Tuning scheme for code division multiplex broadcasting system
First Claim
1. A method for broadcasting a programming signal in a satellite broadcast system having one or more satellites, comprising the steps of:
- interleaving said programming signal with a first interleaver producing a first interleaved signal having a first interleaver delay;
broadcasting said first interleaved signal on a carrier frequency using at least a first orthogonal code; and
broadcasting a tuning signal corresponding to said programming signal, wherein said tuning signal utilizes a shorter interleaver length than said first interleaved signal.
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Abstract
A CDM satellite transmission system is disclosed that broadcasts programming content, such as audio and video information, using one or more geo-synchronous satellites based on Code Division Multiple Access technology. Forward error correction coding and interleaving are used prior to broadcasting the signals over the CDM channel to account for signal loss due to short-term fading. The CDM satellite transmission system provides a tuning channel corresponding to each program channel that reduces the delay when a mobile receiver is first tuned to a selected program channel. The tuning channel utilizes a shorter interleaver length, if any, than the corresponding primary program channel. The CDM satellite transmission system transmits a delayed version of a program signal with the on-time version of the audio output to accommodate uninterrupted reception in the event of such a blockage. In one implementation of the invention, the core layer, C(n), of the delayed version of the audio output of a scalable audio coding scheme is utilized as the tuning channel. The core layer, C1(n), and enhancement layers, E1(n), of the on-time signal and the enhancement layers, E2(n), of the delayed-time signal employ a representative block interleaver having a duration of four seconds. The tuning channel (C2(n), of the delayed-time signal) employs a representative block interleaver having a duration of 500 milliseconds.
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Citations
61 Claims
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1. A method for broadcasting a programming signal in a satellite broadcast system having one or more satellites, comprising the steps of:
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interleaving said programming signal with a first interleaver producing a first interleaved signal having a first interleaver delay;
broadcasting said first interleaved signal on a carrier frequency using at least a first orthogonal code; and
broadcasting a tuning signal corresponding to said programming signal, wherein said tuning signal utilizes a shorter interleaver length than said first interleaved signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A method for broadcasting a programming signal in a satellite broadcast system, comprising the steps of:
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interleaving said programming signal with a first interleaver producing a first interleaved signal having a first interleaver delay;
interleaving said programming signal with a second interleaver producing a second interleaved signal having a second interleaver delay shorter than said first interleaver delay;
broadcasting said first interleaved signal on a carrier frequency using at least a first orthogonal code; and
broadcasting said second interleaved signal as a tuning signal on said carrier frequency using a second orthogonal code. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27)
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28. A method for receiving a programming signal corresponding to a program source in a satellite broadcast system, comprising the steps of:
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receiving a first interleaved signal having a first interleaver delay associated with said programming signal;
receiving a tuning signal corresponding to said programming signal, wherein said tuning signal utilizes a shorter interleaver length than said first interleaved signal; and
reproducing said program source from said tuning signal when a user selects a new program source. - View Dependent Claims (29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40)
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41. A satellite broadcast system, comprising:
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at least one geo-synchronous satellite for broadcasting a first interleaved signal corresponding to a program source on a carrier frequency using at least a first orthogonal code and a tuning signal corresponding to said program source, wherein said tuning signal utilizes a shorter interleaver length than said first interleaved signal; and
a receiver for recovering said program source from at least one of said first interleaved signal or said tuning signal. - View Dependent Claims (42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55)
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56. A receiver in a satellite broadcast system, comprising:
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at least one antenna for receiving a first interleaved signal having a first interleaver delay associated with said programming signal and a tuning signal corresponding to said programming signal, wherein said tuning signal utilizes a shorter interleaver length than said first interleaved signal; and
a decoder for reproducing said program source from said tuning signal when a user selects a new program source.
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57. A transmitter in a satellite broadcast system, comprising:
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a first interleaver for producing a first interleaved signal corresponding to a programming signal having a first interleaver delay;
means for broadcasting said first interleaved signal on a carrier frequency using at least a first orthogonal code; and
means for broadcasting a tuning signal corresponding to said programming signal, wherein said tuning signal utilizes a shorter interleaver length than said first interleaved signal.
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58. A transmitter in a satellite broadcast system, comprising:
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a first interleaver for producing a first interleaved signal corresponding to a programming signal having a first interleaver delay;
a second interleaver for producing a second interleaved signal having a second interleaver delay shorter than said first interleaver delay;
means for broadcasting said first interleaved signal on a carrier frequency using at least a first orthogonal code; and
means for broadcasting said second interleaved signal as a tuning signal on said carrier frequency using a second orthogonal code.
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59. A method for broadcasting a programming signal, comprising the steps of:
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interleaving said programming signal with a first interleaver producing a first interleaved signal having a first interleaver delay;
broadcasting said first interleaved signal on a carrier frequency using at least a first orthogonal code; and
broadcasting a tuning signal corresponding to said programming signal, wherein said tuning signal utilizes a shorter interleaver length than said first interleaved signal. - View Dependent Claims (60, 61)
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Specification