Systems for reducing adverse effects of deep fades in DTV signals designed for mobile reception

US 8,290,035 B2
Filed: 07/11/2008
Issued: 10/16/2012
Est. Priority Date: 07/11/2007
Status: Expired due to Fees

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1. In transmitter apparatus for a digital television broadcast signal manifested as an electromagnetic wave subjected to vestigial sideband amplitude modulation in accordance with an eight-level modulating signal, said eight-level modulating signal formed by two-thirds trellis coding of convolutionally byte-interleaved 207-byte Reed-Solomon codewords generated from 187-byte packets beginning with respective 3-byte headers and concluding with respective 184-byte contents, the improvement wherein:

the contents of special ones of said 187-byte packets encapsulate respective segments of byte-interleaved parallel concatenated convolutional codewords;

the headers of said special ones of said 187-byte packets indicate their special nature;

said parallel concatenated convolutional codewords encode Reed-Solomon-coded ancillary data, time-division multiplexing bytes of said Reed-Solomon-coded ancillary data with bytes of a first parity determination and with bytes of a second parity determination; and

the byte interleaving of said parallel concatenated convolutional codewords disposes the bytes of each of them transversally within the contents of said special ones of said 187-byte packets.

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Abstract

Digital television broadcasting signals employ parallel concatenated convolutional coding, commonly called “turbo coding”, to improve reception by receivers in motor vehicles. Turbo coded Reed-Solomon codewords are transversally disposed in the payload fields of encapsulating MPEG-2-compliant packets to improve the capability of the Reed-Solomon coding to overcome deep fades. Turbo codewords are transmitted more than once in so-called “staggercasting”. Reception of DTV signals is improved by combining soft decisions concerning repeated transmissions of turbo codewords before turbo decoding. Only the data components of turbo codewords are transmitted twice in “punctured” staggercasting of turbo codewords, with parity components being transmitted only once, so code rate is reduced by a smaller factor than two.

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1. In transmitter apparatus for a digital television broadcast signal manifested as an electromagnetic wave subjected to vestigial sideband amplitude modulation in accordance with an eight-level modulating signal, said eight-level modulating signal formed by two-thirds trellis coding of convolutionally byte-interleaved 207-byte Reed-Solomon codewords generated from 187-byte packets beginning with respective 3-byte headers and concluding with respective 184-byte contents, the improvement wherein:
- the contents of special ones of said 187-byte packets encapsulate respective segments of byte-interleaved parallel concatenated convolutional codewords;
  
  the headers of said special ones of said 187-byte packets indicate their special nature;
  
  said parallel concatenated convolutional codewords encode Reed-Solomon-coded ancillary data, time-division multiplexing bytes of said Reed-Solomon-coded ancillary data with bytes of a first parity determination and with bytes of a second parity determination; and
  
  the byte interleaving of said parallel concatenated convolutional codewords disposes the bytes of each of them transversally within the contents of said special ones of said 187-byte packets.
- View Dependent Claims (2, 3, 4, 5)
- - 2. Transmitter apparatus including said improvement set forth in claim 1, said transmitter apparatus comprising:
    - an outer Reed-Solomon forward-error-correction code encoder connected for Reed-Solomon forward-error-correction coding said ancillary data to generate said Reed-Solomon-coded ancillary data;
      
      a turbo coding encoder connected for coding said Reed-Solomon-coded ancillary data to generate said parallel concatenated convolutional codewords in which bytes of said Reed-Solomon-coded ancillary data are time-division multiplexed with bytes of a first parity determination and with bytes of a second parity determination;
      
      an outer byte interleaver connected for receiving said parallel concatenated convolutional codewords and matrix-type block interleaving them to generate an outer byte interleaver response;
      
      apparatus connected for packing the 184-byte payload-data fields of said special packets with segments of said outer byte interleaver response, thereby disposing the bytes of each of said parallel concatenated convolutional codewords transversally within the contents of said special ones of said 187-byte packets;
      
      a transport stream multiplexer connected for time-division multiplexing said special ones of said 187-byte packets with others of said 187-byte packets to generate a complete transport stream;
      
      a data randomizer connected for randomizing said complete transport stream by exclusive-ORing the bits thereof with the bits of a prescribed pseudo-random binary sequence, thereby to generate a data-randomized complete transport stream;
      
      an inner Reed-Solomon forward-error-correction code encoder connected for Reed-Solomon forward-error-correction coding said data-randomized complete transport stream to generate said 207-byte Reed-Solomon codewords for convolutional byte interleaving;
      
      an inner byte interleaver connected for receiving said 207-byte Reed-Solomon codewords for convolutional byte interleaving and convolutionally interleaving their bytes to generate an inner byte interleaver response;
      
      a trellis code encoder connected for receiving said inner byte interleaver response and performing 12-phase two-thirds trellis coding of said inner byte interleaver response to generate successive three-bit sequences descriptive of respective symbols;
      
      a symbol mapper connected for converting said three-bit sequences to respective eight-level symbols;
      
      a symbol-code assembler connected for inserting data segment synchronizing symbols and data field synchronizing symbols at intervals within eight-level symbols from said symbol mapper to generate assembled symbol coding;
      
      apparatus connected for generating a modulating signal by combining an offset with said assembled symbol coding; and
      
      a vestigial-sideband amplitude-modulation digital television transmitter connected for receiving said modulating signal and transmitting said improved digital television broadcast signal.
  - 3. The transmitter apparatus of claim 2 wherein said outer byte interleaver comprises a memory separated into two banks, each connected for the byte storage locations therewithin being written to column by column with said parallel concatenated convolutional codewords generated by said turbo coding encoder while byte storage locations within the other is being read row by row to supply said segments of said outer byte interleaver response to said apparatus connected for packing the 184-byte payload-data fields of said special packets.
  - 4. The transmitter apparatus of claim 2 wherein said outer byte interleaver is of a Spruyt type in which a memory is connected for having byte storage locations therewithin written to column by column with said parallel concatenated convolutional codewords generated by said turbo coding encoder and read row by row to supply said segments of said outer byte interleaver response to said apparatus connected for packing the 184-byte payload-data fields of said special packets.
  - 5. Transmitter apparatus including the improvement set forth in claim 1 operated in a digital television broadcasting system, said digital television broadcasting system further including at least one receiver apparatus comprising:
    - apparatus for converting a selected 8VSB digital television signal received as an amplitude-modulated radio-frequency carrier to a baseband digital television signal, which apparatus includes front-end circuitry, an analog-to-digital converter, a demodulator for 8VSB digital television signals and a channel equalization filter;
      
      a 12-phase trellis decoder connected for providing trellis decoding results that include soft decisions concerning symbols in said baseband digital television signal, said 12-phase trellis decoder connected to receive baseband digital television signal from said apparatus for converting a selected 8VSB digital television signal received as an amplitude-modulated radio-frequency carrier to a baseband digital television signal; and
      
      further apparatus connected for decoding selected portions of said trellis decoding results conveying said PCCC that encodes said ancillary data, thus to reproduce said ancillary data in at least substantially original form.

6. Receiver apparatus for receiving a digital television broadcast signal manifested as an electromagnetic wave subjected to vestigial sideband amplitude modulation in accordance with an eight-level modulating signal, said eight-level modulating signal formed by two-thirds trellis coding of convolutionally byte-interleaved 207-byte Reed-Solomon codewords generated from 187-byte packets beginning with respective 3-byte headers and concluding with respective 184-byte contents, the contents of special ones of said 187-byte packets encapsulating respective segments of parallel concatenated convolutional codewords at least some of which are byte-interleaved , the headers of said special ones of said 187-byte packets indicating their special nature, said parallel concatenated convolutional codewords encoding Reed-Solomon-coded ancillary data, bytes of said Reed-Solomon-coded ancillary data being time-division multiplexed with bytes of a first parity determination and with bytes of a second parity determination, and the byte interleaving of said parallel concatenated convolutional codewords disposing the bytes of each of them transversally within the contents of said special ones of said 187-byte packets, said receiver apparatus comprising:
- apparatus for converting the received improved digital television broadcast signal to a digitized baseband signal;
  
  a decoder for two-thirds trellis coding, connected for receiving said digitized baseband signal and generating soft decisions concerning the symbols encoded therein, which are descriptive of said convolutionally byte-interleaved 207-byte Reed-Solomon codewords;
  
  an inner byte de-interleaver connected for de-interleaving said soft decisions concerning said symbols in said baseband digital television signal that are descriptive of said convolutionally byte-interleaved 207-byte Reed-Solomon codewords;
  
  an inner Reed-Solomon decoder for (207,
  
  187) Reed-Solomon forward-error-correction coding connected for receiving de-interleaved soft decisions concerning said symbols that are descriptive of 207-byte Reed-Solomon codewords and correcting byte errors in the 187-byte packets contained within respective ones of said 207-byte Reed-Solomon codewords, thereby to generate soft decisions concerning those said 187-byte packets;
  
  a data de-randomizer connected for de-randomizing hard decision portions of said soft decisions concerning those said 187-byte packets generated by said inner Reed-Solomon decoder, said de-randomizing being done by exclusive-ORing the bits of said hard decision portions with the bits of a prescribed pseudo-random binary sequence, thereby to generate de-randomized 187-byte packets;
  
  a turbo coding selector connected for selecting interleaved bytes of said parallel concatenated convolutional codewords from those of said de-randomized 187-byte packets that begin with respective 3-byte headers indicative of their said special nature, which interleaved bytes are accompanied by soft-decision information and continue to be so accompanied in the selective response of the turbo coding selector;
  
  an outer byte de-interleaver connected for de-interleaving said selective response of said turbo coding selector including the soft-decision information therein and reproducing said parallel concatenated convolutional codewords;
  
  a turbo decoder connected for receiving said parallel concatenated convolutional codewords reproduced by said outer byte de-interleaver and decoding them to reproduce said Reed-Solomon-coded ancillary data; and
  
  outer Reed-Solomon decoding apparatus connected for receiving said Reed-Solomon-coded ancillary data and correcting byte errors in the packets of ancillary data contained within said Reed-Solomon-coded ancillary data.
- View Dependent Claims (7, 8, 9)
- - 7. The receiver apparatus of claim 6, further comprising:
    - turbo decoding control circuitry for discontinuing turbo coding of any of said parallel concatenated convolutional codewords by said turbo decoder when said outer Reed-Solomon decoding apparatus determines lack of byte error in the Reed-Solomon-coded ancillary data encoded in that particular said parallel concatenated convolutional codeword.
  - 8. The receiver apparatus of claim 6 wherein said outer byte de-interleaver comprises a memory separated into two banks, each connected for the byte storage locations therewithin being written to row by row with said selective response of said turbo coding selector while byte storage locations within the other is being read column by column to reproduce said parallel concatenated convolutional codewords.
  - 9. The receiver apparatus of claim 6 wherein said outer byte de-interleaver is of a Spruyt type in which a memory is connected for having byte storage locations therewithin written to row by row with said selective response of said turbo coding selector and read column by column to reproduce said parallel concatenated convolutional codewords.

10. Receiver apparatus for receiving a digital television broadcast signal manifested as an electromagnetic wave subjected to vestigial sideband amplitude modulation in accordance with an eight-level modulating signal, said eight-level modulating signal formed by two-thirds trellis coding of convolutionally byte-interleaved 207-byte Reed-Solomon codewords generated from 187-byte packets, the contents of special ones of said 187-byte packets encapsulating respective segments of parallel concatenated convolutional codewords at least some of which are byte-interleaved, the headers of said special ones of said 187-byte packets indicating their special nature, said parallel concatenated convolutional codewords encoding Reed-Solomon-coded ancillary data, bytes of said Reed-Solomon-coded ancillary data being time-division multiplexed with bytes of a first parity determination and with bytes of a second parity determination, and the byte interleaving of said parallel concatenated convolutional codewords disposing the bytes of each of them transversally within the contents of said special ones of said 187-byte packets, said receiver apparatus comprising:
- apparatus for converting a selected 8VSB digital television signal received as an amplitude-modulated radio-frequency carrier to a baseband digital television signal, which apparatus includes front-end circuitry, an analog-to-digital converter, a demodulator for 8VSB digital television signals and a channel equalization filter;
  
  a 12-phase trellis decoder connected for providing trellis decoding results that include soft decisions concerning symbols in said baseband digital television signal, said 12-phase trellis decoder connected to receive baseband digital television signal from said apparatus for converting a selected 8VSB digital television signal received as an amplitude-modulated radio-frequency carrier to a baseband digital television signal; and
  
  further apparatus connected for decoding selected portions of said trellis decoding results conveying said parallel concatenated convolutional codewords that encode said ancillary data, thus to reproduce said ancillary data in at least substantially original form.
- View Dependent Claims (11, 12, 13, 14, 15, 16)
- - 11. The receiver apparatus of claim 10, wherein said further apparatus connected for decoding selected portions of said trellis decoding results comprises:
    - apparatus for reproducing in a selective response therefrom bytes of said parallel concatenated convolutional codewords as selected from said trellis decoding results, which bytes of said parallel concatenated convolutional codewords are accompanied by soft-decision information in said trellis decoding results and continue to be so accompanied in said selective response of said apparatus for selecting said bytes of said parallel concatenated convolutional codewords from said trellis decoding results; and
      
      a turbo decoder connected for receiving said selective response of said apparatus for reproducing bytes of said parallel concatenated convolutional codewords as selected from said trellis decoding results and decoding said parallel concatenated convolutional codewords.
  - 12. The receiver apparatus of claim 10, wherein said further apparatus connected for decoding selected portions of said trellis decoding results comprises:
    - apparatus for reproducing in a selective response therefrom interleaved bytes of said parallel concatenated convolutional codewords from said trellis decoding results, which interleaved bytes of said parallel concatenated convolutional codewords are accompanied by soft-decision information in said trellis decoding results and continue to be so accompanied in the selective response of said apparatus for selecting said interleaved bytes of said parallel concatenated convolutional codewords from said trellis decoding results;
      
      an outer byte de-interleaver connected for de-interleaving said selective response of said apparatus for reproducing interleaved bytes of said parallel concatenated convolutional codewords from said trellis decoding results, including the soft-decision information within that said selective response and thus reproducing said parallel concatenated convolutional codewords; and
      
      a turbo decoder connected for receiving said parallel concatenated convolutional codewords reproduced by said outer byte de-interleaver and decoding them.
  - 13. The receiver apparatus of claim 10, wherein said further apparatus connected for decoding selected portions of said trellis decoding results comprises:
    - an inner byte de-interleaver connected for de-interleaving said soft decisions concerning said symbols in said baseband digital television signal that are descriptive of said convolutionally byte-interleaved 207-byte Reed-Solomon codewords;
      
      an inner Reed-Solomon decoder for (207,
      
      187) Reed-Solomon forward-error-correction coding connected for receiving de-interleaved soft decisions concerning said symbols that are descriptive of 207-byte Reed-Solomon codewords and correcting byte errors in the 187-byte packets contained within respective ones of said 207-byte Reed-Solomon codewords, thereby to generate soft decisions concerning those said 187-byte packets;
      
      a data de-randomizer connected for de-randomizing hard decision portions of said soft decisions concerning those said 187-byte packets generated by said inner Reed-Solomon decoder, said de-randomizing being done by exclusive-ORing the bits of said hard decision portions with the bits of a prescribed pseudo-random binary sequence, thereby to generate de-randomized 187-byte packets;
      
      a turbo coding selector connected for selecting interleaved bytes of said parallel concatenated convolutional codewords from those of said de-randomized 187-byte packets that begin with respective 3-byte headers indicative of their said special nature, which interleaved bytes are accompanied by soft-decision information and continue to be so accompanied in the selective response of the turbo coding selector;
      
      an outer byte de-interleaver connected for de-interleaving said selective response of said turbo coding selector including the soft-decision information therein and reproducing said parallel concatenated convolutional codewords;
      
      a turbo decoder connected for receiving said parallel concatenated convolutional codewords reproduced by said outer byte de-interleaver and decoding them to reproduce said Reed-Solomon-coded ancillary data; and
      
      outer Reed-Solomon decoding apparatus connected for receiving said Reed-Solomon-coded ancillary data and correcting byte errors in the packets of ancillary data contained within said Reed-Solomon-coded ancillary data.
  - 14. The receiver apparatus of claim 13, further comprising:
    - turbo decoding control circuitry for discontinuing turbo coding of any of said parallel concatenated convolutional codewords by said turbo decoder when said outer Reed-Solomon decoding apparatus determines lack of byte error in the Reed-Solomon-coded ancillary data encoded in that particular said parallel concatenated convolutional codeword.
  - 15. The receiver apparatus of claim 13 wherein said outer byte de-interleaver comprises a memory separated into two banks, each connected for the byte storage locations therewithin being written to row by row with said selective response of said turbo coding selector while byte storage locations within the other is being read column by column to reproduce said parallel concatenated convolutional codewords.
  - 16. The receiver apparatus of claim 13 wherein said outer byte de-interleaver is of a Spruyt type in which a memory is connected for having byte storage locations therewithin written to row by row with said selective response of said turbo coding selector and read column by column to reproduce said parallel concatenated convolutional codewords.

17. Receiver apparatus for receiving 8-VSB digital television broadcast signals each manifested as an electromagnetic wave subjected to vestigial sideband amplitude modulation in accordance with an eight-level modulating signal, said eight-level modulating signal formed by two-thirds trellis coding of 207-byte Reed-Solomon codewords generated from 187-byte packets and convolutionally byte-interleaved before said two-thirds trellis coding, the contents of special ones of said 187-byte packets each encapsulating data bits and parity bits of parallel concatenated convolutional coding of ancillary data, the headers of said special ones of said 187-byte packets indicative of their special nature, said parallel concatenated convolutional coding encoding ancillary data, said receiver apparatus comprising:
- apparatus for converting a selected 8VSB digital television signal received as an amplitude-modulated radio-frequency carrier to a baseband digital television signal, which apparatus includes front-end circuitry, an analog-to-digital converter, a demodulator for 8VSB digital television signals and a channel equalization filter;
  
  a 12-phase trellis decoder connected for providing trellis decoding results that include soft decisions concerning symbols in said baseband digital television signal, said 12-phase trellis decoder connected to receive baseband digital television signal from said apparatus for converting a selected 8VSB digital television signal received as an amplitude-modulated radio-frequency carrier to a baseband digital television signal; and
  
  further apparatus connected for decoding selected portions of said trellis decoding results conveying said parallel concatenated convolutional coding that encodes said ancillary data, thus to reproduce said ancillary data in at least substantially its original form.
- View Dependent Claims (18, 19)
- - 18. Receiver apparatus as set forth in claim 17, wherein said further apparatus connected for decoding selected portions of said trellis decoding results comprises:
    - a byte de-interleaver connected for de-interleaving said soft decisions concerning said symbols in said baseband digital television signal that are descriptive of said 207-byte data segments that have been convolutionally byte-interleaved;
      
      a Reed-Solomon decoder for (207,
      
      187) Reed-Solomon forward-error-correction coding connected for receiving de-interleaved soft decisions concerning said symbols that are descriptive of 207-byte Reed-Solomon codewords and correcting byte errors in the 187-byte packets contained within respective ones of said 207-byte Reed-Solomon codewords, thereby to generate updated soft decisions concerning those said 187-byte packets as Reed-Solomon decoding results;
      
      apparatus connected for decoding selected portions of said Reed-Solomon decoding results which convey said parallel concatenated convolutional coding that encodes said ancillary data, thus to reproduce said ancillary data in at least substantially its original form.
  - 19. Receiver apparatus as set forth in claim 18, wherein said apparatus connected for decoding selected portions of said Reed-Solomon decoding results which convey said parallel concatenated convolutional coding that encodes said ancillary data comprises:
    - a random-access memory operable for re-interleaving said selected portions of said Reed-Solomon decoding results which convey said parallel concatenated convolutional coding that encodes said ancillary data, thus to restore said parallel concatenated convolutional coding to an original order thereof; and
      
      a turbo decoder for said parallel concatenated convolutional coding as restored to said original order thereof, said turbo decoder operable to reproduce said ancillary data in at least substantially its original form.

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Current Assignee
Cerinet IP LLC.
Original Assignee
Allen Leroy Limberg
Inventors
Limberg, Allen LeRoy
Primary Examiner(s)
Phillips, Hassan
Assistant Examiner(s)
CATTUNGAL, AJAY P

Application Number

US12/218,131
Publication Number

US 20090016432A1
Time in Patent Office

1,558 Days
Field of Search

None
US Class Current

375/240.01
CPC Class Codes

H03M 13/2957   Turbo codes and decoding

H04L 65/611   for multicast or broadcast ...

H04L 65/70   Media network packetisation

H04N 21/2383   Channel coding or modulatio...

Systems for reducing adverse effects of deep fades in DTV signals designed for mobile reception

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Systems for reducing adverse effects of deep fades in DTV signals designed for mobile reception

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