U.S. patent application number 09/726367 was filed with the patent office on 2002-05-30 for backwards compatible real-time program guide capacity increase.
Invention is credited to Arsenault, Robert G., Chapman, Lawrence N., Dulac, Stephen P..
Application Number | 20020066102 09/726367 |
Document ID | / |
Family ID | 24918312 |
Filed Date | 2002-05-30 |
United States Patent
Application |
20020066102 |
Kind Code |
A1 |
Chapman, Lawrence N. ; et
al. |
May 30, 2002 |
Backwards compatible real-time program guide capacity increase
Abstract
A system and method for transmitting program guide information
describing a second set of programs to subscribers is disclosed. In
one embodiment, the method is implemented in a network broadcasting
a first signal having a first set of programs and a second signal
having a second set of programs. The method comprises the steps of
broadcasting first program guide information describing the first
set of programs to the subscribers on a first service channel on a
first signal and broadcasting second program guide information
describing the second set of programs to a subset of the
subscribers on the first service channel on a second signal,
wherein a fundamental signal characteristic of the second signal
differs from the fundamental signal characteristic of the first
signal. In another embodiment, the method comprises the steps of
receiving first program guide information describing the first set
of programs on a first service channel on a first signal; and
receiving second program guide information describing the second
set of programs on the first service channel on a second signal,
wherein a fundamental signal characteristic of the second signal
differs from the fundamental signal characteristic of the first
signal.
Inventors: |
Chapman, Lawrence N.; (Palos
Verdes East, CA) ; Dulac, Stephen P.; (Santa Clarita,
CA) ; Arsenault, Robert G.; (Redondo Beach,
CA) |
Correspondence
Address: |
HUGHES ELECTRONICS CORPORATION
PATENT DOCKET ADMINISTRATION
BLDG 001 M/S A109
P O BOX 956
EL SEGUNDO
CA
902450956
|
Family ID: |
24918312 |
Appl. No.: |
09/726367 |
Filed: |
November 29, 2000 |
Current U.S.
Class: |
725/49 ;
348/E5.097; 348/E5.105; 348/E5.108; 348/E7.063; 725/63 |
Current CPC
Class: |
H04N 5/50 20130101; H04N
21/47 20130101; H04N 7/165 20130101; H04N 21/426 20130101; H04N
21/6143 20130101; H04N 21/4622 20130101; H04N 21/4345 20130101;
H04N 21/2665 20130101 |
Class at
Publication: |
725/49 ;
725/63 |
International
Class: |
H04N 005/445; G06F
003/00; G06F 013/00; H04N 007/20 |
Claims
What is claimed is:
1. In a network broadcasting a first signal having a first set of
programs to a plurality of subscribers and a second signal having a
second set of programs, a method of providing program guide
information describing the second set of programs, comprising:
broadcasting first program guide information describing the first
set of programs to the subscribers on a first service channel on a
first signal; and broadcasting second program guide information
describing the second set of programs to a subset of the
subscribers on the first service channel on a second signal,
wherein a fundamental signal characteristic of the second signal
differs from the fundamental signal characteristic of the first
signal.
2. The method of claim 1, wherein the fundamental signal
characteristic is carrier frequency, and the first signal is
characterized by a first carrier frequency and the second signal is
characterized by a second carrier frequency.
3. The method of claim 1, wherein the fundamental signal
characteristic is polarization and the first signal is
characterized by a first polarization and the second signal is
characterized by a second polarization.
4. The method of claim 1, wherein the first program guide
information includes information describing at least one surrogate
channel.
5. The method of claim 4, wherein a subscriber selection of at
least one of the at least one surrogate channels commands reception
of the second signal.
6. The method of claim 1, wherein the second signal is a spot beam
directed at the subset of subscribers.
7. The method of claim 1, wherein the second set of programs
comprise local programs and the second signal is a spot beam
directed at a subset of the subscribers that are designated to
receive the second set of programs.
8. The method of claim 1, wherein the second signal further
includes a portion of the first set of programs and the second
program information further describes the portion of the first set
of programs.
9. In a network broadcasting a first signal having a first set of
programs to a plurality of subscribers and a second signal having a
second set of programs to a subset of the subscribers, a method of
receiving program guide information describing the second set of
programs, comprising the steps of: receiving first program guide
information describing the first set of programs on a first service
channel on a first signal; and receiving second program guide
information describing the second set of programs on the first
service channel on a second signal, wherein a fundamental signal
characteristic of the second signal differs from the fundamental
signal characteristic of the first signal.
10. The method of claim 9, wherein the fundamental signal
characteristic is carrier frequency, and the first signal is
characterized by a first carrier frequency and the second signal is
characterized by a second carrier frequency.
11. The method of claim 9, wherein the fundamental signal
characteristic is polarization and the first signal is
characterized by a first polarization and the second signal is
characterized by a second polarization.
12. The method of claim 10, wherein the first program guide
information includes information describing at least one surrogate
channel and the method further comprises the step of: accepting a
selection of at least one of the at least one surrogate channels in
a receiver; and receiving the second signal at the second carrier
frequency on the first service channel.
13. The method of claim 12, wherein the second signal is a spot
beam directed at the receiver.
14. The method of claim 12, wherein the second set of programs are
local programs and the second signal is a spot beam directed at a
subset of subscribers designated to receive the second set of
programs.
15. The method of claim 14, wherein the second signal further
includes a portion of the first set of programs and the second
program information further describes the portion of the first set
of programs.
16. A receiver, comprising: a user interface for accepting
subscriber commands; a tuner selectably configurable to receive a
first service channel on a first signal and the first service
channel on a second signal, the first signal comprising a first set
of programs and first program information describing the first set
of programs, and the second signal comprising a second set of
programs and second program guide information describing the second
set of programs; wherein a fundamental signal characteristic of the
second signal differs from the fundamental signal characteristic of
the first signal; and a processor, communicatively coupled to the
user interface and the tuner, for retrieving the first program
information and the second program information for providing the
first and second program information to a presentation device, and
for accepting subscriber commands from the user interface.
17. The receiver of claim 16, wherein the fundamental signal
characteristic is carrier frequency, and the first signal is
characterized by a first carrier frequency and the second signal is
characterized by a second carrier frequency.
18. The receiver of claim 16, wherein the fundamental signal
characteristic is polarization and the first signal is
characterized by a first polarization and the second signal is
characterized by a second polarization.
19. The receiver of claim 16, wherein: the first program guide
includes information describing at least one surrogate channel; the
subscriber commands include a command to select at least one of the
at least one surrogate channels; and the processor further tunes
the tuner to receive the second program guide information in
response to the command to select at least one of the at least one
surrogate channels.
20. The receiver of claim 19, wherein the second signal is a spot
beam directed at the receiver.
21. The receiver of claim 19, wherein the second set of programs
are local programs and the second signal is a spot beam directed at
a subset of subscribers designated to receive the second set of
programs.
22. The receiver of claim 19, wherein the second signal further
includes a portion of the first set of programs and the second
program information further describes the portion of the first set
of programs.
23. An apparatus for use with a system broadcasting a first signal
having a first set of programs to a plurality of subscribers and a
second signal having a second set of programs to a subset of the
subscribers, comprising: a compiler, configured to segment the
programs into the first set of programs and the second set of
programs, and to generate first program guide describing the first
set of programs and second program guide information describing the
second set of programs; a first transmitter, communicatively
coupled to the compiler, for transmitting first program guide
information on a first service channel on a first signal; and a
second transmitter, communicatively coupled to the compiler, for
transmitting the second program guide information on a second
service channel on a second signal; wherein a fundamental signal
characteristic of the second signal differs from the fundamental
signal characteristic of the first signal.
24. The apparatus of claim 23, wherein the fundamental signal
characteristic is carrier frequency, and the first signal is
characterized by a first carrier frequency and the second signal is
characterized by a second carrier frequency.
25. The apparatus of claim 23, wherein the fundamental signal
characteristic is polarization and the first signal is
characterized by a first polarization and the second signal is
characterized by a second polarization.
26. The apparatus of claim 23, wherein the first transmitter
comprises a first transponder and the second transmitter comprises
a second transponder.
27. The apparatus of claim 26, wherein the first transponder and
the second transponder are disposed on a satellite.
28. The apparatus of claim 23, wherein the first transponder is
disposed on a first satellite and the second transponder is
disposed on a second satellite, and wherein the first satellite and
the second satellite are disposed within a beamwidth of a receiver
antenna.
29. The apparatus of claim 23, wherein the first program guide
information includes information describing at least one surrogate
channel.
30. The apparatus of claim 23, wherein a subscriber selection of at
least one of the at least one surrogate channels commands reception
of the second signal.
31. The apparatus of claim 23, wherein the second signal is a spot
beam directed at a subset of subscribers.
32. The apparatus of claim 23, wherein the second set of programs
comprise local programs and the second signal is a spot beam
directed at a subset of the subscribers that are designated to
receive the second set of programs.
33. The apparatus of claim 23, wherein the second signal further
includes a portion of the first set of programs and the second
program information further describes a portion of the first set of
programs.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to systems and methods for
providing video program material to subscribers, and in particular
to a method and system for providing program guides with increased
capacity to accommodate descriptions of local channel content.
[0003] 2. Description of the Related Art
[0004] Television programs are distributed to viewers by a variety
of broadcasting methods. These methods include traditional analog
broadcast television (National Television Systems Committee or
"NTSC" standard), the upcoming digital broadcast television
(Advanced Television Systems Committee or "ATSC" standard), cable
television (both analog and digital), satellite broadcasting (both
analog and digital), as well as other methods. These methods allow
channels of television content to be multiplexed and transmitted
over a common transmission medium.
[0005] In recent years, there has been an increasing demand for
video distribution systems to provide more program channels. In
digital satellite systems, this may be accomplished in many ways.
One way of increasing the number of available channels is to
increase the compression or decrease the error correction provided
in the broadcast signal of existing satellites. Another way of
increasing the number of available channels is to increase the
bandwidth of the downlink from the satellite to the subscribers'
receivers. Unfortunately, this technique is difficult to accomplish
with existing (legacy) satellites and in a way that is compatible
with existing (legacy) receivers.
[0006] As a result, video distribution systems have evolved to
include additional satellites to broadcast additional program
material to subscribers. Typically, satellites broadcasting these
enhanced services are deployed in geosynchronous orbits in orbital
locations proximate to those of the legacy satellites. This allows
a single antenna to receive signals from both satellites with
little or no physical scanning.
[0007] Electronic program guides for television programming are
known in the art. Such program guides typically include a viewer
channel number that identifies the stream of television content
offered by a content provider and a description of each media
program associated with the channel number. Program guide
information is typically transmitted along with the television
content, and typically also includes schedule information for
display on users' televisions. The schedule information informs
users what television programs are currently on, and what
television programs will be shown in the near future.
[0008] Until recently, satellite-based video distribution systems
were prohibited by regulation from transmitting local programs to
subscribers within areas where those local programs were locally
available by conventional broadcast means. For example, one of the
network affiliates for the American Broadcasting Company in Los
Angeles is KABC. These regulations prohibited satellite-based video
distribution systems from re-transmitting the KABC broadcast to
subscribers in the same market area serviced by the regional
broadcast affiliate, KABC. These limitations, however, were
eliminated by Congress through the Satellite Home Viewing
Improvement Act (SHIVA). Satellite-based video distribution systems
can now transmit such "local content" to subscribers within the
market areas serviced by the original broadcast provider.
[0009] While this capability enhances the desirability of a
satellite-based video distribution system, it raises a number of
difficulties. First, there are a large number of local market
areas, each with a large number of channels. In Los Angeles, for
example, there are seven local content providers broadcasting on
very high frequencies (VHF) and more than a dozen local content
providers broadcasting on ultra high frequencies (UHF). Providing
local content to subscribers in all market areas places large
demands on transmission bandwidth. The transmission of program
guide information describing the local content is also problematic.
To serve dozens of local market areas, each with many channels,
program guide information for literally hundreds of local content
programs would be required. Each subscriber's receiver could be
overwhelmed with information about channels that it cannot or
should not receive.
[0010] Further, there are literally millions of satellite broadcast
receivers in service. While it is possible to present local program
guide information by updating or replacing these satellite
broadcast receivers, this cannot be accomplished without incurring
substantial (and prohibitive) costs.
[0011] What is needed is a method and apparatus for providing local
program guide information to media subscribers in designated areas.
It is also necessary that the method and apparatus be compatible
with existing satellite broadcast receivers. The present invention
satisfies that need.
SUMMARY OF THE INVENTION
[0012] In summary, the present invention describes a system and
method for transmitting program guide information describing a
second set of programs to subscribers. In one embodiment, the
method is implemented in a network broadcasting a first signal
having a first set of programs and a second signal having a second
set of programs. The method comprises the steps of broadcasting
first program guide information describing the first set of
programs to the subscribers on a first service channel on a first
signal; and broadcasting second program guide information
describing the second set of programs to a subset of the
subscribers on the first service channel on a second signal,
wherein a fundamental signal characteristic of the second signal
differs from the fundamental signal characteristic of the first
signal. In another embodiment, the method comprises the steps of
receiving first program guide information describing the first set
of programs on a first service channel on a first signal; and
receiving second program guide information describing the second
set of programs on the first service channel on a second signal,
wherein a fundamental signal characteristic of the second signal
differs from the fundamental signal characteristic of the first
signal.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Referring now to the drawings in which like reference
numbers represent corresponding parts throughout:
[0014] FIG. 1 is a diagram showing an overview of a video
distribution system;
[0015] FIG. 2 is a block diagram showing a typical uplink
configuration showing how video program material is uplinked to a
satellite for transmission to subscribers using a single
transponder;
[0016] FIG. 3 is a block diagram of one embodiment of the program
guide subsystem;
[0017] FIG. 4A is a diagram of a representative data stream
received from a satellite;
[0018] FIG. 4B is a diagram illustrating the structure of a data
packet;
[0019] FIG. 5 is a block diagram of one embodiment of an integrated
receiver/decoder;
[0020] FIG. 6 is an illustration of an embodiment of the present
invention using two satellites;
[0021] FIG. 7 is a mapping showing a relationship between service
channels program content for the first and second signals;
[0022] FIG. 8 is a diagram showing one embodiment of a master
program guide providing information regarding the first set of
programs;
[0023] FIG. 9 is a diagram showing one embodiment of a master
program guide providing information regarding the second set of
programs;
[0024] FIG. 10 is a flow chart illustrating exemplary method steps
used to practice one embodiment of the present invention; and
[0025] FIG. 11 is a flow chart illustrating exemplary method steps
used to practice a second embodiment of the present invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0026] In the following description reference is made to the
accompanying drawings which form a part hereof and which show, by
way of illustration, several embodiments of the present invention.
It is understood that other embodiments may be utilized and
structural changes may be made without departing from the scope of
the present invention.
Video Distribution System
[0027] FIG. 1 is a diagram illustrating an overview of a single
satellite video distribution system 100. The video distribution
system 100 comprises a control center 102 in communication with an
uplink center 104 via a ground or other link 114 and with a
subscriber receiver station 110 via a public switched telephone
network (PSTN) or other link 120. The control center 102 provides
program material (e.g. video programs, audio programs and data) to
the uplink center 104 and coordinates with the subscriber receiver
stations 110 to offer, for example, pay-per-view (PPV) program
services, including billing and associated decryption of video
programs.
[0028] The uplink center receives program material and program
control information from the control center 102, and using an
uplink antenna 106 and transmitter 105, transmits the program
material and program control information to the satellite 108. The
satellite receives and processes this information, and transmits
the video programs and control information to the subscriber
receiver station 110 via downlink 118 using transmitter 107. The
subscriber receiving station 110 receives this information using
the outdoor unit (ODU) 112, which includes a subscriber antenna and
a low noise block converter (LNB).
[0029] In one embodiment, the subscriber receiving station antenna
is an 18-inch slightly oval-shaped Ku-band antenna. The slight oval
shape is due to the 22.5 degree offset feed of the LNB (low noise
block converter) which is used to receive signals reflected from
the subscriber antenna. The offset feed positions the LNB out of
the way so it does not block any surface area of the antenna
minimizing attenuation of the incoming microwave signal.
[0030] The video distribution system 100 can comprise a plurality
of satellites 108 in order to provide wider terrestrial coverage,
to provide additional channels, or to provide additional bandwidth
per channel. In one embodiment of the invention, each satellite
comprises 16 transponders to receive and transmit program material
and other control data from the uplink center 104 and provide it to
the subscriber receiving stations 110. Using data compression and
multiplexing techniques the channel capabilities, two satellites
108 working together can receive and broadcast over 150
conventional (non-HDTV) audio and video channels via 32
transponders.
[0031] While the invention disclosed herein will be described with
reference to a satellite-based video distribution system 100, the
present invention may also be practiced with terrestrial-based
transmission of program information, whether by broadcasting means,
cable, or other means. Further, the different functions
collectively allocated among the control center 102 and the uplink
center 104 as described above can be reallocated as desired without
departing from the intended scope of the present invention.
[0032] Although the foregoing has been described with respect to an
embodiment in which the program material delivered to the
subscriber 122 is video (and audio) program material such as a
movie, the foregoing method can be used to deliver program material
comprising purely audio information or other data as well.
Uplink Configuration
[0033] FIG. 2 is a block diagram showing a typical uplink
configuration for a single satellite 108 transponder, showing how
video program material is uplinked to the satellite 108 by the
control center 102 and the uplink center 104. FIG. 2 shows three
video channels (which could be augmented respectively with one or
more audio channels for high fidelity music, soundtrack
information, or a secondary audio program for transmitting foreign
languages), a data channel from a program guide subsystem 206 and
computer data information from a computer data source 208.
[0034] The video channels are provided by a program source of video
material 200A-200C (collectively referred to hereinafter as video
source(s) 200). The data from each video program source 200 is
provided to an encoder 202A-202C (collectively referred to
hereinafter as encoder(s) 202). Each of the encoders accepts a
program time stamp (PTS) from the controller 216. The PTS is a
wrap-around binary time stamp that is used to assure that the video
information is properly synchronized with the audio information
after encoding and decoding. A PTS time stamp is sent with each
I-frame of the MPEG encoded data.
[0035] In one embodiment of the present invention, each encoder 202
is a second generation Motion Picture Experts Group (MPEG-2)
encoder, but other decoders implementing other coding techniques
can be used as well. The data channel can be subjected to a similar
compression scheme by an encoder (not shown), but such compression
is usually either unnecessary, or performed by computer programs in
the computer data source (for example, photographic data is
typically compressed into *.TIF files or *.JPG files before
transmission). After encoding by the encoders 202, the signals are
converted into data packets by a packetizer 204A-204F (collectively
referred to hereinafter as packetizer(s) 204) associated with each
source 200.
[0036] The data packets are assembled using a reference from the
system clock 214 (SCR), and from the conditional access manager
210, which provides the SCID to the packetizers 204 for use in
generating the data packets. These data packets are then
multiplexed into serial data and transmitted.
Program Guide Subsystem
[0037] FIG. 3 is a block diagram of one embodiment of the program
guide subsystem 206. The program guide data transmitting system 206
includes program guide database 302, compiler 304, sub-databases
306A-306C (collectively referred to as sub-databases 306) and
cyclers 308A-308C (collectively referred to as cyclers 308).
[0038] Schedule feeds 310 provide electronic schedule information
about the timing and content of various television channels, such
as that found in television schedules contained in newspapers and
television guides. Schedule feeds 310 preferably include
information from one or more companies that specialize in providing
schedule information, such as GNS, TRIBUNE MEDIA SERVICES, and T.V.
DATA. The data provided by companies such as GNS, TRIBUNE MEDIA
SERVICES and T.V. DATA are typically transmitted over telephone
lines to program guide database 302. These companies provide
television schedule data for all of the television stations across
the nation plus the nationwide channels, such as SHOWTIME, HBO, and
the DISNEY CHANNEL. The specific format of the data that are
provided by these companies varies from company to company. Program
guide database 302 preferably includes schedule data for television
channels across the entire nation including all nationwide channels
and local channels, regardless of whether the channels are
transmitted by the transmission station.
[0039] Program guide database 302 is a computer-based system that
receives data from schedule feeds 310 and organizes the data into a
standard format. Compiler 304 reads the standard form data out of
program guide database 302, identifies common schedule portions,
converts the program guide data into the proper format for
transmission to users (specifically, the program guide data are
converted into objects as discussed below) and outputs the program
guide data to one or more of sub-databases 306.
[0040] Program guide data can also be manually entered into program
guide database 302 through data entry station 312. Data entry
station 312 allows an operator to enter additional scheduling
information, as well as combining and organizing data supplied by
the scheduling companies. As with the computer organized data, the
manually entered data are converted by the compiler into separate
objects and sent to one or more of sub-databases 306.
[0041] The program guide objects are temporarily stored in
sub-databases 306 until cyclers 308 request the information. Each
of cyclers 308 may transmit objects at a different rate than the
other cyclers 308. For example, cycler 308A may transmit objects
every second, while cyclers 308B and 308C may transmit objects
every 5 seconds and every 10 seconds, respectively.
[0042] Since the subscriber's receivers may not always be on and
receiving and saving objects, the program guide information is
continuously re-transmitted. Program guide objects for programs
that will be shown in the next couple of hours are sent more
frequently than program guide objects for programs that will be
shown later. Thus, the program guide objects for the most current
programs are sent to a cycler 308 with a high rate of transmission,
while program guide objects for later programs are sent to cyclers
308 with a lower rate of transmission. One or more of the data
outputs 314 of the cyclers 308 are forwarded to the packetizer of a
particular transponder, as depicted in FIG. 2.
[0043] It is noted that the uplink configuration depicted in FIG. 2
and the program guide subsystem depicted in FIG. 3 can be
implemented by one or more hardware modules, one or more software
modules defining instructions performed by a processor, or a
combination of both.
Broadcast Data Stream Format and Protocol
[0044] FIG. 4A is a diagram of a representative data stream. The
first packet segment 402 comprises information from video channel 1
(data coming from, for example, the first video program source
200A). The next packet segment 404 comprises computer data
information that was obtained, for example from the computer data
source 208. The next packet segment 406 comprises information from
video channel 5 (from one of the video program sources 200). The
next packet segment 408 comprises program guide information such as
the information provided by the program guide subsystem 206. As
shown in FIG. 4A, null packets 410 created by the null packet
module 410 may be inserted into the data stream as desired.
[0045] The data stream therefore comprises a series of packets from
any one of the data sources in an order determined by the
controller 216. The data stream is encrypted by the encryption
module 218, modulated by the modulator 220 (typically using a QPSK
modulation scheme), and provided to the transmitter 222, which
broadcasts the modulated data stream on a frequency bandwidth to
the satellite via the antenna 106. The receiver 500 receives these
signals, and using the SCID, reassembles the packets to regenerate
the program material for each of the channels.
[0046] FIG. 4B is a diagram of a data packet. Each data packet
(e.g. 402-416) is 147 bytes long, and comprises a number of packet
segments. The first packet segment 420 comprises two bytes of
information containing the SCID and flags. The SCID is a unique
12-bit number that uniquely identifies the data packet's data
channel. The flags include 4 bits that are used to control other
features. The second packet segment 422 is made up of a 4-bit
packet type indicator and a 4-bit continuity counter. The packet
type identifies the packet as one of the four data types (video,
audio, data, or null). When combined with the SCID, the packet type
determines how the data packet will be used. The continuity counter
increments once for each packet type and SCID. The next packet
segment 424 comprises 127 bytes of payload data, which in the cases
of packets 402 or 406 is a portion of the video program provided by
the video program source 200. The final packet segment 426 is data
required to perform forward error correction.
Integrated Receiver/Decoder
[0047] FIG. 5 is a block diagram of an integrated receiver/decoder
(IRD) 500 (also hereinafter alternatively referred to as receiver
500). The receiver 500 comprises a tuner/demodulator 504
communicatively coupled to an ODU 112 having one or more LNBs 502.
The LNB 502 converts the 12.2- to 12.7 GHz downlink 118 signal from
the satellites 108 to, e.g., a 950-1450 MHz signal required by the
IRD's 500 tuner/demodulator 504. The LNB 502 may provide either a
dual or a single output. The single-output LNB 502 has only one RF
connector, while the dual output LNB 502 has two RF output
connectors and can be used to feed a second tuner 504, a second
receiver 500, or some other form of distribution system.
[0048] The tuner/demodulator 504 isolates a single, digitally
modulated 24 MHz transponder, and converts the modulated data to a
digital data stream. The digital data stream is then supplied to a
forward error correction (FEC) decoder 506. This allows the IRD 500
to reassemble the data transmitted by the uplink center 104 (which
applied the forward error correction to the desired signal before
transmission to the subscriber receiving station 110) verifying
that the correct data signal was received, and correcting errors,
if any. The error-corrected data may be fed from the FEC decoder
module 506 to the transport module 508 via an 8-bit parallel
interface.
[0049] The transport module 508 performs many of the data
processing functions performed by the IRD 500. The transport module
508 processes data received from the FEC decoder module 506 and
provides the processed data to the video MPEG decoder 514 and the
audio MPEG decoder 517. In one embodiment of the present invention,
the transport module, video MPEG decoder and audio MPEG decoder are
all implemented on integrated circuits. This design promotes both
space and power efficiency, and increases the security of the
functions performed within the transport module 508. The transport
module 508 also provides a passage for communications between the
microcontroller 510 and the video and audio MPEG decoders 514, 517.
As set forth more fully hereinafter, the transport module also
works with the conditional access module (CAM) 512 to determine
whether the subscriber receiving station 110 is permitted to access
certain program material. Data from the transport module can also
be supplied to external communication module 526.
[0050] The CAM 512 functions in association with other elements to
decode an encrypted signal from the transport module 508. The CAM
512 may also be used for tracking and billing these services. In
one embodiment of the present invention, the CAM 512 is a smart
card, having contacts cooperatively interacting with contacts in
the IRD 500 to pass information. In order to implement the
processing performed in the CAM 512, the IRD 500, and specifically
the transport module 508 provides a clock signal to the CAM
512.
[0051] Video data is processed by the MPEG video decoder 514. Using
the video random access memory (RAM) 536, the MPEG video decoder
514 decodes the compressed video data and sends it to an encoder or
video processor 516, which converts the digital video information
received from the video MPEG module 514 into an output signal
usable by a display or other output device. By way of example,
processor 516 may comprise a National TV Standards Committee (NTSC)
or Advanced Television Systems Committee (ATSC) encoder. In one
embodiment of the invention both S-Video and ordinary video (NTSC
or ATSC) signals are provided. Other outputs may also be utilized,
and are advantageous if high definition programming is
processed.
[0052] Audio data is likewise decoded by the MPEG audio decoder
517. The decoded audio data may then be sent to a digital to analog
(D/A) converter 518. In one embodiment of the present invention,
the D/A converter 518 is a dual D/A converter, one for the right
and left channels. If desired, additional channels can be added for
use in surround sound processing or secondary audio programs
(SAPs). In one embodiment of the invention, the dual D/A converter
518 itself separates the left and right channel information, as
well as any additional channel information. Other audio formats may
similarly be supported. For example, other audio formats such as
multi-channel DOLBY DIGITAL AC-3 may be supported.
[0053] A description of the processes performed in the encoding and
decoding of video streams, particularly with respect to MPEG and
JPEG encoding/decoding, can be found in Chapter 8 of "Digital
Television Fundamentals," by Michael Robin and Michel Poulin,
McGraw-Hill, 1998, which is hereby incorporated by reference
herein.
[0054] The microcontroller 510 receives and processes command
signals from the remote control 524, an ERD 500 keyboard interface,
and/or another input device. The microcontroller receives commands
for performing its operations from a processor programming memory,
which permanently stores such instructions for performing such
commands. The processor programming memory may comprise a read only
memory (ROM) 538, an electrically erasable programmable read only
memory (EEPROM) 522 or, similar memory device. The microcontroller
510 also controls the other digital devices of the IRD 500 via
address and data lines (denoted "A" and "D" respectively, in FIG.
5).
[0055] The modem 540 connects to the customer's phone line via the
PSTN port 120. It calls, e.g. the program provider, and transmits
the customer's purchase information for billing purposes, and/or
other information. The modem 540 is controlled by the
microprocessor 510. The modem 540 can output data to other I/O port
types including standard parallel and serial computer I/O
ports.
[0056] The present invention also comprises a local storage unit
such as the video storage device 532 for storing video and/or audio
data obtained from the transport module 508. Video storage device
532 can be a hard disk drive, a read/writable compact disc of DVD,
a solid state RAM, or any other storage medium. In one embodiment
of the present invention, the video storage device 532 is a hard
disk drive with specialized parallel read/write capability so that
data may be read from the video storage device 532 and written to
the device 532 at the same time. To accomplish this feat,
additional buffer memory accessible by the video storage 532 or its
controller may be used. Optionally, a video storage processor 530
can be used to manage the storage and retrieval of the video data
from the video storage device 532. The video storage processor 530
may also comprise memory for buffering data passing into and out of
the video storage device 532. Alternatively or in combination with
the foregoing, a plurality of video storage devices 532 can be
used. Also alternatively or in combination with the foregoing, the
microcontroller 510 can also perform the operations required to
store and or retrieve video and other data in the video storage
device 532.
[0057] The video processing module 516 input can be directly
supplied as a video output to a viewing device such as a video or
computer monitor. In addition, the video and/or audio outputs can
be supplied to an RF modulator 534 to produce an RF output and/or 8
vestigal side band (VSB) suitable as an input signal to a
conventional television tuner. This allows the receiver 500 to
operate with televisions without a video output.
[0058] Each of the satellites 108 comprises a transponder, which
accepts program information from the uplink center 104, and relays
this information to the subscriber receiving station 110. Known
multiplexing techniques are used so that multiple channels can be
provided to the user. These multiplexing techniques include, by way
of example, various statistical or other time domain multiplexing
techniques and polarization multiplexing. In one embodiment of the
invention, a single transponder operating at a single frequency
band carries a plurality of channels identified by respective
service channel identification (SCID).
[0059] Preferably, the IRD 500 also receives and stores a program
guide in a memory available to the microcontroller 510. Typically,
the program guide is received in one or more data packets in the
data stream from the satellite 108. The program guide can be
accessed and searched by the execution of suitable operation steps
implemented by the microcontroller 510 and stored in the processor
ROM 538. The program guide may include data to map viewer channel
numbers to satellite transponders and service channel
identifications (SCIDs), and also provide TV program listing
information to the subscriber 122 identifying program events.
[0060] The functionality implemented in the IRD 500 depicted in
FIG. 5 can be implemented by one or more hardware modules, one or
more software modules defining instructions performed by a
processor, or a combination of both.
[0061] FIG. 6 is a diagram presenting a view of an enhanced video
distribution system 600 utilizing spot beams to provide local
channel content. In this embodiment, one or more satellites such as
satellite 108 broadcast a first signal 616 via beam 604 to provide
services to subscribers having receiver stations 110 located within
a particular large geographical area 606 such as CONUS. The first
signal 616 broadcasts a first set of programs to all subscribers,
including receiver stations 110 and receiver station 612. The first
signal includes a plurality of service channels, each with a unique
service channel identifier (SCID). As described herein, each
program in the first set of programs is typically dedicated to a
particular service channel when it is being broadcast.
[0062] One or more second satellites 602 broadcast a second signal
618 via spot beam 608 to provide services to subscribers having
receiver stations 612 located in a particular local area or region
610. The second signal broadcasts at least a second set of programs
to subscribers having receiver stations 612 located in the local
area or region 610. In one embodiment, the second signal also
includes some or all of the first set of programs as well. Like the
first signal, the second signal includes a plurality of service
channels with unique SCIDs.
[0063] Besides content, the second signal 618 differs from the
first signal 616 in a fundamental signal characteristic. In one
embodiment, the second signal 618 differs from the first signal 616
in frequency. In another embodiment, the second signal 618 differs
from the first signal 616 in polarization. In any case, the
difference in fundamental signal characteristic allows the first
signal 616 and the second signal 618 to be received by the same
receiver station 612 and to be distinguishable from one another.
However, both the first signal 616 and the second signal 618 share
the same channel sharing scheme (i.e. essentially a TDMA scheme
with channels denoted by SCID).
[0064] Essentially, the boundaries of the local area or region 610
separate subscribers into groups that can be defined in many ways.
For example, in one embodiment, the local area or region 610 is an
area defined by the locus of locations wherein a signal broadcast
by a terrestrial transmitter 614 can be received by receiver
stations 612 in the area with a minimum level of quality. Such
boundaries can depend on weather and other atmospheric conditions
as well as terrain. Hence, the local area or region 610 can be
defined according to statistical signal quality. Local area or
region 610 can also be a geopolitical boundary, designated
according to agreement or subscriber characteristics, such as a
designation that the subscriber receive a particular program
set.
[0065] FIG. 6 illustrates an embodiment wherein the first signal
616 is transmitted by a first satellite 108 and the second signal
618 is transmitted by a second satellite 602. However, each of the
satellites 108 and 602 can comprise a plurality of transponders,
each operating at a different frequency, and/or transmitting
signals at a different polarization. Hence, although FIG. 6
illustrates an embodiment in which the first signal 616 and second
signal 618 are transmitted by satellites that are sufficiently
proximate to be within the beamwidth of the receiver station's
antenna, the present invention could also be implemented with a
single satellite transmitting the first signal 616 and the second
signal 618 as well.
[0066] FIG. 7 is a mapping 700 showing how the program guide
information, that is, the program content, is transmitted. The
first content 704 (labeled "CONUS MPG CONTENT") is carried on the
first signal 616 from the first satellite 108, and the second
content 706 (labeled "SPOT BEAM CONTENT") is carried on the second
signal 618 from the second satellite 602. The first content 704
includes descriptive information 716 about the first set of
programs that are transmitted on the first signal 616. The second
content 706 includes descriptive information 718 about the first
set of programs that are transmitted on the first signal 616. As
the first set of programs is available to the entire service area
606, the descriptive information of 716 and 718 is the same. The
first content 704 and second content 706 additionally includes
descriptive information (720 and 722) about the second set of
programs that are transmitted on the second signal 618. However, as
the second set of programs is only available to the service area
610, the descriptive information of 720 is intentionally different
than the descriptive information of 722. In the illustrated
example, the second set of programs 722 is broadcast on SCIDs
0.times.49A-0.times.4FF. The second content 706 includes
descriptive information 722 for local channels 1 through 101, while
the first content 704 includes descriptive information 720 that
does not specifically describe local channels 1 through 101.
[0067] FIG. 8 is a diagram showing one embodiment of the first
content 704. In the illustrated embodiment, the first content 704
includes a channel number column 802 indicating viewer channels, a
channel descriptor column 804 having channel descriptions 814 to
indicate the source of the program provided on the channel, and a
plurality of program content descriptor columns 806A-806C having
program description information 816A-816C for programming time
slots.
[0068] In the illustrated embodiment, the first set of programs 810
are presented with specific information regarding each program also
presented in the succeeding columns.
[0069] In the illustrated embodiment, local channel 1 through local
channel 101 814 are presented generically by "surrogate" channels
900-1000. That is, specific program information is not included,
but an indication that channels 900-1000 are dedicated to
rebroadcast local content is indicated. In one embodiment,
information 816A-816C is also provided in program content
descriptor columns 806A through 806C to indicate that additional
program information regarding these local channels can be obtained
by selecting the viewer channel 802 for the local channel of
interest. This selection is typically made with the use of a user
interface device such as the remote control or keyboard 524.
[0070] When the user selects one of channels 810, the transport
chip 508 in the IRD 500 finds data packets with the proper SCID,
and assembles and prepares them for presentation. However, when the
user selects one of the viewer channels dedicated to local
programming (e.g. local channels 812), the IRD 500 is configured to
receive the second signal 618 from the second satellite 602. This
can be accomplished in a number of ways. In one embodiment, the IRD
500 is simply tuned to receive a different frequency matching the
transmissions from the transponder on the second satellite 602
transmitting the second signal 618. In another embodiment, the
receiver station 110 is reconfigured to receive the second signal
618 at a different polarization than the first signal. In yet
another embodiment, the receiver station's antenna is mechanically
or electronically steered to a second satellite, or a second LNB is
selected effectively displacing the beam sensitivity pattern of the
receiver station 110 antenna. Alternatively or in addition to the
above, the selection of the second signal 618 can be accomplished
by a direct command from the user (rather than by the selection of
a viewer channel associated with one of the local channels
812).
[0071] The second signal 618, includes second program guide
information, as manifested by the second content 706. The IRD 500
loads this second program guide information, and presents it to the
subscriber 112 for viewing.
[0072] FIG. 9 is a diagram showing one embodiment of the second
content 706. In the illustrated embodiment, the second content 706
includes the same information regarding the first set of programs
810. However, in addition, the second content 706 also includes
specific information regarding the local channels 1-101. In the
place of the generic information presented in FIG. 8, columns 804
and 806A-806C include specific information about the source of the
information presented in the viewer channel (e.g. "KCBS 2") and the
content information regarding the programs themselves (e.g. "News"
or "Perry Mason") 906A-906C.
[0073] FIG. 10 is a flow chart illustrating exemplary method steps
used to practice one embodiment of the present invention. As shown
in block 1002 the satellite 108 broadcasts first program guide
information describing a first set of programs to the subscribers
(including, for example, those associated with receiver stations
110 and 612) on a first channel of a first signal 616. As shown in
block 1004, a second satellite 602 broadcasts second program guide
information describing a second set of programs to a subset of the
subscribers (e.g. those associated with receiver stations 616
within the local area or region 610) on the first service channel,
but on a second signal 618 wherein the a signal characteristic of
the first signal and the second signal differ (e.g. polarization,
frequency, or coding). Because the first program guide information
and the second program guide information are presented on the same
service channels, differing program guide information can be
presented for each signal without requiring changes to the IRD
500.
[0074] FIG. 11 is a flow chart illustrating exemplary method steps
used to practice another embodiment of the present invention. First
program guide information describing a first set of programs on a
first service channel on a first signal is received, as shown in
block 1102. The subscriber 112 can select a number of channels from
the first program guide (e.g. CONUS MPG). If at least one of the
selected channel is one of the surrogate channels 900-1000
dedicated to local programming, the receiver station 612 is tuned
to receive second program guide information (e.g. SPOT BEAM MPG) on
the first service channel of the second signal 618. The second
program guide information is received via the second signal 618 and
presented to the subscriber 112. This is depicted in steps
1104-1108.
Conclusion
[0075] This concludes the description of the preferred embodiments
of the present invention. The foregoing description of the
preferred embodiment of the invention has been presented for the
purposes of illustration and description. It is not intended to be
exhaustive or to limit the invention to the precise form disclosed.
Many modifications and variations are possible in light of the
above teaching.
[0076] It is intended that the scope of the invention be limited
not by this detailed description, but rather by the claims appended
hereto. The above specification, examples and data provide a
complete description of the manufacture and use of the composition
of the invention. Since many embodiments of the invention can be
made without departing from the spirit and scope of the invention,
the invention resides in the claims hereinafter appended.
* * * * *