U.S. patent number RE46,304 [Application Number 14/661,925] was granted by the patent office on 2017-02-07 for broadcasting signal receiver and method for transmitting/receiving broadcasting signal.
This patent grant is currently assigned to LG ELECTRONICS INC.. The grantee listed for this patent is LG ELECTRONICS INC.. Invention is credited to In Hwan Choi, Byoung Gill Kim, Jin Pil Kim, Jin Woo Kim, Jong Moon Kim, Kook Yeon Kwak, Hyoung Gon Lee, Won Gyu Song, Chang Sik Yun.
United States Patent |
RE46,304 |
Kim , et al. |
February 7, 2017 |
Broadcasting signal receiver and method for transmitting/receiving
broadcasting signal
Abstract
A broadcasting signal receiver and a method for
transmitting/receiving a broadcasting signal are disclosed. An
identifier of a cell is set in the broadcasting signal and, if the
cell is changed, channel information of the changed cell can be
obtained from program table information having the channel
information of the cell. Accordingly, the broadcasting signal
receiver can continuously output a program although the cell is
changed.
Inventors: |
Kim; Jin Woo (Seoul,
KR), Choi; In Hwan (Gwacheon-si, KR), Kwak;
Kook Yeon (Anyang-si, KR), Lee; Hyoung Gon
(Seoul, KR), Song; Won Gyu (Seoul, KR),
Kim; Jin Pil (Seoul, KR), Kim; Jong Moon
(Gwangmyeong-si, KR), Kim; Byoung Gill (Seoul,
KR), Yun; Chang Sik (Daejeon, KR) |
Applicant: |
Name |
City |
State |
Country |
Type |
LG ELECTRONICS INC. |
Seoul |
N/A |
KR |
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|
Assignee: |
LG ELECTRONICS INC. (Seoul,
KR)
|
Family
ID: |
39681876 |
Appl.
No.: |
14/661,925 |
Filed: |
March 18, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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12027468 |
Oct 25, 2011 |
8045591 |
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60911807 |
Apr 13, 2007 |
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60978733 |
Oct 9, 2007 |
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60947984 |
Jul 4, 2007 |
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Reissue of: |
13241102 |
Sep 22, 2011 |
8401042 |
Mar 19, 2013 |
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Foreign Application Priority Data
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Feb 9, 2007 [KR] |
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10-2007-0013927 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04H
20/26 (20130101); H04H 20/26 (20130101); H04H
20/57 (20130101); H04H 20/22 (20130101); H04H
20/57 (20130101) |
Current International
Class: |
H04N
7/12 (20060101); G06F 11/00 (20060101); H04H
20/26 (20080101); H04H 20/57 (20080101) |
Field of
Search: |
;370/310,314,316,389,392,535,537,542 ;455/12,1 ;375/265
;348/385.1,473,474 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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10-2000-0040481 |
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Jul 2000 |
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KR |
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10-2006-0055959 |
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May 2006 |
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KR |
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10-2006-0068449 |
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Jun 2006 |
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KR |
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10-2007-0013168 |
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Jan 2007 |
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KR |
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01/05157 |
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Jan 2001 |
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WO |
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Other References
The Authoritative Dictionary of IEEE Standards Terms, 7th Ed., (p.
217, 379, 716,872), IEEE, Inc., New York, NY, Dec. 2000. cited by
examiner .
"A Theory of Interleavers", Cornell University, Ithaca, NY, USA,
1997. cited by examiner.
|
Primary Examiner: Worjloh; Jalatee
Attorney, Agent or Firm: Dentons US LLP
Parent Case Text
CROSS REFERENCE TO RELATED APPLICATIONS
.Iadd.More than one reissue application has been filed for the
reissue of U.S. Pat. No. 8,401,042 including reissue patent
application Ser. No. 14/661,925 (present application), and patent
application Ser. No. 15/145,600, filed on May 3, 2016, which is a
divisional reissue patent application of reissue patent application
Ser. No. 14/661,925..Iaddend.
This application .Iadd.is a reissue application of U.S. Pat. No.
8,401,042, issued on Mar. 19, 2013 from U.S. patent application
Ser. No. 13/241,102, filed on Sep. 22, 2011, which .Iaddend.is a
continuation of .[.currently.]. U.S. .[.application Ser..].
.Iadd.patent application Ser. .Iaddend.No. 12/027,468, filed on
Feb. 7, 2008, now U.S. Pat. No. 8,045,591.Iadd., .Iaddend.which
claims the benefit of earlier filing date and right .[.to.].
.Iadd.of .Iaddend.priority to Korean Patent Application No.
10-2007-0013927, filed on Feb. 9, 2007, and .Iadd.also
.Iaddend.claims the benefit of U.S. Provisional Application Nos.
60/911,807, 60/978,733, and 60/947,984.Iadd., .Iaddend.respectively
filed on Apr. 13, 2007, Oct. 9, 2007, and Jul. 4, 2007.Iadd., the
contents of .Iaddend.which are all hereby incorporated by reference
herein in their entirety.
Claims
What is claimed is:
1. A method of transmitting a broadcast signal in a transmitter,
the method comprising: encoding mobile data for forward error
correction (FEC) to build a Reed-Solomon (RS) frame by adding .[.a
parity byte.]. .Iadd.parity data .Iaddend.and cyclic redundancy
check (CRC) data; block processing the encoded mobile data by a
specific code rate; forming data groups including the block
processed mobile data, wherein at least one of the data groups
includes a first region and a second region, wherein the first
region includes known data sequences, wherein the data groups
include signaling information, MPEG header place holders, main
service data place holders and non-systematic RS parity place
holders, and wherein the signaling information includes information
for a plurality of RS code modes for the mobile data and
information for a plurality of serial concatenated convolutional
code (SCCC) modes for the mobile data; deinterleaving data in the
data groups; removing the main service data place holders and the
non-systematic RS parity place holders and replacing the MPEG
header place holders with MPEG headers to form mobile data packets;
multiplexing main data packets including main data and the mobile
data packets; performing systematic RS encoding on the main data in
the multiplexed packets and non-systematic RS encoding on the
mobile data in the multiplexed packets, wherein .Iadd.first
.Iaddend.non-systematic RS parity data is added by the
non-systematic RS encoding; interleaving .[.data in the multiplexed
packets.]. .Iadd.the systematic RS encoded main data and the
non-systematic RS encoded mobile data .Iaddend.as the inverse
process of the deinterleaving; trellis encoding the interleaved
data in a trellis encoder, wherein a memory included in the trellis
encoder is initialized at a start of each of the known data
sequences; and transmitting the broadcast signal including the
trellis-encoded data.
2. The method of claim 1, wherein at least two of the known data
sequences have different patterns.
3. The method of claim 1, further comprising performing
non-systematic RS encoding to recalculate .[.the.]. .Iadd.second
.Iaddend.non-systematic RS parity data.
.[.4. An apparatus for transmitting a broadcast signal, the
apparatus comprising: an encoder configured to encode mobile data
for forward error correction (FEC) to build a Reed-Solomon (RS)
frame by adding a parity byte and cyclic redundancy check (CRC)
data; a block processor configured to block process the encoded
mobile data by a specific code rate; a data group formatter
configured to form data groups including the block processed mobile
data, wherein at least one of the data groups includes a first
region and a second region, wherein the first region includes known
data sequences, wherein the data groups include signaling
information, MPEG header place holders, main service data place
holders and non-systematic RS parity place holders, and wherein the
signaling information includes information for a plurality of RS
code modes for the mobile data and information for a plurality of
serial concatenated convolutional code (SCCC) modes for the mobile
data; a deinterleaver configured to deinterleave data in the data
groups; a packet formatter configured to remove the main service
data place holders and the non-systematic RS parity place holders
and replace the MPEG header place holders with MPEG headers to form
mobile data packets; a multiplexer configured to multiplex main
data packets including main data and the mobile data packets; a
systematic/nonsystematic RS encoder configured to perform
systematic RS encoding on the main data in the multiplexed packets
and non-systematic RS encoding on the mobile data in the
multiplexed packets, wherein nonsystematic RS parity data is added
by the non-systematic RS encoding; an interleaver configured to
interleave data in the multiplexed packets as the inverse process
of the deinterleaving; a trellis encoder configured to trellis
encode the interleaved data in the trellis encoder, wherein a
memory included in the trellis encoder is initialized at a start of
each of the known data sequences; and a transmission unit
configured to transmit the broadcast signal including the
trellis-encoded data..].
.[.5. The apparatus of claim 4, wherein at least two of the known
data sequences have different patterns..].
.[.6. The apparatus of claim 4, further comprising a non-systematic
RS encoder configured to perform non-systematic RS encoding to
recalculate the non-systematic RS parity data..].
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a broadcasting signal receiver and
a method for transmitting/receiving a broadcasting signal.
2. Discussion of the Related Art
A digital broadcasting system for mobile reception, which is
capable of transmitting/receiving a broadcasting signal, has been
developed and commercialized. However, the digital broadcasting
system for mobile reception is designed independent of a
broadcasting system for fixed reception and thus is incompatible
with the conventional broadcasting system for fixed reception.
For example, a transmission system according to an advanced
television systems committee (ATSC) vestigial sideband (VSB) scheme
was designed without considering mobility, due to terrestrial
characteristics. The ATSC broadcasting system is suitable for a
multi-frequency network environment. In the ATSC broadcasting
system, if a user moves to an area where broadcasting contents are
broadcast with a different frequency, the user should tune a
channel again in order to continuously view the broadcasting
contents.
SUMMARY OF THE INVENTION
Accordingly, the present invention is directed to a broadcasting
signal receiver and a method for transmitting/receiving a
broadcasting signal that substantially obviate one or more problems
due to limitations and disadvantages of the related art.
An object of the present invention is to provide a broadcasting
signal receiver and a method for transmitting/receiving a
broadcasting signal, of which mobile reception is possible in a
multi-frequency network environment.
Another object of the present invention is to provide a
broadcasting signal receiver and a method for
transmitting/receiving a broadcasting signal in a broadcasting
system for mobile reception compatible with a broadcasting system
for fixed reception.
Another object of the present invention is to provide a
broadcasting signal receiver and a method for
transmitting/receiving a broadcasting signal, which are capable of
allowing a user to conveniently view a broadcasting program even
when the user moves to an area where a broadcasting program is
broadcast with a different frequency, in a multi-frequency network
environment.
Additional advantages, objects, and features of the invention will
be set forth in part in the description which follows and in part
will become apparent to those having ordinary skill in the art upon
examination of the following or may be learned from practice of the
invention. The objectives and other advantages of the invention may
be realized and attained by the structure particularly pointed out
in the written description and claims hereof as well as the
appended drawings.
To achieve these objects and other advantages and in accordance
with the purpose of the invention, as embodied and broadly
described herein, there is provided a method for transmitting a
broadcasting signal, the method including: outputting the
broadcasting signal in which program table information including
physical channel information of at least one cell and broadcasting
data are multiplexed in the program table information of the
broadcasting signal; modulating the multiplexed broadcasting
signal; and transmitting the modulated broadcasting signal.
The modulating may include setting an identifier of a cell, which
will transmit the broadcasting signal, in signaling information
included in a transmission parameter of the multiplexed
broadcasting signal.
The program table information may include at least one of a central
frequency of the broadcasting signal transmitted from the cell, a
bandwidth, information indicating whether the broadcasting signal
is a burst signal, a modulation method of the broadcasting signal,
and an error correction encoding method of the broadcasting
signal.
In another aspect of the present invention, there is provided a
method for receiving a broadcasting signal, the method including:
receiving the broadcasting signal including program table
information including physical channel information of at least one
cell from a first cell; tuning a channel of the broadcasting cell
transmitted from a second cell using the physical channel
information of the program table information if the power of the
received broadcasting signal is less than a first threshold value;
and receiving and outputting the broadcasting signal from the
second cell if the power of the broadcasting signal received from
the second cell is greater than a second threshold value, and
receiving the broadcasting signal from any one of the first cell or
a third cell if the power of the broadcasting signal received from
the second cell is less than the second threshold value.
The tuning may include obtaining an identifier of the second cell
from signaling information included in a transmission parameter of
the broadcasting signal of the second cell.
The tuning may be performed in a reception off period of the
broadcasting signal received from the first cell.
The broadcasting signal received from the first cell and the
broadcasting signal received from the second cell may include the
same broadcasting program.
In another aspect of the present invention, there is provided a
broadcasting signal receiver including: a tuner which receives
program table information including physical channel information of
at least one cell and a broadcasting signal including an identifier
of the cell; a demodulator which demodulates the broadcasting
signal received by the tuner and outputs the demodulated
broadcasting signal; a demultiplexer which demultiplexes the
broadcasting signal output from the demodulator; a program table
information decoder which obtains the physical channel information
of the cell from the program table information output from the
demultiplexer; a decoder which decodes the broadcasting signal
output from the demultiplexer and outputs a broadcasting program;
an output unit which outputs the broadcasting program output from
the decoder; and a controller which determines whether the cell is
changed from the power of the received broadcasting signal and
outputs the same broadcasting program as the broadcasting program
of the cell before the change using the physical channel
information of the changed cell obtained by the program table
information decoder if the cell is changed.
The demodulator may obtain an identifier of the changed cell from
signaling information of the received broadcasting signal, and the
controller may identify the changed cell from the identifier of the
cell.
The identifier of the cell in the broadcasting signal received by
the tuner may be included in signaling information included in a
transmission parameter of the broadcasting signal.
The broadcasting signal receiver may further include an IF filter
which filters an IF stream included in the broadcasting signal.
The program table information may include the physical channel
information of the identifier of the cell.
It is to be understood that both the foregoing general description
and the following detailed description of the present invention are
exemplary and explanatory and are intended to provide further
explanation of the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
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:
FIG. 1 is a flowchart illustrating a method for
transmitting/receiving a broadcasting signal according to an
embodiment;
FIG. 2 is a flowchart illustrating a method for
transmitting/receiving a broadcasting signal according to another
embodiment;
FIG. 3 is a flowchart illustrating a method for
transmitting/receiving a broadcasting signal according to another
embodiment;
FIG. 4 is a schematic block diagram showing an ATSC broadcasting
system in order to easily describe the present invention;
FIG. 5 is a schematic view illustrating the operation of the
broadcasting signal receiver;
FIG. 6 is a view showing an example of a service multiplexer shown
in FIG. 4;
FIG. 7 is a view illustrating reception of broadcasting data at the
time of occurrence of the handover, by the method for
transmitting/receiving the broadcasting signal according to the
embodiment;
FIG. 8 is a view showing an example of a mobile service multiplexer
of the service multiplexer shown in FIG. 6;
FIG. 9 is a block diagram showing an example of a transmitter shown
in FIG. 4;
FIG. 10 is a view showing an example of a preprocessor shown in
FIG. 9;
FIG. 11 is a flowchart illustrating a method for
transmitting/receiving a broadcasting signal according to an
embodiment;
FIG. 12 is a view showing program table information including
physical channel information of each cell;
FIG. 13 is a view showing a broadcasting signal receiver according
to an embodiment;
FIG. 14 is a view showing an example of a demodulator in the
broadcasting signal receiver;
FIG. 15 is a view showing a broadcasting signal receiver according
to another embodiment;
FIG. 16 is a view showing a broadcasting signal receiver according
to another embodiment; and
FIG. 17 is a view showing a broadcasting signal receiver according
to another embodiment.
DETAILED DESCRIPTION OF THE INVENTION
Reference will now be made in detail to the preferred embodiments
of the present invention, examples of which are illustrated in the
accompanying drawings. Wherever possible, the same reference
numbers will be used throughout the drawings to refer to the same
or like parts.
Hereinafter, exemplary embodiments of the present invention will be
described with reference to the accompanying drawings.
FIG. 1 is a flowchart illustrating a method for
transmitting/receiving a broadcasting signal according to an
embodiment. Hereinafter, the method for transmitting/receiving the
broadcasting signal according to the present embodiment will be
described with reference to FIG. 1.
A broadcasting transmitter side sets an identifier of a cell, which
is a propagation area of a broadcasting signal, in signaling
information included in a transmission parameter of the
broadcasting signal and modulates the broadcasting signal
(S10).
The modulated broadcasting signal is transmitted (520).
A broadcasting receiver side receives the broadcasting signal
including the identifier of the cell which is a propagation area of
the broadcasting signal (S30).
The received broadcasting signal is demodulated so as to obtain the
identifier of the cell from the signaling information included in
the transmission parameter of the broadcasting signal (S40).
In the present embodiment, particularly, if the broadcasting
receiver receives the broadcasting signal while moving in the
multi-frequency network (MFN) environment, the propagation area of
the broadcasting signal transmitted with any one of multiple
frequencies can be identified.
FIG. 2 is a flowchart illustrating a method for
transmitting/receiving a broadcasting signal according to another
embodiment. Hereinafter, the method for transmitting/receiving the
broadcasting signal according to the present embodiment will be
described with reference to FIG. 2.
A broadcasting transmitter side outputs a broadcasting signal
obtained by multiplexing broadcasting data and program table
information including channel information of at least one cell
(S110). The program table information will be described in the
following embodiment.
The program table information may include information on a cell
which is a propagation area of the broadcasting signal, for
example, channel information of cells adjacent to a current cell.
Program channel information of S210 may be physical channel
information and may include physical channel information
transmitted by transmitters of a plurality of broadcasting stations
of cells.
Then, the multiplexed broadcasting signal is modulated (S120) and
the modulated broadcasting signal is transmitted (S130).
A broadcasting receiver side receives the broadcasting signal
including the program table information containing the channel
information of at least one cell (S140).
If the power of the received broadcasting signal is less than a
first threshold value, the channel of a second cell is tuned using
the program table information (S150).
If the power of the broadcasting signal received from the second
cell is greater than a second threshold value, the broadcasting
received from the second cell is output and, if the power of the
broadcasting signal received from the second cell is less than the
second threshold value, the broadcasting signal is received from
any one of the first cell or the third cell (S160).
According to the present embodiment, even when the broadcasting
receiver escapes from the cell which is the propagation cell of the
broadcasting signal, it is possible to continuously view the
broadcasting program.
FIG. 3 is a flowchart illustrating a method for
transmitting/receiving a broadcasting signal according to another
embodiment. Hereinafter, the method for transmitting/receiving the
broadcasting signal according to the present embodiment will be
described with reference to FIG. 3.
A broadcasting transmitter side outputs a broadcasting stream
obtained by multiplexing broadcasting data and program table
information including channel information of at least one cell
(S210).
An identifier of the cell is set in signaling information included
in a transmission parameter of the multiplexed broadcasting signal
and the broadcasting signal is modulated (S220).
The broadcasting signal including the identifier of the cell and
the program table information is transmitted (S230).
A broadcasting receiver side receives the broadcasting signal
including the program channel information containing the channel
information of at least one cell and an identifier of a first cell
(S310).
If the power of the received broadcasting signal is less than a
first threshold value, the channel of a second cell is tuned
according to the channel information included in the program table
information and an identifier of the second cell is received from
the signaling information included in the transmission parameter of
the broadcasting signal of the second cell (S320).
If the power of the broadcasting signal received from the second
cell is greater than a second threshold value, the broadcasting
signal received from the second cell is output and, if the power of
the broadcasting signal received from the second cell is less than
the second threshold value, the broadcasting signal is received
from any one of the first cell or the third cell (S330).
In order to easily describe the present invention, for example, an
ASTC broadcasting system suitable for the MFN environment will be
described, but the present invention is not limited thereto.
FIG. 4 is a schematic block diagram showing the ATSC broadcasting
system in order to easily describe the present invention.
In the ATSC broadcasting system, a device for transmitting a
broadcasting signal includes a service multiplexer and a
transmitter.
Here, the service multiplexer may be located at a studio of each
broadcasting station and the transmitter may be located at one or
more specific sites. A plurality of transmitters may share the same
frequency. In this case, the plurality of transmitters transmits
the same signal. The service multiplexer multiplexes main service
data for fixed reception and mobile service data for mobile
reception. The transmitter modulates the multiplexed broadcasting
data and transmits the modulated broadcasting data. Hereinafter,
for convenience of description, a method for modulating the main
service data for fixed reception and the mobile service data for
mobile reception is called a mobile VSB (MVSB). If the broadcasting
data for mobile reception is transmitted, the transmitter modulates
the mobile service data for mobile reception such that the data can
be stably received, regardless of various distortions or noise
which may occur in a transmission channel.
A broadcasting signal receiver can compensate for the signal
distortions and restore the broadcasting signal. Data communication
between the service multiplexer and the transmitter, both of which
are separated from each other, may be performed by various methods.
For example, the standard such as synchronous serial interface for
transport of MPEG-2 data (SMPTE-310M) may be used.
FIG. 5 is a schematic view illustrating the operation of the
broadcasting signal receiver. For convenience of description,
hereinafter, a range which is influenced by a transmission system
according to one frequency in the MFN environment is called a cell.
According to the present embodiment, even when the broadcasting
signal receiver receives the broadcasting signal while moving over
several cells, a viewer can continuously view the broadcasting
program of the channel which has been received. The broadcasting
signal receiver can receive the broadcasting signal from a current
cell A and then receive the broadcasting signal from another cell
B, that is, can change a cell for receiving the broadcasting
signal. Hereinafter, this is called handover.
A mobile service elementary stream (ES) for mobile reception may be
transmitted through transmitters with different area-based
frequencies. If the mobile service ES for mobile reception is
transmitted, the cell from which the broadcasting signal receiver
receives the broadcasting signal and the physical information of
the channel of the cell are changed. However, although the user
does not perform an additional operation such as the tuning of the
channel, the broadcasting signal of the same channel may be output.
The cell can be identified by a cell ID. In each cell, any ES may
be transmitted through different physical channels
Table 1 shows the broadcasting information and the locations of the
transmitters according to the cell ID.
TABLE-US-00001 TABLE 1 Cell ID 0x0001 0x0002 Location Mt. Gwanak
Mt. Yongmoon Broadcasting information: MBC (11, 15) MBC (11, 14)
channel name ABC1 (9, 14) ABC1 (9, 21) (major, physical) ABC2 (7,
13) ABC2 (7, 22) SBB (6, 16) SBB (6, 12) ESS (10, 29) ESS (10,
25)
In the example of Table 1, a cell having a cell ID of 0x0001 is
located at Mt. Gwanak and a cell having a cell ID of 0x0002 is
located at Mt. Yongmoon. The same broadcasting signal can be
transmitted through different physical channels according to the
cell.
FIG. 6 is a view showing an example of the service multiplexer
shown in FIG. 4 in the broadcasting signal receiver according to
the embodiment. The service multiplexer shown in FIG. 6 includes a
main audio/video (A/V) system 210, main ancillary/control data
system 220, a mobile A/V system 240, a mobile ancillary/control
data system 250, a main service multiplexer 230, a mobile service
multiplexer 260 and a transmission service multiplexer 270.
Main service data is encoded and compressed by the main A/V system
210 and is output to the main service multiplexer 230. If the
number of types of main service data is greater than one, a
plurality of main A/V systems may be included. The main service
multiplexer 230 multiplexes the output of the main A/V system 210
and various types of additional data 220 of the main service and
outputs the multiplexed data to the transmission service
multiplexer 270.
Similarly, mobile service data is encoded and compressed by the
mobile A/V system 240 and is output to the mobile service
multiplexer 260. If the number of types of mobile service data is
greater than one, a plurality of mobile A/V systems may be
included. The mobile service multiplexer 260 multiplexes the output
of the mobile A/V system 240 and various types of additional data
of the mobile service and outputs the multiplexed data to the
transmission service multiplexer 270.
The transmission service multiplexer 270 multiplexes the output of
the main service multiplexer 230 and the output of the mobile
service multiplexer 260 and outputs the multiplexed data to the
transmitter. The output data of the transmission service
multiplexer 270 may be expressed in the form of an MPEG-2 transport
stream (TS) packet.
The transmission service multiplexer 270 can transmit the service
data to the transmitter at a constant data rate. The transmission
service multiplexer 270 can transmit the service data to the
transmitter at a constant data rate even when the service data
transmitted to the transmitter includes only the main service data
or both the main service data and the mobile service data. For
example, if the transmission service multiplexer 270 transmits the
data to the transmitter at 19.39 Mbps, the mobile service data is
multiplexed with the main service data and is transmitted within
19.39 Mbps. The mobile service data may be subjected to be error
correction coding process in the transmitter and thus the data rate
of the mobile service data may be reduced in consideration of the
error correction encoding process.
If the output of the service multiplexer needs to be maintained at
the constant data rate, for example, 19.39 Mbps, at least one of
the main service multiplexer, the mobile service multiplexer and
the transmission data multiplexer may insert null data or null
packet in the multiplexed data so as to match the data rate of the
final output to the constant data rate. Here, the null data may be
generated in the multiplexer or may be received from an external
device.
FIG. 7 is a view illustrating reception of broadcasting data at the
time of occurrence of the handover, by the method for
transmitting/receiving the broadcasting signal according to the
embodiment. Transmission data obtained by multiplexing the main
service data M and mobile service data E1 and E2 may be transmitted
to each cell. The main service data and the mobile service data may
be multiplexed on a time axis and may be transmitted in the form of
a burst, and desired broadcasting service data can be obtained by
turning on/off the receiver only in a time period when the desired
broadcasting service data is transmitted. For example, if
broadcasting data E1 is obtained in the cell A, the signal is
received only in a time period when the broadcasting data E1 is
transmitted. In time periods when the main service data and the
broadcasting data E2 are received, the power of the receiving unit
of the broadcasting signal receiver is turned off. In the case
where the broadcasting signal receiver is turned on/off in order to
receive the signal, the broadcasting signal receiver is turned
on/off earlier than an actual reception period such that a tuner or
a demodulator prepares for the signal reception. Even when the
broadcasting signal receiver receives the broadcasting data E1 in
the cell B, the similar operation with that of the cell A may be
performed.
In the case where the broadcasting signal receiver receives the
broadcasting data E1 while moving over a plurality of cells, the
broadcasting signal receiver can continuously receive the same
broadcasting data (for example, E1) although the handover occurs in
the broadcasting signal receiver.
FIG. 8 is a view showing an example of a mobile service multiplexer
of the service multiplexer shown in FIG. 6. The mobile service
multiplexer shown in FIG. 8 includes a first multiplexer 311, a
program table information generator 312, a second multiplexer 313
and a packet conversion buffer 314.
The first multiplexer 311 multiplexes mobile data of an MPEG-2 TS
format and program table information, such as a program map table
(PMT), generated by the program table information generator 312 and
outputs the multiplexed data to the second multiplexer 313. The
program table information generator 312 generates information
according to program specific information (PSI) or program and
system information protocol (PSIP). The PSI includes information
such as the PMT, a program association table (PAT) and a network
information table (NIT) and the PSIP includes a system time table
(STT), a rating region table (RRT), a master guide table (MGT), a
virtual channel table (VCT), an event information table (EIT) and
an extended text table (ETT). Hereinafter, the information on the
broadcasting signal which is transmitted in the form of at least
one section, such as the PSI/PSIP, is called the program table
information. The program table information generator 312 can
transmit physical channel information of the cells in addition to a
cell, which currently receives the signal, by the program table
information. Hereinafter, for convenience of description, it is
assumed that the physical channel information of the cells is
included in the program table information called the NIT.
The second multiplexer 313 multiplexes the output of the first
multiplexer 311 and the output of the program table information
generator 312 and outputs the multiplexed signal to the packet
conversion buffer 314. The first multiplexer 311 includes a
plurality of multiplexers for multiplexing plural pieces of mobile
service data and the PMT of the data. Here, one mobile service data
may become a single program. Information on a physical layer for
real-time broadcasting, that is, information such as time slicing
of a transmission signal and a burst length, may be included in the
program table information. The packet conversion buffer 314 adjusts
188-byte transport stream output from the second multiplexer 313 to
a block length required in a preprocessor which will be described
later.
FIG. 9 is a block diagram showing an example of the transmitter
shown in FIG. 4.
The transmitter includes a demultiplexer 331, a packet jitter
mitigates 332, an M-VSB preprocessor 333, a first transmission data
multiplexer 334, a data randomizer 335, an RS
encoder/non-systematic RS encoder 336, a data interleaver 337, a
parity replacer 338, a non-systematic RS encoder 339, a trellis
encoding module 340, a second transmission data multiplexer 341, a
pilot inserter 342, a VSB modulator 343, and an RF up-converter
344.
The demultiplexer 331 of the transmitter demultiplexes the data
received from the transmission service multiplexer 270, divides the
data into the main service data and the mobile service data,
outputs the divided main service data to the packet jitter
mitigater 332, and outputs the mobile service data to the M-VSB
preprocessor 333.
If the transmission service multiplexer 270 inserts the null data
into the data and then transmits the data in order to match the
data rate to the constant data rate, the demultiplexer 331 discards
the null data by referring to the identifier which is transmitted
together, processes only the remaining data, and outputs the
processed data to a corresponding block. The demultiplexer 331 may
set other information, such as control information necessary for
transmission in the null data, and transmit the null data.
The M-VSB preprocessor 333 performs an additional encoding process
with respect to the mobile service data in order to rapidly cope
with noise and a channel variation. The mobile service data divided
by the demultiplexer 331 is output to the M-VSB preprocessor 333.
The M-VSB preprocessor 333 may randomize the mobile service data
and perform an error correction coding process. If the M-VSB
preprocessor 33 performs the randomizing process, the data
randomizer 335 of the next stage may omit the randomizing process
of the mobile service data. The randomizer of the mobile service
data may be equal to or different from a randomizer defined in the
ATSC.
The main service data packet and the mobile service data packet
based on 188-byte units in data of a predetermined format output
from the M-VSB preprocessor 333 are multiplexed according to a
predefined multiplexing method and are output to the data
randomizer 335. The multiplexing method can be adjusted by various
variables of the system design.
In the method for multiplexing the data by the first transmission
data multiplexer 334, as shown in FIG. 7, a burst period is
provided on the time axis, a plurality of data groups may be
transmitted in the burst period and only the main service data may
be transmitted in a non-burst period. In contrast, the main service
data may be transmitted in the burst period. That is, as shown in
FIG. 7, a plurality of successive mobile service packets forms one
data group and the plurality of data groups is mixed with the main
service data packets so as to form one burst. The mobile service
data or the main service data may be transmitted in one burst
period.
The main service data may exist in the burst period or the
non-burst period. The numbers of main data packets in the main
service data period of the burst period and the main service data
period of the non-burst period may be different from or equal to
each other.
If the mobile service data is transmitted in the burst structure,
the broadcasting signal receiver for receiving only the mobile
service data is turned on only in the burst period so as to receive
the data and is turned off in the period in which only the main
service data is transmitted, thereby reducing the power consumption
of the receiver.
The packet jitter mitigater 332 readjusts a relative location of
the main service data packet such that overflow or underflow does
not occur in the buffer of the decoder in the broadcasting signal
receiver. Since the mobile service data group is multiplexed with
the main service data in the packet multiplexing process, the
temporal location of the main service packet is relatively changed.
The decoder (for example, the MPEG decoder) of the device for
processing the main service data of the broadcasting signal
receiver may receive and decode only the main service data,
recognize the mobile service data packet as the null packet, and
discard the mobile service data packet. Accordingly, when the
decoder of the broadcasting signal receiver receives the main
service data packet multiplexed with the mobile service data group,
packet jitter may occur.
Since the decoder of the receiver includes multi-stage buffers for
video data and has a large size, the first transmission data
multiplexer 334 may generate the packet jitter. Due to the packet
jitter, overflow or underflow may occur in the buffer for the main
service data of the broadcasting signal receiver, for example, the
buffer for audio data.
The packet jitter mitigater 332 knows the multiplexing information
of the first transmission data multiplexer 334. If it is assumed
that the audio data packets are normally processed, the packet
jitter mitigater 332 may rearrange the audio data packets of the
main service as follows.
First, if one audio data packet is included in the main service
data period of the burst period, for example, in the main service
data period interposed between two mobile service data groups, the
audio data packet is arranged at a foremost location of the main
service data period, if two audio data packets are included in the
main service data period of the burst period, the audio data
packets are arranged at foremost and hindmost locations of the main
service data period, and if at least three audio data packets are
included in the main service data period of the burst period, two
audio data packets are arranged at the foremost and hindmost
locations of the main service data period and the remaining audio
data packet is arranged therebetween at a uniform interval. Second,
the audio data packet is arranged at a hindmost location in the
main service data period before the start of the burst period.
Third, the audio data packet is arranged at a foremost location in
the main service data period after the completion of the burst
period. The packets other than the audio data are arranged in a
period excluding the locations of the audio data packets in input
order.
If the locations of the main service data packets are relatively
readjusted, a program clock reference (PCR) value is corrected. The
PCR value is a time reference value for setting the time of the
MPEG decoder, which is inserted into a specific area of a TS packet
and is transmitted. The packet jitter mitigater 332 may correct the
PCR value.
The output of the packet jitter mitigater 332 is input to the first
transmission data multiplexer 334. The first multiplexer 334
multiplexes the main service data output from the packet jitter
mitigater 332 and the mobile service data output from the M-VSB
preprocessor 333 to the burst structure according to the predefined
multiplexing rule and outputs the burst structure to the data
randomizer 335.
The data randomizer 335 performs the same randomizing process as
the existing randomizer if the received data is the main service
data packet. That is, a sync byte in the main service data packet
is discarded and the remaining 187 bytes are randomized using a
pseudo random byte generated therein and are output to the RS
encoder/non-systematic RS encoder 336.
However, if the received data is the mobile service data packet,
the data randomizer 335 may discard the sync byte of 4-byte MPEG
header included in the mobile service data packet and randomize the
remaining 3 bytes. The remaining mobile service data excluding the
MPEG header is output to the RS encoder/non-system RS encoder 336,
without being randomized. In this case, the randomizing process is
previously performed by the M-VSB preprocessor 333. Known data (or
a known data location holder) included in the mobile service data
packet and an initialization data location holder may be randomized
or may not be randomized.
The RS encoder/non-systematic RS encoder 336 performs RS encoding
process with respect to the data randomized by the data randomizer
335 or bypassed data so as to add a 20-byte RS parity and then
outputs the encoded data to the data interleaver 337. At this time,
if the received data is the main service data packet, the RS
encoder/non-system RS encoder 336 performs a systematic RS encoding
process so as to add the 20-byte RS parity to the back of the
187-byte data, similar to an ATSC VSB system. If the received data
is the mobile service data packet, the 20-byte RS parity obtained
by performing the non-systematic RS encoding process is inserted at
the parity byte location decided in the packet.
The data interleaver 337 performs a convolutional interleaving
process in the unit of bytes. The output of the data interleaver
337 is input to the parity replacer 338 and the non-systematic RS
encoder 339.
The memory of the trellis encoding module 340 may be first
initialized such that output data of the trellis encoding module
340 located at the next stage of the parity replacer 338 is set to
known data defined by the agreement between the transmitter and the
receiver. The memory of the trellis encoding module 340 is first
initialized before the received known data sequence is
trellis-encoded.
If a start part of the received known data sequence is the
initialization data location holder inserted by the M-VSB
preprocessor 333, initialization data is generated and is replaced
with the trellis memory initialization data location holder
immediately before the received known data sequence is
trellis-encoded.
The value of the trellis memory initialization data is decided and
generated according to the memory status of the trellis encoding
module 340. Due to the influence of the replaced initialization
data, the RS parity may be calculated again and may be replaced
with the RS parity output from the data interleaver 337.
The non-systematic RS encoder 339 receives the mobile service data
packet including the initialization data location holder, which
will be replaced with the initialization data, from the data
interleaver 337 and receives the initialization data from the
trellis encoding module 340. The initialization data location
holder of the received mobile service data packet is replaced with
the initialization data, the RS parity data added to the mobile
service data packet is removed, and a new non-systematic RS parity
is calculated and is output to the parity replacer 338. Then, the
parity replacer 338 selects the output of the data interleaver 337
with respect to the data in the mobile service data packet, selects
the output of the non-systematic RS encoder 339 with respect to the
RS parity, and outputs the selected data to the trellis encoding
unit 340.
If the main service data packet is received or if the mobile
service data packet no including the initialization data location
holder to be replaced is received, the parity replacer 338 selects
and outputs the RS parity and the data output from the data
interleaver 337 to the trellis encoding module 340 without
alteration.
The trellis encoding module 340 converts the data based on byte
units into the data based on symbol units, performs 12-way
interleaving, performs the trellis encoding process, and outputs
the encoded data to the second transmission data multiplexer
341.
The second transmission data multiplexer 341 inserts a field sync
signal and a segment sync signal to the output of the trellis
encoding module 340 and outputs the inserted data to the pilot
inserter 342. The data into which the pilot is inserted by the
pilot inserter 342 is VSB-modulated by the VSB modulator 343 and is
transmitted to the broadcasting signal receiver through the RF
up-converter 343.
The transmitter transmits various transmission parameters of the
transmission signal such as the main service data or the mobile
service data and the broadcasting signal receiver needs to receive
the transmission parameters of the transmitted signal in order to
normally receive the transmitted signal. For example, in order to
transmit the mobile service data, information indicating how the
signals of the symbol area are encoded is required and information
indicating how the main service data and the mobile service data
are multiplexed is required. A cell identifier may be required in
the multi-frequency network environment. Here, information on the
transmission parameter is called signaling information. In the
embodiment shown in FIG. 9, the signaling information may be
inserted by the preprocessor 333 or the second transmission data
multiplexer 341 so as to be transmitted. If the second transmission
data multiplexer 341 inserts the signaling information, the
signaling information may be inserted into a field sync segment
area.
FIG. 10 is a view showing an example of the preprocessor shown in
FIG. 9. The preprocessor shown in FIG. 9 may include an M-VSB data
randomizer 401, a RS frame encoder 402, an M-VSB block processor
403, a group formatter 404, a data deinterleaver 405 and a packet
formatter 406.
The M-VSB randomizer 401 randomizes the received mobile service
data and outputs the randomized data to the RS frame encoder 402,
for error correction encoding. If the M-VSB randomizer 401
randomizes the mobile service data, the data randomizer 335 located
at the next stage thereof may omit the randomizing process of the
mobile service data.
The RS frame encoder 402 performs the error correction encoding
process with respect to the randomized mobile service data. If the
RS frame encoder 402 performs the error correction encoding
process, burst error which may occur by a variation in propagation
environment is distributed while making the mobile service data
robust so as to cope with the propagation environment which rapidly
varies. The RS frame encoder 402 may include a process of mixing
mobile service data having a predetermined size in the unit of data
rows.
Hereinafter, as one embodiment, the error correction encoding
process may be performed by performing the RS encoding method or
the cyclic redundancy check (CRC) encoding method. If the RS
encoding method is performed, parity data which will be used for
error correction is generated and, if the CRC encoding method is
performed, CRC data which will be used for error detection is
generated.
The RS encoding method may use a forward error correction (FEC)
structure. The CRC data generated by the CRC encoding process may
indicate whether the mobile service data is damaged by the error
while being transmitted through the channel. The error correction
encoding process may use other error detection encoding methods
other than the CRC encoding method. Alternatively, the overall
error correction capability of the receiver can be increased using
the error correction encoding method. The mobile service data
encoded by the RS frame encoder 402 is input to the M-VSB block
processor 403.
The M-VSB block processor 403 encodes the received mobile service
data at G/H encoding rate again and outputs the encoded data to the
group formatter 404. The M-VSB block processor 403 separates the
received mobile service data based on the byte units into data
based on bit units, encodes the separated G-bit data to H-bit data,
converts the data into data based on byte units, and outputs the
data based on byte units. For example, if 1-bit input data is
encoded to 2-bit data and the 2-bit data is output, G becomes 1 and
H becomes 2. If 1-bit input data is encoded to 4-bit data and the
4-bit data is output, G becomes 1 and H becomes 4. In the present
invention, for convenience of description, the former case is
called encoding of 1/2 encoding rate (also called 1/2 encoding) and
the latter case is called encoding of 1/4 encoding rate (also
called 1/4 encoding). The 1/4 encoding has higher error correction
capability than the 1/2 encoding. Accordingly, the group formatter
404 may allocate the data encoded at the 1/4 encoding rate to an
area having low reception capability and allocate the data encoded
at the 1/2 encoding rate to an area having high reception
capability, thereby reducing a difference in reception
capability.
The M-VSB block processor 403 may receive the signaling information
included in the transmission parameter information. The data
containing the signaling information may be subjected to the 1/2
encoding or the 1/4 encoding. The signaling information is the
information necessary for receiving and processing the data
included in the data group by the broadcasting signal receiver and
may include cell identifier information, data group information,
multiplexing information and burst information.
The group formatter 404 inserts the mobile service data output from
the M-VSB block processor 403 into a corresponding area in the data
group formed according to a predetermined rule. In conjunction with
the data deinterleaving, various types of location holders or known
data may be inserted into the corresponding area in the data group.
The data group may be separated into at least one layered area and
the type of the mobile service data inserted into each area may
vary according to the characteristics of the layered area. For
example, each layered area may be classified according to the
reception capability within the data group.
The group formatter 404 may insert the signaling information such
as the transmission parameter information into the data group
independent of the mobile service data. When the generated known
data is inserted into the corresponding area of the mobile service
data group, the group formatter 404 may insert the signaling
information into at least a portion of the area into which the
known data can be inserted, instead of the known data. For example,
if a long known data sequence is inserted into the start part of a
body area of the mobile service data group, the signaling
information is inserted into a portion of the start part, instead
of the known data. In this case, a portion of the known data
sequence inserted into the remaining area excluding the area, into
which the signaling information is inserted, may be used for
capturing the start point of the mobile service data group and the
other portion may be used for channel equalization in a reception
system.
The group formatter 404 may insert an MPEG header location holder,
a non-systematic RS parity location holder and a main service data
location holder in conjunction with the data deinterleaving of the
next stage, in addition to the encoded mobile service data output
from the M-VSB block processor 403.
The reason why the main service data location holder is inserted is
because an area in which the mobile service data and the main
service data are mixed exists on the basis of the data after the
data interleaving. For example, the location holder for the MPEG
header is allocated to the foremost location of each packet on the
basis of the output data after the data deinterleaving.
The group formatter 404 may insert the known data generated by a
predetermined method or insert the known data location holder for
inserting the known data later. The location holder for
initialization of the trellis encoding module may be inserted into
a previous area of the known data sequence. The size of the mobile
service data which can be inserted into one data group may vary
according to initialization of the trellis inserted into the data
group or the size of the known data, the MPEG header and the RS
parity.
The data deinterleaver 405 deinterleaves the data and the location
holder in the data group output from the group formatter 404 as the
inverse process of the interleaving and outputs the deinterleaved
data to the packet formatter 406.
The packet formatter 406 may remove the main service data location
holder and the RS parity location holder allocated for the
deinterleaving, add 1-byte MPEG sync signal to a 3-byte MPEG header
location holder with respect to the remaining data portions, and
insert a 4-byte MPEG header.
If the group formatter 404 inserts the known data location holder,
the packet formatter 406 may include actual known data to the known
data location holder and output the known data location holder
without adjustment. Then, the packet formatter 406 divides the data
in the packet-formatted data group into mobile service data packets
(that is, the MPEG TS packets) based on 188-byte units and outputs
the divided data to the multiplexer. The packet formatter 406 may
insert the signaling information into at least a portion of the
known data area instead of the known data and output the inserted
data. If the known data location holder is inserted into the start
part of the body area of the mobile service data group, the
signaling information may be inserted into a portion of the known
data location holder.
If the signaling information is inserted, the inserted signaling
information may be block-encoded for a short period and may be
inserted or a predefined pattern may be inserted according to the
signaling information. The body areas of the mobile service data
group may have different known data patterns. Accordingly, in the
reception system, only symbols in a promised period may be divided
from the known data sequence and be recognized as the signaling
information.
FIGS. 8 to 10 show the example of transmitting the broadcasting
signal of which mobile reception is possible. Hereinafter, a method
for transmitting/receiving a broadcasting signal when a
broadcasting signal receiver changes a cell and receives the
broadcasting signal will be described.
The method for transmitting/receiving the broadcasting signal
according to the present embodiment can include a cell identifier
in signaling information and transmit/receive the signaling
information. Information on a cell for receiving a current
broadcasting signal and the other cells, for example, information
on a current cell and adjacent cells, may be set in program table
information and may be transmitted/received.
The broadcasting signal receiver may determine whether the cell for
receiving the broadcasting signal is changed, from the power of the
reception signal. If the cell is changed, the broadcasting signal
receiver may obtain channel information from the changed cell using
the program table information and output the program of the same
channel before and after the cell is changed.
FIG. 11 is a flowchart illustrating a method for
transmitting/receiving a broadcasting signal according to an
embodiment. The method for transmitting/receiving the broadcasting
signal according to the embodiment will be described with reference
to FIG. 11. It is assumed that the broadcasting receiver outputs a
broadcasting program of any channel received from a first cell.
The broadcasting signal receiver receives and parses the program
table information including the channel information of cells from
the first cell and obtains the channel information of the first
cell and the other cells (S410). If the broadcasting signal
receiver moves over the cells, the broadcasting signal receiver may
move from the current cell to a cell adjacent thereto. The program
table information is called a network information table (NIT) for
convenience. The NIT may include the channel information, for
example, physical channel information, of at least one cell. The
NIT will be described in detail with reference to FIG. 12. The
broadcasting signal can be received in a burst period of the
signal.
The broadcasting signal receiver can receive the broadcasting
signal, in which the program table information and the mobile
service data are multiplexed, from the first cell.
The broadcasting signal receiver determines whether reception power
is less than a first threshold value (S420) and tries to tune the
channel of the broadcasting signal transmitted with the frequency
of an adjacent cell using the channel information of the adjacent
cell (S430) if the reception power is less than the first threshold
value. This step may perform in a reception off period of the
broadcasting signal received from the first cell. The channel of
the broadcasting signal transmitted with the frequency of a second
cell which is the adjacent cell is tuned so as to obtain the
identifier of the second cell from the broadcasting signal of the
second cell. The identifier of the second cell may be obtained from
the NIT information or the signaling information of the received
broadcasting signal. The setting of the signaling information was
described in detail with reference to FIG. 10.
It is determined whether the power of the signal received from the
second cell is greater than a second threshold value (S440) and the
broadcasting signal including the mobile service data and the
program table information of the second cell is received from the
second cell (S450) if the signal received from the second cell is
greater than the second threshold value. If the program table
information of the second cell is received and parsed, it is
possible to obtain cell information including the channel
information of the second cell which is the adjacent cell.
If it is determined that the power of the signal received from the
second cell is less than the second threshold value in the step
S440, the physical channel of the broadcasting signal of the first
cell is tuned (S445). The channel tuning is preferably performed in
the reception off period of the signal received from the first
cell. In order to prevent the broadcasting signal from being cut
off, the channel of the signal of the first cell is tuned again
within the reception off period. Alternatively, if the reception
off period is long, the step S430 may be performed in order to tune
the signal of a third cell.
FIG. 12 shows the program table information including the physical
channel information of each cell in the program table information
transmitted according to the present embodiment. The physical
channel information transmitted from each cell may be transmitted
by the NIT of the PSI. The NIT includes the physical channel
information of the current cell or the other cells and, if any
broadcasting station transmits the broadcasting signal according to
an MVSB modulation method, may include the physical channel
information of the other broadcasting stations in addition to the
broadcasting station. In the example shown in FIG. 12, the PID of
the packet transmitted by the NIT is 0x010 and the table identifier
(table_Id) is 0x40. FIG. 12 shows a case where only the channel
information of two cells adjacent to the current cell is
transmitted for convenience of description.
In the example shown in FIG. 12, the identifier of each cell and
the physical channel information of each cell are included in
cell_frequency_link_descriptor of network_descriptor( ) For
example, the identifier (cell_id) of the first cell adjacent to the
current cell is 0x0001, the frequency of the physical channel of
the first cell is 0x03aefe40 (fc=618 MHz), the identifier of the
second cell adjacent to the current cell is 0x0002, and the
frequency of the physical channel of the second cell is 0x4a32240
(fc=778 MHz).
The example shown in FIG. 12 can provide the physical channel
information of at least one cell identified by the identifier of
the cell through a transport stream loop (TS loop) of the NIT.
Service_list_descriptor( ) for providing the list information of
the services according to the IDs of transport streams may be
included in the TS loop. FIG. 12 shows an example of the physical
channel information of each cell for the transport stream
(identifier (transport_stream_identifier) is 0x901) transmitted
from the first cell and the second cell adjacent to the current
cell.
The NIT includes cell information including the physical channel
information of the cell in a terrestrial delivery system descriptor
(terrestrial_delivery_system_descriptor( )) of each cell. For
example, the NIT may include information indicating through which
physical channel any cell transmits a specific transport
stream.
In the example shown in FIG. 12, with respect to the first cell for
delivering the transport stream identified by 0x901, information on
the central frequency (618 MHz; 0x03aefe40) of a transmission
signal information, a bandwidth (6 MHz; 010), an indicator
(time_slicing_indicator) indicating whether the signal can be
received by a time slicing scheme according to burst signal
transmission, a modulation method (modulation) indicating whether
it is the mobile VSB, a value indicating a first error correction
encoding rate (sccc_rate-HP_stream) of a high priority channel may
be included. Information on a value indicating a first error
correction encoding rate (sccc_rate-LP_stream) of a low priority
channel, a value indicating a second error correction encoding rate
(rs_code_rate-HP_stream) of the high priority channel, a value
indicating a second error correction encoding rate
(rs_code_rate-LP_stream) of the low priority channel and an
identifier (other_frequency_flag) indicating whether the transport
stream is transmitted with different frequencies may be included as
the channel information of the first cell.
In the example shown in FIG. 12, information on the second cell for
delivering the same transport stream (identifier 0x0901) as the
first cell may include cell information including the physical
channel information such as the central frequency (778 MHz;
0x04a32240) and the bandwidth (6 MHz; 010).
As shown in FIG. 12, the NIT transmitted from any cell includes
information indicating through which physical channel of another
cell all the transport streams transmitted from the cell are
transmitted. The NIT transmitted from any cell may, for example,
transmit the cell information including the physical channel
information of the cells adjacent to the cell. Accordingly, if the
handover of the broadcasting signal receiver occurs from the first
cell to the second cell, although broadcasting contents which were
received from the first cell are received from the second cell
through another physical channel, the changed physical channel
information can be obtained from the second cell and thus the same
broadcasting contents can be output. At the time of the occurrence
of handover, the user can continuously view the broadcasting
contents of the same channel without additionally tuning the
channel.
According to the present embodiment, the identifier of the cell can
be identified according to the handover method shown in FIG. 11 and
the channel information of the cell to which the broadcasting
signal receiver is handed over can be obtained by referring to the
program table information shown in FIG. 12. Accordingly, the
broadcasting signal receiver can continuously output the
broadcasting program of the same channel before and after the
handover, although the broadcasting signal receiver moves over the
cells.
FIG. 13 is a view showing a broadcasting signal receiver according
to an embodiment. The broadcasting signal receiver shown in FIG. 13
includes a tuner 510, a demodulator 520, a demultiplexer 530, a
decoder 540, an output unit 550, a controller 560, a memory 570,
and a program table information decoder 580.
The operation of the broadcasting signal receiver according to the
present embodiment will be described with reference to FIG. 13.
The tuner 510 receives the broadcasting signal in which the
identifier of the cell is set in the signaling information and
selects and outputs the broadcasting signal of a channel according
to a control signal of the controller 560 among the broadcasting
signals received from the current cell.
The demodulator 520 may demodulate and output the received signal.
The output signal may also include the signaling information
including the identifier of the cell. The demodulator 520 will be
described in detail with reference to FIG. 13.
The demultiplexer 530 may demultiplex program table information
(PSI/PSIP) and an audio/video stream in the received signal.
Alternatively, a broadcasting stream which will be recorded in or
reproduced from a digital recording device may be received. For
example, an input signal according to the IEEE1394 may be directly
received without the tuner.
The decoder 540 may decode the audio/video broadcasting signal
demultiplexed by the demultiplexer 530. The decoder 540 decodes the
audio/video elementary stream packet and outputs the decoded
audio/video signal to the output unit 550.
The output unit 550 receives and outputs the audio/video signal
decoded by the decoder 540. The output unit 550 includes an
on-screen-display (OSD) unit for outputting a graphic signal
displayed on a display screen.
The program table information decoder 580 may decode the program
table information demultiplexed by the demultiplexer 530 and
temporarily store the decoded table information. The program table
information decoder 580 may parse the program table information
including the physical channel information of all the cells, that
is, the NIT, acquire the physical information of all the cells, and
output the information on the acquired cell to the controller
540.
The controller 560 includes an interface for receiving the control
signal from the user. The controller 560 stores channel map
information in which a physical channel and a virtual channel are
mapped such that the tuner 510 selects the channel and controls the
decoder 540 such that the broadcasting stream according to the
channel request of the user is decoded and output. If the program
table information decoder 580 parses the updated table information,
the controller 560 stores the updated channel information in the
channel map. The controller 560 may store other control information
including information necessary for the handover of the
broadcasting signal receiver, information on an application and the
request information of the user in the memory 570.
The controller 560 determines whether the power of the signal tuned
by the tuner 510 or the signal demodulated by the demodulator 520
is less than the first threshold value and controls the tuner 510
to tune the channel to the channel transmitted by a cell (for
example, an adjacent cell) different from the current cell if the
power of the signal is less than the first threshold value. In this
case, the controller 560 may control the tuner 510 to tune the
channel using the physical channel information of all the adjacent
cells acquired from the parsed NIT information. The information
included in the NIT was shown in FIG. 12.
When the tuner 510 tunes the channel with a specific frequency
among the signals received from the cell (referred to as the second
cell) adjacent to the current cell, the demodulator 520 may output
the signaling information of the signal of the tuned channel The
controller 560 may obtain the identifier of the cell from the
signaling information output from the demodulator 520 and identify
from which cell the signal received currently is received. The
controller 560 determines whether the power of the signal received
from the second cell is greater than the second threshold value and
hands over from the previous cell to the second cell if the power
of the signal is greater than the second threshold value. If so
not, the broadcasting signal may be received from the previous cell
again or the channel may be tuned to another cell (third cell). If
the tuner 510 tunes the channel of the signal transmitted from the
second cell, the controller 560 may control the tuner 510, the
demodulator 520, the demultiplexer 530 and the decoder 540 such
that the broadcasting signal of the channel received from the cell
before the handover is output. That is, since the controller 560
can obtain information indicating, through which channel of the
second cell the same broadcasting signal as the broadcasting signal
of the channel received from the cell before the handover, from the
parsed NIT information, the same broadcasting signal can be
continuously output although the handover occurs.
The controller 560 may parse the NIT information from the signal
received from the second cell to which the broadcasting signal
receiver is handed over, obtain the physical channel information of
the second cell and the cells adjacent to the second cell, and
acquire the physical channel information of the cells according to
the handover which may occur later in advance.
FIG. 14 is a view showing an example of the demodulator in the
broadcasting signal receiver. Hereinafter, the demodulator of the
present embodiment will be described with reference to FIG. 14.
The broadcasting signal receiver restores a carrier sync signal,
restores a frame sync signal and performs channel equalization
using the known data information inserted in the mobile service
data period in a transmission system, thereby improving reception
capability.
The broadcasting signal receiver includes a VSB demodulator 702, an
equalizer 703, a known sequence detector 704, an M-VSB block
decoder 705, an M-VSB data deformatter 706, a RS frame decoder 707,
an M-VSB derandomizer 708, a data deinterleaver 709, a RS decoder
710, a data derandomizer 711, and a signaling information decoder
712. In FIG. 14, for convenience of description, the M-VSB data
deformatter 706, the RS frame decoder 707, and the M-VSB
derandomizer 708 are collectively called a mobile service data
processor and the data deinterleaver 709, the RS decoder 710 and
the data derandomizer 711 are collectively called a main service
data processor.
The VSB demodulator 702 and the known sequence detector 704 receive
the signal of which the frequency is tuned by the tuner and is
down-converted into an intermediate frequency (IF).
The VSB demodulator 702 performs the automatic gain control, the
recovery of a carrier and the restoration of a timing in
consideration of the VSB method so as to convert the received IF
signal to a baseband signal, and outputs the baseband signal to the
equalizer 703 and the known sequence detector 704.
The equalizer 703 compensates for the distortion on the channel
included in the demodulated signal and outputs the compensated
signal to the M-VSB block decoder 705.
At this time, the known sequence detector 704 detects the location
of known data inserted at the transmitter side from the
input/output data of the VSB demodulator 702, that is, the data
before the VSB demodulation or the data after the demodulation. The
known sequence detector 704 outputs the location information and
the symbol sequence of the known data generated at the location to
the VSB demodulator 702 and the equalizer 703. The known sequence
detector 704 outputs information for allowing the M-VSB block
decoder 705 to distinguish the mobile service data, which is
subjected to the additional error correction encoding at the
transmitter side, and the main service data, which is not subjected
to the additional error correction encoding, to the M-VSB block
decoder 705. Although the connection state is not shown in FIG. 14,
the information detected by the known sequence detector 704 can be
used in the receiver and can be used in the M-VSB data deformatter
706 and the RS frame decoder 707.
The VSB demodulator 702 can improve demodulation capability using
the known data symbol sequence at the time of the restoration of
the timing or the recovery of the carrier and the equalizer 703 can
improve equalization capability using the known data. The decoded
result of the M-VSB block decoder 705 may be fed back to the
equalizer 703 so as to improve the equalization capability.
If the data received from the equalizer 703 is the mobile service
data which is subjected to the additional error correction encoding
and the trellis encoding at the transmitter side, the M-VSB block
decoder 705 performs trellis decoding and additional error
correction decoding as the inverse processes of the transmitter
side. If the data is the main service data which is not subjected
to the additional encoding and is subjected to the trellis encoding
at the transmitter side, only the trellis decoding is
performed.
The data group decoded by the M-VSB block decoder 705 is input to
the M-VSB data deformatter 706 and the main service data packet is
input to the data deinterleaver 709.
If the received data is the main service data, the M-VSB block
decoder 705 may perform viterbi decoding with respect to the
received data and output a hard decision value or a soft decision
value.
If the received data is the mobile service data the M-VSB block
decoder 705 outputs the hard decision value or the soft decision
value with respect to the received mobile service data. If the
received data is the mobile service data, the M-VSB block decoder
705 decodes the data which is encoded by the M-VSB block processor
and the trellis encoder of the transmission system. In this case,
the RS frame encoder of the M-VSB preprocessor of the transmitter
side may become an outer code and the M-VSB block processor and the
trellis encoder may become an inner code. The decoder of the inner
code may output the soft decision value such that the capability of
the outer code can be maximized at the time of the decoding of the
concatenated code.
Accordingly, the M-VSB block decoder 705 may output the hard
decision value with respect to the mobile service data and
preferably may output the soft decision value if necessary.
The data deinterleaver 709, the RS decoder 710 and the derandomizer
711 receive and process the main service data. The data
deinterleaver 709 deinterleaves the main service data output from
the M-VSB block decoder 705 as the inverse process of the data
interleaver of the transmitter side and outputs the deinterleaved
data to the RS decoder 710.
The RS decoder 710 performs systematic RS decoding with respect to
the deinterleaved data and outputs the decoded data to the
derandomizer 711. The derandomizer 711 receives the output of the
RS decoder 710, generates the same pseudo random byte as the
randomizer of the transmitter, performs a bitwise exclusive OR
(XOR) with respect to the pseudo random byte, inserts the MPEG sync
data in front of every packet, and outputs 188-byte main service
data in the packet units.
The data output from the M-VSB block decoder 705 to the M-VSB data
deformatter 706 has a data group form. At this time, since the
M-VSB data deformatter 706 already knows the configuration of the
received data group, it is possible to distinguish the mobile
service data and the signaling information having the system
information within the data group. The signaling information
indicates information for delivering the system information and can
deliver the information on the transmission parameter including the
identifier of the cell.
The mobile service data is output to the RS frame decoder 707 and
the M-VSB data deformatter 706 removes the known data inserted into
the data group and the main service data, the trellis
initialization data, the MPEG header and the RS parity added in the
RS encoder/non-systematic RS encoder or the non-systematic RS
encoder of the transmission system and outputs the mobile service
data to the RS frame decoder 707.
That is, the RS frame decoder 707 receives only the mobile service
data which is subjected to the RS encoding and/or CRC-encoding,
from the M-VSB data deformatter 706.
The RS frame decoder 707 performs the inverse process of the RS
frame encoder of the transmission system, corrects errors in the RS
frame, adds a 1-byte MPEG sync signal which is removed in the RS
frame encoding process to the error-corrected mobile service data
packet, and the added mobile service data to the M-VSB derandomizer
708.
The M-VSB derandomizer 708 performs the derandomizing process
corresponding to the inverse process of the M-VSB randomizer of the
transmission system with respect to the received mobile service
data and outputs the derandomized data, thereby obtaining the
mobile service data transmitted from the transmission system.
The signaling information decoder 712 may decode the signaling
information included in the received signal. FIG. 14 shows an
example of decoding the signaling information including the
identifier of the cell from the M-VSB data deformatter 706 or the
equalizer 703 according to the location of the signal carried in
the signaling information.
FIG. 15 is a view showing a broadcasting signal receiver according
to another embodiment. Hereinafter, the operation of the
broadcasting signal receiver according to the present embodiment
will be described with reference to FIG. 15.
The broadcasting signal receiver according to the present
embodiment further includes a second memory 620 for storing a
program and a memory controller 610 for controlling the second
memory 620, in addition to the memory 570 of the broadcasting
signal receiver shown in FIG. 13.
The broadcasting service data demultiplexed by the demultiplexer
530 may be decoded by the decoder 540 and may be output and may be
input to or read from the second memory 620 by the memory
controller 610 for controlling the second memory 620. The
demultiplexer 530 may store the main service data or the mobile
service data demodulated by the demodulator 520 in the second
memory 620.
The controller 560 may control an instant recording function, a
reservation recording function, and a time shift function of the
broadcasting service data demultiplexed by the demultiplexer 530
through the memory controller 610. The controller 560 may reproduce
the broadcasting service data which is already stored in the second
memory 620 through the memory controller 610 and the demultiplexer
530.
The second memory 620 may be divided into a temporary storage area
for storing the data according to the time shift and a permanent
storage area for permanently storing the data according to the
selection of the user.
The memory controller 610 may control a play function, a fast
forward function, a rewind function, a slow motion function and an
instant replay function of the data stored in the second memory 620
according to the control signal of the controller 560. Here, the
instant replay function is a function for repeatedly viewing a
desired scene. The data which is currently being received in real
time as well as the data which is previously stored can be
instantly replayed in conjunction with the time shift function.
The memory controller 610 may scramble and store the received data
in order to prevent the unauthorized copy of the data stored in the
second memory 620. In contrast, the memory controller 610 may read,
descramble and store the data which is scrambled and stored in the
second memory 620.
If the broadcasting data for data broadcasting is included in the
main service data or the mobile service data, the program table
information decoder 580 may decode the broadcasting data. The data
for data broadcasting may be decoded by the program table
information decoder 580 and may be stored in a data storage unit
630.
If the controller 560 operates a data broadcasting application
according to the request of the user, the program table information
decoder 580 decodes the broadcasting data for data broadcasting and
outputs the decoded broadcasting data. The application operated by
the controller 560 may implement the data broadcasting output from
the program table information decoder 580 and output it to the
output unit 550.
The program table information decoder 580 may decode, for example,
the service information such as DVB-SI or the broadcasting data
according to the PSI or the PSIP. The broadcasting data for data
broadcasting may be of a packetized elementary stream type or a
section type. That is, the data for data broadcasting includes PES
type data or section type data.
For example, the data for data broadcasting is included in a
digital storage media-command and control (DSM-CC) section and the
DSM-CC section may be composed of the TS packet based on 188-byte
units. The identifier of the TS packet included in the DSM-CC
section is included in the program table information which is a
data service table (DST). If the DST is transmitted, 0x95 is
allocated as the value of a stream_type field in the service
location descriptor of the PMT or the VCT. The broadcasting signal
receiver determines that the data for data broadcasting is received
if the value of the stream-type field of the PMT or the VCT is
0x95. The data for data broadcasting may be transmitted by a data
carousel method.
In order to process the data for data broadcasting, the
demultiplexer 530 may perform section filtering under the control
of the program table information decoder 580, discard the
overlapping section, and output the non-overlapping section to the
program table information decoder 580. The program table
information decoder 580 can determine whether the data for data
broadcasting included in the broadcasting signal is received
according to the PID of the VCT. The PID of the VCT may be set in
an MGT and have a fixed value.
The demultiplexer 530 may output only an application information
table (AIT) to the program table information decoder 580 through
the section filtering. The AIT includes information on an
application executed on the broadcasting signal receiver, for the
data service.
The AIT may include the information on the application, for
example, the name of the application, the version of the
application, the priority of the application, the ID of the
application, the status of the application (auto-start, operability
of the user, kill or the like), the type of the application (Java
or HTML), the class of the application, the location of the stream
including a data file, the base directory of the application, and
the location of the icon of the application. Accordingly,
information necessary for executing the application may be stored
in the data storage unit 630 using the above-described
information.
The application executed by the controller 560 may be received
together with the broadcasting data and may be updated. A data
broadcasting application manager which is executed in order to
allow the controller 560 to execute the application may include a
platform for executing an application program. The platform may be,
for example, the Java virtual machine for executing the Java
program.
If it is assumed that the data broadcasting service is a traffic
information service, the broadcasting signal receiver can provide
the service to the users through at least one of characters, voice,
graphics, still images, moving images or the like although an
electronic map or a global positioning system (GPS) module is not
mounted. If the broadcasting signal receiver includes the GPS
module, the data broadcasting application may be implemented after
the GPS module extracts current location information (longitude,
latitude, and altitude) received from a satellite. The data storage
unit 630 of the broadcasting signal receiver 630 may store the
electronic map including information on links and nodes and a
variety of graphic information.
FIG. 16 is a view showing a broadcasting signal receiver according
to another embodiment. Hereinafter, the operation of the
broadcasting signal receiver according to the present embodiment
will be described with reference to FIG. 16. The embodiment shown
in FIG. 16 can process the scrambled reception signal.
The broadcasting signal receiver according to the embodiment shown
in FIG. 16 further includes a first descrambler 640, a second
descrambler 650 and an authentication unit 660, in addition to the
embodiment shown in FIG. 15. Alternatively, in the embodiment shown
in FIG. 16, any one of the first descrambler 640 and the second
descrambler 650 may be included. The first descrambler 640 receives
and descrambles the signal demultiplexed by the demultiplexer 530.
At this time, the first descrambler 640 may receive and use the
data necessary for descrambling and the authentication result from
the authentication unit 660 in the descrambling. The decoder 540
receives and decodes the signal descrambled by the first
descrambler 640 and outputs the decoded signal. If the embodiment
shown in FIG. 16 does not include the first descrambler 640, the
signal output from the decoder 540 may be descrambled by the second
descrambler 650.
The broadcasting signal transmitter may scramble broadcasting
contents and transmit the scrambled broadcasting contents in order
to provide a service for preventing unauthorized copy or
unauthorized viewing of the main service data or the mobile service
data or a pay broadcasting service.
The broadcasting signal receiver descrambles the scrambled
broadcasting contents and outputs the descrambled broadcasting
contents. At this time, an authentication process may be performed
by authentication means before the descrambling. In the embodiment
shown in FIG. 16, the first descrambler 640, the second descrambler
650 and the authentication unit 660 may be attached to or detached
from the broadcasting signal receiver in the form of a slot or a
memory stick.
If the scrambled broadcasting contents are received through the
tuner 510 and the demodulator 520, the controller 560 may determine
whether the received broadcasting contents are scrambled or not. If
the received broadcasting contents are scrambled, the
authentication unit 660 operates the authentication means.
The authentication unit 660 performs the authentication process in
order to determine whether the broadcasting signal receiver is a
proper host (broadcasting signal receiver) which can receive the
pay broadcasting contents. Various authentication processes may be
performed. For example, the authentication unit 660 may perform
authentication process by comparing the Internet protocol (IP)
address of an IP datagram in the received broadcasting contents
with the unique address of the broadcasting signal receiver. The
unique address of the broadcasting signal receiver may be a media
access control (MAC) address. The authentication unit 660 extracts
the IP address from the decapsulated IP datagram and obtains the
receiver information mapped with the address. The authentication
unit 660 may previously include information (for example, a table
form) which can map the IP address with the receiver information
and determine whether the IP address and the receiver information
are equal to each other by comparison.
Alternatively, the authentication process may be performed by
defining standardized identifier at the transmitter/receiver side,
transmitting the identifier of the receiver for applying for the
pay broadcasting service at the transmitter side, and determining
whether the received identifier is equal to the identifier of the
receiver at the receiver side. The transmitter side generates and
stores the unique identifier of the receiver, which applies for the
pay broadcasting service, in a database, and includes the
identifier in an entitlement management message (EMM) and transmits
the EMM if the broadcasting contents are scrambled. If the
broadcasting contents are scrambled, a message (for example, an
entitlement control message (ECM) or the EMM) such as conditional
access system (CAS) information, mode information and message
location information applied to the scrambling may be transmitted
through the data header or another packet.
The ECM may include a control word (CW) used for scrambling. At
this time, the CW may be encrypted by an authentication key. The
EMM may include the authentication key and the entitlement
information of the data. The authentication key may be encrypted by
the distribution key of the receiver. If the broadcasting data is
scrambled using the CW and information for authentication and
information for descrambling are transmitted from the transmitter
side, the receiver side may encrypt the CW by the authentication
key, include the CW in the ECM, and transmit the ECM.
The transmitter side includes the authentication key used for
encrypting the CW and the reception entitlement of the broadcasting
signal receiver (for example, a standardized serial number of the
broadcasting signal receiver having the reception entitlement) in
the EMM and transmits the EMM.
Accordingly, the authentication unit 660 of the broadcasting signal
receiver extracts the unique identifier of the receiver, extracts
the identifier included in the EMM of the received broadcasting
service, determines whether the two identifiers are equal to each
other, and performs the authentication process. If it is determined
that the two identifiers are equal to each other by the
authentication unit 660, the broadcasting signal receiver determine
that the broadcasting signal receiver is the proper broadcasting
signal receiver having the reception entitlement
Alternatively, the broadcasting signal receiver may include
authentication means 3008 in a detachable external module. At this
time, the broadcasting signal receiver and the external module
interface with each other through a common interface (CI). The
external module may receive the scrambled data from the receiver
through the CI, perform the descrambling, and transmit only the
information necessary for descrambling to the receiver.
The CI includes a physical layer and at least one protocol layer.
The protocol layer may have the structure including at least one
layer for providing independent function in consideration of
extensibility.
The external module may be a memory or card which does not include
the descrambling function or a card which includes the descrambling
function, while storing the key information and the authentication
information used for scrambling. That is, the module may include
the descrambling function in the form of hardware, middleware or
software.
At this time, the receiver and the external module should be
authenticated in order to provide the pay broadcasting service
provided by the transmitter side to the user. Accordingly, the
transmitter side may provide the pay broadcasting service to the
pair of authenticated receiver and module.
The receiver and the external module may authenticate each other
through the CI. The external module may communicate with the
controller 560 of the receiver through the CI and authenticate the
receiver. The broadcasting signal receiver may authenticate the
module through the CI. The module may extract and transmit the
unique ID of the broadcasting signal receiver and the unique ID of
the module to the transmitter in the mutual authentication process.
The transmitter side may use the IDs as service start information
and payment information. The controller 560 may transmit the
payment information to the remote transmitter side through a
communication module 670 if necessary.
The authentication unit 660 authenticates the receiver and/or the
external module and recognizes the receiver as the proper receiver
which can receive the pay broadcasting service if the
authentication process is successfully completed. The
authentication unit 660 may receive authentication-related data
from a mobile communication service provider in which the user of
the receiver registers, instead of the transmitter for providing
the broadcasting contents. In this case, the authentication-related
data may be scrambled by the transmitter side for providing the
broadcasting contents and may be transmitted through the mobile
communication service provider or may be scrambled and transmitted
by the mobile communication service provider.
If the authentication process of the authentication unit 660 is
successfully completed, the receiver may descramble the scrambled
broadcasting contents. The descrambling is performed by the
descramblers 640 and 650 and the descramblers 640 and 650 may be in
the receiver or the external module. The broadcasting signal
receiver may include the CI, communicate with the external module
including the descramblers 640 and 650, and descramble the received
signal.
If the descramblers 640 and 650 are included in the receiver, the
transmitter side (including at least one of the service provider
and the broadcasting station) may scramble the data by the same
scrambling method and transmit the scrambled data. If the
descramblers 640 and 650 are included in the external module, the
transmitters may scramble the data by different scrambling methods
and transmit the scrambled data.
The controller 560 may communicate with the descramblers 640 and
650 by a predetermined interface. A CI protocol between the
receiver and the external module includes a function for
periodically checking the status of the counterpart in order to
maintain normal mutual communication. The receiver and the module
include a function for managing the status of the counterpart using
this function, and, if any one of the receiver and the external
module malfunctions, reporting the malfunction to the user or the
transmitter side and performing a recovery function.
Alternatively, the authentication process may be performed by
software, instead of hardware.
That is, if a memory card for previously storing CAS software
through downloading is inserted, the broadcasting signal receiver
receives and loads the CAS software from the memory card and
performs the authentication process. The CAS software read from the
memory card is stored in the memories 570 and 620 in the
broadcasting signal receiver and is executed on the middleware in
the form of one application. The middleware may be, for example,
the Java middleware.
The broadcasting signal receiver may include a CI for connection to
the memory card. The first memory 570 may be a volatile memory, a
non-volatile memory or a flash memory (or a flash ROM). The memory
card mainly uses a flash memory or a small-sized hard disc. The
memory card may be used in at least one broadcasting signal
receiver according to the contents of the stored CAS software, the
authentication, the scrambling and the payment method. However, the
CAS software includes at least information necessary for
authentication and information necessary for descrambling.
Accordingly, the authentication unit 660 performs the
authentication between the transmitter side and the broadcasting
signal receiver or the broadcasting signal receiver and the memory
card. The memory card may include the information on the proper
broadcasting receiver which can be authenticated. For example, the
information on the broadcasting signal receiver includes unique
information such as the standardized serial number of the
broadcasting signal receiver. Accordingly, the authentication unit
660 may compare the unique information such as the standardized
serial number included in the memory card with the unique
information of the broadcasting signal receiver and perform the
authentication process of the memory card and the broadcasting
signal receiver.
If the CAS software is executed on the Java middleware, the
authentication process of the broadcasting signal receiver and the
memory card is performed. For example, it is checked whether the
unique number of the broadcasting signal receiver included in the
CAS software is equal to the unique number of the broadcasting
signal receiver read through the controller 560 of the broadcasting
signal receiver. If the unique numbers are equal to each other, the
memory card is the normal memory card which can be used in the
broadcasting signal receiver. At this time, the CAS software may be
included in the memories 570 and 620 at the time of shipment of the
broadcasting signal receiver or may be stored in the memories 570
and 620 from the transmitter side, the module or the memory card.
The descrambling function may be performed by the data broadcasting
application in the form of one application.
The CAS software may parse the EMM/ECM packet output from the
demultiplexer 530, check whether the receiver has the reception
entitlement, and obtain and provide the information (that is, the
CW) necessary for descrambling to the descramblers 640 and 650. The
CAS software executed on the middleware reads the unique number of
the broadcasting signal receiver from the broadcasting signal
receiver, compares it with the unique number of the broadcasting
signal receiver received by the EMM, and checks the reception
entitlement of the current broadcasting signal receiver.
When the reception entitlement of the broadcasting signal receiver
is checked, it is checked whether the broadcasting signal receiver
has the entitlement for receiving the broadcasting service using
the reception entitlement of the broadcasting service and the
broadcasting service information transmitted by the ECM. If the
entitlement for receiving the broadcasting service is checked, the
encrypted CW transmitted by the ECM is decrypted using the
authentication key transmitted by the EMM and is output to the
descramblers 640 and 650. The descramblers 640 and 650 descramble
the broadcasting service using the CW.
The CAS software stored in the memory card can extend according to
the pay service provided by the broadcasting station. The CAS
software may include information related to the authentication and
the descrambling and additional information. The broadcasting
signal receiver may download the CAS software from the transmitter
side and upgrade the CAS software stored in the memory card.
The descramblers 640 and 650 may be included in the module in the
hardware or software form. In this case, the scrambled reception
data may be descrambled by the module and may be decoded.
If the scrambled reception data is stored in the second memory 620,
the scrambled data may be descrambled and stored or the scrambled
data may be stored in a state of being descrambled and may be
descrambled at the time of reproduction thereof. If the
scrambling/descrambling algorithm is included in the memory
controller 610, the memory controller 610 may scramble the
scrambled reception signal again and store the scrambled data in
the second memory 620.
Alternatively, the descrambled (conditionally accessed)
broadcasting contents are transmitted through a broadcasting
network and information related to the authentication for releasing
conditional access and the descrambling is transmitted/received
through the communication module 670 such that the bidirectional
communication is possible in the broadcasting signal receiver.
The broadcasting signal receiver transmits/receives the unique
information ID such as the MAC address or the serial number of the
broadcasting signal receiver to/from the communication module 670
in the transmitter side such that the transmitter side recognizes
the broadcasting data which is desired to be transmitted/received
to/from the remote transmitter side and the broadcasting signal
receiver to which the broadcasting data is transmitted.
The communication module 670 of the broadcasting signal receiver
may support a protocol necessary for performing the bidirectional
communication with the communication module 670 of the transmitter
side in the broadcasting signal receiver which does not support the
bidirectional communication function. The broadcasting signal
receiver configures a protocol data unit (PDU) using a
tag-length-value (TLV) coding method including the unique
information ID and the data to be transmitted. The tag field
includes the indexing of the PDU and the length field includes the
length of the value field, and the value field includes the unique
number ID of the broadcasting signal receiver and actual data to be
transmitted.
The broadcasting signal device may mount the Java platform and
configure the platform which is operated after downloading the Java
application to the broadcasting signal receiver through a network.
In this case, the PDU including the tag field which is arbitrarily
defined by the transmitter side may be downloaded to the storage
medium of the broadcasting signal receiver and may be transmitted
to the communication module 670.
At this time, the broadcasting signal receiver may include the CI
and may include a wireless application protocol (WAP) and a CDMA
1.times.EV-D0, both of which are accessible through a mobile
communication base station such as a CDMA or a GSM and a wireless
LAN, the mobile Internet, the WiBro, and the Wimax interface, all
of which are accessible through an access point, in
transmission/reception through a wireless data network.
FIG. 17 is a view showing a broadcasting signal receiver according
to another embodiment. The broadcasting signal receiver according
to the present embodiment will be described with reference to FIG.
17. The broadcasting signal receiver includes a tuner 510, a
demodulator 520, a demultiplexer 530, an IP filter 535, a decoder
540, an output unit 550, a controller 560, a memory 570 and a
program table information decoder 580. The operations of the
components of the broadcasting signal receiver shown in FIG. 17,
which are equal to those of FIG. 13, were described with reference
to FIG. 13.
For example, the controller 560 determines whether the handover
occurs, using the power of the signal tuned by the tuner 510 or the
signal demodulated by the demodulator 520. The controller 560
controls the tuner 510 to tune the broadcasting channel received
from the second cell using the physical channel information of all
the adjacent cells obtained from the parsed NIT information if it
is determined that the handover occurs. The controller 560 may
obtain the identifier of the cell from the signaling information
output from the demodulator 520 and determine from which cell the
received signal is received, using the identifier. The controller
560 determines whether the power of the signal received from the
second cell is greater than the second threshold value and hands
over from the previous cell to the second cell if the power is
greater than the second threshold value. If so not, the
broadcasting signal is received from the previous cell or the
channel is tuned to another cell (third cell).
The controller 560 may parse the NIT information from the signal
from the second cell to which the broadcasting signal receiver is
handed over, obtain the physical channel information of the second
cell and the cells adjacent to the second cell, and previously
acquire the physical channel information of the cells according to
the handover which will occur later.
The broadcasting signal device shown in FIG. 17 may receive the
broadcasting signal including an IP stream and process and output
the video/audio/data signal included in the IP stream.
The examples of the tuner 510, the demodulator 520 and the
demultiplexer 530 are shown in FIG. 13. The tuner 510 tunes the
channel selected by the user and outputs the broadcasting signal of
the channel. The demodulator 520 demodulates the signal output from
the tuner 510 and outputs the demodulated signal. The demultiplexer
530 demultiplexes the signal output from the demodulator 520 and
outputs the demultiplexed signal.
In the example shown in FIG. 17, the demultiplexer 530 may
demultiplex the IP stream in addition to the video/audio stream and
the program table information from the demodulated signal. If the
IP stream is included in a private section of the MPEG-2 TS and is
transmitted, the demultiplexer 530 outputs the private section
including the IP stream to the program table information decoder
580. The program table information decoder 580 may decode the
private section and output the IP stream to the IP filter 535.
Alternatively, if the IP stream is not included in the private
section and an IP datagram is included directly in demodulated
stream, the IP datagram may be demultiplexed from the demodulated
signal and may be output to the IP filter 535.
The IP filter 535 may selectively output the IP stream selected by
the user according to the control signal of the controller 560. The
output IP stream may be output to the decoder 540 and the
video/audio information included in the IP stream may be output
from the output unit 550. The IP stream may include the program
table information including channel information of at least one
cell
A data handler 561 may process and output the data broadcasting
signal transmitted from the IP filter 535 by the IP datagram and a
middleware engine 563 controls the environment of the broadcasting
receiving system such that the broadcasting data is output and
processes and outputs the broadcasting data together with the
video/audio data output from the output unit 550.
The effects of the broadcasting signal receiver and the method for
transmitting/receiving the broadcasting signal are as follows.
First, the cell can be identified in the MFN environment and thus
the mobile reception of the broadcasting signal is possible.
Second, a mobile reception broadcasting system compatible with a
fixed reception broadcasting system can be provided. Third,
although the user moves to an area in which the broadcasting signal
is transmitted with a different frequency in the MFN environment,
the same broadcasting program can be conveniently viewed without
tuning the channel.
It will be apparent to those skilled in the art that various
modifications and variations can be made in the present invention
without departing from the spirit or scope of the invention. Thus,
it is intended that the present invention covers the modifications
and variations of this invention provided they come within the
scope of the appended claims and their equivalents.
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