression mode 00 HC_MODE_TS
1 01 HC_MODE_TS 2 10 HC_MODE_TS 3 11 HC_MODE_TS 4
[0691] HC_MODE_IP: This 2-bit field indicates an IP header
compression mode when DP_PAYLOAD_TYPE is set to IP (`01`).
HC_MODE_IP is signaled according to the following Table 20.
TABLE-US-00020 TABLE 20 Value Header compression mode 00 No
compression 01 HC_MODE_IP 1 10 to 11 Reserved
[0692] PID: This 13-bit field indicates the PID number for TS
header compression when DP_PAYLOAD_TYPE is set to TS (`00`) and
HC_MODE_TS is set to `01` or `10`.
[0693] RESERVED: This 8-bit field is reserved for future use.
[0694] The following fields appear only if FIC_FLAG is equal to
`1`.
[0695] FIC_VERSION: This 8-bit field indicates the version number
of the FIC.
[0696] FIC_LENGTH_BYTE: This 13-bit field indicates the length, in
bytes, of the FIC.
[0697] RESERVED: This 8-bit field is reserved for future use.
[0698] The following fields appear only if AUX_FLAG is equal to
`1`.
[0699] NUM_AUX: This 4-bit field indicates the number of auxiliary
streams. Zero means no auxiliary stream is used.
[0700] AUX_CONFIG_RFU: This 8-bit field is reserved for future
use.
[0701] AUX_STREAM_TYPE: This 4-bit is reserved for future use for
indicating a type of a current auxiliary stream.
[0702] AUX_PRIVATE_CONFIG: This 28-bit field is reserved for future
use for signaling auxiliary streams.
[0703] FIG. 26 illustrates PLS2 data according to another
embodiment of the present invention.
[0704] FIG. 26 illustrates PLS2-DYN data of the PLS2 data. Values
of the PLS2-DYN data may change during the duration of one frame
group while sizes of fields remain constant.
[0705] Details of fields of the PLS2-DYN data are as below.
[0706] FRAME_INDEX: This 5-bit field indicates a frame index of a
current frame within a superframe. An index of a first frame of the
superframe is set to `0`.
[0707] PLS_CHANGE_COUNTER: This 4-bit field indicates the number of
superframes before a configuration changes. A next superframe with
changes in the configuration is indicated by a value signaled
within this field. If this field is set to a value of `0000`, it
means that no scheduled change is foreseen. For example, a value of
`1` indicates that there is a change in the next superframe.
[0708] FIC_CHANGE_COUNTER: This 4-bit field indicates the number of
superframes before a configuration (i.e., content of the FIC)
changes. A next superframe with changes in the configuration is
indicated by a value signaled within this field. If this field is
set to a value of `0000`, it means that no scheduled change is
foreseen. For example, a value of `0001` indicates that there is a
change in the next superframe.
[0709] RESERVED: This 16-bit field is reserved for future use.
[0710] The following fields appear in a loop over NUM_DP, which
describe parameters associated with a DP carried in a current
frame.
[0711] DP_ID: This 6-bit field uniquely indicates a DP within a PHY
profile.
[0712] DP_START: This 15-bit (or 13-bit) field indicates a start
position of the first of the DPs using a DPU addressing scheme. The
DP_START field has differing length according to the PHY profile
and FFT size as shown in the following Table 21.
TABLE-US-00021 TABLE 21 DP START field size PHY profile 64K 16K
Base 13 bits 15 bits Handheld -- 13 bits Advanced 13 bits 15
its
[0713] DP_NUM_BLOCK: This 10-bit field indicates the number of FEC
blocks in a current TI group for a current DP. A value of
DP_NUM_BLOCK ranges from 0 to 1023.
[0714] RESERVED: This 8-bit field is reserved for future use.
[0715] The following fields indicate FIC parameters associated with
the EAC.
[0716] EAC_FLAG: This 1-bit field indicates the presence of the EAC
in a current frame. This bit is the same value as EAC_FLAG in a
preamble.
[0717] EAS_WAKE_UP_VERSION_NUM: This 8-bit field indicates a
version number of a wake-up indication.
[0718] If the EAC_FLAG field is equal to `1` the following 12 bits
are allocated to EAC_LENGTH_BYTE. If the EAC_FLAG field is equal to
`0`, the following 12 bits are allocated to EAC_COUNTER.
[0719] EAC_LENGTH_BYTE: This 12-bit field indicates a length, in
bytes. of the EAC.
[0720] EAC_COUNTER: This 12-bit field indicates the number of
frames before a frame where the EAC arrives.
[0721] The following fields appear only if the AUX_FLAG field is
equal to `1`.
[0722] AUX_PRIVATE_DYN: This 48-bit field is reserved for future
use for signaling auxiliary streams. A meaning of this field
depends on a value of AUX_STREAM_TYPE in a configurable
PLS2-STAT.
[0723] CRC_32: A 32-bit error detection code, which is applied to
the entire PLS2.
[0724] FIG. 27 illustrates a logical structure of a frame according
to an embodiment of the present invention.
[0725] As above mentioned, the PLS, EAC, FIC, DPs, auxiliary
streams and dummy cells are mapped to the active carriers of OFDM
symbols in a frame. PLS1 and PLS2 are first mapped to one or more
FSSs. Thereafter, EAC cells, if any, are mapped to an immediately
following PLS field, followed next by FIC cells, if any. The DPs
are mapped next after the PLS or after the EAC or the FIC, if any.
Type 1 DPs are mapped first and Type 2 DPs are mapped next. Details
of types of the DPs will be described later. In some cases. DPs may
carry some special data for EAS or service signaling data. The
auxiliary streams or streams, if any, follow the DPs, which in turn
are followed by dummy cells. When the PLS, EAC, FIC, DPs, auxiliary
streams and dummy data cells are mapped all together in the above
mentioned order. i.e. the PLS, EAC, FIC, DPs, auxiliary streams and
dummy data cells, cell capacity in the frame is exactly filled.
[0726] FIG. 28 illustrates PLS mapping according to an embodiment
of the present invention.
[0727] PLS cells are mapped to active carriers of FSS(s). Depending
on the number of cells occupied by PLS, one or more symbols are
designated as FSS(s), and the number of FSS(s) NFSS is signaled by
NUM_FSS in PLS1. The FSS is a special symbol for carrying PLS
cells. Since robustness and latency are critical issues in the PLS,
the FSS(s) have higher pilot density, allowing fast synchronization
and frequency-only interpolation within the FSS.
[0728] PLS cells are mapped to active carriers of the FSS(s) in a
top-down manner as shown in the figure. PLS1 cells are mapped first
from a first cell of a first FSS in increasing order of cell index.
PLS2 cells follow immediately after a last cell of PLS1 and mapping
continues downward until a last cell index of the first FSS. If the
total number of required PLS cells exceeds the number of active
carriers of one FSS, mapping proceeds to a next FSS and continues
in exactly the same manner as the first FSS.
[0729] After PLS mapping is completed, DPs are carried next. If an
EAC, an FIC or both are present in a current frame, the EAC and the
FIC are placed between the PLS and "normal" DPs.
[0730] Hereinafter, description will be given of encoding an FEC
structure according to an embodiment of the present invention. As
above mentioned, the data FEC encoder may perform FEC encoding on
an input BBF to generate an FECBLOCK procedure using outer coding
(BCH), and inner coding (LDPC). The illustrated FEC structure
corresponds to the FECBLOCK. In addition, the FECBLOCK and the FEC
structure have same value corresponding to a length of an LDPC
codeword.
[0731] As described above, BCH encoding is applied to each BBF
(Kbch bits), and then LDPC encoding is applied to BCH-encoded BBF
(K.sub.ldpc bits=N.sub.bch bits).
[0732] A value of N.sub.ldpc is either 64,800 bits (long FECBLOCK)
or 16,200 bits (short FECBLOCK).
[0733] Table 22 and Table 23 below show FEC encoding parameters for
the long FECBLOCK and the short FECBLOCK. respectively.
TABLE-US-00022 TABLE 22 LDPC BCH error correction N.sub.bch- rate
N.sub.ldpc K.sub.ldpc K.sub.bch capability K.sub.bch 5/15 64800
21600 21408 12 192 6/15 25920 25728 7/15 30240 30048 8/15 34560
34368 9/15 38880 38688 10/15 43200 43008 11/15 47520 47328 12/15
51840 51648 13/15 56160 55968
TABLE-US-00023 TABLE 23 LDPC BCH error rate N.sub.ldpc K.sub.ldpc
K.sub.bch correction capability N.sub.bch-Kbch 5/15 16200 5400 5232
12 168 6/15 6480 6312 7/15 7560 7392 8/15 8640 8472 9/15 9720 9552
10/15 10800 10632 11/15 11880 11712 12/15 12960 12792 13/15 14040
13872
[0734] Detailed operations of BCH encoding and LDPC encoding are as
below.
[0735] A 12-error correcting BCH code is used for outer encoding of
the BBF. A BCH generator polynomial for the short FECBLOCK and the
long FECBLOCK are obtained by multiplying all polynomials
together.
[0736] LDPC code is used to encode an output of outer BCH encoding.
To generate a completed B.sub.ldpc (FECBLOCK), P.sub.ldpc (parity
bits) is encoded systematically from each I.sub.ldpc (BCH--encoded
BBF), and appended to I.sub.ldpc. The completed B.sub.ldpc
(FECBLOCK) is expressed by the following Equation.
B ldpc = [ I ldpc P ldpc ] = [ i 0 , i 1 , .times. .times. , i K
ldpc - 1 , p 0 , p 1 , .times. , p N ldpc - K ldpc - 1 ] [ Equation
.times. .times. 2 ] ##EQU00002##
[0737] Parameters for the long FECBLOCK and the short FECBLOCK are
given in the above Tables 22 and 23, respectively.
[0738] A detailed procedure to calculate N.sub.ldpc-K.sub.ldpc
parity bits for the long FECBLOCK. is as follows.
[0739] ) Initialize the parity bits
p 0 = p 1 = p 2 = = p N ldpc - K ldpc - 1 = 0 [ Equation .times.
.times. 3 ] ##EQU00003##
[0740] ) Accumulate a first information bit--i.sub.0, at a parity
bit address specified in a first row of addresses of a parity check
matrix. Details of the addresses of the parity check matrix will be
described later. For example, for the rate of 13/15,
p.sub.983=p.sub.983.sym.i.sub.0 p.sub.285=p.sub.281.sym.i.sub.0
p.sub.4837=p.sub.4873.sym.i.sub.0
p.sub.4989=p.sub.4989.sym.i.sub.0
p.sub.6138=p.sub.6138.sym.i.sub.0
p.sub.6458=p.sub.6458.sym.i.sub.0
p.sub.6921=p.sub.6921.sym.i.sub.0
p.sub.6974=p.sub.6974.sym.i.sub.0
p.sub.7572=p.sub.7572.sym.i.sub.0
p.sub.8260=p.sub.8260.sym.i.sub.0
p.sub.8496=p.sub.9496.sym.i.sub.0 [Equation 4]
[0741] 3) For the next 359 information bits, is, s=1, 2, . . . ,
359, accumulate is at parity bit addresses using following
Equation.
{x+(s mod 360).times.Q.sub.ldpc}mod(N.sub.ldpc-K.sub.ldpc)
[Equation 5]
[0742] Here, x denotes an address of a parity bit accumulator
corresponding to a first bit i.sub.0, and Q.sub.ldpc is a code rate
dependent constant specified in the addresses of the parity check
matrix. Continuing with the example, Q.sub.ldpc=24 for the rate of
13/15, so for an information bit i1, the following operations are
performed.
p.sub.1007=p.sub.1007.sym.i.sub.1
p.sub.2839=p.sub.2839.sym.i.sub.1
p.sub.4861=p.sub.4861.sym.i.sub.1
p.sub.5013=p.sub.5013.sym.i.sub.1
p.sub.6162=p.sub.6162.sym.i.sub.1
p.sub.6482=p.sub.6482.sym.i.sub.1
p.sub.6945=p.sub.6945.sym.i.sub.1
p.sub.6998=p.sub.6998.sym.i.sub.1
p.sub.7596=p.sub.7596.sym.i.sub.1
p.sub.8284=p.sub.8284.sym.i.sub.1
p.sub.8520=p.sub.8520.sym.i.sub.1 [Equation 6]
[0743] 4) For a 361th information bit i.sub.360, an address of the
parity bit accumulator is given in a second row of the addresses of
the parity check matrix. In a similar manner, addresses of the
parity bit accumulator for the following 359 information bits is,
s=361, 362, . . . , 719 are obtained using Equation 6, where x
denotes an address of the parity bit accumulator corresponding to
the information bit i.sub.360, i.e., an entry in the second row of
the addresses of the parity check matrix.
[0744] 5) In a similar manner, for every group of 360 new
information bits, a new row from the addresses of the parity check
matrix is used to find the address of the parity bit
accumulator.
[0745] After all of the information bits are exhausted, a final
parity bit is obtained as below.
[0746] 6) Sequentially perform the following operations starting
with i=1.
p i = p i .sym. p i - 1 , i = 1 , 2 , .times. , N ldpc - K ldpc - 1
[ Equation .times. .times. 7 ] ##EQU00004##
[0747] Here, final content of p.sub.i (i=0, 1, . . . ,
N.sub.ldpc-K.sub.ldpc-1) is equal to a parity bit p.sub.i.
TABLE-US-00024 TABLE 24 Code rate Q.sub.ldpc 5/15 120 6/15 108 7/15
96 8/15 84 9/15 72 10/15 60 11/15 48 12/15 36 13/15 24
[0748] This LDPC encoding procedure for the short FECBLOCK is in
accordance with t LDPC encoding procedure for the long FECBLOCK,
except that Table 24 is replaced with Table 25, and the addresses
of the parity check matrix for the long FECBLOCK are replaced with
the addresses of the parity check matrix for the short
FECBLOCK.
TABLE-US-00025 TABLE 51 Code rate Q.sub.ldpc 5/15 30 6/15 27 7/15
24 8/15 21 9/15 18 10/15 15 11/15 12 12/15 9 13/15 6
[0749] FIG. 29 illustrates time interleaving according to an
embodiment of the present invention.
[0750] (a) to (c) show examples of a TI mode.
[0751] A time interleaver operates at the DP level. Parameters of
time interleaving (TI) may be set differently for each DP.
[0752] The following parameters, which appear in part of the
PLS2-STAT data, configure the TI.
[0753] DP_TI_TYPE (allowed values: 0 or 1): This parameter
represents the TI mode. The value of `0` indicates a mode with
multiple TI blocks (more than one TI block) per TI group. In this
case, one TI group is directly mapped to one frame (no inter-frame
interleaving). The value of `1` indicates a mode with only one TI
block per TI group. In this case, the TI block may be spread over
more than one frame (inter-frame interleaving).
[0754] DP_TI_LENGTH: If DP_TI_TYPE=`0`, this parameter is the
number of TI blocks NTI per TI group. For DP_TI_TYPE=`1`, this
parameter is the number of frames PI spread from one TI group.
[0755] DP_NUM_BLOCK_MAX (allowed values: 0 to 1023): This parameter
represents the maximum number of XFECBLOCKs per TI group.
[0756] DP_FRAME_INTERVAL (allowed values: 1, 2, 4, and 8): This
parameter represents the number of the frames I.sub.JUMP between
two successive frames carrying the same DP of a given PHY
profile.
[0757] DP_TI_BYPASS (allowed values: 0 or 1): If time interleaving
is not used for a DP, this parameter is set to `1`. This parameter
is set to `0` if time interleaving is used.
[0758] Additionally, the parameter DP_NUM_BLOCK from the PLS2-DYN
data is used to represent the number of XFECBLOCKs carried by one
TI group of the DP.
[0759] When time interleaving is not used for a DP, the following
TI group, time interleaving operation, and TI mode are not
considered. However, the delay compensation block for the dynamic
configuration information from the scheduler may still be required.
In each DP, the XFECBLOCKs received from SSD/MIMO encoding are
grouped into TI groups. That is, each TI group is a set of an
integer number of XFECBLOCKs and contains a dynamically variable
number of XFECBLOCKs. The number of XFECBLOCKs in the TI group of
index n is denoted by N.sub.xBLOCK_Group(n) and is signaled as
DP_NUM_BLOCK in the PLS2-DYN data. Note that N.sub.xBLOCK_Group(n)
may vary from a minimum value of 0 to a maximum value of
N.sub.xBLOCK_Group_MAX (corresponding to DP_NUM_BLOCK_MAX), the
largest value of which is 1023.
[0760] Each TI group is either mapped directly to one frame or
spread over PI frames. Each TI group is also divided into more than
one TI block (N.sub.TI), where each TI block corresponds to one
usage of a time interleaver memory. The TI blocks within the TI
group may contain slightly different numbers of XFECBLOCKs. If the
TI group is divided into multiple TI blocks, the TI group is
directly mapped to only one frame. There are three options for time
interleaving (except an extra option of skipping time interleaving)
as shown in the following Table 26.
TABLE-US-00026 TABLE 26 Modes Descriptions Op- Each TI group
contains one TI block and is mapped directly to tion 1 one frame as
shown in (a). This option is signaled in PLS2-STAT by
DP_TI_TYPE=`0` and DP_TI_LENGTH = `1` (N.sub.T1=1). Op- Each TI
group contains one TI block and is mapped to more tion 2 than one
frame. (b) shows an example, where one TI group is mapped to two
frames, i.e., DP_TI_LENGTH =`2` (P.sub.1=2) and DP_FRAME_INTERVAL
(I.sub.JUMP = 2). This provides greater time diversity for low
data-rate services. This option is signaled in PLS2-STAT by
DP_TI_TYPE = `1`. Op- Each TI group is divided into multiple TI
blocks and is mapped tion 3 directly to one frame as shown in (c).
Each TI block may use a full TI memory so as to provide a maximum
bit-rate for a DP. This option is signaled in PLS2-STAT by
DP_TI_TYPE=`0` and DP_TI_LENGTH = N.sub.T1, while P.sub.1=1.
[0761] Typically, the time interleaver may also function as a
buffer for DP data prior to a process of frame building. This is
achieved by means of two memory banks for each DP. A first TI block
is written to a first bank. A second TI block is written to a
second bank while the first bank is being read from and so on.
[0762] The TI is a twisted row-column block interleaver. For an sth
TI block of an nth TI group, the number of rows N.sub.r of a TI
memory is equal to the number of cells Ncells, i.e.,
N.sub.r=N.sub.cells while the number of columns N.sub.c is equal to
the number N.sub.xBLOCK_TI(n,s).
[0763] FIG. 30 illustrates a basic operation of a twisted
row-column block interleaver according to an embodiment of the
present invention.
[0764] FIG. 30(a) shows a write operation in the time interleaver
and FIG. 30(b) shows a read operation in the time interleaver. A
first XFECBLOCK is written column-wise into a first column of a TI
memory, and a second XFECBLOCK is written into a next column, and
so on as shown in (a). Then, in an interleaving array, cells are
read diagonal-wise. During diagonal-wise reading from a first row
(rightwards along a row beginning with a left-most column) to a
last row, Nr cells are read out as shown in (b). In detail.
assuming Z.sub.n,s,i (i=0, . . . N.sub.rN.sub.c) as a TI memory
cell position to be read sequentially, a reading process in such an
interleaving array is performed by calculating a row index
R.sub.n,s,i, a column index C.sub.n,s,i, and an associated twisting
parameter T.sub.n,s,i as in the following Equation.
GENERATE .times. .times. ( R n , s , i , C n , s , i ) = .times. {
.times. R n , s , i = mod .function. ( i , N r ) , .times. T n , s
, i = mod .times. .times. ( S shift .times. R n , s , i , N c ) ,
.times. C n , s , i = mod .times. .times. ( T n , s , i + i N r , N
c ) .times. } [ Equation .times. .times. 8 ] ##EQU00005##
[0765] Here, S.sub.shift is a common shift value for a
diagonal-wise reading process regardless of N.sub.xBLOCK_TI(n,s),
and the shift value is determined by N.sub.xBLOCK_TI_MAX given in
PLS2-STAT as in the following Equation.
for .times. { N xBLOCK_TI .times. _MAX ' = N xBLOCK_TI .times. _MAX
+ 1 , if .times. .times. N xBLOCK_TI .times. _MAX .times. mod
.times. .times. 2 = 0 N xBLOCK_TI .times. _MAX ' = N xBLOCK_TI
.times. _MAX , if .times. .times. N xBLOCK_TI .times. _MAX .times.
mod .times. .times. 2 = 1 , .times. S shift = N xBLOCK_TI .times.
_MAX ' - 1 2 [ Equation .times. .times. 9 ] ##EQU00006##
[0766] As a result, cell positions to be read are calculated by
coordinates z.sub.n,s,i=N.sub.r,C.sub.n,s,i+R.sub.n,s,i.
[0767] FIG. 31 illustrates an operation of a twisted row-column
block interleaver according to another embodiment of the present
invention.
[0768] More specifically, FIG. 31 illustrates an interleaving array
in a TI memory for each TI group, including virtual XFECBLOCKs when
N.sub.xBLOCK_TI(0,0)=3, N.sub.xBLOCK_TI(1,0)=6, and
N.sub.xBLOCK_TI(2,0)=5.
[0769] A variable number N.sub.xBLOCK_TI(n,s)=N.sub.r may be less
than or equal to N'.sub.xBLOCK_TI_MAX. Thus, in order to achieve
single-memory deinterleaving at a receiver side regardless of
N.sub.xBLOCK_TI(n,s), the interleaving array for use in the twisted
row-column block interleaver is set to a size of
N.sub.r.times.N.sub.c=N.sub.cells.times.N'.sub.xBLOCK_TI_MAX by
inserting the virtual XFECBLOCKs into the TI memory and a reading
process is accomplished as in the following Equation.
p = 0 ; .times. .times. for .times. .times. i = 0 ; i < N cells
.times. N xBLOCK_TI .times. _MAX ' ; i = i + 1 .times. .times. {
GENERATE .times. .times. ( R n , s , i , C n , s , i ) ; .times. V
i = N r .times. C n , s , j + R n , s , j .times. .times. if
.times. .times. V i < N cells .times. N xBLOCK_TI .function. ( n
, s ) .times. .times. { .times. Z n , s , p = V i ; p = p + 1 ;
.times. } .times. } [ Equation .times. .times. 10 ]
##EQU00007##
[0770] The number of TI groups is set to 3. An option of the time
interleaver is signaled in the PLS2-STAT data by DP_TI_TYPE=`0`,
DP_FRAME_INTERVAL=`1`, and DP_TI_LENGTH=`1`, i.e., NTI=1, IJUMP=1,
and PI=1. The number of XFECBLOCKs, each of which has Ncells=30
cells, per TI group is signaled in the PLS2-DYN data by
NxBLOCK_TI(0,0)=3, NxBLOCK_TI(1,0)=6. and NxBLOCK_TI(2,0)=5,
respectively. A maximum number of XFECBLOCKs is signaled in the
PLS2-STAT data by NxBLOCK_Group_MAX, which leads to .left
brkt-bot.N.sub.xBLOCK_Group_MAX/N.sub.TI.right
brkt-bot.=N.sub.xBLOCK_TI_MAX=6.
[0771] The purpose of the Frequency Interleaver, which operates on
data corresponding to a single OFDM symbol. is to provide frequency
diversity by randomly interleaving data cells received from the
frame builder. In order to get maximum interleaving gain in a
single frame, a different interleaving-sequence is used for every
OFDM symbol pair comprised of two sequential OFDM symbols.
[0772] Therefore, the frequency interleaver according to the
present embodiment may include an interleaving address generator
for generating an interleaving address for applying corresponding
data to a symbol pair.
[0773] FIG. 32 illustrates an interleaving address generator
including a main pseudo-random binary sequence (PRBS) generator and
a sub-PRBS generator according to each FFT mode according to an
embodiment of the present invention.
[0774] (a) shows the block diagrams of the interleaving-address
generator for 8K FFT mode, (b) shows the block diagrams of the
interleaving-address generator for 16K FFT mode and (c) shows the
block diagrams of the interleaving-address generator for 32K FFT
mode.
[0775] The interleaving process for the OFDM symbol pair is
described as follows, exploiting a single interleaving-sequence.
First, available data cells (the output cells from the Cell Mapper)
to be interleaved in one OFDM symbol O.sub.m,l is defined as
O.sub.m,l=[x.sub.m,l,0, . . . , x.sub.m,l,p, . . .
x.sub.m,l,N.sub.data.sub.-1] for l=0, . . . ,N-1 where xm,l,p is
the pth cell of the lth OFDM symbol in the mth frame and N.sub.data
is the number of data cells: N.sub.data=C.sub.FSS for the frame
signaling symbol(s). N.sub.data=C.sub.data for the normal data, and
N.sub.data=C.sub.FES for the frame edge symbol. In addition, the
interleaved data cells are defined as
P m , l = [ v m , l , 0 , .times. , v m , l , N data - 1 ] .times.
.times. for .times. .times. l = 0 , .times. , N sym - 1.
##EQU00008##
[0776] For the OFDM symbol pair, the interleaved OFDM symbol pair
is given by v.sub.m,l,H.sub.i(p)=x.sub.m,l,p, p=0, . . .
,N.sub.data-1, for the first OFDM symbol of each pair
v.sub.m,l,p(p)=x.sub.m,l,H.sub.i.sub.(p), p=0, . . . ,N.sub.data-1,
for the second OFDM symbol of each pair, where H.sub.i(p) is the
interleaving address generated by a PRBS generator.
[0777] FIG. 33 illustrates a main PRBS used for all FFT modes
according to an embodiment of the present invention.
[0778] (a) illustrates the main PRBS, and (b) illustrates a
parameter Nmax for each FFT mode.
[0779] FIG. 34 illustrates a sub-PRBS used for FFT modes and an
interleaving address for frequency interleaving according to an
embodiment of the present invention.
[0780] (a) illustrates a sub-PRBS generator, and (b) illustrates an
interleaving address for frequency interleaving. A cyclic shift
value according to an embodiment of the present invention may be
referred to as a symbol offset.
[0781] FIG. 35 illustrates a write operation of a time interleaver
according to an embodiment of the present invention.
[0782] FIG. 35 illustrates a write operation for two TI groups.
[0783] A left block in the figure illustrates a TI memory address
array, and right blocks in the figure illustrate a write operation
when two virtual FEC blocks and one virtual FEC block are inserted
into heads of two contiguous TI groups, respectively.
[0784] Hereinafter, description will be given of a configuration of
a time interleaver and a time interleaving method using both a
convolutional interleaver (CI) and a block interleaver (BI) or
selectively using either the CI or the BI according to a physical
layer pipe (PLP) mode. A PLP according to an embodiment of the
present invention is a physical path corresponding to the same
concept as that of the above-described DP, and a name of the PLP
may be changed by a designer.
[0785] A PLP mode according to an embodiment of the present
invention may include a single PLP mode or a multi-PLP mode
according to the number of PLPs processed by a broadcast signal
transmitter or a broadcast signal transmission apparatus. The
single PLP mode corresponds to a case in which one PLP is processed
by the broadcast signal transmission apparatus. The single PLP mode
may be referred to as a single PLP.
[0786] The multi-PLP mode corresponds to a case in which one or
more PLPs are processed by the broadcast signal transmission
apparatus. The multi-PLP mode may be referred to as multiple
PLPs.
[0787] In the present invention, time interleaving in which
different time interleaving schemes are applied according to PLP
modes may be referred to as hybrid time interleaving. Hybrid time
interleaving according to an embodiment of the present invention is
applied for each PLP (or at each PLP level) in the multi-PLP
mode.
[0788] FIG. 36 illustrates an interleaving type applied according
to the number of PLPs in a table.
[0789] In a time interleaving according to an embodiment of the
present invention, an interleaving type may be determined based on
a value of PLP_NUM. PLP_NUM is a signaling field indicating a PLP
mode. When PLP_NUM has a value of 1, the PLP mode corresponds to a
single PLP. The single PLP according to the present embodiment may
be applied only to a CI.
[0790] When PLP_NUM has a value greater than 1, the PLP mode
corresponds to multiple PLPs. The multiple PLPs according to the
present embodiment may be applied to the CI and a BI. In this case,
the CI may perform inter-frame interleaving, and the BI may perform
intra-frame interleaving.
[0791] FIG. 37 is a block diagram including a first example of a
structure of a hybrid time interleaver described above.
[0792] The hybrid time interleaver according to the first example
may include a BI and a CI. The time interleaver of the present
invention may be positioned between a BICM chain block and a frame
builder.
[0793] The BICM chain block illustrated in FIGS. 37 and 38 may
include the blocks in the processing block 5000 of the BICM block
illustrated in FIG. 19 except for the time interleaver 5050. The
frame builder illustrated in FIGS. 37 and 38 may perform the same
function as that of the frame building block 1020 of FIG. 18.
[0794] As described in the foregoing, it is possible to determine
whether to apply the BI according to the first example of the
structure of the hybrid time interleaver depending on values of
PLP_NUM. That is, when PLP_NUM=1. the BI is not applied (BI is
turned OFF) and only the CI is applied. When PLP_NUM>1, both the
BI and the CI may be applied (BI is turned ON). A structure and an
operation of the CI applied when PLP_NUM>1 may be the same as or
similar to a structure and an operation of the CI applied when
PLP_NUM=1.
[0795] FIG. 38 is a block diagram including a second example of the
structure of the hybrid time interleaver described above.
[0796] An operation of each block included in the second example of
the structure of the hybrid time interleaver is the same as the
above description in FIG. 20. It is possible to determine whether
to apply a BI according to the second example of the structure of
the hybrid time interleaver depending on values of PLP_NUM. Each
block of the hybrid time interleaver according to the second
example may perform operations according to embodiments of the
present invention. In this instance, an applied structure and
operation of a CI may be different between a case of PLP_NUM=1 and
a case of PLP_NUM>1.
[0797] FIG. 39 is a block diagram including a first example of a
structure of a hybrid time deinterleaver.
[0798] The hybrid time deinterleaver according to the first example
may perform an operation corresponding to a reverse operation of
the hybrid time interleaver according to the first example
described above. Therefore, the hybrid time deinterleaver according
to the first example of FIG. 39 may include a convolutional
deinterleaver (CDI) and a block deinterleaver (BDI).
[0799] A structure and an operation of the CDI applied when
PLP_NUM>1 may be the same as or similar to a structure and an
operation of the CDI applied when PLP_NUM=1.
[0800] It is possible to determine whether to apply the BDI
according to the first example of the structure of the hybrid time
deinterleaver depending on values of PLP_NUM. That is, when
PLP_NUM=1, the BDI is not applied (BDI is turned OFF) and only the
CDI is applied.
[0801] The CDI of the hybrid time deinterleaver may perform
inter-frame deinterleaving, and the BDEI may perform intra-frame
deinterleaving. Details of inter-frame deinterleaving and
intra-frame deinterleaving are the same as the above
description.
[0802] A BICM decoding block illustrated in FIGS. 39 and 40 may
perform a reverse operation of the BICM chain block of FIGS. 37 and
38.
[0803] FIG. 40 is a block diagram including a second example of the
structure of the hybrid time deinterleaver.
[0804] The hybrid time deinterleaver according to the second
example may perform an operation corresponding to a reverse
operation of the hybrid time interleaver according to the second
example described above. An operation of each block included in the
second example of the structure of the hybrid time deinterleaver
may be the same as the above description in FIG. 39.
[0805] It is possible to determine whether to apply a BDI according
to the second example of the structure of the hybrid time
deinterleaver depending on values of PLP_NUM. Each block of the
hybrid time deinterleaver according to the second example may
perform operations according to embodiments of the present
invention. In this instance, an applied structure and operation of
a CDI may be different between a case of PLP_NUM=1 and a case of
PLP_NUM>1.
[0806] FIG. 41 is a diagram illustrating a protocol stack for
supporting a hybrid-based next-generation broadcast service
according to an embodiment of the present invention.
[0807] In a broadcast transmitter, a data link (encapsulation)
layer delivers an MPEG-2 TS and/or IP packet, which is delivered
from an upper layer, to a physical layer. Further, signalling
information necessary for an operation of the physical layer may be
delivered.
[0808] The data link layer may be referred to by various terms such
as encapsulation layer, link layer, Layer 2, etc.
[0809] A broadcast system according to the present invention may
correspond to a hybrid broadcast system in which an IP centric
broadcast network is combined with broadband. In addition, the
broadcast system according to the present invention may be designed
to be compatible with an existing MPEG-2 based broadcast
system.
[0810] The broadcast system according to the present invention may
correspond to a hybrid broadcast system based on a combination of
an IP centric broadcast network, a broadband network, and/or a
mobile communication network (or cellular network).
[0811] Further, the physical layer may use a physical protocol
employed in a broadcast system such as an ATSC system and/or a DVB
system.
[0812] In a broadcast receiver, a link layer acquires an IP
datagram from information which is acquired from a physical layer,
or converts the acquired IP datagram into a particular frame (for
example, RS frame, GSE-lite, GSE, or signal frame). Here, a frame
may include a set of IP datagrams.
[0813] A broadcast service according to an embodiment of the
present invention may provide an additional service such as an
HTML5 application, an interactive service, an ACR service, a second
screen service, a personalization service, etc. in addition to
audio/video (A/V) data. Further, an emergency alert service may be
provided as the broadcast service.
[0814] The broadcast service may be received by the broadcast
receiver through a broadcast network such as a terrestrial
broadcast network, a cable satellite, etc., that is, a physical
layer. In addition, the broadcast service according to the present
embodiment may be received through a broadband network.
[0815] MPEG2 TS encapsulation may acquire an MPEG2 TS using
information acquired from the physical layer. An FIC corresponds to
signaling information, which is also referred to as an FIT or an
SLT, and may include information necessary to acquire a service
and/or content, and/or information necessary to scan a channel.
[0816] The broadcast receiver may extract a UDP datagram from the
acquired IP datagram, and extract signaling information from the
extracted UDP datagram. In this instance, the signaling information
may have an XML form. In addition, the broadcast receiver may
extract an asynchronous layered coding/layered coding transport
(ALC/LCT) packet from the extracted UDP datagram. Further, the
broadcast receiver may extract a file delivery over unidirectional
transport (FLUTE) packet from the ALC/LCT packet. In this instance,
the FLUTE packet may include real-time audio/video/captioning data,
NRT data, and ESG data. Furthermore, the broadcast receiver may
extract a real-time transport protocol (RTP) packet and an RTP
control protocol (RTCP) packet from the extracted UDP datagram. In
addition, the broadcast receiver may extract A/V data and
additional data from a real-time transport packet such as the
extracted RTP/RTCP packet. In this instance, at least one of the
NRT data. the A/V data, and the additional data may have the form
of an ISO base media file format (ISO BMFF). In addition, the
broadcast receiver may extract signaling information such as NRT
data, A/V data, and PSI/PSIP from the MPEG-2 TS packet or the IP
packet. In this instance, the signaling information may have the
XML or binary form, and may include information for supporting
effective acquisition of a service and/or content.
[0817] Meanwhile, when the broadcast service is transmitted through
the broadband network. the broadcast receiver may receive an IP
packet from the broadband network. The broadcast receiver may
extract a TCP packet from the IP packet. Further, the broadcast
receiver may extract an HTTP packet from the extracted TCP packet,
and extract A/V data, additional data, signaling information, etc.
from the extracted HTTP packet. In this instance, at least one of
the A/V data and the additional data may have an ISO BMFF form. In
addition, the signaling information may have an XML form.
[0818] The broadcast receiver may combine data received through the
above-described protocol stack to provide a viewer with various
enhanced services such as an interactive service, a second screen
service, an emergency alert service, etc.
[0819] FIG. 42 illustrates another example of the protocol stack
for supporting the broadcast service according to the present
invention.
[0820] In FIG. 42, the broadcast service may be provided in an
application form. In FIG. 42, the broadcast service may be
transmitted through a broadcast network such as a terrestrial
broadcast network, a cable satellite, etc., that is, a physical
layer, and may be transmitted through a broadband network.
[0821] When the broadcast service is received through the physical
layer of the broadcast network, the broadcast receiver may acquire
an IP datagram using information acquired from the physical layer.
In addition, the broadcast receiver may extract a UDP datagram from
the acquired IP datagram, and extract at least one of MMTP
sessions, ROUTE sessions, and signaling information (for example,
FIT, MMT specific signaling, and ROUTE specific signaling) from the
extracted UDP datagram. Further, the broadcast receiver provides
the broadcast service by decoding MPUs received through the MMTP
sessions based on the extracted signaling information or by
decoding MPEG-DASH segments received through the ROUTE session.
[0822] Meanwhile, when the broadcast service is transmitted through
the broadband network, the broadcast receiver may receive an IP
packet from the broadband network. The broadcast receiver may
extract a TCP packet from the IP packet. In addition, the broadcast
receiver may extract an HTTP packet from the extracted TCP packet,
and provide the broadcast service by decoding an MPEG-DASH segment
transmitted through the extracted HTTP packet or provide an NRT
service by processing NRT files. In other words, in the case of the
broadband network, data encapsulated in the ISO BMFF form may be
delivered to a receiving side based on a streaming scheme. For
example, the streaming scheme may include MPEG-DASH.
[0823] In this instance, video data, audio data, captioning data,
etc. in data for the broadcast service may be encapsulated in the
ISO BMFF form. For example, the data encapsulated in the ISO BMFF
form may conform to a form such as a segment of MPEG-DASH or an MPU
of MMTP.
[0824] Here, ROUTE is a protocol for transmission of files through
IP multicast networks. The ROUTE protocol uses ALC and LCT
corresponding to base protocols designed for massively scalable
multicast distribution, and other well-known Internet standards.
ROUTE is an improved version or functional substitute having
additional characteristics when compared to FLUTE. ROUTE may
transmit signaling messages, ESG messages, and NRT content. In
particular, ROUTE is suitable for transmission of streaming media
such as MPEG-DASH media segment files. When compared to FLUTE,
ROUTE provides lower end-to-end latency through a delivery chain.
In addition, ROUTE provides an easy MPEG-DASH combination. The
MPEG-DASH combination allows synergy between broadcast and
broadband delivery modes.
[0825] One ROUTE session may include at least one LCT transport
session. LCT transport sessions may be a subset of the ROUTE
session. For media delivery, one LCT transport session may
typically transmit one media component (for example, DASH
representation). From the viewpoint of broadcast DASH, the ROUTE
session may be regarded as a complex of the LCT transport session
transmitting at least one media component corresponding to a
component of at least one DASH media representation. At least one
relevant object may be transmitted in each LCT transport session.
For example, objects may be DASH segments related to one
representation. Together with each object, metadata properties may
be delivered such that the objects can be used in applications. The
applications may include DASH media presentations, HTML-5
presentations, or other object-consuming applications, and are not
restricted thereto.
[0826] The ROUTE sessions may or may not be bounded in a temporal
sense (The ROUTE sessions may be bounded or unbounded from the
temporal perspective). The ROUTE session may include at least one
LCT transport session. Each transport session is uniquely
identified by a unique TSI present in an LCT header.
[0827] In addition, a representation of MPEG-DASH has a concept
corresponding to an MMTP packet flow in the MMT protocol, and may
be mapped to an asset identifier (or asset ID, asset_id). Further,
a segment of MPEG-DASH has a concept corresponding to an MPU in the
MMT protocol, and may be mapped to information (or an MPU
identifier) included in an mmpu box.
[0828] Signaling data (also referred to as signaling information)
such as an FIT, MMT specific signaling, ROUTE specific signaling,
etc. may be transmitted using a scheme below.
[0829] In the case of a broadcast network, the signaling data may
be transmitted through a particular physical layer pipe, etc.
corresponding to a particular data pipe of a physical layer frame
(or frame) delivered to a physical layer of the broadcast network
and a next-generation broadcast transmission system according to
attributes of signaling. For example, signaling may be encapsulated
in a bit stream or IP/UDP datagram. In the case of a broadband
network, signaling data may be returned and delivered in response
to a request from a receiver.
[0830] The FIT corresponds to low level signaling, and may be
referred to as an FIC or an SLT. The broadcast receiver builds a
basic service list based on the FIT, and allows bootstrapping of
discovery of service layer signaling for each service. The FIT (or
SLT) may be transmitted through link layer signaling.
Alternatively, the FIT (or SLT) may be transmitted in each physical
layer frame for rapid acquisition. According to a given embodiment,
the FIT (or SLT) may be transmitted through at least one of a
physical layer pipe that transmits a physical layer frame and a
signal and/or a physical layer pipe that transmits data to be
actually serviced. Hereinafter, a description will be focused on
the FIT.
[0831] SLS such as MMT specific signaling or ROUTE specific
signaling enables the receiver to discover and access at least one
service and/or at least one content component. When the SLS is
transmitted through the broadcast network, the SLS may be
transmitted in at least one LCT session included in a ROUTE session
by ROUTE/UDP/IP. In this instance, the SLS may be transmitted at a
suitable carousel rate that supports rapid channel joining and
switching. When the SLS is transmitted through the broadband
network, the SLS may be transmitted by HTTP(S)/TCP/IP.
[0832] ESG data and NRT content data may be transmitted using a
scheme below.
[0833] In the case of the broadcast network, the ESG data and NRT
content data may be encapsulated in an application layer transport
protocol packet. Then, the data encapsulated in the application
layer transport protocol packet may be similarly transmitted as
described above.
[0834] In the case of the broadband network, the ESG data and NRT
content data may be returned and delivered in response to a request
from the receiver.
[0835] A relation between a ROUTE/LCT session and/or an MMTP
session for transmitting at least one content component of a
service is as below.
[0836] For broadcast delivery of a linear service without app-based
enhancement, a content component of the service may be transmitted
through 1) at least one ROUTE/LCT session and/or 2) at least one
MMTP session.
[0837] For broadcast delivery of a linear service with app-based
enhancement, a content component of the service may be transmitted
only through 1) at least one ROUTE/LCT session. Alternatively, the
content component of the service may be transmitted through at
least one ROUTE/LCT session and/or at least one MMPT session.
[0838] For broadcast delivery of an app-based service, a content
component of the service may be transmitted through at least one
ROUTE/LCT session.
[0839] Each ROUTE session may include at least one LCT session.
Each LCT session may include all or some content components
included in the service.
[0840] In transmission of streaming services, the LCT session may
transmit a separate component of a user service such as an audio,
video, and/or closed caption stream. Streaming media may be
formatted in at least one DASH segment by MPEG-DASH.
[0841] Each MMTP session may include at least one MMTP packet flow.
Each MMTP packet flow may transmit an MMT signaling message. In
addition, each MMTP packet flow may include some or all content
components included in the service.
[0842] The MMTP packet flow may transmit at least one content
component formatted in at least one MPU by an MMT signaling message
and/or an MMT.
[0843] For transmission of an NRT user service and/or system
metadata, the LCT session may transmit at least one file-based
content item. The at least one file-based content item may include
a time-based or non-time-based media component of the NRT service.
In addition, the at least one file-based content item may include
service signaling and/or an ESG fragment.
[0844] A broadcast stream may be an abstract concept of an RF
channel. The RF channel may be defined based on a carrier frequency
within a particular bandwidth. The RF channel may be defined by a
pair of [geographic area, frequency]. Information about the
geographic area and the frequency may be defined and/or maintained
by administrative authorities together with a BSID. A PLP (or DP)
may correspond to a portion of the RF channel.
[0845] Each PLP (or DP) may include at least one modulation and/or
coding parameter. The PLP (or DP) may be identified by a PLP (or
DP) identifier (PLPID or DPID) having a unique value within a
broadcast stream to which the PLP (or DP) belongs.
[0846] Each service may be identified by two types of service IDs.
One type corresponds to a compressed form, which is used in an FIT
and has a unique value only within a broadcast area. The other type
corresponds to a globally unique form used in SLS and/or ESG.
[0847] A ROUTE session may be identified by a source IP address, a
destination IP address. and/or a destination port number. An LCT
session may be identified by a unique TSI within a parent ROUTE
session.
[0848] An S-TSID may include information about common
characteristics of at least one LCT session and/or a unique
characteristic of at least one individual LCT session. The S-TSID
may be a ROUTE signaling structure, and may be a part of service
level signaling.
[0849] Each LCT session may be transmitted through one PLP (or DP).
Different LCT sessions within one ROUTE session may be included in
different PLPs (DPs) or the same PLP (or DP).
[0850] At least one characteristic described in the S-TSID may
include a TSI and a PLPID (or DPID) for each LCT session, at least
one descriptor for at least one delivery object or file, and/or at
least one application layer FEC parameter.
[0851] An MMT session may be identified by a source IP address, a
destination IP address, and/or a destination port number. An MMTP
packet flow may be identified by a unique packet_id within a range
of a parent MMTP session.
[0852] An S-TSID may include information about a common
characteristic of each MMTP packet flow and/or a unique
characteristic of at least one individual MMTP packet flow.
[0853] At least one characteristic of each MMTP session may be
transmitted by an MMT signaling message which is transmitted within
the MMTP session.
[0854] Each MMTP packet flow may be transmitted through one PLP (or
DP). Different MMTP packet flows within one MMTP session may be
included in different PLPs (DPs) or included in the same PLP (or
DP).
[0855] At least one characteristic described in an MMT signaling
message may include a packet_id and/or a PLPID (or DPID) of each
MMTP packet flow.
[0856] FIG. 43 illustrates a configuration of a media content
transmission/reception system through an IP network, that is, a
broadband network according to an embodiment of the invention.
[0857] Transmission/reception of media content according to an
embodiment of the present invention is divided into
transmission/reception of a transmission packet including actual
media content and transmission/reception of media content
reproduction information. A broadcast receiver 55 receives the
media content reproduction information, and receives the
transmission packet including the media content. In this instance,
the media content reproduction information indicates information
necessary to reproduce media content. The media content
reproduction information may include at least one of spatial
information and temporal information necessary to reproduce media
content. The broadcast receiver 55 reproduces media content based
on the media content reproduction information.
[0858] For example, media content may be transmitted and received
through an IP network according to an MPEG-DASH standard. In this
case, a content server 50 transmits MPD including the media content
reproduction information. However, according to a specific
embodiment, the MPD may be transmitted by an external server rather
than the content server 50. In addition, the content server 50
transmits a segment including media content based on a request from
the broadcast receiver 55. The broadcast receiver 55 receives the
MPD. The broadcast receiver 55 requests that the content server
transmit media content based on the MPD. The broadcast receiver 55
receives a transmission packet including media content based on a
request. The broadcast receiver 55 reproduces the media content
based on the MPD. To this end, the broadcast receiver 55 may
include a DASH client. The DASH client may include an MPD parser
that parses the MPD, a segment parser that parses a segment, an
HTTP client that transmits an HTTP request message and receives an
HTTP response message through an IP transceiver (not illustrated),
and a media engine that reproduces media.
[0859] As another embodiment, media content may be transmitted and
received through the IP network according to an MMT standard. In
this instance, the content server 50 transmits a reproduction
information document (presentation information document, PI
document) including media content reproduction information. In
addition, the content server 50 transmits an MMTP packet including
media content based on a request from the broadcast receiver 55.
The broadcast receiver 55 receives the PI document. The broadcast
receiver 55 receives a transmission packet including media content.
The broadcast receiver 55 extracts media content from the
transmission packet including the media content. The broadcast
receiver 55 reproduces the media content based on the PI
document.
[0860] Meanwhile, the broadcast receiver may receive emergency
information related to a natural disaster, a terrorist attack, a
war, etc. through the broadcast network. In addition, the broadcast
receiver may report the information to a user. In this way, many
people may rapidly and efficiently detect a national disaster
situation. However, the user may not detect an emergency alert
unless the user continuously monitors the broadcast receiver. Even
when the user does not continuously monitor the broadcast receiver,
the user is likely to carry a linkage device such as a mobile
phone, a tablet PC, etc. at all times. Therefore, when the
broadcast receiver can transmit an emergency alert to the linkage
device, and the linkage device can display the emergency alert, the
national disaster situation may be rapidly and efficiently reported
to the user.
[0861] In the broadcast transmitter, an emergency alert message may
be generated in the form of a section table or a packet in a link
layer, and then transmitted to a physical layer. Alternatively. the
emergency alert message may be directly input to the physical layer
without passing through the link layer. In the physical layer, the
emergency alert message may be assigned to a physical layer pipe
symbol, i.e. a data pipe symbol within the frame, and transmitted.
Here, a physical layer pipe may be a data pipe that transmits
signaling information. a data pipe that transmits actual data, or a
general data pipe, use of which is not designated. Alternatively,
as described in the foregoing, in the physical layer, the emergency
alert message may be assigned to between a PLS symbol and a data
pipe symbol within the frame, and transmitted. In addition,
emergency alert-related signaling information may be transmitted
through a physical layer parameter symbol within the frame, or may
be included in a transmission parameter of the physical layer as
described above and transmitted through a preamble symbol or a PLS
symbol. The emergency alert-related signaling information
transmitted through the preamble symbol or the PLS symbol may be
signaled to at least one of an EAC_FLAG field, an
EAS_WAKE_UP_VERSION_NUM field, an EAC_LENGTH_BYTE field, an
EAC_COUNTER field, and an EA_WAKE_UP field. In this instance, it is
possible to refer to or not refer to information provided in the
link layer or the upper layer. Details of each field have been
described above, and are omitted here.
[0862] Next, a description will be given of examples of
transmitting and receiving an emergency alert message by the
broadcast transmitter and the broadcast receiver according to the
invention. In particular, signaling information for receiving and
decoding an emergency alert message is needed when the broadcast
receiver receives the emergency alert message and provides an
emergency alert service to the user, and the present invention
describes a method of signaling the emergency alert message.
[0863] FIG. 44 is a block diagram of an emergency alert system
according to an embodiment of the present invention, and the
emergency alert system includes a broadcast transmitter 72 for
transmitting an emergency alert message, and a broadcast receiver
70 for receiving and processing the emergency alert message
transmitted from the broadcast transmitter 72. In addition, the
emergency alert system may further include alert authorities 76 and
an information aggregator 74.
[0864] In this instance, the emergency alert message refers to a
message obtained by converting emergency alert information for
reporting an emergency state to a broadcast viewer in a form which
is transmissible through the broadcast network. Delivery of
emergency alert, normally emergency alert information, is normally
led and operated by a government, and thus a specific structure may
vary according to nation to which a broadcast system is applied.
Therefore, in the present embodiment, a description will be given
of a method of configuring an emergency alert message and a method
and apparatus for transmitting/receiving the emergency alert
message which are commonly applicable to a method of transmitting
emergency alert information through the broadcast network.
[0865] The alert authorities 76 may include a nation or an
institution of a corresponding region. When transmission of
emergency alert information needs to be delivered through the
broadcast network, the alert authorities 76 generate an emergency
alert and deliver the emergency alert to the information aggregator
74 (or institution). In this instance, the information aggregator
74 may be an integrated public alert warning system (IPAWS)
aggregator.
[0866] The information aggregator 74 configures the emergency alert
information to be delivered through the broadcast network as a
common alerting protocol (CAP)-based message, and delivers the
information to the broadcast transmitter 72. Here, the CAP
corresponds to an XML file format for warning against an emergency
state and exchanging information. The CAP may simultaneously
propagate an emergency alert message through a plurality of
emergency alert systems.
[0867] Hereinafter, a description will be focused on a process
after the CAP message is delivered to the broadcast transmitter
72.
[0868] In response to the CAP message delivered to the broadcast
transmitter 72, the broadcast transmitter 72, which processes the
message, transmits related A/V content and an additional service
together with the CAP message. Specifically, the broadcast
transmitter 72 inserts the related A/V content or the additional
service together with the CAP message into a broadcast signal, and
transmits the broadcast signal to the broadcast receiver 70.
According to a given embodiment, emergency alert-related data
including the CAP message may be transmitted through different
routes according to purpose and form. As a specific example, a
different route may correspond to one of a signaling channel, a
physical layer pipe, and a broadband network.
[0869] The broadcast receiver 70 receives the broadcast signal
including the emergency alert-related data from the broadcast
transmitter 72. Then, the broadcast receiver 70 decodes the
broadcast signal received through an emergency alert signaling
decoder. The broadcast receiver 70 receives an A/V service
according to information acquired by decoding the broadcast signal.
Specifically, the broadcast receiver 70 may acquire physical layer
frame information including the A/V service from the broadcast
signal. In this instance, a physical layer frame may correspond to
a unit of data transmitted through a physical layer pipe. In
addition, the broadcast receiver 70 may receive A/V service data
related to an emergency alert message from the physical layer
frame.
[0870] Further, the broadcast receiver 70 may extract NRT service
information related to an emergency alert from the information
acquired by decoding the broadcast signal. Specifically, the NRT
service information may be address information that allows an NRT
service to be acquired. For example, the NRT service may be
delivered via broadband, and the address information may be URI
information for acquiring the NRT service.
[0871] According to an embodiment of the present invention, the
broadcast transmitter 72 may transmit an emergency alert message
through a protocol layer included in a protocol stack. In this
case, the protocol layer may be a link layer. According to an
embodiment, the broadcast transmitter 72 may format the emergency
alert message in the form of a table according to a transport
protocol. In this instance, the emergency alert message may be
formatted in the form of a table in the link layer included in the
protocol stack. In addition, the emergency alert message may
include information that signals link layer and physical layer
operations.
[0872] According to another embodiment, the broadcast transmitter
72 may packetize the emergency alert message according to the
transport protocol. Specifically, the broadcast transmitter 72 may
encapsulate the emergency alert message in the physical layer
frame. In this case, emergency alert information may be prevented
from being signaled to the broadcast receiver 70 through several
layers.
[0873] For transmission, the emergency alert message needs to be
configured in a form that can be transmitted in the broadcast
system. To this end, in an embodiment, a table in the form of a
section may be generally used to transmit the emergency alert
message. In another embodiment, the emergency alert message may be
transmitted as a part of another section table in a configuration
of a descriptor form. In still another embodiment, the emergency
alert message may be transmitted in a packet of a physical layer.
Specifically, the emergency alert message may be transmitted in the
form of a packet through a data pipe corresponding to a physical
layer pipe. In this case, the emergency alert message may be
included in a payload. which is included in a packet, and
transmitted.
[0874] FIG. 45 illustrates syntax of EAT information according to
an embodiment of the present invention. In this instance, an EAT
may have a form of an emergency alert message. In an embodiment,
when the emergency alert message (also referred to as an EAS
message) is transmitted in a payload of a packet, EAT information
corresponding to signaling information of the emergency alert
message may be included in a header of the packet. In another
embodiment, the EAT information may be included in an extended
header.
[0875] As illustrated in FIG. 45, the EAT information may include
version information of a protocol included in an EAT. In a specific
example, the information may be an EAT_protocol_version field.
[0876] In addition, the EAT information may include information
that reports whether to automatically tune to a channel to the
broadcast receiver 70. For example, the EAT information may include
information that reports whether to automatically tune to a channel
on which specific information about an emergency alert is reported
to the broadcast receiver 70. In a specific example, the
information that reports whether to automatically tune to a channel
may be an automatic_tuning_flag field.
[0877] In addition, the EAT information may include information
about the number of messages included in the EAT. In a specific
example, the information about the number of messages may be a
num_EAS_message field.
[0878] FIG. 46 illustrates syntax of an emergency alert message
according to an embodiment of the present invention. In an
embodiment of the present invention, the emergency alert message
may directly include a CAP message. In another embodiment, the
emergency alert message may include information about a route
through which the CAP message is delivered. In addition, the
emergency alert message may be included in an EAT and
transmitted.
[0879] As illustrated in FIG. 46, the emergency alert message
according to the present embodiment may include identifier
information for identifying an EAS message. In a specific
embodiment, the identifier information may be an EAS_message_id
field. In this case, the EAS_message_id field may correspond to 32
bits.
[0880] In addition, syntax for the emergency alert message may
include information that indicates an IP version. In this case, the
version information may be an EAS_IP_version_flag field. In a
specific embodiment, when the EAS_IP_version_flag field has a value
of 0, the value may indicate that an IP version is IPv4. In another
embodiment, when the EAS_IP_version flag field has a value of 1,
the value may indicate that an IP version is IPv6. The
EAS_IP_version flag field may correspond to 1 bit.
[0881] Further, the emergency alert message may include information
that indicates a delivery form of the EAS message. In this case,
the information that indicates a delivery form of the EAS message
may be an EAS_message_transfer_type field. The EAS_message_transfer
type field may correspond to 3 bits.
[0882] In a specific embodiment, the EAS_message_transfer_type
field may indicate that a delivery form of the emergency alert
message, that is, the EAS message, has not been specified. In this
case, the EAS_message_transfer_type field may have a value of
000(2).
[0883] In another embodiment, the EAS_message_transfer_type field
may indicate that a delivery form of the EAS message is a form not
including the emergency alert message. In other words, the field
may indicate that the EAT transmitted through a broadcast signal
only includes information about A/V content without the emergency
alert message. In this case, the EAS_message_transfer type field
may have a value of 001(2).
[0884] In another embodiment, the EAS_message_transfer_type field
may indicate that the EAS message is included in the EAT and
delivered. In this case, the EAS_message_transfer type field may
have a value of 010(2).
[0885] Further, when the EAS_message_transfer_type field has the
value of 010(2), a table including the EAS message may indicate a
length of the EAS message. In this case, information indicating the
length of the EAS message may be an EAS_message_length field. The
EAS_message_length field may correspond to 12 bits. In addition,
when the EAS_message_transfer_type field has the value of 010(2),
the table including the EAS message may additionally include
information about the EAS message.
[0886] In another embodiment, the EAS_message_transfer_type field
may indicate that the EAS message is transmitted through a data
pipe corresponding to a physical layer pipe in the form of an IP
datagram. In this case, the EAS_message_transfer type field may
have a value of 011(2). Further, when the EAS_message_transfer type
field has the value of 011(2), the table including the emergency
alert message may additionally include one of IP address
information for acquiring an IP datagram, UDP port information, and
information about a transmitted physical layer frame.
[0887] In addition, the emergency alert message may include
information that indicates an encoding type of the EAS message. In
this case, the information about the encoding type of the EAS
message may be an EAS_message_encoding_type field. The
EAS_message_encoding_type field may correspond to 3 bits.
[0888] In a specific embodiment, the EAS_message_encoding_type
field may indicate that the encoding type of the EAS message has
not been specified. In this case, the EAS_message_encoding_type
field may have a value of 000(2).
[0889] In another embodiment, the EAS_message_encoding_type field
may indicate that the EAS message has not be encoded. In this case,
the EAS_message_encoding_type field may have a value of 001(2).
[0890] In another embodiment, the EAS_message_encoding_type field
may indicate that the EAS message has been encoded by a DEFLATE
algorithm. The DEFLATE algorithm is a lossless compression data
format. In this case, the EAS_message_encoding_type field may have
a value of 010(2).
[0891] In addition, the emergency alert message may indicate
whether information about NRT content and additional data related
to the received EAS message is included in the emergency alert
table. In this case, information indicating whether the NRT content
and the additional data are present may be an EAS_NRT_flag field.
The EAS_NRT_flag field may correspond to 1 bit.
[0892] In a specific embodiment, when the EAS_NRT_flag field is set
to 0, the field indicates that the information about the NRT
content related to the received EAS message is not included in the
emergency alert table. In another embodiment, when the EAS_NRT_flag
field is set to 1, the field indicates that the information about
the NRT content related to the received EAS message is included in
the table.
[0893] FIG. 47 illustrates syntax for automatic channel tuning
information according to an embodiment of the present invention.
When A/V content related to an emergency alert is transmitted
simultaneously with the emergency alert message, the automatic
channel tuning information includes information for automatically
tuning to a channel on which the AN content related to the
emergency alert is transmitted. In other words, when a channel
currently displayed in the broadcast receiver 70 does not include
content that includes the emergency alert message, the automatic
channel tuning information is information for automatically tuning
to the channel on which the A/V content related to the emergency
alert is transmitted. In a specific embodiment, the emergency alert
table may include the automatic channel tuning information when the
automatic_tuning_flag field of FIG. 45 is enabled. For example,
when the automatic_tuning_flag field has a value of 1, the
emergency alert table may include the automatic channel tuning
information.
[0894] In an embodiment, a table for the automatic channel tuning
information may indicate information about a number of a channel to
be tuned to. Specifically, the table may indicate information about
a channel including content related to the emergency alert
information. In this case, the information about the number of the
channel to be tuned to may be an automatic_tuning_channel_number
field. In a specific embodiment, the
automatic_tuning_channel_number field may correspond to 8 bits.
[0895] In another embodiment, the table for the automatic channel
tuning information may indicate route information for receiving
content related to the emergency alert message. Specifically, the
table for the automatic channel tuning information may indicate
information for identifying a physical layer frame including the
A/V content related to the emergency alert message. In this case,
the information may be an automatic_tuning_DP_id field. The
automatic_tuning_DP_id field may correspond to 8 bits.
[0896] In another embodiment, the table for the automatic channel
tuning information may indicate identification information of
content related to the emergency alert message. Specifically. the
table may indicate service ID information of content related to the
emergency alert message. In this case, the information may be an
automatic_tuning_service_id field. The automatic_tuning_service_id
field may correspond to 16 bits.
[0897] FIG. 48 illustrates syntax for NRT service information
related to an emergency alert message according to an embodiment of
the present invention. In other words, the NRT service information
includes information for acquiring NRT data related to the
emergency alert message. The NRT service information may be
included in an EAT when the EAS_NRT_flag field of FIG. 46 is
enabled. For example, the NRT service information may be included
in the EAT when the EAS_NRT_flag field has a value of 1.
[0898] When NRT content and data related to the emergency alert
message are transmitted to the broadcast receiver 70, the NRT
service information includes identifier information for an NRT
service. In this instance, the identifier information for the NRT
service may be an EAS_NRT_service_id field. The EAS_NRT_service_id
field may correspond to 16 bits.
[0899] FIG. 49 illustrates an embodiment of an EAT having a section
form for transmitting an emergency alert message according to an
embodiment of the present invention. Even though the EAT of FIG. 49
is prepared in an MPEG-2 private section form to assist in
understanding, a format of data of the EAT is not restricted
thereto.
[0900] Examples of fields transmissible through the EAT are given
below.
[0901] A table_id field (8 bits) is a field for distinguishing a
type of a table, and a table may be found to be the EAT through
this field.
[0902] A section_syntax_indicator field (1 bit) is an indicator
that defines a section form of the EAT. For example, the section
form may be short-form syntax ("0") of MPEG.
[0903] A private_indicator field (1 bit) indicates whether the EAT
conforms to a private section.
[0904] A section_length field (12 bits) indicates a section length
of a remaining EAT after the field.
[0905] A table_id_extension field (16 bits) is dependent on a
table, and is a logical part of a table_id field that provides a
range of remaining fields. The table_id_extension field includes an
EAT_protocol_version field.
[0906] The EAT_protocol_version field (8 bits) reports a protocol
version for permitting an EAT transmitted by a parameter having a
different structure from that of others defined in a current
protocol.
[0907] A version_number field (5 bits) indicates a version number
of an EAT.
[0908] A current_next_indicator field (1 bit) indicates whether the
EAT section is currently applicable.
[0909] A section_number field (8 bits) indicates a number of a
current EAT section.
[0910] A last_section_number field (8 bits) indicates a last
section number included in an EAT.
[0911] An automatic_tuning_flag field (1 bit) indicates whether to
automatically tune to a channel.
[0912] A num_EAS_messages field (7 bit) indicates the number of
emergency alert messages included in an emergency alert table.
[0913] When the automatic_tuning_flag field has a value of "1",
that is, indicates automatic channel tuning, the emergency alert
table further includes an automatic_tuning_info( ) field. The
automatic_tuning_info( ) field includes information for automatic
tuning. For example, the automatic_tuning_info( ) field may include
information about a channel transmitting content related to
emergency alert information, information for identifying a physical
layer pipe transmitting A/V content related to an emergency alert
message, and service ID information of content related to the
emergency alert message. Therefore, when forced tuning to a channel
number at which the emergency alert message is broadcast is needed,
the above fields may be used.
[0914] In addition, an emergency_alert_message( ) field of FIG. 49
is included in a "for" loop, and transmits an emergency alert
message corresponding to a value of the num_EAS_messages field.
When the EAS_NRT_flag field has a value of 1, the "for" loop
further includes an NRT_service_info( ) field. The
NRT_service_info( ) field transmits NRT service information related
to an emergency alert.
[0915] FIG. 50 illustrates another embodiment of a section table
for transmitting an emergency alert message according to the
present invention.
[0916] In an emergency alert table of FIG. 50, a table_id field
identifies a type of a current table. The broadcast receiver may
identify the present table as an emergency alert table using the
table_id field.
[0917] A table_id_extension field includes the EAT_protocol_version
field. When a structure of the emergency alert table is changed,
the EAT_protocol_version field identifies version information
thereof. Details of fields of a section header of FIG. 50 have been
described with reference to FIG. 49, and will not be described
here.
[0918] An automatic_tuning_flag field (1 bit) indicates whether to
automatically tune to a channel.
[0919] A num_EAS_messages field (7 bits) indicates the number of
emergency alert messages included in the emergency alert table.
[0920] When the automatic_tuning_flag field has a value of "1",
that is, indicates automatic channel tuning, the emergency alert
table further includes an automatic_tuning_channel_number field, an
automatic_DP_id field, and an automatic_service_id field.
[0921] The automatic_tuning_channel_number field (8 bits) indicates
information about a channel including content related to emergency
alert information.
[0922] The automatic_DP_id field (8 bits) indicates information for
identifying a data pipe, that is. a physical layer pipe including
A/V content related to the emergency alert message.
[0923] The automatic_service_id field (16 bits) indicates service
ID information of content related to the emergency alert
message.
[0924] In addition, a "for" loop repeated the number of times
corresponding to a value of the num_EAS_messages field includes an
EAS_message_id field, an EAS_IP_version_flag field. an
EAS_message_transfer_type field, an EAS_message_encoding_type
field, and an EAS_NRT_flag field.
[0925] The EAS_message_id field (32 bits) indicates a unique ID for
identifying an emergency alert message. A value of this field may
be changed when the emergency alert message is updated or canceled.
As another embodiment, this field may be extracted from a CAP
message ID.
[0926] The EAS_IP_version_flag field (1 bit) indicates an IP
version in which the emergency alert table is transmitted. The
IP_address field includes an IPv4 address when this field has a
value of "0" and includes an IPv6 address when this field has a
value of "1".
[0927] The EAS_message_transfer_type field (3 bits) indicates a
transmission type of the emergency alert message. In a specific
embodiment, the EAS_message_transfer_type field may indicate that a
transmission type of an EAS message has not been specified. In this
case, the EAS_message_transfer type field may have a value of
000(2).
[0928] In another embodiment, the EAS_message_transfer_type field
may indicate that a transmission type of the EAS message is a type
in which no emergency message is included. In this case, the
EAS_message_transfer_type field may have a value of 001(2).
[0929] In another embodiment, the EAS_message_transfer_type field
may indicate that the EAS message is included in the EAT and
delivered. In this case, the EAS_message_transfer_type field may
have a value of 010(2).
[0930] Further, when the EAS_message_transfer_type field has the
value of 010(2), the emergency alert table including the EAS
message may additionally indicate a length of the EAS message. In
this case, information indicating the length of the EAS message may
be an EAS_message_length field. The EAS_message_length field may
correspond to 12 bits. In addition, an EAS_message_bytes( ) field
subsequent to the EAS_message_length field transmits an emergency
alert message including emergency alert content corresponding to a
length which corresponds to a value of the EAS_message_length
field.
[0931] In another embodiment, the EAS_message_transfer_type field
may indicate that the EAS message is transmitted in the form of an
IP datagram through a physical layer pipe. In this case, the
EAS_message_transfer type field may have a value of 011(2).
[0932] When the EAS_message_transfer_type field has the value of
011(2), the emergency alert table may additionally include at least
one of an IP_address field (32 or 128 bits) indicating IP address
information for acquiring an IP datagram that transmits the EAS
message, a UDP_port_num field (16 bits) indicating a UDP port
number, and a DP_id field (8 bits) indicating identification
information of a physical layer frame (that is, a PLP or DP) in
which the EAS message is transmitted.
[0933] Meanwhile, the EAS_message_encoding_type field (3 bits)
indicates an encoding type of the emergency alert message. In a
specific embodiment, the EAS_message_encoding_type field may
indicate that an encoding type of the emergency alert message has
not been specified. In this case, the EAS_message_encoding_type
field may have a value of 000(2).
[0934] In another embodiment, the EAS_message_encoding_type field
may indicate that the emergency alert message has not been encoded.
In this case, the EAS_message_encoding type field may have a value
of 001(2).
[0935] In another embodiment, the EAS_message_encoding_type field
may indicate that the emergency alert message has been encoded by
the DEFLATE algorithm. The DEFLATE algorithm is a lossless
compression data format. In this case, the
EAS_message_encoding_type field may have a value of 010(2).
[0936] In the emergency alert table, when the EAS_NRT_flag field
has a value of "1", an NRT_service_id field is further included.
The NRT_service_id field (16 bits) indicates identification
information for identifying an NRT service related to an emergency
alert.
[0937] FIG. 51 and FIG. 52 illustrate embodiments in which the EAT
is transmitted in the form of a packet through a physical layer
frame according to the invention.
[0938] In general, a broadcast packet includes a packet payload
into which data to be transmitted through the packet is inserted,
and a packet header into which information for signaling the packet
payload is inserted. Therefore, according to an embodiment of the
present invention, the broadcast transmitter may insert an
emergency alert message to be transmitted into the payload of the
packet, and insert signaling information for signaling the
emergency alert message into the header of the packet.
[0939] FIG. 51 illustrates an embodiment in which a form of the
above-described emergency alert table is not changed, and the
emergency alert table is inserted into the payload of the packet
without change and transmitted. As illustrated in FIG. 51, the
packet payload includes the emergency alert table without change,
and may additionally include an ID for the emergency alert table
and length information of the emergency alert table.
[0940] In addition, the packet header may include information that
indicates a type of the packet. In an embodiment, packet type
information may indicate that the payload of the packet includes
data for emergency alert signaling. In a specific embodiment,
information indicating a packet type may be 110(2).
[0941] In addition, the packet header may include information that
indicates a type of signaling data included in the payload of the
packet. In an embodiment, signaling data type information may
indicate that the signaling data has the form of a section table.
In a specific embodiment, when the signaling data type information
has a value of 00(2), the signaling data type information may
indicate that the signaling data has the form of a section
table.
[0942] FIG. 52 illustrates an embodiment in which an emergency
alert message is inserted into the packet payload as individual
information rather than in the form of a section table. In this
instance, the section table refers to an intermediate form for
configuring a final table. Specifically, the broadcast receiver 70
may configure the section table by gathering packets. and the
broadcast receiver 70 may configure the final table by gathering
section tables. Therefore, the embodiment of FIG. 52 illustrates
that each field included in the emergency alert message is
packetized into a separate packet. Thus, the broadcast receiver 70
may acquire complete information from one packet without the need
to configure the section table by gathering one or more packets.
For example, one packet payload may include only EAT protocol
version information, or include only automatic channel tuning
information.
[0943] In this case, information that indicates a type of a packet
may indicate that a payload of the packet includes data for
emergency alert signaling. In this case, the information that
indicates a type of a packet may be set to 110(2). In addition,
information that indicates a type of signaling may indicate that
data included in the packet payload has the form of individual
information. In this case, the information that indicates a type of
signaling may be set to 10(2).
[0944] Further, unlike FIG. 51, data for an emergency alert
included in the packet payload may vary, and thus the packet header
may additionally include information for identifying the data. The
information may be an Info Type field.
[0945] In a specific embodiment, when the Info Type field has a
value of 000(2), the data for an emergency alert included in the
packet payload may be an emergency alert message. In another
embodiment, when the Info Type field has a value of 001(2), the
data for an emergency alert included in the packet payload may be
automatic channel tuning information. In another embodiment, when
the Info Type field has a value of 010(2), the data for an
emergency alert included in the packet payload may be NRT service
information.
[0946] Hereinafter, FIG. 53 to FIG. 59 illustrate various
embodiments of transmitting an EAT. In a specific embodiment, a PLP
(or DP) that transmits the EAT may vary according to embodiment,
which will be described through FIG. 53 to FIG. 59.
[0947] FIG. 53 is an embodiment of the present invention, and
illustrates that the broadcast transmitter 72 transmits the EAT
through a designated PLP (or DP).
[0948] In FIG. 53, reference numeral 70 denotes a broadcast
receiver, reference numeral 72 denotes a broadcast transmitter, and
reference numeral 78 denotes a physical layer processor included in
each of the broadcast transmitter 72 and the broadcast receiver 70.
In an embodiment, when the physical layer processor 78 is included
in the broadcast transmitter, an emergency alert signaling
formatting block for an emergency alert message and a delivery
protocol block for A/V content correspond to a link layer
processor. In addition, in an embodiment, when the physical layer
processor 78 is included in the broadcast receiver, an emergency
alert signaling decoding block and a parser block for the emergency
alert message and a protocol stack and a decoder block for the A/V
content correspond to the link layer processor.
[0949] In an embodiment, the broadcast transmitter 72 may transmit
the emergency alert table through a designated physical layer pipe
(dedicated physical layer pipe). In this instance, the physical
layer pipe designated to transmit the emergency alert table may be
referred to as an EAC. In other words, the EAC may be a dedicated
physical layer pipe for transmitting only a physical layer frame
including the emergency alert table. Here, the physical layer frame
may be a unit of data transmitted through a physical layer. The
physical layer may include one or more physical layer pipes, and
the physical layer frame may be transmitted through the physical
layer pipes. Hereinafter, the present embodiment will be described
in more detail with reference to FIG. 53.
[0950] The emergency alert signaling formatting block of the
broadcast transmitter 72 generates the EAT based on emergency alert
information gathered from the alert authorities 76. etc. Here, the
emergency alert information gathered by the broadcast transmitter
72 may be a CAP message received from the information aggregator
74.
[0951] In addition, as described in the foregoing, the designated
physical layer pipe may be an emergency alert channel that
transmits only the EAT. The physical layer processor 78 of the
broadcast transmitter 72 generates a broadcast signal including a
generated emergency alert table. Specifically, the broadcast signal
may include a physical layer frame including the emergency alert
table. In addition, the broadcast transmitter 72 transmits the
broadcast signal including the emergency alert channel.
Specifically, the broadcast transmitter 72 may transmit the
broadcast signal through a physical layer pipe designated only for
a physical layer frame including the EAT. The physical layer
processor 78 of the broadcast receiver 70 receives the broadcast
signal through the designated physical layer pipe. As described in
the foregoing, the physical layer pipe may be a data pipe
designated to transmit only emergency alert information in a
physical layer. The decoding and parser block of the broadcast
receiver 70 may extract the EAT from the physical layer frame
received through the EAC. In addition, the broadcast receiver 70
may acquire information, which indicates whether the EAC is
included in the physical layer that delivers the physical layer
frame, from the physical layer frame. In this instance, information
indicating whether the EAC is included in the physical layer may be
referred to as PHY signaling. The broadcast receiver 70 may
determine a data pipe that transmits emergency alert information
based on the PHY signaling. The decoding block of the broadcast
receiver 70 decodes a physical layer frame including the EAT. In
this instance, the broadcast receiver 70 may acquire a CAP message,
related content information, and related NRT service information
from the physical layer frame.
[0952] The parser block of the broadcast receiver 70 may acquire
the emergency alert information by parsing the acquired CAP
message. In a specific embodiment, the parser block (that is. CAP
parser) may parse the CAP message. In this case, the broadcast
receiver 70 may acquire the related NRT service information
together with the emergency alert information. When overlapping
information between the EAT and the CAP message is present, the
broadcast transmitter 72 may adjust the information in a process of
adjusting the EAT.
[0953] The protocol stack block of the broadcast receiver 70 may
receive A/V content based on the acquired related content
information. Specifically, the acquired related content information
may be information for identifying a physical layer pipe that
transmits the A/V content. Further, the related content information
may be information for identifying related A/V content.
[0954] The protocol stack block of the broadcast receiver 70
identifies a physical layer pipe to extract a physical layer frame
including the related content based on the related content
information. In addition, the decoder block of the broadcast
receiver 70 decodes the physical layer frame received through the
identified physical laver pipe to acquire the A/V content. In this
instance, the physical layer pipe that transmits the related
content may be distinguished from the physical layer pipe that
transmits the emergency alert information. In addition, the
broadcast receiver 70 may acquire an NRT service related to the
emergency alert information based on the acquired NRT service
information. Specifically, the broadcast receiver 70 may acquire
address information for acquiring an NRT service from the NRT
service information. In this instance, the broadcast receiver 70
may receive the NRT service through the broadband network.
[0955] The broadcast receiver 70 provides the acquired emergency
alert message together with the A/V content. When information about
automatic channel tuning is transmitted, the broadcast receiver 70
may provide the emergency alert message while automatically tuning
to a channel including the information about automatic channel
tuning.
[0956] FIG. 54 and FIG. 55 illustrate that the broadcast
transmitter 72 encapsulates an EAT in a packet and transmits the
packet as an embodiment of the present invention. The packet
including the EAT may be referred to as an emergency alert
packet.
[0957] In an embodiment, a plurality of physical layer pipes may be
included in a physical layer of a broadcast signal. In addition, a
separate physical layer pipe may be present to transmit specific
information about a plurality of broadcast services transmitted
through the plurality of physical layer pipes included in the
physical layer of the broadcast signal. In this instance, a
separate physical layer pipe transmitting broadcast service
information may be referred to as a base data pipe. Specifically,
the broadcast transmitter 72 may transmit signaling information of
a broadcast service or common data applied to a plurality of
broadcast services through the base data pipe. Here, the signaling
information or the common data may be information that signals a
physical layer frame transmitted through a physical layer or data
commonly applied to a physical layer frame.
[0958] FIG. 54 illustrates that the broadcast transmitter 72
transmits an EAT through a base data pipe as an embodiment.
[0959] In FIG. 54, reference numeral 70 denotes a broadcast
receiver, reference numeral 72 denotes a broadcast transmitter, and
reference numeral 78 denotes a physical layer processor included in
each of the broadcast transmitter 72 and the broadcast receiver 70.
In an embodiment, when the physical layer processor 78 is included
in the broadcast transmitter, an emergency alert packet
encapsulation block for an emergency alert message and a delivery
protocol block for A/V content correspond to a link layer
processor. In addition, in an embodiment, when the physical layer
processor 78 is included in the broadcast receiver, a
filtering/decoding block and a CAP parser block for the emergency
alert message and a protocol stack and a decoder block for the A/V
content correspond to the link layer processor.
[0960] The emergency alert packet encapsulation block of the
broadcast transmitter 72 generates a packet to be transmitted
through a physical layer by encapsulating emergency alert
information gathered from the alert authorities 76, etc. In this
instance, a packet obtained by encapsulating the emergency alert
information may be referred to as an emergency alert packet. Here,
the emergency alert information received by the broadcast
transmitter 72 may be a CAP message received from the information
aggregator 74.
[0961] In an embodiment, the emergency alert packet may include a
packet header and a packet payload. In a specific embodiment, the
packet payload may include an EAT without change. In another
embodiment, the packet payload may include only partial information
in the EAT. Here, the partial information may be partial
information having a high importance in the EAT.
[0962] In addition, the packet header may include signaling
information indicating that data included in the packet payload is
emergency alert information. Further, the packet header may signal
that the packet includes the emergency alert information.
Specifically, the packet header may indicate that the packet
includes different type information from that of a general packet,
and the packet includes emergency alert information. In other
words, the packet header may indicate that the packet is an
emergency alert packet.
[0963] The physical layer processor 78 of the broadcast transmitter
72 transmits a packet in which the EAT is encapsulated through a
physical layer pipe for transmitting signaling information of a
broadcast service or common data. In other words, the broadcast
transmitter 72 transmits the emergency alert packet through a base
data pipe. In this case, the base data pipe is a form of a physical
layer pipe, and may be distinguished from another physical layer
pipe (or data pipe).
[0964] Meanwhile, a physical layer including the base data pipe may
transmit information signaling that the base data pipe is present
in the physical layer. In this instance, the information signaling
the presence of the base data pipe may be referred to as PHY
signaling. The physical layer processor 78 of the broadcast
receiver 70 may verify that the base data pipe is present in a
physical layer of a broadcast signal received based on the PHY
signaling. In addition, the physical layer processor 78 of the
broadcast receiver 70 may acquire emergency alert information
through the base data pipe which is a form of the physical layer
pipe. In this instance, the acquired emergency alert information
may have the form of an emergency alert packet. The broadcast
receiver 70 receives a broadcast signal through the base data pipe.
In other words, the broadcast receiver 70 receives a physical layer
frame including the emergency alert packet through the base data
pipe.
[0965] The filtering and decoding block of the broadcast receiver
70 may extract the physical layer frame including the emergency
alert packet from the received broadcast signal. In addition, the
filtering and decoding block of the broadcast receiver 70 may
acquire the emergency alert information by decoding the extracted
physical layer frame. Specifically, the emergency alert information
may be acquired by decoding the emergency alert packet included in
the physical layer frame.
[0966] In this instance, the emergency alert packet may include a
packet payload into which an EAT is inserted and a packet header
that signals the packet payload. In a specific embodiment, the
broadcast receiver 70 may determine whether the packet includes the
emergency alert information from the packet header. In other words,
the broadcast receiver 70 may determine whether the packet is an
emergency alert packet based on information extracted from the
packet header.
[0967] In addition, the broadcast receiver 70 may determine a form
of the emergency alert information included in the packet payload
from the packet header. For example, the broadcast receiver 70 may
determine whether the packet payload includes the whole EAT.
[0968] The broadcast receiver 70 acquires the emergency alert
information from the packet payload based on the information
acquired from the packet header. Here, the acquired emergency alert
information may be an EAT or a CAP message. Alternatively, the
acquired emergency alert information may be emergency alert related
content information or emergency alert related NRT service
information.
[0969] The CAP parser block of the broadcast receiver 70 may parse
the acquired CAP message to acquire the emergency alert
information. In this case, the broadcast receiver 70 may acquire
related NRT service information together with the emergency alert
information. When overlapping information between the EAT and the
CAP message is present, the broadcast transmitter 72 may omit the
overlapping information in a process of configuring the EAT.
Hereinafter, a process of acquiring a related service based on the
emergency alert information is the same as the above-described
content, and thus is omitted.
[0970] FIG. 55 illustrates that the broadcast transmitter 72
transmits an EAT through a normal physical layer pipe as an
embodiment of the present invention. Here, the normal physical
layer pipe may be a physical layer pipe, use of which is not
designated.
[0971] The present embodiment is a case in which a base data pipe
is not included in a physical layer unlike the embodiment of FIG.
54, and the description will focus on a difference from FIG. 54.
That is, the physical layer processor 78 is different between FIG.
55 and FIG. 54.
[0972] In the present embodiment, the emergency alert packet
encapsulation block of the broadcast transmitter 72 configures a
packet header differently from a general packet header while
encapsulating emergency alert information. Specifically, the
broadcast transmitter 72 may differently set a value that indicates
a packet type included in the packet header. For example, the value
may be set to 000(2) in a general packet and may be set to 110(2)
in an emergency alert packet, thereby distinguishing between the
packets.
[0973] Meanwhile, the physical layer processor 78 of the broadcast
transmitter 72 may transmit information that signals a physical
layer pipe in a physical layer. In this instance, the information
that signals the physical layer pipe in the physical layer may be
referred to as PHY signaling.
[0974] The physical layer processor 78 of the broadcast transmitter
72 may acquire information of the physical layer pipe included in
the physical layer received based on the PHY signaling.
[0975] In the embodiment of FIG. 55, the broadcast receiver 70 may
receive a packet including an emergency alert and a packet
including broadcast content through a plurality of physical layer
pipes included in the physical layer. In addition, the broadcast
receiver 70 may acquire emergency alert information from the packet
including the emergency alert. Further, the broadcast receiver 70
may identify another physical layer pipe that transmits broadcast
content related to the emergency alert based on the emergency alert
information. Furthermore. the broadcast receiver 70 may acquire
route information for receiving NRT content related to the
emergency alert based on the emergency alert information.
[0976] FIG. 56 to FIG. 59 illustrate that the broadcast transmitter
72 transmits emergency alert information through another form of
the physical layer pipe as an embodiment of the present invention.
In this case, the other form of the physical layer pipe may be a
physical layer pipe for scanning a broadcast service included in a
physical layer of a broadcast signal. Specifically, the broadcast
transmitter 72 may transmit service signaling information for
scanning a broadcast service directly to the physical layer of the
broadcast signal through a physical layer pipe without passing
through another layer. In this instance, the physical layer pipe
for scanning the broadcast service may be referred to as a
signaling channel. The broadcast receiver 70 may acquire at least
one of configuration information of a broadcast stream, brief
broadcast service information, and component information from the
signaling channel. In a specific embodiment, the signaling channel
may be one of an FIC and LLS. The FIC is also referred to as an FIT
or an SLT.
[0977] In an embodiment of the present invention, the broadcast
transmitter 72 may transmit an emergency alert message based on a
CAP message through the signaling channel. The present embodiment
will be described in more detail with reference to FIG. 56 and FIG.
57.
[0978] In FIG. 56, reference numeral 70 denotes a broadcast
receiver, reference numeral 72 denotes a broadcast transmitter, and
reference numeral 78 denotes a physical layer processor included in
each of the broadcast transmitter 72 and the broadcast receiver 70.
In an embodiment, when the physical layer processor 78 is included
in the broadcast transmitter, an emergency alert signaling
formatting block for an emergency alert message, an FIC signaling
block for signaling channel information, and a delivery protocol
block for A/V content correspond to a link layer processor. In
addition, in an embodiment, when the physical layer processor 78 is
included in the broadcast receiver, an emergency alert signaling
decoding block and a CAP parser block for the emergency alert
message, an FIC decoding block for the signaling channel
information, and a protocol stack and a decoder block for the A/V
content correspond to the link layer processor.
[0979] In another embodiment of the present invention, the
broadcast transmitter 72 may transmit only minimum information that
indicates an emergency alert through a signaling channel, and an
actual emergency alert message (for example, an EAT) may be
transmitted through a physical layer pipe distinguished from the
signaling channel. The present embodiment will be described in more
detail with reference to FIG. 58 and FIG. 59. The physical layer
processor 78 is different between FIG. 58 and FIG. 56.
[0980] FIG. 56 illustrates a block diagram of an emergency alert
system for directly transmitting an emergency alert message through
a signaling channel according to an embodiment of the present
invention.
[0981] The emergency alert signaling formatting block of the
broadcast transmitter 72 generates an EAT based on emergency alert
information gathered from the alert authorities 76, etc. Here, the
emergency alert information received by the broadcast transmitter
72 may be a CAP message received from the information aggregator
74.
[0982] The physical layer processor 78 of the broadcast transmitter
72 generates a broadcast signal including the generated EAT.
Specifically, the EAT may be transmitted through a signaling
channel which is a form of a physical layer pipe of a broadcast
signal. In this instance, the signaling channel may refer to a
general signaling channel rather than a designated signaling
channel described in the embodiment of FIG. 53. In addition, the
broadcast transmitter 72 transmits a broadcast signal including the
emergency alert information through the signaling channel.
[0983] The physical layer processor 78 of the broadcast receiver 70
may extract a physical layer frame including the emergency alert
information from the broadcast signal received through the
signaling channel. Specifically. the extracted physical layer frame
may include the EAT. The decoding block of the broadcast receiver
70 decodes the extracted physical layer frame. In a specific
embodiment, the broadcast receiver 70 decodes the physical layer
frame to acquire the emergency alert information. In this instance,
the broadcast receiver 70 may acquire a CAP message, emergency
alert-related content information, and emergency alert-related NRT
service information from the physical layer frame.
[0984] The CAP parser block of the broadcast receiver 70 may parse
the acquired CAP message to acquire emergency alert information. In
this case, the broadcast receiver 70 may acquire the emergency
alert-related NRT service information together with the emergency
alert information. When overlapping information between the EAT and
the CAP message is present, the broadcast transmitter 72 may omit
the overlapping information in a process of configuring the EAT.
Hereinafter, a process of acquiring a related service based on the
emergency alert information is the same as the above-described
content, and thus is omitted.
[0985] FIG. 57 illustrates syntax of the emergency alert message
transmitted through the signaling channel according to the
embodiment of FIG. 56. In a specific embodiment, the emergency
alert message may be a part of a table transmitted through the
signaling channel. In addition, a field illustrated in FIG. 57 may
be changed as necessary in the future.
[0986] FIG. 57 illustrates an example of transmitting the emergency
alert message through an FIC in the signaling channel. In FIG. 57,
a FIT_data_version field (8 bits) illustrates version information
of semantics and syntax included in the FIC. A receiver according
to an embodiment of the present invention may determine whether to
process signaling included in the FIC using the FIT_data_version
field.
[0987] A num_broadcast field (8 bits) indicates the number of
broadcasters that transmit broadcast services or content through a
frequency or a transmitted transmission frame.
[0988] An emergency_alert_flag field (1 bit) indicates whether
emergency alert-related signaling information is included in the
FIC. In an embodiment, the emergency_alert_flag field indicates
that the FIC does not include the emergency alert-related signaling
information when the emergency_alert_flag field has a value of 0,
and the emergency_alert_flag field indicates that the FIC includes
the emergency alert-related signaling information when the
emergency_alert_flag field has a value of 1.
[0989] The emergency alert-related signaling information may
include information related to automatic channel tuning. In
addition, when the emergency_alert_flag field has the value of 1,
an emergency alert message and/or emergency alert-related NRT
service information may be transmitted through the FIC. To this
end, when the emergency_alert_flag field has the value of 1, the
FIC includes an automatic_tuning_flag field and a num_EAS_messages
field. In addition, automatic channel tuning information, an
emergency alert message, NRT service information. etc. may be
transmitted through the FIC according to each field value.
[0990] The automatic_tuning_flag field (I bit) indicates whether to
automatically tune to a channel.
[0991] The num_EAS_messages field (7 bits) indicates the number of
emergency alert messages included in the FIC.
[0992] When the automatic_tuning_flag field has a value of 1, that
is, indicates automatic channel tunning, the FIC further includes
an automatic_tuning_info( ) field. The automatic_tuning_info( )
field includes information for automatic tuning. For example, the
automatic_tuning_info( ) field may include at least one of
information about a channel that transmits content related to
emergency alert information, information for identifying a physical
layer pipe that transmits A/V content related to an emergency alert
message, and service ID information of content related to the
emergency alert message. Therefore, when automatic channel tuning
is needed, the above field may be used.
[0993] In addition, an emergency_alert_message( ) field transmits
an emergency alert message, and an NRT_service_info( ) field
transmits NRT service information related to an emergency alert
while being repeated the number of times corresponding to a value
of the num_EAS_messages field.
[0994] Meanwhile, in the FIC, a broadcast_id field (16 bits)
indicates a unique ID of a broadcaster that transmits content or a
broadcast service or a frequency. In a broadcaster that transmits
MPEG-2 TS-based data, a broadcast_id may have the same value as
that of a transport_stream_id of an MPEG-2 TS.
[0995] A delivery_system_id field (16 bits) indicates an ID of a
broadcast transmission system processed by applying the same
transmission parameter in a used broadcast network.
[0996] A base_DP_id field (8 bits) indicates an ID of a physical
layer pipe corresponding to a data pipe that delivers a broadcast
service signal transmitted by a particular broadcaster which is
identified by a broadcast_id. The base_DP_id field may indicate an
ID of a representative data pipe, that is, a representative
physical layer pipe that can decode a component included in a
broadcast service transmitted by the particular broadcaster which
is identified by the broadcast_id. Here, the physical layer pipe
may refer to a data pipe of a physical layer, and the broadcast
service transmitted by the particular broadcaster may include
PSI/SI information, etc.
[0997] A base_DP_version field (5 bits) indicates version
information according to change of data transmitted through a data
pipe, that is. a PLP identified by base_DP_id. For example, when a
service signal such as a PSI/SI is delivered through a base DP, a
value of the base_DP_version field may be incremented by 1 each
time the service signal is changed.
[0998] A num_service field (8 bits) indicates the number of
broadcast services transmitted by a broadcaster identified by a
broadcast_id within a corresponding frequency or transport
frame.
[0999] A service_id field (16 bits) indicates an ID that can
identify a corresponding broadcast service.
[1000] A service_category field (8 bits) indicates a category of a
corresponding broadcast service. For example, the service category
field may indicate that the category is Basic TV when a value
thereof is 0x01, the category is Basic Radio when a value thereof
is 0x02, the category is RI service when a value thereof is 0x03,
the category is Service Guide when a value thereof is 0x08, and the
category is Emergency Alert when a value thereof is 0x09.
[1001] A service_hidden_flag field (1 bit) indicates whether a
corresponding broadcast service is hidden. When the service is
hidden, the service corresponds to a test service or an internally
used service, and thus a receiver according to an embodiment of the
present invention may ignore the above-described hidden broadcast
service or hide the service from a service list.
[1002] An SP_indicator field (1 bit) indicates whether service
protection is applied to one or more components in a corresponding
broadcast service.
[1003] A num_component field (8 bits) indicates the number of
components included in a corresponding broadcast service.
[1004] A component_id field (8 bits) indicates an ID that
identifies a component in a broadcast service.
[1005] A DP_id field (16 bits) indicates an ID that identifies a
PLP corresponding to a data pipe through which a component in a
broadcast service is transmitted.
[1006] An RoHC_init_descriptor( ) transmits compression information
in an embodiment such that the broadcast receiver may release
compression of a component when the component is compressed in a
broadcast service, in particular, when a header of a packet that
transmits the component is compressed using an RoHC scheme.
[1007] FIG. 58 illustrates a block diagram of an emergency alert
system for transmitting/receiving only a delivery route of
emergency alert information through a signaling channel according
to an embodiment of the present invention. That is, an emergency
alert message is not transmitted through the signaling channel.
[1008] To this end, the broadcast transmitter 72 signals emergency
alert information gathered from the alert authorities 76, etc. in a
transmissible form.
[1009] Specifically, the broadcast transmitter 72 may configure
signaling information for an emergency alert (for example, a CAP
message and related data) in a table, a descriptor, or a packet. In
this instance, when the broadcast transmitter 72 does not include a
module only for separate emergency alert signaling information, the
emergency alert signaling information (or emergency alert
information) may be signaled through a general signaling module in
a transmissible form.
[1010] The broadcast transmitter 72 may insert information about
whether an emergency alert message is transmitted and information
about a route through which the emergency alert message is
transmitted together with the emergency alert information into a
physical layer frame. In this instance, the information about
whether an emergency alert message is transmitted and the
information about the transmission route may be indicated using an
emergency alert indicator. The descriptor included in the physical
layer frame may include the emergency alert indicator. In addition,
the table included in the physical layer frame may include the
emergency alert indicator as a field. Information included in the
emergency alert indicator may be included as a separate field as
necessary, and only information having high priority may be
included according to order of priority. Here, the order of
priority may be determined for each piece of information according
to importance in transmitting the emergency alert information.
[1011] A physical channel processor 78 of the broadcast transmitter
72 transmits a physical layer frame including an emergency alert
indicator and related data. In addition, the physical channel
processor 78 of the broadcast transmitter 72 may transmit
information related to an emergency alert through a physical layer
pipe other than a signaling channel. In this instance, the physical
layer pipe other than the signaling channel may be regarded as a
general physical layer pipe.
[1012] In addition, emergency alert-related data transmitted by the
broadcast transmitter 72 may be path information for acquiring
emergency alert information from a data pipe. Specifically, the
emergency alert-related data may be information for identifying a
general data pipe corresponding to a general physical layer pipe
that transmits emergency alert information.
[1013] A physical channel processor 78 of the broadcast receiver 70
receives the physical layer frame including the emergency alert
indicator and the related data through the signaling channel. In
addition, the physical layer frame may include information
indicating whether a signaling channel that transmits emergency
alert information to a physical layer is present. In this instance,
the information indicating whether the signaling channel is present
may be referred to as PHY signaling. The broadcast receiver 70
verifies whether the signaling channel is present in the physical
layer based on the PHY signaling, and receives the physical layer
frame including the emergency alert indicator and the related data
from the signaling channel.
[1014] The broadcast receiver 70 may decode the physical layer
frame through an emergency alert signaling decoder, and acquire the
emergency alert indicator and the related data from the physical
layer frame.
[1015] The broadcast receiver 70 acquires delivery path information
of the emergency alert message based on the emergency alert
indicator and the related data acquired from the physical layer
frame. Specifically, the broadcast receiver 70 may acquire
information about the physical layer pipe through which the
emergency alert message is transmitted from the emergency alert
indicator. Specifically, the broadcast receiver 70 may acquire
identification information for identifying the physical layer pipe
that transmits the emergency alert message from the emergency alert
indicator.
[1016] The broadcast receiver 70 decodes a packet transmitted
through the physical layer pipe which is identified based on the
emergency alert indicator.
[1017] In a specific embodiment, the broadcast receiver 70 may
determine whether the packet includes the emergency alert
information based on a packet header. In addition, the broadcast
receiver 70 may determine a form of the emergency alert information
included in a packet payload from the packet header. For example,
the broadcast receiver 70 may determine whether the packet payload
includes the whole EAT.
[1018] The broadcast receiver 70 acquires the emergency alert
information from the packet payload based on information acquired
from the packet header. Here, the acquired emergency alert
information may be an EAT or a CAP message. Alternatively, the
emergency alert information may be related content information or
NRT service information.
[1019] The CAP parser block of the broadcast receiver 70 may
acquire the emergency alert information by parsing the acquired CAP
message. In this case, the broadcast receiver 70 may acquire
related NRT service information together with the emergency alert
information. When overlapping information is present between the
EAT and the CAP message, the overlapping part may be omitted in a
process in which the broadcast transmitter 72 configures the
EAT.
[1020] The broadcast receiver 70 may receive A/V content based on
the acquired related content information. Specifically, the
acquired related content information may be information for
identifying a data pipe that transmits the A/V content. Further,
the acquired related content information may be information for
identifying the A/V content. The broadcast receiver 70 identifies a
data pipe that transmits the A/V content based on the related
content information. In addition, the broadcast receiver 70 may
acquire the A/V content by decoding a physical layer frame
transmitted through the identified data pipe, and acquire content
related to the emergency alert information in the acquired A/V
content. In this instance, the physical layer pipe that transmits
the content is distinguished from the physical layer pipe that
transmits the emergency alert information. In addition. the
broadcast receiver 70 may acquire an NRT service related to the
emergency alert information based on the acquired NRT service
information. Specifically, the broadcast receiver 70 may acquire
address information that allows the NRT service to be acquired from
the NRT service information. In this instance, the broadcast
receiver 70 may receive the NRT service through the broadband
network.
[1021] The broadcast receiver 70 may provide the acquired emergency
alert message together with the A/V content. When information about
automatic channel tuning is transmitted together with the emergency
alert message, the broadcast receiver 70 may provide the emergency
alert message while automatically tuning to a channel.
[1022] FIG. 59 is an example of syntax for signaling an emergency
alert transmitted through a signaling channel according to the
embodiment of FIG. 58. In a specific embodiment, the emergency
alert message may be a part of a table transmitted through the
signaling channel. In addition, fields illustrated in FIG. 59 may
be changed as necessary in the future.
[1023] FIG. 59 illustrates another example of transmitting
emergency alert signaling information which is transmitted through
the FIC in the signaling channel.
[1024] An FIC of FIG. 59 is the same as the FIC of FIG. 57 except
that an EAS_message_id field and an EAS_DP_id field are added
instead of the emergency_alert_message( ) field and the
NRT_service_info( ) field of FIG. 57. Therefore, fields not
described with reference to FIG. 59 will be inferred from FIG. 57.
and a description thereof will be omitted herein.
[1025] The EAS_message_id field (32 bits) of FIG. 59 indicates an
ID for identifying an emergency alert message transmitted through a
data pipe which is identified by the EAS_DP_id field.
[1026] In addition, the EAS_DP_id field (8 bits) indicates an ID
for identifying a data pipe (that is, a PLP) that transmits an
emergency alert message which is identified by the EAS_message_id
field.
[1027] Meanwhile, the EAS_message_id field and the EAS_DP_id field
of the FIC of FIG. 59 may be used as an emergency alert indicator
that indicates whether the emergency alert message is transmitted
and information about a transmission path.
[1028] FIG. 60 is a flowchart illustrating an operation method of
the broadcast transmitter 72 according to an embodiment of the
present invention.
[1029] The broadcast transmitter 72 receives emergency alert
information from the alert authorities 76 (S101). Here, the alert
authorities 76 may be one of disaster management authorities and an
involved department. In addition, the broadcast transmitter 72 may
receive the emergency alert information from the information
aggregator 74. In this case, the broadcast transmitter 72 may
receive the emergency alert information processed in a CAP
message.
[1030] The broadcast transmitter 72 generates a table including the
emergency alert information or an emergency alert packet including
the emergency alert information based on the received emergency
alert information (S103). Specifically, the broadcast transmitter
72 may generate an EAT or an emergency alert packet according to a
physical layer pipe that transmits the emergency alert
information.
[1031] In an embodiment, when the emergency alert information is
transmitted through a designated physical layer pipe, the broadcast
transmitter 72 may generate an EAT including the emergency alert
information. In this case, in a first embodiment, the EAT may
include all of the emergency alert information. In addition, in a
second embodiment, the EAT may include some of the emergency alert
information. Here, the some of the emergency alert information may
include minimum information for transmitting the whole emergency
alert information.
[1032] In another embodiment, when the broadcast transmitter 72
transmits the emergency alert information through a physical layer
pipe for packet transmission, the broadcast transmitter 72 may
encapsulate the emergency alert information in a packet. The packet
in which the emergency alert information is encapsulated may be
referred to as an emergency alert packet. In an embodiment, the
broadcast transmitter 72 may encapsulate the emergency alert
information in a payload of the packet. In another embodiment, the
broadcast transmitter 72 may encapsulate the EAT in the payload of
the packet.
[1033] In addition, the broadcast transmitter 72 may encapsulate
information for identifying data of the packet payload in a packet
header. Further, information encapsulated in the packet header may
be information indicating that the packet is a packet including the
emergency alert information.
[1034] The broadcast transmitter 72 inserts the generated EAT or
emergency alert packet into the physical layer frame (S105).
Specifically, the broadcast transmitter 72 inserts the EAT or
emergency alert packet into the physical layer frame transmitted
through the physical layer pipe. In this instance, the physical
layer frame may include information indicating that the frame
includes the emergency alert information.
[1035] In response to the emergency alert information inserted into
the physical layer frame, the broadcast transmitter 72 transmits a
broadcast signal including the physical layer frame through a
particular physical layer pipe (S107). In an embodiment, the
particular physical layer pipe may be a physical layer pipe
designated to transmit only the emergency alert information. In
another embodiment, the particular physical layer pipe may be a
physical layer pipe that transmits signaling information for a
broadcast service or data for common use applied to a plurality of
broadcast services. In another embodiment, the particular physical
layer pipe may be a physical layer pipe that transmits information
necessary for service scanning including at least one of
configuration information of a broadcast stream, brief broadcast
service information, and component information. In another
embodiment, the particular physical layer pipe may be a general
physical layer pipe, use of which has not been designated.
[1036] FIG. 61 is a flowchart illustrating an operation method of
the broadcast receiver 70 according to an embodiment of the present
invention.
[1037] The broadcast receiver 70 receives the broadcast signal
including the emergency alert information through the physical
layer pipe (S201). In an embodiment, the physical layer pipe may be
a physical layer pipe designated to transmit only the emergency
alert information. In another embodiment, the particular physical
layer pipe may be a physical layer pipe that transmits signaling
information for a broadcast service or data for common use applied
to a plurality of broadcast services. In another embodiment, the
particular physical layer pipe may be a physical layer pipe that
transmits at least one of configuration information of a broadcast
stream, brief broadcast service information, and component
information. In another embodiment, the particular physical layer
pipe may be a general physical layer pipe, use of which has not
been designated.
[1038] The broadcast receiver 70 extracts the physical layer frame
including the emergency alert information from the received
broadcast signal (S203). In an embodiment, the physical layer frame
may include an EAT. In this case, the EAT may include only minimum
information for acquiring the emergency alert information. In
another embodiment, the physical layer frame may include an
emergency alert packet. The broadcast receiver 70 acquires the
emergency alert information by decoding the extracted physical
layer frame (S205). Specifically, the broadcast receiver 70
acquires the emergency alert information by decoding the EAT or the
emergency alert packet included in the physical layer frame. In an
embodiment, the broadcast receiver 70 may decode the physical layer
frame based on particular information of the EAT or a header of the
emergency alert packet. In another embodiment, the broadcast
receiver 70 may decode the physical layer frame based on
information acquired by decoding the EAT. Specifically, the
broadcast receiver 70 may identify the physical layer frame
including the emergency alert information from the EAT, and decode
the identified physical layer frame.
[1039] The broadcast receiver 70 determines whether the acquired
emergency alert information includes related service information
(S207). Specifically, the broadcast receiver 70 determines whether
information about related content which is related to the emergency
alert information is included. Here, the related content may be one
of real-time content and NRT content.
[1040] When the related content is determined to be present, the
broadcast receiver 70 determines whether the acquired related
content information is real-time content (S209). Specifically. the
broadcast receiver 70 determines whether content related to the
emergency alert information is real-time content or NRT content.
Here, the real-time content may be A/V content. Whether content is
real-time content may be determined based on particular information
of the EAT. Alternatively, whether content is real-time content may
be determined based on information included in the packet
header.
[1041] Upon determining that the related content is real-time
content, the broadcast receiver 70 acquires the related content by
decoding the physical layer frame included in the received
broadcast signal (S211). Specifically, the emergency alert
information may include path information that allows the related
content to be acquired. Therefore, the broadcast receiver 70 may
acquire content by identifying the physical layer frame including
the related content based on the information.
[1042] However, when the related content is determined to be NRT
content, the broadcast receiver 70 extracts path information for
acquiring the NRT content (S215). The information for acquiring the
NRT content may be address information. For example, the
information may be URI information.
[1043] The broadcast receiver 70 acquires an NRT service through an
IP communication unit based on the extracted path information
(S217). Specifically, the broadcast receiver 70 acquires the NRT
service through the broadband network using the address
information.
[1044] The broadcast receiver 70 provides the acquired emergency
alert information together with the related service (S213).
Specifically, the broadcast receiver 70 outputs the emergency alert
information together with the related service. In this instance,
the related service may be one of a real-time service or an NRT
service.
[1045] Meanwhile, signaling information for broadcast services in
the broadcast transmitter is transmitted to the physical layer by
being included in a payload of the link layer packet, and the
physical layer may configure the physical layer packet by means of
one or more link layer packets, map the physical layer packet into
a specific data pipe (that is, PLP) and then transmit the physical
layer packet to a receiving side through a coding and modulation
process. In the present invention, the packet of the link layer may
be referred to as a generic packet, and the packet of the physical
layer may be referred to as a baseband packet.
[1046] Particularly, as one embodiment of the present invention,
the emergency alert message and/or the emergency alert related
signaling information is packetized into the link layer packet, and
the link layer packet is again packetized into the physical layer
packet, mapped into a specific data pipe and then transmitted to
the broadcast receiver through the coding and modulation
process.
[1047] If a structure of the link layer packet that enables
transmission of signaling information is defined in the system, the
structure of the corresponding packet is used as one embodiment of
the present invention. At this time, as one embodiment, the
existing field or a new field is used to transmit signaling
information indicating that the corresponding packet is an
emergency alert related packet.
[1048] Generally, it is convenient that the signaling information
related to the emergency alert message is transmitted at one time,
and the signaling information may quickly be delivered to the
broadcast receiver. However, if there is no dedicated data path
that can transmit emergency alert information in view of a
structure of the system, or for a structure that is difficult to
transmit every kind of emergency alert information at one time, a
method for transmitting emergency alert related information through
classification and segmentation of the emergency alert related
information based on a certain reference may be used.
[1049] FIG. 62 illustrates a conceptual view of a link layer packet
according to one embodiment of the present invention. Referring to
FIG. 62, the link layer packet includes a link layer packet header
and a link layer packet payload. For convenience of description,
the link layer packet header will be used to refer to "header", and
the link layer packet payload will be used to refer to
"payload`.
[1050] A header 210 of FIG. 62 may be divided into a fixed header
of 1 byte and an extended header of a variable length.
[1051] FIG. 64 illustrates a header structure of FIG. 63 as a
syntax format, and relates to the same as that of FIG. 63.
[1052] Therefore, each field of the link layer header will be
described with reference to FIGS. 63 and 64.
[1053] That is, a packet type field (3 bits) of the fixed header
indicates a type of data transmitted to the corresponding
packet.
[1054] For example, if a value of a packet_type field is `000`, it
indicates data of IPv4 transmitted to the corresponding packet. If
the value of the packet type field is `010`, it indicates data of a
header compressed IP packet transmitted to the corresponding
packet.
[1055] And, if the value of a packet type field is `110`, it
indicates data transmitted to the corresponding packet is signaling
information (or signaling data). The signaling information may be
either a signaling table (or descriptor) or a signaling packet. The
signaling table may include a signaling table/table section
included in DVB_SI (service information), PSI/PSIP, NRT (Non Real
Time), ATSC 2.0, and MH (Mobile/Handheld), which exist
conventionally.
[1056] In the present invention, the case where the value of the
packet type field is `110` will be described in detail.
[1057] That is, if the value of the packet type field is `110`,
fields of the fixed header and fields of the extended header, which
are subsequent to a payload_config field, are varied depending on a
value of the payload_config field (1 bit). That is, information
signaled to the fixed header and information signaled to the
extended header are determined depending on the value of the
payload_config field. The payload_config field may be referred to
as a packet configuration (PC) field.
[1058] One embodiment indicates whether the signaling information
is segmented by the upper layer and then provided to the link
layer. According to one embodiment, if the value of the
payload_config field is `0`, the signaling information is provided
without being segmented by the upper layer, and if the value of the
payload_config field is `1`, the signaling information is provided
after being segmented by the upper layer.
[1059] If the value of the payload_config field is `0`, a
concatenation_count field of 4 bits is included in the fixed
header. Also, the extended header includes a signaling_class field
of 3 bits, an information_type field of 3 bits, and a
signaling_format field of 2 bits. The extended field further
includes a payload_length_part field of a variable length depending
on a value of the signaling_format field.
[1060] If the value of the payload_config field is `1`, an LI field
of 1 bit and a segment_ID field of 3 bits are included in the fixed
header. Also, the extended header includes a
segment_sequence_number field of 4 bits, a segment_length_ID field
of 4 bits, a signaling_class field of 3 bits, an information_type
field of 3 bits, and a signaling_format field of 2 bits, or
includes a segment_sequence_number field of 4 bits and a
segment_length_ID field of 4 bits, or includes a
segment_sequence_number field of 4 bits and a last_segment_length
field of 12 bits.
[1061] The concatenation_count field (4 bits) corresponds to a
count field of FIG. 64, and one embodiment of the present invention
indicates how many link layer packets through which signaling
information provided by the upper layer is transmitted are used.
Alternatively, the field may indicate how many kinds of individual
signaling information configure one payload.
[1062] The signaling_class field (3 bits) indicates a type of the
signaling information included in the corresponding link layer
packet. especially a payload of the corresponding link layer
packet.
[1063] FIG. 65 illustrates an example of a type of signaling
information defined depending on a value of a signaling_class field
according to the present invention.
[1064] For example, if the value of the signaling_class field is
`000`, it indicates that the corresponding packet includes
signaling information (for example, SLT) for channel scan and
service acquisition. If the value of the signaling_class field is
`001`, it indicates that the corresponding packet includes
signaling information for emergency alert. If the value of the
signaling_class field is `010`, it indicates that the corresponding
packet includes signaling information for header compression.
[1065] In the present invention, if the value of the
signaling_class field is `001`, it indicates that the corresponding
packet includes signaling information for emergency alert. However,
this is one embodiment for assisting understanding of the present
invention, and a reserved value of the signaling_class field may be
used to indicate that the corresponding packet includes signaling
information for emergency alert.
[1066] If the type of the signaling information transmitted to the
corresponding packet is determined by the value of the
signaling_class field, the information_type field indicates a type
of data (that is, emergency alert information) transmitted to the
payload of the corresponding packet regarding the determined
signaling information. Also, detailed information may additionally
be included depending on the type of the data.
[1067] In the present invention, if the value of the
signaling_class field is 001, the corresponding packet will be
referred to as an emergency alert packet.
[1068] FIG. 66 illustrates an example of meanings defined depending
on a value of the information_type field of the emergency alert
packet according to the present invention.
[1069] If the value of the information_type field is `000`, it
indicates that the emergency alert message is transmitted to a
payload of the corresponding emergency alert packet. If the value
of the information_type field is `001`, it indicates that link (or
connection) information of the emergency alert message is
transmitted to the payload of the corresponding emergency alert
packet. If the value of the information_type field is `010`. it
indicates that information for automatic channel tuning is
transmitted to the payload of the corresponding emergency alert
packet. If the value of the information_type field is `011`, it
indicates that emergency alert related NRT service information is
transmitted to the payload of the corresponding emergency alert
packet.
[1070] And, if the value of the information_type field is `111`, it
indicates that wake_up indication information is transmitted to the
payload of the corresponding emergency alert packet. The wake_up
indication information is required to indicate whether the
corresponding emergency alert message needs a wake-up function.
That is, the wake-up indication information is required to support
a wake-up function of the broadcast receiver during the occurrence
of disaster. The wake-up function means that the broadcast receiver
should forcibly be switched to an active mode when an emergency
alert message is issued, which is serious enough to switch a
sleeping mode (or standby mode) to the active mode even though the
broadcast receiver is in the sleeping mode (or standby mode). In
order to support the wake-up function, the broadcast receiver
should continue to monitor a broadcast signal even in case of the
sleeping mode, and should know how the occurrence of disaster is
emergent, as quickly as possible.
[1071] In FIG. 66, the value allocated to the information_type
field and the meaning of the value are embodiments for assisting
understanding of the present invention, and addition and deletion
of information included in the information_type field may easily be
varied by the person with ordinary skill in the art. Therefore, the
present invention will not be limited to the aforementioned
embodiments. That is, if a procedure related to emergency alert is
additionally provided later, a reserved value of the
information_type field may be used to transmit the packet related
to the corresponding procedure.
[1072] The signaling format field indicates a format of signaling
information for emergency alert included in the corresponding
packet as one embodiment. Examples of the format that may be
indicated by the signaling format field may include a section table
such as EAT, a descriptor within an EAT, and XML. For example, if
the corresponding signaling information has its length value in the
same manner as the section table and the descriptor, a separate
length field may not be required. However, a separate length field
may be required in case of signaling information having no separate
length value. In case of the signaling information having no
separate length value, a payload_length_part field (length field in
FIG. 64) is used to indicate a length as one embodiment. In this
case, the payload_length part includes length fields equivalent to
the number of count fields as one embodiment.
[1073] That is, if the value of the signaling format field is
`1.times.`, the payload_length_part field indicates a length of
signaling information included in the payload of the corresponding
packet. At this time, the payload length part may be a set of
length fields indicating a length of each of signaling information
which are concatenated.
[1074] Meanwhile, if a value of the PC field is `1`, that is, if
signaling information for emergency alert is provided by the upper
layer through segmentation, fields included in the extended header
are determined depending on a value of the LI field.
[1075] The LI (last segment indicator) field indicates whether the
corresponding segment is the last segment, as one embodiment.
[1076] If the value of the LI field is `0`, that is, if the
corresponding segment is not the last segment, the segment_ID field
indicates information for identifying the corresponding
segment.
[1077] The segment_sequence_number field indicates the order of
respective segments when the signaling information for emergency
alert is segmented by the upper layer.
[1078] If the value of the LI field is `0` and the value of the
segment_sequence_number field value is `0000`, that is, the first
segment of the signaling information for emergency alert, the
extended header includes a segment_length_ID field of 4 bits, a
signaling_class field of 3 bits, an information_type field of 3
bits, and a signaling_format field of 2 bits. The segment_length_ID
field indicates a length of the first segment as one embodiment.
Details of the signaling_class field, the information_type field
and the signaling_format field will be understood with reference to
the aforementioned description.
[1079] If the value of the LI field is `0` and the value of the
segment_sequence_number field value is not `0000`. that is, neither
the first segment nor the last segment of the signaling information
for emergency alert, the extended header includes a
segment_sequence_number field of 4 bits and a segment_length_ID
field of 4 bits. As one embodiment, the segment_sequence_number
field indicates a segment number indicating an order of a
corresponding segment of the signaling information for emergency
alert, and the segment_length_ID field indicates a length of the
corresponding segment. That is. according to one embodiment, the
segment length ID field is used to indicate a length of each
segment except the last one of a plurality of segments.
[1080] If the value of the LI field is `1`, that is, the last
segment, the extended header includes a segment_sequence_number
field of 4 bits and a last_segment_length field of 12 bits. As one
embodiment, the segment_sequence_number field indicates a number of
the last segment, and the last_segment_length field indicates a
length of the last segment.
[1081] Therefore, when the signaling information for emergency
alert is segmented, the signaling information for emergency alert
may be completed in such a manner that the broadcast receiver
sequentially combines segments having the same segment ID by using
the above fields.
[1082] FIG. 67 illustrates a syntax of an example of fields
included in a payload of a link layer packet when a value of a
packet_type field of a corresponding link layer packet header
according to the present invention is `110` and a value of an
information_type field value is `000`. That is. FIG. 67 illustrates
an example of a syntax when the payload of the corresponding link
layer packet includes an emergency alert message of the signaling
information for emergency alert.
[1083] The emergency alert message is intended to mainly deliver a
CAP message, and the payload of the link layer packet directly
includes the CAP message. At this time, a concatenation method
supported by a packet structure of a link layer may be used to
transmit several emergency alert messages. In this case, the value
of the payload_config field is set to `0` and the value of the
count field signals the number of emergency alert messages, as one
embodiment. Also, when the emergency alert message is delivered
using the link layer packet, version information of the
corresponding emergency alert message is given to repeatedly
process the emergency alert message.
[1084] Each field of the payload of the link layer packet for
transmitting the emergency alert message in FIG. 67 will be
described as follows.
[1085] An EAS_message_id field (32 bits) indicates an identifier
for identifying each emergency alert message. As one embodiment,
each emergency alert message has an identifier identified from
another one.
[1086] An EAS_mesage_encoding_type field (4 bits) indicates
encoding type information of the emergency alert message. For
example, if a value of the EAS_message_encoding_type field is
`000`. it indicates that an encoding type of the emergency alert
message (or EAS message) has not been specified. If the value of
the EAS_message_encoding_type field is `001`. it indicates that the
emergency alert message has not been encoded. If the value of the
EAS_message_encoding_type field is `010`, it indicates that the
emergency alert message has been encoded by a DEFLATE algorithm. If
a new encoding method is used later, a reserved value of the
EAS_message_encoding_type field may be used to indicate the new
encoding method.
[1087] An EAS_message_version field (4 bits) indicates version
information of the corresponding emergency alert message. As one
embodiment of the present invention, the version information
included in the EAS_message_version field is used to determine
whether to process the emergency alert messages having the same EAS
message_id. In the present invention, a value increased as much as
1 whenever a new emergency alert message is generated is given to
the EAS_message_version field. In this case, if the value of the
EAS_message_version field is high, it indicates a new emergency
alert message. And, if the value of the EAS_message_version field
reaches a maximum value, next value has `0`. If the version
information of the emergency alert message can be identified
through the EAS_message_id field, the EAS_message_version field may
be omitted.
[1088] An EAS_message_protocol field (4 bits) indicates a protocol
of a corresponding emergency alert message. If the emergency alert
message is a CAP message, the EAS_message_protocol field indicates
a protocol of the CAP message as one embodiment. Also, if another
protocol other than the protocol of the CAP message is used, the
EAS_message_protocol field indicates the corresponding protocol.
For example, the EAS_message_protocol field may be used for
interworking of the emergency alert message with another network
such as a mobile network.
[1089] An EAS_message_length field (12 bits) indicates a length of
an emergency alert message actually included in a payload of a
corresponding packet. An emergency alert message which is intended
to be actually transmitted is transmitted through an
EAS_message_bytes( ) field. That is, the EAS_message_bytes( ) field
transmits the emergency alert message as much as a length
corresponding to a value of the EAS_message_length field.
[1090] FIG. 68 is a flowchart illustrating one embodiment of a
method for receiving and processing an emergency alert message in a
broadcast receiver according to the present invention.
Particularly. FIG. 68 illustrates one embodiment of a processing
method when an emergency alert message is received by being
included in a payload of a link layer packet in the same manner as
FIG. 67.
[1091] That is, if a packet for emergency alert is received (S301).
an identifier of the emergency alert message is identified (S302).
The packet received in the above step is the link layer packet
decapsulated from the physical layer packet, and it is identified
whether the packet is a packet for emergency alert, especially a
packet for transmitting an emergency alert message, by using
information signaled to the header of the link layer packet as one
embodiment. The identifier of the emergency alert message is
identified using the EAS_message_id field included in the payload
of the corresponding packet as one embodiment.
[1092] If the identifier of the emergency alert message is
identified in the step S302, it is identified whether the emergency
alert message (that is, EAS message) included in the payload of the
corresponding packet is effective (S303). If it is identified that
the emergency alert message is effective, version information of
the emergency alert message is identified (S304). That is, if it is
identified that the emergency alert message is effective, the
version information is identified using the EAS_message_version
field included in the payload of the corresponding packet. It is
identified whether the corresponding emergency alert message is the
updated message or the message which has been conventionally
received, based on the identified version information (S305). If
the corresponding emergency alert message is a message of a new
version, a decoding type and a protocol of the corresponding
emergency alert message are identified using the
EAS_message_encoding_type field and the EAS_message_protocol field
of the payload of the corresponding packet (S306). The
corresponding emergency alert message is processed in accordance
with the identified decoding type and protocol (S307). However, if
it is identified that the emergency alert message is not effective
in the step S303, or if it is identified that the corresponding
emergency alert message is not new version in the step S305, the
packet received in the step S301 is disregarded (S308). That is, if
the received emergency alert message is not effective or if the
corresponding emergency alert message is not new version newer than
the emergency alert message which has been conventionally received,
the corresponding packet is disregarded and may return to a standby
state for receiving another packet.
[1093] FIG. 69 is a syntax illustrating examples of fields included
in a payload of a corresponding link layer packet when a packet
type field value of the link layer packet header according to the
present invention indicates `110`, a signaling_class field value
indicates `001` and an information_type field value indicates
`001`. That is, FIG. 49 is an example of a syntax when a payload of
a corresponding link layer packet includes link or connection
information of an emergency alert message among signaling
information for emergency alert.
[1094] FIG. 69 illustrates an example of transmitting link or
connection information of the emergency alert message to the
payload of the link layer packet when the emergency alert message
is transmitted through a separate path due to a lack of
bandwidth.
[1095] Each field of the payload of the link layer packet for
transmitting link or connection information of the emergency alert
message in FIG. 69 will be described as follows.
[1096] Since an EAS_message_id field (32 bits), an
EAS_message_encoding_type field (4 bits), an EAS_message_version
field (4 bits), and an EAS_message_protocol field (4 bits) mean the
EAS_message_id field, the EAS_message_encoding_type field, the
EAS_message_version field and the EAS_message_protocol field of
FIG. 67, their detailed description will be understood with
reference to FIG. 67 and thus will be omitted here.
[1097] Meanwhile, in FIG. 69, a message_link_type field (4 bits)
indicates a type of link information for acquiring the emergency
alert message when the emergency alert message is transmitted
through another path other than the payload of the corresponding
packet.
[1098] For example, if a value of the message_link_type field is
`0000`. it indicates that IP datagram of the emergency alert
message is transmitted through a data pipe (that is, PLP). That is,
this case may be applied to a case where the emergency alert
message is transmitted through a data pipe, which is located within
a channel to which the corresponding packet is received. in the
form of IP datagram. In this case, access information for accessing
IP datagram of the emergency alert message is additionally
signaled. The access information includes at least one of an IP
address, a UDP port number, and identification information of the
corresponding data pipe as one embodiment.
[1099] That is, if the value of the message_link_type field is
`0000`, the corresponding payload includes an IP address field, a
UDP_port_num field, and a DP_id field.
[1100] The IP address field (32 or 128 bits) indicates an IP
address of IPv4 or an IP address of IPv6 of the IP datagram of the
emergency alert message, and the UDP_port_num field (16 bits)
indicates a UDP port number of the IP datagram of the emergency
alert message. The DP_id field (8 bits) indicates an identifier of
a data pipe that transmits the IP datagram of the emergency alert
message.
[1101] If the value of message_link_type field is `0001`, it
indicates that the emergency alert message is transmitted through
another channel not the channel to which the corresponding packet
is transmitted. In this case, access information for accessing the
emergency alert message transmitted to another channel is
additionally signaled. The access information includes at least one
of channel information, data pipe identification information, and
service information as one embodiment.
[1102] That is, if the value of the message_link_type field is
`0001`, the corresponding payload includes an EAS_channel_number
field, an EAS_DP_id field, and an EAS_service_id field.
[1103] The EAS_channel_number field (8 bits) indicates channel
information to which the emergency alert message is transmitted. In
this case, the channel information may be a frequency number, or
may be a major channel number and a minor channel number. That is,
the EAS_channel_number field indicates a corresponding channel
number when the emergency information message is received from
another channel not the channel currently received by the broadcast
receiver. If the channel number is related with the frequency
number, the corresponding field may be replaced with the frequency
number.
[1104] The EAS_DP_id field (8 bits) indicates an identifier of a
data pipe that transmits the emergency alert message from a channel
signaled to the EAS_channel_number field value. The EAS_DP_id field
is optionally used. For example, if there is a separate path in the
corresponding channel instead of the data pipe to which the
emergency alert message is transmitted, the corresponding field may
not be provided additionally.
[1105] The EAS_service_id field (16 bits) indicates an identifier
of a service that includes the emergency alert message. That is,
when several services are transmitted to one channel, the
EAS_service_id field indicates an identifier of a service for
acquiring the emergency alert message. If it is required to acquire
a separate service in receiving the emergency alert message, the
field may not be provided additionally.
[1106] If the value of the message_link_type field is `0010`. it
indicates that the emergency alert message is transmitted through a
broadband when the broadcast receiver is connected to the
broadband. If the value of the message_link_type field is `0010`, a
broadband_link_info( ) field of a variable length is provided
additionally. The broadband_link_info( ) field indicates link
information for the emergency alert message transmitted through the
broadband.
[1107] If the value of the message_link_type field is `0011`, it
indicates that the emergency alert message is transmitted through
another network (for example, mobile network) not a broadcast
network and a broadband network. If the value of the
message_link_type field `0011`, an external_network_information( )
field of a variable length is provided additionally. The
external_network_information ( ) field indicates link information
for the emergency alert message transmitted through another network
such as a mobile network and information for the corresponding
network. The other values of the message_link_type field are
reserved for future use. Therefore, the remaining values may be
used later depending on new link. Also, if the emergency alert
message is transmitted through a network not the broadcast network,
the remaining values may be used to transmit additional emergency
alert message.
[1108] FIG. 70 is a flowchart illustrating another embodiment of a
method for receiving and processing an emergency alert message in a
broadcast receiver according to the present invention.
Particularly. FIG. 70 illustrates an embodiment of a processing
method when link information of an emergency alert message is
received by being included in a payload of a link layer packet in
the same manner as FIG. 69.
[1109] That is, if a packet for emergency alert is received (S401),
an identifier of the emergency alert message is identified (S402).
The packet received in the above step is the link layer packet
decapsulated from the physical layer packet, and it is identified
whether the packet is a packet for emergency alert, especially a
packet for transmitting link information of the emergency alert
message, by using information signaled to the header of the link
layer packet as one embodiment. The identifier of the emergency
alert message is identified using the EAS_message_id field included
in the payload of the corresponding packet as one embodiment.
[1110] If the identifier of the emergency alert message is
identified in the step S402, it is identified whether the emergency
alert message (that is, EAS message) is effective (S403). If it is
identified that the emergency alert message is effective, version
information of the emergency alert message is identified using the
EAS_message_version field included in the payload of the
corresponding packet (S404). It is identified whether the
corresponding emergency alert message is the updated message or the
message which has been conventionally received, based on the
identified version information (S405). If the corresponding
emergency alert message is a message of a new version, a decoding
type and a protocol of the corresponding emergency alert message
are identified using the EAS_message_encoding_type field and the
EAS_message_protocol field which are included in the payload of the
corresponding packet (S406).
[1111] Connection or link information to which the corresponding
emergency alert message is transmitted is identified using the
message_link_type field included in the payload of the
corresponding packet (S407). It is identified whether a network
that transmits the emergency alert message is an available network
based on the connection or link information identified in the step
S407 (S408). If it is identified that the corresponding network is
the available network in the step S408, the emergency alert message
is received using access information included in the payload of the
corresponding packet (S409). That is, if the corresponding
connection or link information is an effective network or a link
that may be linked by the broadcast receiver, the emergency alert
message is received using access information of the corresponding
link.
[1112] For example, if a value of the message_link_type field is
`0000`, that is, if the emergency alert message is received through
a data pipe. which is located within a channel to which the
corresponding packet is received, in the form of IP datagram. the
access information may be at least one of an IP address, a UDP port
number, and identification information of the data pipe.
[1113] If the value of the message_link_type field is `0001`, that
is, if the emergency alert message is received through another
channel not the channel to which the corresponding packet is
received, the access information may be at least one of channel
information, data pipe identification information, and service
identification information.
[1114] If the value of the message_link_type field is `0010`, that
is, if the emergency alert message is received through a broadband,
the access information may be acquired from a broadband_link_info(
) field included in the payload of the corresponding packet.
[1115] If the value of the message_link_type field is `0011`, that
is, if the emergency alert message is received through another
network (for example, mobile network) not a broadcast network and a
broadband network, the access information may be acquired from an
external_network_information (field included in the packet of the
corresponding packet.
[1116] If the emergency alert message is received in the step S409.
the received emergency alert message is processed in accordance
with the decoding type and protocol identified in the step S406
(S410). However, if it is identified that the emergency alert
message is not effective in the step S403, if it is identified that
the corresponding emergency alert message is not new version in the
step S405, or if it is identified that the corresponding network is
not available network in the step S408, the packet received in the
step S401 is disregarded (S411). That is, if the link for
transmitting the emergency alert message is not effective, if it is
not possible to access the corresponding link, or if the
corresponding emergency alert message is not new version newer than
the emergency alert message which has been conventionally received,
the corresponding packet is disregarded and may return to a standby
state for receiving another packet.
[1117] FIG. 71 is a syntax illustrating examples of fields included
in a payload of a corresponding link layer packet w % ben a packet
type field value of the link layer packet header according to the
present invention indicates `110`, a signaling_class field value
indicates `001` and an information_type field value indicates
`010`. That is, FIG. 71 is an example of a syntax when a payload of
a corresponding link layer packet includes information for
automatic tuning to a channel for transmitting contents related to
an emergency alert message among signaling information for
emergency alert.
[1118] In other words, FIG. 71 illustrates an example of
transmitting automatic tuning information for automatic tuning from
a current channel to a channel, to which emergency alert related
contents are transmitted, to a payload of a link layer packet in a
broadcast receiver when audio/video contents related to emergency
alert are transmitted simultaneously with the emergency alert
message.
[1119] Each field of the payload of the link layer packet for
transmitting automatic tuning information related to emergency
alert in FIG. 71 will be described as follows.
[1120] A num_associated_EAS_messages field (8 bits) indicates the
number of emergency alert messages related to channel tuning
information. A `for` loop (or message identification loop) is
performed as much as a value of the num_associated_EAS_messages
field, whereby identification information of the related emergency
alert message is provided. To this end, an
associated_EAS_message_id field (32 bits) is included in the `for`
loop. That is, the associated_EAS_message_id field indicates an
identifier of each emergency alert message related to automatic
tuning information transmitted to a current packet. The
associated_EAS_message_id field may be used to identify whether the
broadcast receiver has received the emergency alert message for
channel tuning earlier than the tuning information.
[1121] An automatic_tuning_channel number field (8 bits) indicates
channel information which should be tuned to receive audio/video
contents related to emergency alert. In this case, the channel
information may be a frequency number, or may be a major channel
number and a minor channel number. That is, the
automatic_tuning_channel_number field may indicate a channel number
for transmitting audio/video contents related to emergency alert.
If the channel number is related with the frequency number, the
corresponding field may be replaced with the frequency number or
may be used together with the frequency number.
[1122] An automatic tuning_DP_id field (8 bits) indicates an
identifier of a data pipe (that is. physical layer pipe) that
transmits audio/video contents related to emergency alert from a
channel signaled to the automatic tuning_channel_number field.
[1123] An automatic tuning_service_id field (16 bits) indicates an
identifier of a service for acquiring audio/video contents related
to emergency alert.
[1124] FIG. 72 is a flowchart illustrating still another embodiment
of a method for receiving and processing an emergency alert message
in a broadcast receiver according to the present invention.
Particularly, FIG. 72 illustrates an embodiment of a processing
method when automatic tuning information related to emergency alert
is received by being included in a payload of a link layer packet
in the same manner as FIG. 51.
[1125] That is, if a packet for emergency alert is received (S501),
an identifier of the emergency alert message is identified (S502).
The packet received in the above step is the link layer packet
decapsulated from the physical layer packet, and it is identified
whether the packet is a packet for emergency alert, especially a
packet for transmitting information for automatic tuning, by using
information signaled to the header of the link layer packet as one
embodiment.
[1126] The identifier of the emergency alert message is identified
using the associated_EAS_message_id field included in the payload
of the corresponding packet as one embodiment.
[1127] If the identifier of the emergency alert message is
identified in the step S502, it is identified whether the emergency
alert message (that is, EAS message) is effective (S503). As one
embodiment of the present invention, when the packet is received,
it is identified whether the related emergency alert message is
received earlier than the packet, using the
associated_EAS_message_id field, and if not so, it may be
identified that the corresponding emergency alert message is not
effective. In this case, the corresponding packet is disregarded
without being processed as one embodiment.
[1128] If it is identified that the emergency alert message is
effective, tuning information is acquired from the payload of the
corresponding packet (S504). The tuning information may be acquired
from at least one of the automatic_tuning_channel_number field, the
automatic_tuning_DP_id field, and the automatic_tuning_service_id
field.
[1129] Then, it is identified whether channel tuning is ready
(S505), and if it is identified that channel tuning is ready, a
current channel is automatically tuned to a channel for
transmitting emergency alert related audio/video contents based on
the channel information, whereby emergency alert service is
acquired (S506). If the current channel is the channel for
transmitting emergency alert related audio/video contents indicated
by the channel information, the current channel is maintained
without channel tuning. However, if it is identified that the
emergency alert message is not effective in the step S503, or if it
is identified that channel tuning is not ready in the step S505,
the packet received in the step S501 is disregarded and returns to
a standby state for receiving another packet (S507).
[1130] Meanwhile, as one embodiment of the present invention, if
the received packet is a packet for emergency alert, especially a
packet for transmitting information for automatic tuning, it may
indicate that an automatic tuning flag is enabled. Also, if the
corresponding packet is received, it is identified whether the
related emergency alert message is received earlier than the
packet, and if the related emergency alert message is not received
earlier than the packet, the corresponding packet is disregarded.
To this end, a list of emergency alert messages related to channel
information to be currently tuned may be transmitted to the payload
of the corresponding packet by using the associated_EAS_message_id
field.
[1131] FIG. 73 is a syntax illustrating examples of fields included
in a payload of a corresponding link layer packet when a
packet_type field value of the link layer packet header according
to the present invention indicates `110`, a signaling_class field
value indicates `001` and an information_type field value indicates
`011`. That is, FIG. 73 is an example of a syntax when a payload of
a corresponding link layer packet includes NRT service information
related to emergency alert among signaling information for
emergency alert.
[1132] Each field of the payload of the link layer packet for
transmitting NRT service information related to emergency alert in
FIG. 73 will be described as follows.
[1133] A num_associated_EAS_messages field (8 bits) indicates the
number of emergency alert messages related to channel tuning
information. A `for` loop (or message identification loop) is
performed as much as a value of the num_associated_EAS_messages
field, whereby identification information of the related emergency
alert message is provided. To this end, an
associated_EAS_message_id field (32 bits) is included in the `for`
loop. That is, the associated_EAS_message_id field indicates an
identifier of each emergency alert message related to automatic
tuning information which is transmitted. The
associated_EAS_message_id field may be used to identify whether the
broadcast receiver has received the emergency alert message for
channel tuning earlier than the channel tuning information.
[1134] An EAS_NRT_service_id field (16 bits) indicates an
identifier of NRT service corresponding to a case where NRT
contents and data related to the received emergency alert message
are transmitted, that is, a case where EAS_NRT_flag is enabled.
[1135] FIG. 74 is a flowchart illustrating further still another
embodiment of a method for receiving and processing an emergency
alert message in a broadcast receiver according to the present
invention. Particularly, FIG. 74 illustrates an embodiment of a
processing method when NRT service information related to emergency
alert is received by being included in a payload of a link layer
packet in the same manner as FIG. 73.
[1136] That is, if a corresponding packet is received, the
broadcast receiver may identify an identifier of NRT service and
enter a procedure of acquiring NRT service.
[1137] That is, if a packet for emergency alert is received (S601),
an identifier of the emergency alert message is identified (S602).
The packet received in the above step is the link layer packet
decapsulated from the physical layer packet, and it is identified
whether the packet is a packet for emergency alert, especially a
packet for transmitting NRT service information related to
emergency alert, by using information signaled to the header of the
link layer packet as one embodiment. The identifier of the
emergency alert message is identified using the
associated_EAS_message_id field included in the payload of the
corresponding packet as one embodiment.
[1138] If the identifier of the emergency alert message is
identified in the step S602, it is identified whether the emergency
alert message (that is, EAS message) is effective (S603). As one
embodiment of the present invention, when the packet is received,
it is identified whether the related emergency alert message is
received earlier than the packet, using the
associated_EAS_message_id field, and if not so, it may be
identified that the corresponding emergency alert message is not
effective. In this case, the corresponding packet is disregarded
without being processed as one embodiment (S606).
[1139] If it is identified that the emergency alert message is
effective, an identifier of the NRT service is identified from the
payload of the corresponding packet (S604). The identifier of the
NRT service may be identified using the EAS_NRT_service_id field
included in the payload of the packet.
[1140] If the identifier of the NRT service is identified in the
step S604, the corresponding NRT service is acquired based on the
identified identifier (S605).
[1141] Meanwhile, as one embodiment of the present invention, if
the received packet is a packet for emergency alert, especially a
packet for transmitting NRT service information related to
emergency alert, it is identified whether the related emergency
alert message is received earlier than the NRT service information,
and if the related emergency alert message is not received earlier
than the NRT service, the corresponding packet is disregarded. To
this end, a list of emergency alert messages related to channel
information to be currently tuned may be transmitted to the payload
of the corresponding packet by using the associated_EAS_message_id
field.
[1142] Meanwhile, the method for processing emergency alert
information, as described with reference to FIGS. 62 to 74, may be
performed by any one of the emergency alert systems of FIGS. 53 to
56 and FIG. 58.
[1143] FIGS. 75 to 77 illustrate various embodiments of a receiving
apparatus of a next generation broadcasting system for processing
emergency alert information in accordance with the present
invention.
[1144] FIG. 75 is a schematic block diagram illustrating a
receiving apparatus of a next generation broadcasting system
according to one embodiment of the present invention.
[1145] A receiving apparatus M100 according to one embodiment of
the present invention includes a receiving module M1110, a
controller M1150, and an Internet protocol (IP) communication
module M1130. The receiving module M1110 includes a channel
synchronizer M1111, a channel equalizer M1115, and a channel
decoder M1113. The controller M1150 may include a signaling decoder
M1151. a baseband operation controller M1157, a service map DB
M1161, a transport packet interface M1153, a broadband packet
interface M1155, a common protocol stack M1159, a service signaling
channel processing buffer & parser M1163, an A/V processor
M1165, a service guide processor M1167, an application processor
M1169, and/or a service guide DB M1171.
[1146] In FIG. 75, the channel synchronizer M1111 of the receiving
module M1110 synchronizes symbol frequency with timing to decode a
signal received from a baseband. In this case, the baseband
indicates an area where a broadcast signal is transmitted and
received.
[1147] The channel equalizer M1115 performs channel equalization on
the received signal. The channel equalizer M1115 serves to
compensate for the received signal when the received signal is
distorted due to multipath, Doppler effect, etc.
[1148] The channel decoder M1113 recovers the received signal to a
transport frame which is meaningful. The channel decoder M1113
performs forward error correction (FEC) for data included in the
received signal or the transport frame.
[1149] The signaling decoder M1151 extracts and decodes signaling
data included in the received signal. In this case, the signaling
data include signaling data, which will be described later, and/or
service information (SI). Also, the signaling data may include an
emergency alert message or emergency alert related signaling
information.
[1150] The baseband operation controller M1157 controls signal
processing at the baseband.
[1151] The service map DB M1161 stores signaling data and/or
service information therein. The service map DB M1161 may store
signaling data transmitted by being included in a broadcast signal
and/or signaling data transmitted by being included in a broadband
packet.
[1152] The transport packet interface M1153 extracts a transport
packet from the transport frame or the broadcast signal. In this
case, the transport packet is a link layer packet acquired by
decapsulation of a baseband packet included in the transport frame
as one embodiment.
[1153] The transport packet interface M1153 extracts signaling data
or IP datagram from the transport packet. The broadband packet
interface M1155 receives a broadcasting related packet through the
broadband. The broadband packet interface M1155 extracts the packet
acquired through the broadband, and combines or extracts signaling
data or A/V data from the corresponding packet.
[1154] The common protocol stack M1159 processes the received
packet in accordance with a protocol included in a protocol stack.
For example, the common protocol stack M1159 may process the
received packet in each protocol in accordance with the
aforementioned method.
[1155] The service signaling channel processing buffer & parser
M1163 extracts signaling data included in the received packet. The
service signaling channel processing buffer & parser M1163
extracts signaling information related to scan and/or acquisition
of services and/or contents from the IP datagram, and parses the
extracted signaling information. The signaling data may exist at a
given location or channel within the received packet. This location
or channel may be referred to as a service signaling channel. For
example, the service signaling channel may have a specific IP
address, a UDP port number, a transport session identifier, etc.
The receiver may recognize data transmitted to the specific IP
address, the UDP port number and the transport session as signaling
data.
[1156] The A/V processor M1165 performs decoding and presentation
processing for received audio and video data.
[1157] The service guide processor M1167 extracts announcement
information from the received signal, manages a service guide DB
M1171, and provides a service guide.
[1158] The application processor M1169 extracts application data
and/or application related information included in the received
packet and processes the extracted application data and application
related information.
[1159] The service guide DB M1171 stores service guide data
therein.
[1160] Also, the controller M1150 processes emergency alert related
information according to the present invention, which is received
from the link layer packet, as one embodiment. To this end, the
controller M1150 may further include an emergency alert processor
(not shown), and the transport packet interface M1153 may process
the emergency alert related information according to the present
invention. In FIG. 75, the transport packet interface M1153
processes the emergency alert related information as one
embodiment. That is, the transport packet interface M1153 extracts
the transport packet from the transport frame (or physical layer
frame) or the broadcast signal. At this time, the transport packet
may be a physical layer packet or a link layer packet. If the
transport packet is a physical layer packet, the link layer packet
is acquired by decapsulation of the physical layer packet as one
embodiment. The link layer packet depends on the structures of
FIGS. 62 to 64 as one embodiment. This is one embodiment for
assisting understanding of the present invention, and since the
link layer packet structure according to the present invention may
be modified by a designer, the present invention is not limited to
the aforementioned embodiment.
[1161] The transport packet interface M1153 may identify that data
received in the link layer packet using each field included in the
header of the link layer packet as shown in FIGS. 62 to 66 is
signaling information and especially is a packet that includes
signaling information for emergency alert. In addition, the
transport packet interface MI 153 may identify whether the payload
of the link layer packet includes an emergency alert message of
signaling information for emergency alert, link information of an
emergency alert message. emergency alert related automatic tuning
information, emergency alert related NRT service information, or
wake-up indication information. The method and steps for this
identification have been described in detail as above and thus
their description will be omitted herein.
[1162] If it is identified that the payload of the corresponding
link layer packet includes the emergency alert message of signaling
information for emergency alert, the transport packet interface
M1153 processes the emergency alert message included in the
corresponding payload with reference to each field included in the
payload of the corresponding packet as described with reference to
FIGS. 67 and 68.
[1163] If it is identified that the payload of the corresponding
link layer packet includes link information of the emergency alert
message of signaling information for emergency alert, the transport
packet interface M1153 acquires link information and/or access
information for acquiring the emergency alert message with
reference to each field included in the payload of the
corresponding packet as described with reference to FIGS. 69 and
70, and receives and processes the emergency alert message by using
the acquired link information and/or access information.
[1164] For example, if it is identified that the emergency alert
message is received in the form of IP datagram through a data pipe
within a channel to which the corresponding packet is received, the
link and access information may be at least one of an IP address, a
UDP port number and identification information of the data pipe.
For another example, if it is identified that the emergency alert
message is received through another channel not the channel to
which the corresponding packet is received, the link and access
information may be at least one of channel information,
identification information of the data pipe, and service
identification information.
[1165] If it is identified that the payload of the corresponding
link layer packet includes emergency alert related automatic tuning
information of signaling information for emergency alert, the
transport packet interface M1153 acquires tuning information, which
will be tuned automatically, with reference to each field included
in the payload of the corresponding packet as described with
reference to FIGS. 71 and 72, and controls channel tuning by using
the acquired tuning information.
[1166] If it is identified that the payload of the corresponding
link layer packet includes emergency alert related NRT service
information of signaling information for emergency alert, the
transport packet interface MI 153 acquires emergency alert related
NRT service information with reference to each field included in
the payload of the corresponding packet as described with reference
to FIGS. 73 and 74, and acquires NRT service based on the acquired
information.
[1167] FIG. 76 is a schematic block diagram illustrating a
broadcast receiver of a next generation broadcasting system
according to another embodiment of the present invention.
[1168] In the embodiment of FIG. 76, the broadcast receiver
includes a broadcasting receiving module M2110, an Internet
protocol (IP) communication module M2130, and a controller
M2150.
[1169] The broadcasting receiving module M2110 may include a tuner,
a physical frame parser, and a physical layer controller.
[1170] The tuner extracts a physical frame by receiving a broadcast
signal through a broadcast channel. The physical frame is a
transport unit on a physical layer. The physical frame parser
acquires a link layer packet by parsing the received physical
frame. For example, the physical frame parser acquires the link
layer packet by decapsulation of a baseband packet included in the
physical frame as one embodiment. The link layer packet may be
referred to as a link layer frame, and a link layer packet parser
may be referred to as a link layer frame parser. The physical layer
controller controls operations of the tuner and the physical frame
parser. In one embodiment, the physical layer controller may
control the tuner by using RF information of the broadcast channel.
In more detail, if the physical layer controller transmits
frequency information to the tuner, the tuner may acquire the
physical frame corresponding to the received frequency information
from the broadcast signal.
[1171] In another embodiment, the physical layer controller may
control the operation of the physical layer parser through an
identifier of a physical layer pipe. In more detail, the physical
layer controller transmits identifier information for identifying a
specific one of a plurality of physical layer pipes to the physical
frame parser. The physical frame parser may identify the physical
layer pipe based on the received identifier information and acquire
the link layer packet from the identified physical layer pipe.
[1172] The controller M2150 includes a link layer packet parser, an
IP/UDP datagram filter, a control engine, an ALC/LCT+ client, a
timing controller, a DASH client, an ISO BMFF parser, and a media
decoder.
[1173] The link layer packet parser extracts data from the link
layer packet. In more detail, the link layer packet parser may
acquire link layer signaling from the link layer packet. Also, the
link layer packet parser may acquire IP/UDP datagram from the link
layer packet.
[1174] The IP/UDP datagram filter filters a specific one from the
IP/UDP datagram received from the link layer packet parser.
[1175] The ALC/LCT+ client processes an application layer transport
packet. The application layer transport packet may include an
ALC/LCT+ packet. In more detail, the ALC/LCT+ client may generate
one or more ISO BMFF media file format objects by collecting a
plurality of application layer transport packets.
[1176] The timing controller processes a packet that includes
system time information, and controls a system clock in accordance
with the processed result.
[1177] The DASH client processes real time streaming or adaptive
media streaming. In more detail, the DASH client may acquire a DASH
segment by processing adaptive media streaming based on HTTP. At
this time, the DASH segment may be a format of ISO BMFF object.
[1178] The ISO BMFF parser extracts audio/video data from the ISO
BMFF object received from the DASH client. At this time, the ISO
BMFF parser may extract the audio/video data in a unit of an access
unit. Also, the ISO BMFF parser may acquire timing information for
audio/video from the ISO BMFF object.
[1179] The media decoder decodes the received audio and video data.
Also, the media decoder performs presentation for the decoded
result through a media output terminal.
[1180] The control engine serves as an interface between the
respective modules. In more detail, the control engine may control
the operation of each module by transmitting a parameter required
for the operation of each module.
[1181] The Internet protocol communication module M2130 may include
an HTTP access client. The HTTP access client may transmit and
receive a request to and from an HTTP server, or may transmit and
receive a response to the request to and from the HTTP server.
[1182] As one embodiment of the present invention, the emergency
alert related information according to the present invention, which
is received from the link layer packet parser to the link layer
packet, is processed. As another embodiment, the present invention
may further include an emergency alert processor (not shown). The
link layer packet acquired by the physical layer packet parser
depends on the structures of FIGS. 62 to 64 as one embodiment. This
is one embodiment for assisting understanding of the present
invention, and since the link layer packet structure according to
the present invention may be modified by a designer, the present
invention is not limited to the aforementioned embodiment.
[1183] The link layer packet parser may identify that data received
in the link layer packet using each field included in the header of
the link layer packet as shown in FIGS. 62 to 66 is signaling
information and especially is a packet that includes signaling
information for emergency alert. In addition, the link layer packet
parser may identify whether the payload of the link layer packet
includes an emergency alert message of signaling information for
emergency alert, link information of an emergency alert message,
emergency alert related automatic tuning information, emergency
alert related NRT service information, or wake-up indication
information. The method and steps for this identification have been
described in detail as above and thus their description will be
omitted herein.
[1184] If it is identified that the payload of the corresponding
link layer packet includes the emergency alert message of signaling
information for emergency alert, the link layer packet parser
processes the emergency alert message included in the corresponding
payload with reference to each field included in the payload of the
corresponding packet as described with reference to FIGS. 67 and
68.
[1185] If it is identified that the payload of the corresponding
link layer packet includes link information of the emergency alert
message of signaling information for emergency alert, the link
layer packet parser acquires link information and/or access
information for acquiring the emergency alert message with
reference to each field included in the payload of the
corresponding packet as described with reference to FIGS. 69 and
70, and receives and processes the emergency alert message by using
the acquired link information and/or access information.
[1186] If it is identified that the payload of the corresponding
link layer packet includes emergency alert related automatic tuning
information of signaling information for emergency alert, the link
layer packet parser acquires tuning information, which will be
tuned automatically, with reference to each field included in the
payload of the corresponding packet as described with reference to
FIGS. 71 and 72, and controls channel tuning by using the acquired
tuning information.
[1187] If it is identified that the payload of the corresponding
link layer packet includes emergency alert related NRT service
information of signaling information for emergency alert, the link
layer packet parser acquires emergency alert related NRT service
information with reference to each field included in the payload of
the corresponding packet as described with reference to FIGS. 73
and 74, and acquires NRT service based on the acquired
information.
[1188] FIG. 77 is a schematic block diagram illustrating a
broadcast receiver of a next generation broadcasting system
according to still another embodiment of the present invention.
[1189] In the embodiment of FIG. 77, the broadcast receiver M3100
includes a broadcasting receiving module M3110, an Internet
protocol (IP) communication module M3130, and a controller
M3150.
[1190] The broadcasting receiving module M3110 may include one or a
plurality of processors for performing each of a plurality of
functions performed by the broadcasting receiving module M3110, one
or a plurality of circuits, and one or a plurality of hardware
modules. In more detail, the broadcasting receiving module M3110
may be a system on chip (SOC) in which a plurality of semiconductor
parts are integrated into one. At this time, the SOC may be a
semiconductor obtained by combining various multimedia parts, such
as graphic, audio, video, and modem, with a processor and DRAM. The
broadcasting receiving module M3110 may include a physical layer
module M3119 and a physical layer IP frame module M3117. The
physical layer module M3119 receives and processes a broadcasting
related signal through a broadcast channel of a broadcast network.
The physical layer IP frame module M3117 converts a data packet
such as IP datagram acquired from the physical layer module M3119
to a specific frame. For example, the physical layer IP frame
module M3117 may convert the IP datagram to a link layer frame, a
link layer packet, or GSE.
[1191] The IP communication module M3130 may include one or a
plurality of processors for performing each of a plurality of
functions performed by the IP communication module M3130, one or a
plurality of circuits, and one or a plurality of hardware modules.
In more detail, the IP communication module M3130 may be a system
on chip (SOC) in which a plurality of semiconductor parts are
integrated into one. At this time, the SOC may be a semiconductor
obtained by combining various multimedia parts, such as graphic,
audio, video, and modem, with a processor and DRAM. The IP
communication module M3130 may include an Internet access control
module M3131. The Internet access control module M3131 controls the
operation of the broadcast receiver M3100 for acquiring at least
one of services, contents and signaling data through an Internet
communication network (broadband).
[1192] The controller M3150 may include one or a plurality of
processors for performing each of a plurality of functions
performed by the controller M3150, one or a plurality of circuits,
and one or a plurality of hardware modules. In more detail, the
controller M3150 may be a system on chip (SOC) in which a plurality
of semiconductor parts are integrated into one. At this time, the
SOC may be a semiconductor obtained by combining various multimedia
parts, such as graphic, audio, video, and modem, with a processor
and DRAM.
[1193] The controller M3150 may include at least one of a signaling
decoder M3151, a service map database M3161, a service signaling
channel parser M3163, an application signaling parser M3166, an
emergency alert signaling parser M3168, a targeting signaling
parser M3170, a targeting processor M3173, an A/V processor M3161,
an emergency alert processor M3162, an application processor M3169,
a scheduled streaming decoder M3181, a file decoder M3182, a user
request streaming decoder M3183, a file database, a component
synchronizer M3185, a service/content acquisition controller M3187,
a redistribution module M3189, a device manager M3193, and a data
sharing module M3191.
[1194] The service/content acquisition controller M3187 controls
the operation of the receiver for acquiring services, contents, and
signaling data related to services or contents, which are acquired
through a broadcast network or Internet communication network.
[1195] The signaling decoder M3151 decodes signaling
information.
[1196] The service signaling parser M3163 parses service signaling
information.
[1197] The application signaling parser M3166 extracts and parses
signaling information related to services. At this time, the
signaling information related to services may be signaling
information related to service scan. Also, the signaling
information related to services may be signaling information
related to contents provided through services.
[1198] The emergency alert signaling parser M3168 extracts and
parses emergency alert related signaling information.
[1199] The targeting signaling parser M3170 extracts and parses
information for personalizing services or contents or information
for signaling targeting information.
[1200] The targeting processor M3173 processes information for
personalizing services or contents.
[1201] The emergency alert processor M3162 processes emergency
alert related signaling information.
[1202] The application processor M3169 controls running of
application and application related information. In more detail,
the application processor M3169 processes a state of a downloaded
application and a display parameter.
[1203] The A/V processor M3161 processes a rendering related
operation of audio/video on the basis of decoded audio or video,
application data. etc.
[1204] The scheduled streaming decoder M3181 previously decodes
scheduled streaming which is a content streamed in accordance with
a schedule determined by a content provider such as a broadcasting
station.
[1205] The file decoder M3182 decodes downloaded files.
Particularly. the file decoder M3182 decodes files downloaded
through a broadband.
[1206] The user request streaming decoder M3183 decodes an on
demand command provided by a user request.
[1207] The file database stores files therein. In more detail, the
file database may store files downloaded through the broadband.
[1208] The component synchronizer M3185 synchronizes contents or
services. In more detail, the component synchronizer M3185 performs
synchronization for a play time of a content acquired through at
least one of the scheduled streaming decoder M3181, the file
decoder M3182 and the user request streaming decoder M3183.
[1209] The service/content acquisition controller M3187 controls
the operation of the receiver for acquiring at least one of
services, contents, and signaling information related to services
or contents.
[1210] The redistribution module M3189 performs an operation for
supporting acquisition of at least one of service, content, service
related information and content related information if service or
content is not received through a broadcast network. In more
detail, the redistribution module M3189 may request an external
management device M3300 of at least one of service, content,
service related information and content related information. At
this time, the external management device M3300 may be a content
server.
[1211] The device manager M3193 manages an interworking external
device. In more detail, the device manager M3193 may perform at
least one of addition, deletion and update of the external device.
Also, the external device may enable connection and data exchange
with the broadcast receiver M3100.
[1212] The data sharing module M3191 performs a data transmission
operation between the broadcast receiver M3100 and the external
device, and processes exchange related information. In more detail,
the data sharing module M3191 may transmit A/V data or signaling
information to the external device. Also, the data sharing module
M3191 may receive A/V data or signaling information from the
external device.
[1213] Meanwhile, the physical layer IP frame module 117 converts a
baseband packet included in a physical layer frame to a link layer
packet through decapsulation as one embodiment. As one embodiment,
the emergency alert signaling parser M3168 extracts and parses
emergency alert related signaling information from the link layer
packet, and the emergency alert processor M3162 processes the
parsed emergency alert related signaling information.
[1214] The link layer packet parsed by the emergency alert
signaling parser M3168 depends on the structures of FIGS. 62 to 64
as one embodiment. This is one embodiment for assisting
understanding of the present invention, and since the link layer
packet structure according to the present invention may be modified
by a designer. the present invention is not limited to the
aforementioned embodiment.
[1215] The emergency alert signaling parser M3168 may identify that
data received in the link layer packet using each field included in
the header of the link layer packet as shown in FIGS. 62 to 66 is
signaling information and especially is a packet that includes
signaling information for emergency alert. In addition, the
emergency alert signaling parser M3168 may identify whether the
payload of the link layer packet includes an emergency alert
message of signaling information for emergency alert, link
information of an emergency alert message, emergency alert related
automatic tuning information, emergency alert related NRT service
information, or wake-up indication information. The method and
steps for this identification have been described in detail as
above and thus their description will be omitted herein.
[1216] If it is identified that the payload of the corresponding
link layer packet includes the emergency alert message of signaling
information for emergency alert, the emergency alert processor
M3162 processes the emergency alert message included in the
corresponding payload with reference to each field included in the
payload of the corresponding packet as described with reference to
FIGS. 67 and 68.
[1217] If it is identified that the payload of the corresponding
link layer packet includes link information of the emergency alert
message of signaling information for emergency alert, the emergency
alert processor M3162 acquires link information and/or access
information for acquiring the emergency alert message with
reference to each field included in the payload of the
corresponding packet as described with reference to FIGS. 69 and
70, and receives and processes the emergency alert message by using
the acquired link information and/or access information.
[1218] If it is identified that the payload of the corresponding
link layer packet includes emergency alert related automatic tuning
information of signaling information for emergency alert, the
emergency alert processor M3162 acquires tuning information, which
will be tuned automatically, with reference to each field included
in the payload of the corresponding packet as described with
reference to FIGS. 71 and 72, and controls channel tuning by using
the acquired tuning information.
[1219] If it is identified that the payload of the corresponding
link layer packet includes emergency alert related NRT service
information of signaling information for emergency alert, the
emergency alert processor M3162 acquires emergency alert related
NRT service information with reference to each field included in
the payload of the corresponding packet as described with reference
to FIGS. 73 and 74, and acquires NRT service based on the acquired
information.
[1220] FIG. 78 is a diagram illustrating an FIC according to an
embodiment of the present invention.
[1221] In terrestrial broadcasting, in general, one frequency is
used by one broadcaster. However, according to the present
embodiment, one frequency may be shared by one or more
broadcasters. Hereinafter, a description will be given of a method
of sharing one frequency by one or more broadcasters based on low
level signaling information.
[1222] The low level signaling information is signaling information
that supports bootstrapping of rapid channel scanning and service
acquisition by a receiver. The low level signaling information may
include a fast information table (FIT) (or an SLT). The low level
signaling information may be transmitted through a dedicated
channel. For example, the dedicated channel may include an FIC. The
FIC may include information necessary for acquisition of a service
transmitted on a current frequency for rapid channel reception and
scanning. The FIC may be a dedicated channel for cross-layer
information that allows rapid service acquisition and channel
scanning. This information may mainly include channel binding
information between DPs and services of respective
broadcasters.
[1223] The signaling information may include a plurality of low
level signaling information. For example, a plurality of low level
signaling information may be present within a dedicated channel.
However, each broadcaster may transmit one low level signaling
information (or FIT). Alternatively, each broadcaster may transmit
at least one low level signaling information (or FIT).
[1224] The low level signaling information may include information
for identifying each broadcaster. For example, the information for
identifying each broadcaster may be a provider_id field. Here, each
broadcaster is identified by the provider_id field, and services of
one broadcaster may have the same provider_id field value.
[1225] Therefore, even when one frequency is shared by a plurality
of broadcasters, a receiver may receive and/or acquire a low level
signal from a particular broadcaster based on a provider_id
field.
[1226] Hereinafter, details of the FIC will be described. The FIC,
the FIT, and the SLT may indicate the low level signaling
information.
[1227] Referring to the figure, the FIC may include at least one of
an FIC_protocol_version field, a broadcaststream_id field, a
num_services field, a service_id field, a service_data_version
field, a service_channel_number field, a service_category field, a
partition_id field, a short_service_name_length field, a
short_service_name field, a service_status field, an sp_indicator
field, an IP_version_flag field, an SSC_source_IP_address_flag
field, a num_min_capability field, a min_capability_type field, a
min_capability_value field, an SSC_source_IP_address field, an
SSC_destination_IP_address field, an SSC_destintion_UDP_port field,
an SSC_TSI field, an SSC_DP_ID field, a
num_service_level_descriptors field, a service_level_descriptor( )
field, a num_FIC_level_descriptors field, and/or an
FIC_level_descriptor( ) field.
[1228] The FIC_protocol_version field may indicate a version of a
structure of the FIC.
[1229] The broadcaststream_id field may indicate an ID of an
overall broadcast stream.
[1230] The num_services field may indicate the number of services
having at least one component within each broadcast stream. Each
"for" loop subsequent to the num_services field may include
information about each service.
[1231] The service_id field may indicate an ID for identifying a
service.
[1232] A value of the service_data_version field may be incremented
when a service entry for a service is changed within an FIC or when
a signaling table for a service transmitted through a service
signaling channel is changed. The service_data_version field allows
a receiver to monitor an FIC, and enables the receiver to detect
whether signaling for services has changed.
[1233] The service_channel_number field may indicate a channel
number of a corresponding service.
[1234] The service_category field may indicate a category of a
corresponding service.
[1235] The partition_id field may indicate an ID of a partition in
which a service is broadcast.
[1236] For example, the partition_id field may indicate an ID for
identifying a broadcaster related to the service.
[1237] The short_service_name_length field may indicate the number
of byte pairs in the short_service_name field. A value of the
short_service_name_length field may be indicated by "m" in the
number of bits for the short_service_name field. When there is no
short name in a service, the short_service_name length field may
have a value of "0". The short_service_name_length field may have a
value of 3 bits.
[1238] The short_service_name field may indicate a short name of a
service. Each character of the short name may be encoded in UTF-8 [
]. When there is an odd number of bytes in the short name, the
second byte of the last byte pair for a pair count indicated by the
short_service_name_length field may include "0x00".
(short_service_name field indicates the short name of the Service,
each character of which shall be encoded per UTF-8 [ ]. When there
is an odd number of bytes in the short name, the second byte of the
last of the byte pair per the pair count indicated by the
short_service_name_length field shall contain 0x00)
[1239] The service_status field may indicate a status of a service.
For example, the service_status field may indicate whether the
service is in an "active" status or a "suspended" state. In
addition, the service_status field may indicate whether the service
is in a "hidden" status or a "shown" status.
[1240] The sp_indicator field may indicate a service protection
flag. The sp_indicator field may indicate whether to interpret at
least one protected component for significant presentation.
[1241] The IP_version_flag field may indicate a version of an
Internet protocol. For example, when the IP_version_flag field has
a value of "0", the IP_version_flag field may indicate that the
SSC_source_IP_address field and the SSC_destination_IP_address
field have IPv4 addresses. When the IP_version_flag field has a
value of "I", the IP_version_flag field may indicate that the
SSC_source_IP_address field and the SSC_destination_IP_address
field have IPv6 addresses.
[1242] The SSC_source_IP_address_flag field may indicate whether a
service signaling channel source IP address value for a service is
present.
[1243] The num_min_capability field may indicate the number of
minimum capabilities of each service. Each of at least one "for"
loop subsequent to the num_min_capability field may include
information related to a capability.
[1244] The min_capability_type field may indicate a type of a
minimum capability.
[1245] The min_capability_value field may indicate a value of a
minimum capability.
[1246] The SSC_source_IP_address field may be present when the
SSC_source_IP_address_flag field has a value of "1". In addition,
the SSC_source_IP_address field may not be present when the
SSC_source_IP_address_flag field has a value of "0". When the
SSC_source_IP_address field is present, the SSC_source_IP_address
field may include source IP addresses of all JP datagrams that
transmit a signal for a corresponding service. Conditional use of a
128-bit address version of this field enables IPv6 to be used in
the future.
[1247] The SSC_destination_IP_address field may include destination
IP addresses of all IP datagrams transmitting a signal for a
corresponding service. Conditional use of a 128-bit address version
of this field enables IPv6 to be used in the future.
[1248] The SSC_destintion_UDP_port field may indicate a destination
UDP port number for a UDP/IP stream that transmits a stream for a
corresponding service.
[1249] The SSC_TSI field may indicate a transport session
identifier (TSI) of an LCT channel (or an LCT session) that
transmits signaling tables for a corresponding service.
[1250] The SSC_DP_ID field may indicate an ID of a DP (or a
physical DP) including signaling tables for a corresponding
service. The DP may be the most robust pipe within a partition.
[1251] The num_service_level_descriptors field may indicate the
number of service level descriptors for a corresponding service.
Each of at least one "for" loop subsequent to the
num_service_level_descriptors field may include at least one
service level descriptor.
[1252] The service_level_descriptor( ) field may include at least
one descriptor that provides additional information for a
service.
[1253] The num_FIC_level_descriptors field may indicate the number
of descriptors of an FIC level for a corresponding FIC.
[1254] The FIC_level descriptor( ) field may include at least one
descriptor that provides additional information for an FIC.
[1255] FIG. 79 is a diagram illustrating a service category
according to an embodiment of the present invention.
[1256] Low level signaling information and/or an FIC may include
the service category field. The service category field may indicate
a category of a corresponding service.
[1257] For example, the service_category field may indicate one of
an audio/video (A/V) service, an audio service, an electronic
service guide (ESG) service, a content on demand (CoD) service, an
app-based service, and/or an emergency alert message (EAM) service
(or an emergency alert signaling (EAS) service).
[1258] For example, when a value of the service_categoty field
indicates "0x00 or informative only", the value of the service
category field may be treated as an informative description of a
category of a service. In addition, a receiver needs to investigate
a component mapping table (CMT) that refers to a service map table
(SMT) to identify an actual category of a service transmitted
through an ATSC 3.0 service. With regard to services having a video
and/or audio component, the services may include an NTP timebase
component.
[1259] In addition, when a value of the service category field
indicates "0x01", the service_category field may indicate that a
service category is an A/V service. In addition, when a value of
the service_category field indicates "0x02", the service_category
field may indicate that a service category is an audio service. In
addition, when a value of the service_category field indicates
"0x03", the service category field may indicate that a service
category is an app-based service. In addition, when a value of the
service_category field indicates "0x08", the service category field
may indicate that a service category is an ESG service.
[1260] FIG. 80 is a diagram illustrating a form in which one
frequency is shared by two broadcasters according to an embodiment
of the present invention.
[1261] An emergency alert message (or disaster information, EAS
message) may be delivered through a dedicated PHY pipe such as an
EAC, or transmitted through link layer signaling (or low level
signaling) of a general PHY pipe (or DP, PLP). Alternatively. the
emergency alert message may be transmitted in the form of a
service.
[1262] When the emergency alert message is transmitted through the
general PHY pipe, the emergency alert message may be transmitted
through a separate pipe separated for each broadcaster, or the
emergency alert message may be transmitted through one pipe.
[1263] When the emergency alert message is transmitted through a
separate pipe separated for each broadcaster, the receiver may
distinguish the emergency alert message for each broadcaster.
[1264] However, when emergency alert messages of several
broadcasters are transmitted together through one pipe, the
receiver cannot distinguish the emergency alert messages for
respective broadcasters. Further, when emergency alert messages are
transmitted through the dedicated PHY pipe, emergency alert
messages transmitted from several broadcasters are mixed and
transmitted through one pipe, and thus the receiver cannot filter
the emergency alert messages for the respective broadcasters.
[1265] Referring to the figure, one frequency may be shared by
broadcaster A and broadcaster B.
[1266] At least one service may be transmitted through one
frequency. For example, broadcaster A may transmit service 1 and/or
service 2. In addition, broadcaster B may transmit service k-1
and/or service k.
[1267] In addition, a plurality of low level signaling information
(for example, the FIC and the SLT) for services may be transmitted
through one frequency. For example, low level signaling information
may include first low level signaling information for services
transmitted from broadcaster A and second low level signaling
information for services transmitted from broadcaster B. The first
low level signaling information may include a partition_id field
that identifies broadcaster A. For example, a value of the
partition_id field included in the first low level signaling
information may indicate "1". In addition, the second low level
signaling information may include a partition_id field that
identifies broadcaster B. For example, a value of the partition_id
field included in the second low level signaling information may
indicate "2".
[1268] Therefore, when one frequency is shared by two broadcasters
(broadcaster A and broadcaster B), a partition_id field according
to an embodiment of the present invention may be used as a factor
for identifying a broadcaster.
[1269] Referring to the figure, one frequency is shared by two
broadcasters, and each of the broadcasters may be identified by a
partition_id field. When a user is viewing a service (e.g., service
1) of broadcaster A in which a value of the partition_id field is
recognized as "1", the receiver may need to receive and process an
emergency alert message delivered by broadcaster A.
[1270] Forms in which an emergency alert message is delivered may
be sorted as below.
[1271] First, an emergency alert message may be transmitted through
one pipe (a dedicated pipe or a general pipe) for each
broadcaster.
[1272] For example, when one frequency is used by one broadcaster,
the receiver may know that the emergency alert message is
transmitted from one broadcaster irrespective of a form of a pipe
(e.g., a dedicated pipe, a general pipe, etc.). In addition, when
the emergency alert message is transmitted through a separate pipe
for each broadcaster, the receiver may know that the emergency
alert message is transmitted from one broadcaster.
[1273] Second, emergency alert messages of two or more broadcasters
may be transmitted through one pipe (a dedicated pipe or a general
pipe).
[1274] For example, when several broadcasters share and use a
frequency, emergency alert messages of two or more broadcasters may
be transmitted through one pipe. When the emergency alert messages
are transmitted through the dedicated pipe or a particular pipe,
the receiver cannot distinguish the emergency alert messages for
the respective broadcasters.
[1275] To solve the above-described problem, an embodiment of the
present invention may provide a method of filtering an emergency
alert message transmitted through one pipe for each broadcaster. To
this end, mapping information in which each emergency alert message
is mapped to each broadcaster needs to be present.
[1276] For example, the partition_id field of the low level
signaling information (the FIC or the SLT) according to the
embodiment of the present invention may be used as the mapping
information in which each emergency alert message is mapped to each
broadcaster.
[1277] FIG. 81 is a diagram illustrating Emergency_Alert_Table( )
according to an embodiment of the present invention.
[1278] Referring to the figure, an emergency alert table
(Emergency_Alert_Table( )) may include at least one of a table_id
field, a table_id_extension field, an EAT_protocol_version field,
an automatic_tuning_flag field, a num_EAS_messages field, an
automatic_tuning_channel_number field, an automatic_DP_id field, an
automatic_service_id field, an EAS_message_id field, an
EAS_IP_version_flag field, an EAS_message_transfer type field, an
EAS_message_encoding_type field, an EAS_NRT_flag field, an
EAS_message_length field, an EAS_message_bytes( ) field, an
IP_address field, a UDP_port_num field, a DP_id field, and/or an
NRT_service_id field.
[1279] The table_id field identifies a type of a current table. A
broadcast receiver may identify that a present table is an
emergency alert table using the table_id field.
[1280] The table_id_extension field includes the
EAT_protocol_version field. In addition. when a structure of an
emergency alert table is changed, the EAT_protocol_version field
identifies version information thereof.
[1281] The automatic_tuning_flag field (1 bit) indicates whether to
automatically change a channel.
[1282] The num_EAS_messages field (7 bits) indicates the number of
emergency alert messages included in an emergency alert table.
[1283] When the automatic_tuning_flag field indicates "1", that is.
automatic channel conversion, the emergency alert table further
includes the automatic_tuning_channel_number field, the
automatic_DP_id field, and the automatic_service_id field.
[1284] The automatic_tuning_channel_number field (8 bits) indicates
information about a channel which includes content related to
emergency alert information.
[1285] The automatic_DP_id field (8 bits) indicates information for
identifying a DP, that is, a PHY pipe including A/V content related
to the emergency alert message.
[1286] The automatic_service_id field (16 bits) indicates service
ID information of content related to the emergency alert
message.
[1287] Further, a "for" loop repeated a number of times
corresponding to a value of the num_EAS_messages field includes the
EAS_message_id field, the EAS_IP_version_flag field, the
EAS_message_transfer_type field, the EAS_message_encoding_type
field, and the EAS_NRT_flag field.
[1288] The EAS_message_id field (32 bits) indicates a unique ID for
identifying an emergency alert message. A value of this field may
be changed when a previous emergency alert message is updated or
canceled. As another example, this field may be extracted from a
CAP message ID.
[1289] The EAS_IP_version_flag field (I bit) indicates an IP
version in which the emergency alert table is transmitted. The
IP_address field includes an IPv4 address when a value of this
field is "0", and includes an IPv6 address when a value of this
field is "1".
[1290] The EAS_message_transfer type field (3 bits) indicates a
transmission type of an emergency alert table. In a specific
example, the EAS_message_transfer_type field may indicate that a
transmission type of an EAS message (emergency alert message) has
not been specified. In this case, the EAS message_transfer_type
field may have a value of "0x00".
[1291] In another example, the EAS_message_transfer_type field may
indicate that a transmission type of an EAS message (emergency
alert message) is a type in which the emergency alert message is
not included. In this case, the EAS message_transfer_type field may
have a value of "0x01".
[1292] In another example, the EAS_message_transfer type field may
indicate that the EAS message (emergency alert message) is included
and transferred in an EAT. In this case, the EAS_message_transfer
type field may have a value of "0x02".
[1293] Further, when the EAS_message_transfer type field has the
value of "0x02", an emergency alert table including the EAS message
(emergency alert message) may additionally indicate a length of the
EAS message (emergency alert message). In this case, information
indicating the length of the EAS message (emergency alert message)
may correspond to the EAS_message_length field. The
EAS_message_length field may correspond to 12 bits. In addition,
the EAS_message_bytes( ) field subsequent to the EAS_message_length
field transmits an emergency alert message including emergency
alert content corresponding to a length of a value of the
EAS_message_length field.
[1294] In another example, the EAS_message_transfer type field may
indicate that the EAS message (emergency alert message) is
transmitted through a PHY pipe in the form of an IP datagram. In
this case, the EAS_message_transfer_type field may have a value of
"0x03".
[1295] When the EAS_message_transfer_type field has the value of
"0x03", the emergency alert table may additionally include at least
one of the IP_address field (32 or 128 bits) that indicates IP
address information for acquiring an IP datagram which transmits
the EAS message (emergency alert message), the UDP_port num field
(16 bits) that indicates a UDP port number, and the DP_id field (8
bits) that indicates identification information of a physical layer
frame (that is, a PLP or a DP) in which the EAS message is
transmitted.
[1296] Meanwhile, the EAS_message_encoding_type field (3 bits)
indicates an encoding type of an emergency alert message. In a
specific example, the EAS_message_encoding_type field may indicate
that an encoding type of an emergency alert message has not been
specified. In this case, the EAS_message_encoding_type field may
have a value of "0x00".
[1297] In another example, the EAS_message_encoding_type field may
indicate that an emergency alert message has not been encoded. In
this case, the EAS_message_encoding_type field may have a value of
"0x01".
[1298] In another example, the EAS_message_encoding_type field may
indicate that an emergency alert message has been encoded by a
DEFLATE algorithm. The DEFLATE algorithm is a lossless compression
data format. In this case, the EAS_message_encoding_type field may
have a value of "0x02".
[1299] When the EAS_NRT_flag field has a value of "I", the
emergency alert table includes the NRT_service_id field. The
NRT_service_id field (16 bits) indicates identification information
for identifying an NRT service related to an emergency alert.
[1300] The emergency alert table may further include the
partition_id field. The partition_id field may indicate an ID of a
partition in which a service is broadcast. For example, the
partition_id field may indicate an ID for identifying a broadcaster
related to a service.
[1301] For example, an emergency alert table according to an
embodiment of the present invention may include at least one
emergency alert message provided by at least one broadcaster. In
addition, the emergency alert message may include the partition_id
field.
[1302] The receiver may receive an emergency alert message from at
least one broadcaster. The receiver may filter an emergency alert
message delivered by a broadcaster that provides a current
channel/service based on the partition_id field. Then, the receiver
may express an emergency alert message filtered for each
broadcaster to the user.
[1303] FIG. 82 is a diagram illustrating a flow of a broadcast
receiver according to an embodiment of the present invention.
[1304] The figure illustrates an operation flow of filtering an
emergency alert message (or an EAS message) for each broadcaster by
the broadcast receiver.
[1305] The broadcast receiver according to the embodiment of the
present invention may check a value of a partition_id field of the
emergency alert message (EAS message). Then, the broadcast receiver
may verify whether the value of the partition_id field of the
emergency alert message (EAS message) is the same as a value of a
partition_id field of a currently viewed channel/service.
[1306] When the values are the same, the broadcast receiver may
process the emergency alert message (EAS message). When the values
are different from each other, the broadcast receiver may discard
the emergency alert message (EAS message).
[1307] Hereinafter, a detailed description will be given of the
flowchart of the broadcast receiver.
[1308] The broadcast receiver may receive a packet for the
emergency alert message using a broadcast receiving unit and/or a
controller (CS820010).
[1309] Then, the broadcast receiver may check a value of the
partition_id field of the emergency alert message using the
controller (CS820020).
[1310] Then, the broadcast receiver may verify whether the value of
the partition_id field of the emergency alert message is the same
as the value of the partition_id field of the currently viewed
channel/service (CS820030).
[1311] When the values are the same, the broadcast receiver may
check an ID of the emergency alert message using the controller
(CS820040). For example, the broadcast receiver may check the ID of
the emergency alert message based on the EAS_message_id field.
[1312] When the values are different from each other, the broadcast
receiver may discard the packet for the emergency alert message
(CS820100).
[1313] Then, the broadcast receiver may verify whether the
emergency alert message which is included in a payload of the
packet is a valid message using the controller (CS820050).
[1314] When the emergency alert message an invalid message, the
broadcast receiver may discard the packet for the emergency alert
message (CS820100). That is, when the received emergency alert
message is invalid, the broadcast receiver may ignore the packet
and return to a reception standby state for another packet.
[1315] When the emergency alert message is a valid message, the
broadcast receiver may check version information of the emergency
alert message using the controller (CS820060). For example, the
broadcast receiver may check the version information of the
emergency alert message based on the EAS_message_version field.
[1316] Then, the broadcast receiver may verify whether the
emergency alert message is an updated message or a previously
received message using the controller (CS820070).
[1317] When the emergency alert message is the previously received
message, the broadcast receiver may discard the packet for the
emergency alert message (CS820100). That is, when the received
emergency alert message is the previously received message, the
broadcast receiver may ignore the packet and return to a reception
standby state for another packet.
[1318] When the emergency alert message is a message of a new
version, the broadcast receiver may check a decoding type and a
protocol of the emergency alert message using the controller
(CS820080). For example, the broadcast receiver may check the
decoding type and the protocol of the emergency alert message based
on the EAS_message_encoding_type field and the EAS_message_protocol
field.
[1319] Then, the broadcast receiver may process the emergency alert
message according to the checked decoding type and protocol using
the controller (CS820090).
[1320] FIG. 83 is a diagram illustrating a flow of a broadcast
receiver according to an embodiment of the present invention.
[1321] When several broadcasters use one pipe (dedicated pipe or
general pipe) for transmission of an emergency alert message (EAS
message), two cases may be sorted as below.
[1322] First, in a case in which the user views a channel of a
broadcaster transmitting the emergency alert message (EAS
message):
[1323] When a broadcaster of a currently viewed channel transmits
the emergency alert message (EAS message), the broadcast receiver
may normally filter and/or receive the emergency alert message (EAS
message) to inform the user of an emergency situation.
[1324] Second, in a case in which the user does not view a channel
of a broadcaster transmitting the emergency alert message (EAS
message):
[1325] Even though broadcasters share a pipe for transmission of
the emergency alert message (EAS message), a broadcaster of a
currently viewed channel may not transmit the emergency alert
message (EAS message). In this case, the broadcast receiver may
receive the emergency alert message (EAS message) of another
broadcaster other than the broadcaster of the currently viewed
channel and inform the user of an emergency situation.
[1326] An operation flow of the broadcast receiver that supports
the above operation is as below.
[1327] The broadcast receiver may receive a packet for an emergency
alert message using a broadcast receiving unit and/or a controller
(CS830010). For example, a broadcast signal may include a plurality
of emergency alert tables transmitted by a plurality of
broadcasters. A particular broadcaster may not transmit an
emergency alert table. In addition, an emergency alert table may
include a plurality of emergency alert messages. One emergency
alert table may include a plurality of emergency alert messages for
a plurality of broadcasters. For example, the respective emergency
alert messages may include partition_id fields for the plurality of
broadcasters.
[1328] Then, the broadcast receiver may verify whether an emergency
alert message having a value of a partition_id field which
indicates a broadcaster of a currently viewed channel is present
among all emergency alert messages (EAS messages) defined in an
emergency alert table (Emergency_Alert_Table) using the controller
(CS830015).
[1329] When there is no emergency alert message having the value of
the partition_id field which indicates the broadcaster of the
currently viewed channel, the broadcast receiver may process the
received emergency alert message (EAS message) without filtering.
That is, the broadcast receiver may proceed to CS830040. In this
case, the broadcast receiver needs to process all received
emergency alert messages.
[1330] When there is an emergency alert message having the value of
the partition_id field which indicates the broadcaster of the
currently viewed channel, the broadcast receiver may check the
value of the partition_id field of the emergency alert message
using the controller (CS830020). For example, the broadcast
receiver may check a value of a partition_id field with respect to
each emergency alert message included in an emergency alert
table.
[1331] Then, the broadcast receiver may verify whether the value of
the partition_id field of the emergency alert message is the same
as the value of the partition_id field of the currently viewed
channel/service using the controller (CS830030). That is, the
broadcast receiver may filter and process the emergency alert
message (EAS message) by comparing the value of the partition_id
field of the emergency alert message with the value of the
partition_id field of the currently viewed channel/service.
[1332] When the values are the same as a result of comparison, the
broadcast receiver may check an ID of the emergency alert message
using the controller (CS830040). For example, the broadcast
receiver may check the ID of the emergency alert message based on
the EAS_message_id field.
[1333] When the values are different from each other as a result of
comparison, the broadcast receiver may discard the packet for the
emergency alert message (CS830100).
[1334] Then, the broadcast receiver may verify whether the
emergency alert message which is included in a payload of the
packet is a valid message using the controller (CS830050).
[1335] When the emergency alert message is an invalid message, the
broadcast receiver may discard the packet for the emergency alert
message (CS830100). That is, when the received emergency alert
message is invalid, the broadcast receiver may ignore the packet
and return to a reception standby state for another packet.
[1336] When the emergency alert message is a valid message, the
broadcast receiver may check version information of the emergency
alert message using the controller (CS830060). For example, the
broadcast receiver may check the version information of the
emergency alert message based on the EAS_message_version field.
[1337] Then, the broadcast receiver may verify whether the
emergency alert message is an updated message or a previously
received message using the controller (CS830070).
[1338] When the emergency alert message is the previously received
message, the broadcast receiver may discard the packet for the
emergency alert message (CS830100). That is, when the received
emergency alert message is the previously received message, the
broadcast receiver may ignore the packet and return to a reception
standby state for another packet.
[1339] When the emergency alert message is a message of a new
version, the broadcast receiver may check a decoding type and a
protocol of the emergency alert message using the controller
(CS830080). For example, the broadcast receiver may check the
decoding type and the protocol of the emergency alert message based
on the EAS_message_encoding_type field and the EAS_message_protocol
field.
[1340] Then, the broadcast receiver may process the emergency alert
message according to the checked decoding type and protocol using
the controller (CS830090).
[1341] Even when broadcaster A of a channel currently viewed by the
user does not transmit an emergency alert message, the broadcast
receiver may use an emergency alert table and/or an emergency alert
message of broadcaster B which is transmitting the emergency alert
message. In this instance, the emergency alert table transmitted by
broadcaster B may include an emergency alert message for
broadcaster A in addition to an emergency alert message for
broadcaster B. Therefore, the broadcast receiver may provide an
emergency alert message to the user on a current channel based on
the emergency alert table and/or the emergency alert message of
broadcaster B.
[1342] FIG. 84 is a diagram illustrating syntax related to an EAC
added to PLS according to an embodiment of the present
invention.
[1343] Hereinafter, a description will be given of a method that
allows transmission of a private data stream according to an
embodiment of the present invention. For example, a description
will be given of a method of transmitting and/or receiving a WARN
message according to an embodiment of the present invention.
[1344] An emergency alert message (or emergency alert data)
according to an embodiment of the present invention may include the
WARN message and/or a common alert protocol (CAP) message. The WARN
message refers to a disaster broadcast message used in a disaster
broadcast construction system constructed by PBS (Public
Broadcasting Service of the United States). In addition, an EAS
message generally refers to a disaster message used in disaster
broadcasting. Further, the CAP message means that the EAS message
is transmitted in a form of a CAP. Here, the CAP message and the
EAS message may have the same meaning.
[1345] An embodiment of the present invention describes a method of
transmitting and/or receiving the WARN message through an EAC. To
transmit the WARN message through the EAC, PLS according to an
embodiment of the present invention may include syntax related to
the EAC.
[1346] The PLS according to the embodiment of the present invention
may include at least one of an EAC_Flag field, a num_EA_data field,
an EA_data_Type field, a WARN_data_version field, a
WARN_data_target field, a WARN_data_version field, a
WARN_data_target field, a WARN_data_Length field, and/or a
CAP_message_info( ) field.
[1347] The EAC_Flag field may indicate whether an EAC is present
within a corresponding PHY frame (or a frame of a physical layer).
When a value of the EAC Flag field is "true", the EAC may be
present. The num_EA_data field may indicate the number of
transmitted emergency alert messages (or emergency alert data). A
"for" loop subsequent to the num_EA_data field may include content
related to emergency alert messages, the number of which is
indicated by a value of the num_EA_data field.
[1348] The EA_data_Type field may indicate a type of an emergency
alert message. A value of this field may be assigned as below, and
a remaining value may be assigned based on a possibility that a new
type may be added in the future.
[1349] For example, when a value of the EA_data_Type field is "0",
a type of an emergency alert message may be "WARN only". In this
case, the emergency alert message may include only the WARN
message.
[1350] In addition, when a value of the EA_data_Type field is "1",
a type of an emergency alert message may be "WARN+CAP". In this
case, the emergency alert message may include the WARN message and
the CAP message.
[1351] In addition, when a value of the EA_data_Type field is "2",
a type of an emergency alert message may be "CAP only". In this
case, the emergency alert message may include only the CAP
message.
[1352] When a value of the EA_data_Type field is "0", the PLS
according to the embodiment of the present invention may include at
least one of the WARN_data_version field and/or the
WARN_data_target field.
[1353] The WARN_data_version field may indicate a version of a
transmitted WARN message (or WARN data).
[1354] The WARN_data_target field may indicate target information
of the transmitted WARN message (or WARN data). For example, when a
value of the WARN_data_target field is "0", the target information
of the WARN message (or WARN data) may indicate "Communities of
Amber Alerts". In addition, when a value of the WARN_data_target
field is "1", the target information of the WARN message (or WARN
data) may indicate "Imminent threats to safety or life". In
addition, when a value of the WARN_data_target field is "2", the
target information of the WARN message (or WARN data) may indicate
"Presidential Alerts via geographically-targeted".
[1355] When a value of the EA_data_Type field is "1", the PLS
according to the embodiment of the present invention may include at
least one of the WARN_data_version field, the WARN_data_target
field, the WARN_data_Length field, and/or the CAP_message_info( )
field.
[1356] Content about the WARN_data_version field and the
WARN_data_target field has been described above.
[1357] The WARN_data_Length field may indicate length information
of the WARN message. When a broadcast transmitter transmits both
the WARN message and the CAP message. the broadcast transmitter may
transmit the WARN message having the corresponding length, and
transmit a message subsequent to the data length as the CAP
message.
[1358] The CAP_message_info( ) field may include CAP message
information. For example, the CAP_message_info( ) field may include
at least one of a message_id field that identifies a
CAP_message_info( ) field message and/or a CAP message encoding
type field that indicates an encoding type of the CAP message.
[1359] When a value of the EA_data_Type field is "2", the PLS
according to the embodiment of the present invention may include
the CAP_message_info( ) field.
[1360] Content about the CAP_message_info( ) field has been
described above.
[1361] FIG. 85 is a diagram illustrating a form in which only the
WARN message is transmitted through the EAC according to an
embodiment of the present invention.
[1362] A broadcast transmitter according to an embodiment of the
present invention may transmit PLS information.
[1363] PLS may include at least one of an EAC_Flag field, an
EA_data_Type field, a WARN_data_version field, and/or a
WARN_data_target field. Content about signaling information
included in the PLS has been described above.
[1364] For example, the EAC_Flag field may have a value of "true"
to indicate that the EAC is present.
[1365] In addition, the EA_data_Type field may have a value of "00"
to indicate that a type of an emergency alert message is "WARN
only". In this case, the emergency alert message may include only a
WARN message.
[1366] In addition, the WARN_data_version field may have a value of
"1".
[1367] In addition, the WARN data target field may have a value of
"1" to indicate that target information of a WARN message (or WARN
data) is "Imminent threats to safety or life".
[1368] The broadcast transmitter according to the embodiment of the
present invention may transmit an FIT (or SLT). For example, the
FIT may be transmitted through an FIC. In addition, the FIT may be
encapculated in an IP/UDP datagram and transmitted.
[1369] The FIT is signaling information that supports bootstrapping
of rapid channel scanning and service acquisition by the receiver.
The FIT may include signaling information used to establish basic
service listing and signaling information that provides discovery
of a bootstrap of SLS.
[1370] For example, the FIT may include bootstrap information for
SLS information of a service (Srv #1) and/or a service (Srv
#1).
[1371] The broadcast transmitter according to the embodiment of the
present invention may transmit a WARN message through a dedicated
PLP. In this instance, the PLP designated to transmit the WARN
message may be referred to as an EAC. In other words, the EAC may
be a dedicated PLP for transmission of only a physical layer frame
including the WARN message.
[1372] Here, the physical layer frame may be a unit of data
transmitted through a physical layer. The physical layer may
include one or more PLPs, and the physical layer frame may be
transmitted through the PLP.
[1373] The broadcast transmitter according to the embodiment of the
present invention may transmit service data and SLS information for
a service.
[1374] The service data may include at least one of a video
component, an audio component. and/or a captioning component. The
service data may be transmitted through a ROUTE session. The ROUTE
session may be identified through a destination IP address (dIP1),
a destination port number (dPort1), and/or a source IP address
(sIP1). In addition, the ROUTE session may be transmitted through
at least one PLP. For example, the ROUTE session may be transmitted
through one PLP (PLP #1).
[1375] The ROUTE session may include at least one LCT session (or
LCT channel). Each LCT session may be identified by a TSI. Each of
the video component, the audio component. and the SLS information
may be transmitted through the LCT session. For example, the video
component may be transmitted through a first LCT session (tsi-v),
the audio component may be transmitted through a second LCT session
(tsi-a), and the SLS information may be transmitted through a third
LCT session (tsi-sls).
[1376] SLS may be signaling that provides information for
discovering and acquiring a service and a content component
thereof. The SLS may include a USD, an S-LSID, and/or an MPD. The
USD may be expressed as a USBD, and the S-LSID may be expressed as
a S-TSID.
[1377] The USD may include reference information of SLS for a
service (Srv #1).
[1378] The MPD may include a period element. The period element may
include a first AdaptationSet element having information about at
least one video component and a second AdaptationSet element having
information about at least one audio component.
[1379] Each of the first AdaptationSet element and the second
AdaptationSet element may include a Representation element. For
example, the first AdaptationSet element may include a first
Representation element including information for a first
Representation and a second Representation element including
information for a second Representation. The second AdaptationSet
element may include a third Representation element including
information for a third Representation and a fourth Representation
element including information for a fourth Representation.
[1380] The first Representation and the second Representation may
be interchanged. In addition, the third Representation and the
fourth Representation may be interchanged.
[1381] Each Representation element may include information about a
representation related to a component. The Representation element
may include a rep_id attribute (or id attribute) that identifies a
representation.
[1382] For example, the first Representation element may include a
value of the rep_id attribute which has a value of "rep_v1", the
second Representation element may include a value of the rep_id
attribute which has a value of "rep_v2", the third Representation
element may include a value of the rep_id attribute which has a
value of "rep_a1", and the fourth Representation element may
include a value of the rep_id attribute which has a value of
"rep_a2".
[1383] The S-LSID may include at least one RS element (ROUTE
session element) which includes information about a ROUTE session
for the service (Srv #1). Each ROUTE session element may include at
least one TS element (LCT session element) which includes
information about an LCT session.
[1384] Each TS element may include a tsi attribute and an appID
element. The tsi attribute may identify an LCT session. The appID
element may be referred to as a ContentInfo element. The
ContentInfo element may include additional information mapped to a
service (or application service) transmitted through a transmission
session. For example, the ContentInfo element may include a
Representation ID of DASH content and/or Adaptation Set parameters
of a DASH media representation in order to select an LCT
transmission session for rendering. The Representation ID is an ID
related to a component for a service, and may be referred to as a
rep_id attribute.
[1385] For example, the RS element may include a first TS element
for a video component, a second TS element for an audio component,
and/or a third TS element for SLS information.
[1386] A tsi element included in the first TS element may have a
value of "tsi-v", and an appID element may have a value of
"rep_v1". A tsi element included in the second TS element may have
a value of "tsi-a", and an appID element may have a value of
"rep_a1". A tsi element included in the third TS element may have a
value of "tsi-sls".
[1387] FIG. 86 is a diagram illustrating a form in which a WARN
message and a CAP message are transmitted through an EAC according
to an embodiment of the present invention.
[1388] A broadcast transmitter according to an embodiment of the
present invention may transmit a PLS, an FIT (or SLT), an emergency
alert message, service data, and SLS. Content related to the FIT
(or SLT), the service data, and the SLS is the same as the above
description. Hereinafter, differences will be mainly described.
[1389] A PLS according to an embodiment of the present invention
may at least one of an EAC_Flag field, an EA_data_Type field, a
WARN_data_version field, a WARN_data_target field, a
WARN_data_Length field, and/or a CAP_message_info( ) field. Content
about signaling information included in the PLS is the same as the
above description.
[1390] For example, the EAC_Flag field may have a value of "true"
to indicate that an EAC is present.
[1391] In addition, the EA_data_Type field may have a value of "I"
to indicate that a type of an emergency alert message is
"WARN+CAP". In this case, the emergency alert message may include a
WARN message and a CAP message.
[1392] In addition, the WARN_data_version field may have a value of
"1".
[1393] In addition, the WARN data target field may have a value of
"1" to indicate that target information of a WARN message (or WARN
data) is "Imminent threats to safety or life".
[1394] In addition, the WARN_data_Length field may have a value of
"90" to indicate that a length of a WARN message is "90".
[1395] In addition, the CAP_message_info( ) field may include
information related to a CAP message. For example, the
CAP_message_info( ) field may include at least one of message_id
that identifies a CAP_message_info( ) field message and/or a CAP
message encoding type field that indicates an encoding type of the
CAP message.
[1396] The broadcast transmitter according to the embodiment of the
present invention may transmit the WARN message and the CAP message
through a designated PLP. In this instance, the PLP designated to
transmit the WARN message and the CAP message may be referred to as
an EAC. In other words, the EAC may be a dedicated PLP for
transmitting only a physical layer frame including the WARN message
and the CAP message.
[1397] For example, when the broadcast transmitter transmits both
the WARN message and the CAP message, the broadcast transmitter may
transmit the WARN message corresponding to a length of "90"
indicated by the WARN_data_Length field, and transmit the CAP
message after the data length.
[1398] FIG. 87 is a diagram illustrating a link layer header
according to an embodiment of the present invention.
[1399] The figure illustrates a header structure of a link layer
packet according to an embodiment of the present invention. Content
about each field of a header of the link layer packet may include
all of the above description. Hereinafter, differences will be
mainly described.
[1400] An embodiment of the present invention may provide a method
of transmitting a WARN message through link layer signaling. In
order for the broadcast transmitter to transmit the WARN message as
one link layer packet, an LLS packet header may include information
that indicates a type of the WARN message.
[1401] For example, the LLS packet header according to the present
embodiment may include a signaling_class field and an
information_type field. The signaling_class field and/or the
information_type field may indicate a type of the WARN message.
[1402] The signaling_class field indicates a type of signaling
information included in the link layer packet, in particular, a
payload of the link layer packet. When a type of signaling
information transmitted in the packet is determined by a value of
the signaling_class field, the information_type field indicates a
type of data transmitted in a payload of the packet (that is, a
target of the WARN message) with regard to the determined signaling
information. In addition, specific information may be additionally
included according to data type.
[1403] FIG. 88 is a diagram illustrating a signaling_class field
according to an embodiment of the present invention.
[1404] For example, when a value of the signaling_class field is
"000", the value indicates that a packet includes signaling
information (e.g., SLT) for channel scanning and service
acquisition. When a value of the signaling_class field is "001",
the value indicates that the packet includes signaling information
for a CAP message (or an EAS message or an emergency alert). When a
value of the signaling_class field is "010". the value indicates
that the packet includes signaling information for header
compression.
[1405] In addition, when a value of the signaling_class field
according to the present embodiment is "011", the value indicates
that the packet includes signaling information for a WARN
message.
[1406] When a value of the signaling_class field according to the
present embodiment is "011", the packet is referred to as a WARN
message packet.
[1407] FIG. 89 is a diagram illustrating an information_type field
according to an embodiment of the present invention.
[1408] When the signaling_class field indicates that a
corresponding packet includes signaling information for a WARN
message, the information_type field indicates a type of data
transmitted in a payload of the packet (that is, a target of the
WARN message) with regard to determined signaling information.
[1409] That is, the information_type field may indicate target
information of the transmitted WARN message (or WARN data).
[1410] For example, when a value of the information_type field is
"000", the target information of the WARN message (or WARN data)
may indicate "Communities of Amber Alerts". In addition, when a
value of the information_type field is "001", the target
information of the WARN message (or WARN data) may indicate
"Imminent threats to safety or life". In addition, when a value of
the information_type field is "010", the target information of the
WARN message (or WARN data) may indicate "Presidential Alerts via
geographically-targeted". A value of the information_type field is
not fixed, and may be changed.
[1411] FIG. 90 is a diagram illustrating syntax related to a WARN
message added to PLS according to an embodiment of the present
invention.
[1412] When the broadcast transmitter transmits a WARN message (or
WARND) in a link layer packet, PLS according to an embodiment of
the present invention may include signaling information for the
WARN message.
[1413] For example, the PLS according to the embodiment of the
present invention may include at least one of an EAC_Flag field, a
WARN_data_version field, and/or a WARN_PLP_ID field.
[1414] The EAC_Flag field may indicate whether an EAC is present in
a PHY frame. For example, when a value of the EAC Flag field is
"true", the EAC may be present in the physical frame. When a value
of the EAC_Flag field is "false", the EAC may not be present in the
physical frame.
[1415] The WARN_data_version field may indicate a version of the
WARN message (or WARN data) transmitted in the PLP.
[1416] The WARN_PLP_ID field may indicate a PLP identifier (or PLP
ID) that identifies a PLP which transmits the WARN message in the
PHY frame.
[1417] In addition, when the WARN message (or WARND) is transmitted
in the link layer packet, and the WARN message is transmitted
through a base PLP, the PLS may not include WARN_PLP_ID. Since the
base PLP is a PLP which is decoded at all times, the PLS may not
include the WARN_PLP_ID field. The broadcast receiver may receive
and acquire the WARN message transmitted through the base PLP.
[1418] FIG. 91 is a diagram illustrating a form in which a WARN
message is transmitted through LLS according to an embodiment of
the present invention.
[1419] A broadcast transmitter according to an embodiment of the
present invention may transmit PLS, an FIT (or SLT), an emergency
alert message, service data, and SLS. The FIT (or SLT), the service
data, and the SLS are the same as described above. Hereinafter,
differences will be mainly described.
[1420] The PLS according to the present embodiment may include
signaling information for the WARN message. The PLS may include at
least one of an EAC_Flag field, a WARN_data_version field, and/or a
WARN_PLP_ID field. The signaling information included in the PLS is
the same as described above.
[1421] For example, the EAC_Flag field may have a value of "false"
to indicate that an EAC is not present in a PHY frame. That is, the
WARN message may not be transmitted through an EAC and may be
transmitted through the LLS.
[1422] In addition, the WARN_data_version field may have a value of
"01" to indicate that a version of the WARN message (or WARN data)
is "01".
[1423] In addition, the WARN_PLP_ID field may have a value of "#E"
to indicate that an ID of a PLP that transmits the WARN message is
"#E".
[1424] The WARN message may be transmitted through link layer
signaling. The WARN message (or WARND) and/or a CAP message (or EAS
message, EAD) may be transmitted through a PLP. For example, the
WARN message and/or the CAP message may be transmitted through a
base PLP and/or a general PLP (or a general data pipe). Signaling
information for the WARN message and the CAP message may be
included in the PLS.
[1425] FIG. 92 is a diagram illustrating PLS in a case in which
signaling information for a WARN message is transmitted through an
EAC according to an embodiment of the present invention.
[1426] Even though the WARN message according to the present
embodiment is transmitted in a link layer packet, the signaling
information for the WARN message may be transmitted through the
EAC. In addition, signaling information for the EAC may be included
in the PLS.
[1427] Referring to the figure, the PLS may include an EAC_Flag
field. The signaling information included in the PLS is the same as
described above.
[1428] For example, the EAC_Flag field may have a value of "true"
to indicate that the EAC is present in a PHY frame. In addition, an
EAT of the EAC may include information that signals a position at
which the WARN message is transmitted. In addition, the WARN
message may not be transmitted through the EAC, and may be
transmitted through LLS.
[1429] FIG. 93 is a diagram illustrating an EAT that includes
signaling information for a WARN message according to an embodiment
of the present invention.
[1430] The broadcast transmitter may transmit the EAT through an
EAC. After entering the EAC, the broadcast receiver may acquire the
EAT transmitted through the EAC, and acquire transmission path
information of the WARN message from the EAT.
[1431] Referring to the figure, the EAT may include at least one of
a table_id field, a version_number field, a num_EA_data field, an
EA_data_type field, a PLP_ID field, and/or a data_version
field.
[1432] The table_id field may indicate an ID (or table ID) that
identifies the EAT transmitted through the EAC.
[1433] The version_number field may indicate a version number of
the EAT.
[1434] The num_EA_data field may indicate the number of emergency
alert messages described in the EAT.
[1435] The EA_data_type field may indicate a data type of an
emergency alert message described in the EAT. For example, when a
value of the EA_data_type field is "00", the data type of the
emergency alert message may indicate "unspecified". In addition,
when a value of the EA_data_type field is "01", the data type of
the emergency alert message may indicate the "WARN message". When a
value of the EA_data_type field is "01", the data type of the
emergency alert message may indicate a "CAP message".
[1436] A value of the EA_data_type field may be assigned as
described above, and a remaining value may be assigned based on a
possibility that a new type may be added in the future. Information
that needs to be notified when a transmission path of the emergency
alert message is signaled may vary for each type.
[1437] When a value of the EA_data_type field is "01", the EAT may
include at least one of the PLP_ID field and/or the data_version
field.
[1438] The PLP_ID field may indicate a PLP identifier (or PLP ID)
that identifies a PLP which transmits the WARN message in a
corresponding PHY frame.
[1439] The data_version field may indicate a version of the WARN
message (or WARN data) transmitted through the PLP.
[1440] FIG. 94 is a diagram illustrating a form in which signaling
information for a WARN message is transmitted through an EAC
according to an embodiment of the present invention.
[1441] A broadcast transmitter according to an embodiment of the
present invention may transmit PLS, an FIT (or SLT), an EAT, an
emergency alert message, service data. and SLS. The FIT (or SLT),
the service data, and the SLS are the same as described above.
Hereinafter, differences will be mainly described.
[1442] The PLS according to the present embodiment may include
signaling information for the WARN message. The PLS may include an
EAC Flag field. The signaling information included in the PLS is
the same as described above. For example, the EAC_Flag field may
have a value of "true" to indicate that an EAC is present in a
corresponding PHY frame. That is, most signaling information for
the WARN message may be transmitted through the EAC, and the WARN
message may be transmitted through LLS.
[1443] The EAT according to the present embodiment may be
transmitted through the EAC. The EAT may indicate a type and a
transmission path of the emergency alert message. The EAT may
include an EA_data_type field, a data_version field, and/or a
PLP_ID field.
[1444] For example, a value of the EA_data_type field may be "01",
and the EA_data_type field may indicate that a data type of the
emergency alert message is the "WARN message". In addition, the
data_version field may indicate that a version of the WARN message
(or WARN data) transmitted through a PLP is "01". In addition, the
PLP_ID field may indicate that an ID of the PLP that transmits the
WARN message in a corresponding PHY frame is "#EA".
[1445] The WARN message according to the present embodiment may be
transmitted in a link layer packet. The WARN message may be
transmitted through a general PLP (or general data pipe). An ID of
the general PLP through which the WARN message is transmitted may
be "#EA" which is indicated by the PLP_ID field.
[1446] FIG. 95 is a diagram illustrating PLS that includes
signaling information for a WARN message according to an embodiment
of the present invention.
[1447] The WARN message according to the present embodiment may be
transmitted through an LCT session. In addition, the signaling
information for the WARN message may be included in the PLS. For
example, the PLS may include information about a path through which
the WARN message is transmitted and attribute information of the
WARN message.
[1448] Referring to the figure, the PLS may include at least one of
a num_EA_data field, an EA_data_Type field, a WARN_data_version
field, a WARN_data_target field, a sourceIPaddress field, a
destIPaddress field, a destPort field, a tsi field, a PLP_ID field,
a WARN_data_Length field, and/or a CAP_message_info( ) field.
[1449] The num_EA_data field may indicate the number of transmitted
emergency alert messages (or emergency alert data). A "for" loop
subsequent to the num_EA_data field may include content related to
emergency alert data, the number of which is indicated by a value
of the num_EA_data field.
[1450] The EA_data_Type field may indicate a type of an emergency
alert message. For example, when a value of the EA_data_Type field
is "00", a type of an emergency alert message may be "WARN only".
In this case, the emergency alert message may include only the WARN
message. In addition, the PLS may include the WARN_data_version
field, the WARN_data_target field, the sourceIPaddress field, the
destIPaddress field, the destPort field, the tsi field, and the
PLP_ID field.
[1451] In addition, when a value of the EA_data_Type field is "01".
a type of an emergency alert message may be "WARN+CAP". In this
case, the emergency alert message may include the WARN message and
the CAP message. In addition, the PLS may include the
WARN_data_version field, the WARN_data_target field, the
sourceIPaddress field, the destIPaddress field, the destPort field,
the tsi field, the PLP_ID field, the WARN_data_Length field, and
the CAP_message_info( ) field.
[1452] In addition, when a value of the EA_data_Type field is "10".
a type of an emergency alert message may be "CAP only". In this
case, the emergency alert message may include only the CAP message.
In addition, the PLS may include the CAP_message_info( ) field.
[1453] The WARN_data_version field may indicate a version of a
transmitted WARN message (or WARN data).
[1454] The WARN_data_target field may indicate target information
of the transmitted WARN message (or WARN data).
[1455] The sourceIPaddress field may indicate a source IP address
of a session in which the WARN message is transmitted.
[1456] The destIPaddress field may indicate a destination IP
address of a session in which the WARN message is transmitted.
[1457] The destPort field may indicate a destination port number of
a session in which the WARN message is transmitted.
[1458] The tsi field may indicate an ID of an LCT session through
which the WARN message is transmitted.
[1459] The PLP_ID field may indicate an ID of a PLP through which
the WARN message is transmitted.
[1460] The WARN_data_Length field may indicate length information
of the WARN message.
[1461] The CAP_message_info( ) field may include CAP message
information. For example, the CAP_message_info( ) field may include
at least one of a message_id field that identifies a
CAP_message_info( ) field message and/or a CAP message encoding
type field that indicates an encoding type of the CAP message.
[1462] FIG. 96 is a diagram illustrating a form in which a WARN
message is transmitted through an LCT session according to an
embodiment of the present invention.
[1463] A broadcast transmitter according to an embodiment of the
present invention may transmit PLS, an FIT (or SLT), an emergency
alert message, service data, and SLS. The FIT (or SLT), the service
data, and the SLS are the same as described above. Hereinafter,
differences will be mainly described.
[1464] The PLS according to the present embodiment may include
signaling information for the WARN message. The PLS may include at
least one of an EAC_Flag field, a WARN_data_version field, a
WARN_data_target field, a WARN_PLP_ID field, a sourceIPaddress
field, a destIPaddress field, a destPort field, and/or a tsi field.
The signaling information included in the PLS is the same as
described above.
[1465] For example, the EAC_Flag field may have a value of "false"
to indicate that an EAC is not present in a corresponding PHY
frame. That is, the WARN message may not be transmitted through an
EAC, and the WARN message may be transmitted through the LCT
session.
[1466] In addition, the WARN_data_version field may have a value of
"3".
[1467] In addition, the WARN_data_target field may have a value of
"10" to indicate that target information of the WARN message is
"Presidential Alerts via geographically-targeted".
[1468] In addition, the WARN_PLP_ID field may have a value of "#E"
to indicate that an ID of a PLP that transmits the WARN message is
"#E".
[1469] In addition, the sourceIPaddress field may have a value of
"0", the destIPaddress field may have a value of "0", and the
destPort field may have a value of "0". The sourceIPaddress field,
the destIPaddress field, and the destPort field may uniquely
identify a session (or ROUTE session) through which the WARN
message is transmitted.
[1470] In addition, the tsi field may have a value of "tsi-wam" to
indicate that an ID of an LCT session through which the WARN
message is transmitted is "tsi-wam".
[1471] The WARN message according to the present embodiment may be
transmitted through the LCT session. One ROUTE session may include
at least one LCT session. The ROUTE session may be transmitted
through at least one PLP. For example, signaling information that
indicates a path through which the WARN message is transmitted may
be included in the PLS. The WARN message may be transmitted through
a PLP, a ROUTE session, and/or an LCT session identified by the
signaling information included in the PLS. A ROUTE session through
which the WARN message is transmitted may be different from a ROUTE
session through which service data and/or SLS is transmitted. In
addition, a PLP through which the WARN message is transmitted may
be different from a PLP through which service data and/or SLS is
transmitted.
[1472] FIG. 97 is a diagram illustrating an EAT in a case in which
signaling information for a WARN message is transmitted through an
EAC according to an embodiment of the present invention.
[1473] The WARN message according to the present embodiment may be
transmitted through an LCT session. In addition, the signaling
information for the WARN message (for example, information about a
path through which the WARN message is transmitted) may be included
in the EAT of the EAC. In this case, signaling information for the
EAC may be included in PLS.
[1474] Referring to the figure, the EAT according to the present
embodiment may include at least one of a table_id field, a
version_number field, a num_EA_data field, an EA_data_type field, a
data_version field, a data target field, a sourceIPaddress field, a
destIPaddress field, a destPort field, a PLP_ID field, and/or a tsi
field.
[1475] The table_id field may indicate an ID (or table ID) that
identifies the EAT transmitted through the EAC.
[1476] The version_number field may indicate a version number of
the EAT.
[1477] The num_EA_data field may indicate the number of emergency
alert messages described in the EAT.
[1478] The EA_data_type field may indicate a data type of an
emergency alert message described by the EAT. For example, when a
value of the EA_data_type field is "01". the data type of the
emergency alert message may indicate the "WARN message".
[1479] The data_version field may indicate a version of the WARN
message which is transmitted through a PLP.
[1480] The data_target field may indicate target information of the
transmitted WARN message.
[1481] The sourceIPaddress field may indicate a source IP address
of a session through which the WARN message is transmitted.
[1482] The destIPaddress field may indicate a destination IP
address of a session through which the WARN message is
transmitted.
[1483] The destPort field may indicate a destination port number of
a session through which the WARN message is transmitted.
[1484] The PLP_ID field may indicate a PLP identifier (or PLP ID)
that identifies a PLP which transmits the WARN message in a
corresponding PHY frame.
[1485] The tsi field may indicate an ID of a transmitted LCT
session of an LCT session in which the WARN message is
transmitted.
[1486] FIG. 98 is a diagram illustrating a form in which signaling
information for a WARN message is transmitted through an EAC
according to an embodiment of the present invention.
[1487] A broadcast transmitter according to an embodiment of the
present invention may transmit PLS, an FIT (or SLT), an EAT, an
emergency alert message, service data, and SLS. The FIT (or SLT),
the service data, and the SLS are the same as described above.
Hereinafter. differences will be mainly described.
[1488] The PLS according to the present embodiment may include
signaling information for the EAC. The PLS may include an EAC_Flag
field. The signaling information included in the PLS is the same as
described above.
[1489] For example, the EAC_Flag field may have a value of "true"
to indicate that an EAC is present in a corresponding PHY frame.
That is, the signaling information for the WARN message may be
transmitted through the EAT of the EAC, and the WARN message may be
transmitted through an LCT session.
[1490] The EAT according to the present embodiment may be
transmitted through the EAC.
[1491] For example, the EAT may include at least one of an
EA_data_type field, a data_version field, a data_target field, a
sourceIPaddress field, a destIPaddress field, a destPort field, a
PLP_ID field, and/or a tsi field.
[1492] A value of the EA_data_type field may be "00", and a type of
the emergency alert message may be "WARN only". In this case, the
emergency alert message may include only the WARN message.
[1493] In addition, a value of the data_version field may be
"01".
[1494] In addition, a value of the data_target field may be "10",
and target information of the WARN message may indicate
"Presidential Alerts via geographically-targeted".
[1495] In addition, a value of the PLP_ID field may be "#1", and
the PLP_ID field may indicate that an ID of a PLP that transmits
the WARN message is "#E".
[1496] In addition, a value of the sourceIPaddress field may be
"#1" a value of the destIPaddress field may be "#1", and a value of
the destPort field may be "#1". The sourceIPaddress field, the
destIPaddress field, and the destPort field may uniquely identify a
ROUTE session through which the WARN message is transmitted.
[1497] In addition, a value of the tsi field may be "tsi-wam", and
the tsi field may indicate that the WARN message is transmitted
through an LCT session identified by "tsi-wam".
[1498] The WARN message according to the present embodiment may be
transmitted through the LCT session.
[1499] Referring to the figure. the WARN message. the service data,
and service layer signaling information may be transmitted through
one ROUTE session (dIP1/dPort1/sIP1). The ROUTE session
(dIP1/dPort1/sIP1) may be transmitted through one PLP (#1). In
addition, the ROUTE session (dIP1/dPort1/sIP1) may include an LCT
session (tsi-wam) that transmits the WARN message, an LCT session
(tsi-v) that transmits a video component, an LCT session (tsi-a)
that transmits an audio component, and an LCT session (tsi-sls)
that transmits the service layer signaling information.
[1500] FIG. 99 is a diagram illustrating a form in which a WARN
message is transmitted through a dedicated PLP or a dedicated LCT
session according to an embodiment of the present invention.
[1501] An embodiment of the present invention may use a PLP ID
designated for Private Data Stream Delivery, a designated LCT
session ID, or an ID value that may be assigned to a corresponding
protocol.
[1502] For example, the WARN message may be transmitted through a
dedicated PLP in which a value of a PLP ID is "#911". In addition,
the WARN message may be transmitted through a dedicated LCT session
in which a value of an LCT session ID is "tsi-911". When the WARN
message is transmitted through the dedicated PLP or the dedicated
LCT session, the broadcast receiver may receive the WARN message
transmitted through the dedicated PLP or the dedicated LCT session,
and immediately process the WARN message.
[1503] FIG. 100 is a diagram illustrating a broadcast transmission
method according to an embodiment of the present invention.
[1504] A broadcast transmitter according to an embodiment of the
present invention may include a controller and/or a transmitting
unit.
[1505] The broadcast transmitter according to the present
embodiment may generate service data using the controller
(CS1000100).
[1506] Then, the broadcast transmitter according to the present
embodiment may generate signaling data using the controller
(CS1000200).
[1507] Then, the broadcast transmitter according to the present
embodiment may transmit a broadcast signal including the service
data and the signaling data using the transmitting unit
(CS1000300).
[1508] The broadcast transmitter may encapsulate an emergency alert
message and the signaling data in a link layer packet using the
controller. In addition, the broadcast transmitter may transmit a
broadcast signal including the link layer packet.
[1509] The signaling data may include bootstrapping information
that supports bootstrapping of service acquisition. For example,
the signaling data may include low level signaling data. and the
low level signaling data may include an FIT and/or an SLT.
[1510] The signaling data may include a broadcaster ID that
identifies a broadcaster related to a service. For example, the
broadcaster ID included in the signaling data may refer to a
partition_id field included in the FIT and/or the SLT.
[1511] The emergency alert message may include a broadcaster ID
that identifies a broadcaster related to the emergency alert
message. For example, the broadcaster ID included in the emergency
alert message may refer to a partition_id field included in an
EAT.
[1512] According to an embodiment of the present invention, the
partition_id field included in the FIT and/or the SLT may be
matched to the partition_id field included in the EAT. Therefore,
the broadcast receiver may receive the emergency alert message
based on the partition_id field included in the FIT and/or the SLT
and the partition_id field included in the EAT.
[1513] The signaling data may further include category information
that indicates a category of the service. For example, the category
information may refer to a service_category field. For example, the
service category field may indicate one of an A/V service, an audio
service, an ESG service, a Content on Demand (CoD) service, an
app-based service, and/or an emergency alert message (EAM) service
(or EAS service).
[1514] The signaling data may further include the emergency alert
message. For example, the emergency alert message may be
transmitted through link layer signaling. In addition, the
emergency alert message may be included in the signaling data and
transmitted.
[1515] The emergency alert message may further include a message ID
that identifies the emergency alert message. For example, the
message ID may refer to an EAS_message_id field.
[1516] The link layer packet may include a header and a payload. In
addition, the header may include a first header having a fixed
length and a second header having a variable length. In addition,
the first header may include type information that indicates a
packet type of input data, and the first header may further include
configuration information that indicates a configuration of the
payload. For example, the type information may refer to a packet
type field. In addition, the configuration information may refer to
a payload_config field.
[1517] A broadcast signal according to an embodiment of the present
invention may be shared by a plurality of broadcasters. That is,
the broadcasters may use a portion of the broadcast signal or the
whole broadcast signal to broadcast a service. For example, the
plurality of broadcasters may share one frequency.
[1518] In addition, the broadcast signal may include a plurality of
emergency alert messages transmitted from the plurality of
broadcasters.
[1519] For example, the plurality of broadcasters may include a
first broadcaster and a second broadcaster. An emergency alert
message transmitted from the second broadcaster may include an
emergency alert message for the first broadcaster.
[1520] Even when the broadcast receiver provides a service
transmitted from the first broadcaster to a user, the broadcast
receiver may provide the emergency alert message transmitted from
the second broadcaster to the user.
[1521] FIG. 101 is a diagram illustrating a broadcast reception
method according to an embodiment of the present invention.
[1522] A broadcast receiver according to an embodiment of the
present invention may include a controller and/or a broadcast
receiving unit.
[1523] The broadcast receiver according to the embodiment of the
present invention may receive a broadcast signal including service
data and signaling data using the broadcast receiving unit
(CS1010100).
[1524] The broadcast receiver according to the embodiment of the
present invention may acquire the signaling data using the
controller (CS1010200).
[1525] Then, the broadcast receiver according to the embodiment of
the present invention may acquire the service data based on the
signaling data using the controller (CS1010300).
[1526] In addition, the broadcast receiver may receive a broadcast
signal including a link layer packet. Then, the broadcast receiver
may decapsulate the link layer packet into an emergency alert
message and the signaling data using the controller.
[1527] The signaling data may include bootstrapping information
that supports bootstrapping of service acquisition. For example,
the signaling data may include low level signaling information, and
the low level signaling information may include an FIT and/or an
SLT.
[1528] The signaling data may include a broadcaster ID that
identifies a broadcaster related to a service. For example, the
broadcaster ID included in the signaling data may refer to a
partition_id field included in the FIT and/or the SLT.
[1529] The emergency alert message may include a broadcaster ID
that identifies a broadcaster related to the emergency alert
message. For example, the broadcaster ID included in the emergency
alert message may refer to a partition_id field included in an
EAT.
[1530] According to an embodiment of the present invention, the
partition_id field included in the FIT and/or the SLT may match the
partition id field included in the EAT. Therefore, the broadcast
receiver may receive the emergency alert message based on the
partition_id field included in the FIT and/or the SLT and the
partition_id field included in the EAT.
[1531] The signaling data may further include category information
that indicates a category of the service. For example, the category
information may refer to a service category field. For example, the
service category field may indicate one of an A/V service, an audio
service, an ESG service, a CoD service, an app-based service,
and/or an EAM service (or EAS service).
[1532] The signaling data may further include the emergency alert
message. For example, the emergency alert message may be
transmitted through link layer signaling. In addition, the
emergency alert message may be included in the signaling data and
transmitted.
[1533] The emergency alert message may further include a message ID
that identifies the emergency alert message. For example, the
message ID may refer to an EAS_message_id field.
[1534] The link layer packet may include a header and a payload. In
addition, the header may include a first header having a fixed
length and a second header having a variable length. In addition,
the first header may include type information that indicates a
packet type of input data, and the first header may further include
configuration information that indicates a configuration of the
payload. For example, the type information may refer to a packet
type field. In addition, the configuration information may refer to
a payload_config field.
[1535] A broadcast signal according to an embodiment of the present
invention may be shared by a plurality of broadcasters. That is, a
broadcaster may use a portion of the broadcast signal or the whole
broadcast signal to broadcast a service. For example, the plurality
of broadcasters may share one frequency.
[1536] In addition, the broadcast signal may include a plurality of
emergency alert messages transmitted from the plurality of
broadcasters.
[1537] For example, the plurality of broadcasters may include a
first broadcaster and a second broadcaster. An emergency alert
message transmitted from the second broadcaster may include an
emergency alert message for the first broadcaster.
[1538] Even when the broadcast receiver provides a service
transmitted from the first broadcaster to a user, the broadcast
receiver may provide the emergency alert message transmitted from
the second broadcaster to the user.
[1539] Modules or units may be processors executing consecutive
processes stored in a memory (or a storage unit). The steps
described in the aforementioned embodiments can be performed by
hardware/processors. Modules/blocks/units described in the above
embodiments can operate as hardware/processors. The methods
proposed by the present invention can be executed as code. Such
code can be written on a processor-readable storage medium and thus
can be read by a processor provided by an apparatus.
[1540] While the embodiments have been described with reference to
respective drawings for convenience, embodiments may be combined to
implement a new embodiment. In addition, designing
computer-readable recording medium storing programs for
implementing the aforementioned embodiments is within the scope of
the present invention.
[1541] The apparatus and method according to the present invention
are not limited to the configurations and methods of the
above-described embodiments and all or some of the embodiments may
be selectively combined to obtain various modifications.
[1542] The methods proposed by the present invention may be
implemented as processor-readable code stored in a
processor-readable recording medium included in a network device.
The processor-readable recording medium includes all kinds of
recording media storing data readable by a processor. Examples of
the processor-readable recording medium include a ROM, a RAM, a
CD-ROM, a magnetic tape, a floppy disk, an optical data storage
device and the like, and implementation as carrier waves such as
transmission over the Internet. In addition, the processor-readable
recording medium may be distributed to computer systems connected
through a network, stored and executed as code readable in a
distributed manner.
[1543] Although the preferred embodiments of the present invention
have been disclosed for illustrative purposes, those skilled in the
art will appreciate that various modifications, additions and
substitutions are possible, without departing from the scope and
spirit of the invention as disclosed in the accompanying claims.
Such modifications should not be individually understood from the
technical spirit or prospect of the present invention.
[1544] Both apparatus and method inventions are mentioned in this
specification and descriptions of both the apparatus and method
inventions may be complementarily applied to each other.
[1545] Those skilled in the art will appreciate that the present
invention may be carried out in other specific ways than those set
forth herein without departing from the spirit and essential
characteristics of the present invention. Therefore, the scope of
the invention should be determined by the appended claims and their
legal equivalents, not by the above description, and all changes
coming within the meaning and equivalency range of the appended
claims are intended to be embraced therein.
[1546] In the specification, both the apparatus invention and the
method invention are mentioned and description of both the
apparatus invention and the method invention can be applied
complementarily.
[1547] Various embodiments have been described in the best mode for
carrying out the invention.
[1548] The present invention is applied to broadcast signal
providing fields.
[1549] Various equivalent modifications are possible within the
spirit and scope of the present invention, as those skilled in the
relevant art will recognize and appreciate. Accordingly, it is
intended that the present invention cover the modifications and
variations of this invention provided they come within the scope of
the appended claims and their equivalents.
* * * * *