Concatenated coded vestigial sideband modulation for high definition television

• US 5,398,073 A
• Filed: 04/12/1994
• Issued: 03/14/1995
• Est. Priority Date: 04/12/1994
• Status: Expired due to Term

• Current Assignee: Agere Systems Incorporated (Broadcom, Inc.)
• Original Assignee: AT&T Corporation (AT&T, Inc.)
• Inventors: Wei, Lee-Fang
• Primary Examiner(s): Kostak, Victor R.
• Application Number:
  US08/226,606
• Time in Patent Office: 336 Days
• Field of Search: 348/426, 348/432, 348/433, 348/469, 348/427, 348/724, 375/18, 375/43, 375/39
• US Class Current: 348/487
• CPC Class Codes: H04L 27/02 Amplitude-modulated carrier systems, e.g. using on-off keying; Single sideband or vestigial sideband modulation H04L27/32 takes precedence
• CPC Class Codes: H04N 21/2383 Channel coding or modulation of digital bit-stream, e.g. QPSK modulation arrangements for detecting or preventing errors in the information received by adapting the channel coding H04L1/0009; analogue front ends or means for connecting modulators, demodulators or transceivers to a transmission line H04L27/0002
• CPC Class Codes: H04N 21/4382 Demodulation or channel decoding, e.g. QPSK demodulation analog front ends or means for connecting modulators, demodulators or transceivers to a transmission line H04L27/0002

Abstract

A modulation scheme for HDTV, for example, uses a concatenated code comprised of a Reed-Solomon coder followed by an N-dimensional trellis coder whose N-dimensional output symbols with N>1, are used to modulate a one-dimensional vestigial sideband modulator. Specifically, each N-dimensional symbol is a sequence of N one-dimensional signal points--specifically signal points of a one-dimensional VSB constellation.

Claims

1. A method of transmitting a digital signal over a television channel, the method comprising the steps of

Reed-Solomon encoding the digital signal,

generating a sequence of N-dimensional symbols as a function of the Reed-Solomon-encoded signal using an N-dimensional trellis code, N>

1,

representing each of said symbols as a sequence of N one-dimensional signal points of a one-dimensional M-ary transmitter constellation,

generating a vestigial sideband modulation signal which represents the resulting sequence of signal point representations, and

applying said vestigial sideband modulation signal to said television channel.

2. The invention of claim 1 wherein said television channel is a cable channel and wherein M=16.

3. The invention of claim 1 wherein the symbol-generating step includes the steps of interleaving the Reed-Solomon-encoded signal and trellis-encoding the resulting interleaved signal.

4. The invention of claim 1 wherein said trellis code is a four-dimensional trellis code.

5. The invention of claim 4 wherein said trellis code is an eight-state trellis code.

6. The invention of claim 4 wherein said television channel is an over-the-air channel and wherein M is selected from the group consisting of 4 and 6.

7. The invention of claim 1 wherein said trellis code is an eight-dimensional trellis code.

8. The invention of claim 7 wherein said television channel is an over-the-air channel and wherein M=4.

9. The invention of claim 7 wherein said trellis code is a 16-state trellis code.

10. Apparatus for transmitting a digital signal over a television channel, the apparatus comprising

means for Reed-Solomon encoding the digital signal,

means for generating a sequence of N-dimensional symbols as a function of the Reed-Solomon-encoded signal using an N-dimensional trellis code, N>

1,

means for representing each of said symbols as a sequence of N one-dimensional signal points of a one-dimensional M-ary transmitter constellation, and

means for generating a vestigial sideband modulation signal which represents the resulting sequence of signal point representations and for applying said vestigial sideband modulation signal to said television channel.

11. The invention of claim 10 wherein said television channel is a cable channel and wherein M=16.

12. The invention of claim 10 wherein the symbol-generating means includes means for interleaving the Reed-Solomon-encoded signal and means for trellis-encoding the resulting interleaved signal.

13. The invention of claim 10 wherein said trellis code is a four-dimensional trellis code.

14. The invention of claim 13 wherein said trellis code is an eight-state trellis code.

15. The invention of claim 13 wherein said television channel is an over-the-air channel and wherein M is selected from the group consisting of 4 and 6.

16. The invention of claim 10 wherein said trellis code is an eight-dimensional trellis code.

17. The invention of claim 16 wherein said television channel is an over-the-air channel and wherein M=4.

18. The invention of claim 16 wherein said trellis code is a 16-state trellis code.

19. A method of processing a television channel signal, said television channel signal having been generated by Reed-Solomon encoding a digital signal;

generating a sequence of N-dimensional symbols as a function of the Reed-Solomon-encoded signal using an N-dimensional trellis code, N>

1;

representing each of said symbols as a sequence of N one-dimensional signal points of a one-dimensional M-ary transmitter constellation;

generating a vestigial sideband modulation signal which represents the resulting sequence of signal point representations; and

applying said vestigial sideband modulation signal to a television channel to produce said television channel signal;

said method comprising the step of

receiving said television channel signal from said television channel, and

recovering said digital signal from said received television channel signal.

20. The invention of claim 19 wherein said recovering step comprises the steps of

demodulating said received television channel signal to generate a demodulated signal;

processing the demodulated signal to recover said sequence of N-dimensional symbols, and

processing the recovered sequence of N-dimensional symbols to recover said digital signal.

21. The invention of claim 20 wherein said step of processing the demodulated signal includes the step of Viterbi decoding said demodulated signal.

22. The invention of claim 20 wherein said step of processing the recovered sequence of N-dimensional symbols includes Reed-Solomon decoding.

23. The invention of claim 20 wherein said television channel is a cable channel and wherein M=16.

24. The invention of claim 20 wherein said trellis code is a four-dimensional trellis code.

25. The invention of claim 24 wherein said trellis code is an eight-state trellis code.

26. The invention of claim 24 wherein said television channel is an over-the-air channel and wherein M is selected from the group consisting of 4 and 6.

27. The invention of claim 20 wherein said trellis code is an eight-dimensional trellis code.

28. The invention of claim 27 wherein said television channel is an over-the-air channel and wherein M=4.

29. The invention of claim 27 wherein said trellis code is a 16-state trellis code.

30. A method for processing a television channel signal, said television channel signal having been generated by Reed-Solomon encoding a digital signal;

interleaving the Reed-Solomon-encoded signal;

generating a sequence of N-dimensional symbols in response to the Reed-Solomon-encoded signal using an N-dimensional trellis code, N>

1;

representing each of said symbols as a sequence of N one-dimensional signal points of a one-dimensional M-ary transmitter constellation;

generating a vestigial sideband modulation signal which represents the resulting sequence of signal point representations; and

applying said vestigial sideband modulation signal to a television channel to produce said television channel signal;

said method comprising the steps of

receiving said television channel signal from said television channel,

demodulating said television channel signal to generate a demodulated signal;

Viterbi decoding said demodulated signal to recover said sequence of N-dimensional symbols,

deinterleaving the recovered sequence of N-dimensional symbols, and

Reed-Solomon decoding the deinterleaved symbols to recover said digital signal.

31. Apparatus for processing a television channel signal, said television channel signal having been generated by Reed-Solomon encoding a digital signal;

generating a sequence of N-dimensional symbols as a function of the Reed-Solomon-encoded signal using an N-dimensional trellis code, N>

1;

representing each of said symbols as a sequence of N one-dimensional signal points of a one-dimensional M-ary transmitter constellation;

generating a vestigial sideband modulation signal which represents the resulting sequence of signal point representations; and

applying said vestigial sideband modulation signal to a television channel to produce said television channel signal;

said apparatus comprising

means for receiving said television channel signal from said television channel, and

means for recovering said digital signal from said received television channel signal.

32. The invention of claim 31 wherein said recovering means includes

means for demodulating said television channel signal to generate a demodulated signal;

means for processing the demodulated signal to recover said sequence of N-dimensional symbols, and

means for processing the recovered sequence of N-dimensional symbols to recover said digital signal.

33. The invention of claim 32 wherein said means for processing the demodulated signal includes means for Viterbi decoding said demodulated signal.

34. The invention of claim 33 wherein said means for processing the recovered sequence of N-dimensional symbols includes a Reed-Solomon decoder.

35. The invention of claim 32 wherein said television channel is a cable channel and wherein M=16.

36. The invention of claim 32 wherein said trellis code is a four-dimensional trellis code.

37. The invention of claim 36 wherein said trellis code is an eight-state trellis code.

38. The invention of claim 36 wherein said television channel is an over-the-air channel and wherein M is selected from the group consisting of 4 and 6.

39. The invention of claim 32 wherein said trellis code is an eight-dimensional trellis code.

40. The invention of claim 39 wherein said television channel is an over-the-air channel and wherein M=4.

41. The invention of claim 39 wherein said trellis code is a 16-state trellis code.

42. Apparatus for processing a television channel signal, said television channel signal having been generated by Reed-Solomon encoding a digital signal;

interleaving the Reed-Solomon-encoded signal;

generating a sequence of N-dimensional symbols in response to the Reed-Solomon-encoded signal using an N-dimensional trellis code, N>

1;

representing each of said symbols as a sequence of N one-dimensional signal points of a one-dimensional M-ary transmitter constellation;

generating a vestigial sideband modulation signal which represents the resulting sequence of signal point representations; and

applying said vestigial sideband modulation signal to a television channel to produce said television channel signal;

said apparatus comprising

means for receiving said television channel signal from said television channel,

means for demodulating said television channel signal to generate a demodulated signal;

means for Viterbi decoding said demodulated signal to recover said sequence of N-dimensional symbols,

means for deinterleaving the recovered sequence of N-dimensional symbols, and

means for Reed-Solomon decoding the deinterleaved symbols to recover said digital signal.