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US 5,907,582 AGranted
System for turbo-coded satellite digital audio broadcasting
AssigneeOrbital Sciences Corporation
InventorByung Kwan Yi
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Abstract
A system and method for broadcasting an audio signal in a turbo-coded satellite digital audio broadcasting system is provided that utilizes the combination of a turbo coding system having code combining and code diversity techniques to lower the power required for transmittal and to transmit at a higher code rate of 1/4 by utilizing the puncturing sequence and a pilot signal assisted orthogonal CDMA; the invention includes an improved receiver system that uses modified RAKE receivers in order to mitigate the Rayleigh multipath fading, shadowing, and temporal blockage and improve performance. The invention further uses a terrestrial gap filler network having a reduced amount of gap fillers.
Claims31
A digital audio broadcasting (DAB) system adapted to broadcast signals of digital radio information, comprising:
- a broadcast source for transmitting a first encoded broadcast signal comprising a first representation of the digital radio information and a first parity sequence and for transmitting a second encoded broadcast signal comprising a second representation of the digital radio information and a second parity sequence, said second representation of the digital radio information being different from said first representation of the digital radio information, said first and second encoded broadcast signals being transmitted on at least one predetermined path;
- and
- a plurality of receivers for receiving said first and second encoded broadcast signals, said receivers being located at or near the surface of the earth, each of said receivers including means for outputting the digital radio information from said first and second encoded broadcast signals.
A digital audio broadcasting (DAB) system adapted to broadcast signals of digital radio information and to reduce multipath fading, signal shadowing and temporal blockage, the system comprising:
- a broadcast source having means for transmitting a first turbo encoded broadcast signal and a second turbo encoded broadcast signal that includes the digital radio information, said first and second turbo encoded broadcast signals being transmitted on at least one predetermined oath;
- and
- a plurality of receivers for receiving said first and second turbo encoded broadcast signals, said receivers being located at or near the surface of the earth, each of said receivers including means for outputting the digital radio information from said first and second turbo encoded broadcast signals, wherein:
- said broadcast source transmits said first turbo encoded broadcast signal on a first path to a first satellite and transmits said second turbo encoded signal on a second path to a second satellite,
- said broadcast source transmits said first and second turbo encoded broadcast signals to a network of gap fillers,
- said network of said gap fillers includes delay means for delaying said first and second turbo encoded broadcast signals to compensate for propagation signal delay through said first and second satellites, and
- said first turbo encoded broadcast signal consists essentially of uninterleaved data and parity check elements.
4 more elements
A digital communication system, comprising:
- (A) a broadcast data source comprising:
- (1) a first turbo encoder for turbo encoding digital source information into a first code sequence,
- (2) an interleaver for interleaving the digital source information,
- (3) a second turbo encoder for turbo encoding the interleaved digital source information into a second code sequence,
- (4) a first code puncturer for selectively replacing data in the first code sequence with selected data from the second code sequence, to form a first punctured code sequence, and
- (5) a second code puncturer for selectively replacing data in the second code sequence with selected data from the first code sequence, to form a second punctured code sequence;
- (B) a broadcast system, comprising at least one transmitter, for broadcasting first and second channels over a geographic area, the first channel carrying the digital source information together with the first punctured code sequence, and the second channel carrying the interleaved digital source information together with the second punctured code sequence;
- and
- (C) a plurality of receiver stations, each of which comprises:
- (i) an antenna for receiving broadcast signals from the broadcast system,
- (ii) processing circuitry, coupled to the antenna, for recovering data from the first channel if contained in the broadcast signals received by the antenna and for recovering data from the second channel if contained in the broadcast signal received by the antenna, and
- (iii) an intelligent turbo decoder coupled to the processing circuitry, for decoding the data from the first and second channels to recover a representation of the digital source information if both channels are received, and for decoding either the data from the first channel or the data from the second channel to recover a representation of the digital source information if only one of the channels are received.
9 more elements
A digital communication system, comprising:
- (A) a first encoder, responsive to digital source information, for producing a first data sequence containing turbo coded information, said first data sequence comprising a first representation of the digital source information and a first parity sequence;
- (B) a second encoder, responsive to the digital source information, for producing a second data sequence containing turbo coded information, said second data sequence comprising a second representation of the digital source information and a second parity sequence, said second representation of the digital source information being different from the first representation of the digital source information;
- (C) a first transmitter for broadcasting signals including the first data sequence over a first path into a geographic area;
- (D) a second transmitter for broadcasting signals including the second data sequence over a second path into the geographic area, at least a portion of the second path being separate from the first path;
- and
- (E) a plurality of receiver stations, each of which comprises (i) an antenna for receiving one or more of the broadcast signals, and (ii) a decoder, responsive to code information contained in signals from the antenna, for decoding one or more of the data sequences to recover a representation of the digital source information.
3 more elements
Dependencies are inferred from the claim text.