Trellis coded modulation employing lower dimensionality convolutional encoder
First Claim
1. A method of N-dimensional trellis coded modulation for encoding a digital signal, the method comprising the step of:
- generating a sequence of N-dimensional symbols as a function of the digital signal using an N'"'"'-dimensional convolutional encoder, where N>
N'"'"'≧
1, said encoder being used to generate for each of a plurality of N-dimensional signal intervals, a plurality of groups of outputs, each said group of outputs being a function of a respective different group of inputs, the N-dimensional symbols comprising J P-dimensional signal points and the digital signal having an integer number of bits per each P-dimensional signal point.
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Abstract
Coding gain is improved by employing an N-dimensional trellis encoder incorporating an N'"'"'-dimensional convolutional encoder where N'"'"' is less than N. The additional coding gain is realized as a shaping gain. This unique modulator encodes a digital signal by generating a sequence of N-dimensional symbols as a function of the digital signal using an N'"'"'-dimensional convolutional encoder within the trellis encoder more than once (integer N/N'"'"' times) during each N-dimensional symbol interval. This allows the trellis encoder to produce an output of higher dimensionality than would normally be expected from the lower dimensionality convolutional encoder. The trellis encoder is applicable to television transmission.
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Citations
47 Claims
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1. A method of N-dimensional trellis coded modulation for encoding a digital signal, the method comprising the step of:
generating a sequence of N-dimensional symbols as a function of the digital signal using an N'"'"'-dimensional convolutional encoder, where N>
N'"'"'≧
1, said encoder being used to generate for each of a plurality of N-dimensional signal intervals, a plurality of groups of outputs, each said group of outputs being a function of a respective different group of inputs, the N-dimensional symbols comprising J P-dimensional signal points and the digital signal having an integer number of bits per each P-dimensional signal point.- View Dependent Claims (2, 3, 47)
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4. A method of concatenated encoding a digital signal, the method comprising the steps of:
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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 convolutional encoder, said encoder including a finite state machine which advances multiple states for each of a plurality of hi-dimensional signaling intervals, where N>
N'"'"'≧
1, the N-dimensional symbols comprising J P-dimensional signal points and the Reed-Solomon encoded signal having an integer number of bits per each P-dimensional signal point. - View Dependent Claims (5)
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6. A method of transmitting a digital signal over a television channel, the method comprising the steps of:
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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 convolutional code within an N-dimensional trellis code, where N>
N'"'"'≧
1, said convolutional code being used to generate for each of a plurality of N-dimensional signaling intervals a plurality of groups of outputs each said group of outputs being a function of a respective different group of inputs;representing each of said symbols as a sequence of J P-dimensional signal points of a P-dimensional M-ary transmitter constellation, where J×
P=N and the number of bits in the Reed-Solomon encoded digital signal per each P-dimensional signal point is integral;generating a modulated signal which represents the resulting sequence of signal point representations; and applying said modulated signal to said television channel. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. An N-dimensional trellis coded modulator comprising
means for receiving a digital signal, and an N'"'"'-dimensional convolutional encoder for generating a sequence of N-dimensional symbols as a function of the digital signal, where N> - N'"'"'≧
1, said encoder including a finite state machine which advances multiple states for each of a plurality of N-dimensional signaling intervals, the N-dimensional symbols comprising J P-dimensional signal points and the digital signal having an integer number of bits per each P-dimensional signal point. - View Dependent Claims (17, 18, 46)
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19. Apparatus for concatenated encoding a digital signal, the apparatus comprising:
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means for Reed-Solomon encoding the digital signal, and means for generating a sequence of N-dimensional symbols as a function of the Reed-Solomon encoded signal using an N'"'"'-dimensional convolutional encoder, said encoder being used to generate for each N-dimensional signaling interval a plurality of groups of outputs, each said group of outputs being a function of a respective different group of inputs, where N>
N'"'"'≧
1, the N-dimensional symbols comprising J P-dimensional signal points and the Reed-Solomon encoded signal having an integer number of bits per each P-dimensional signal point. - View Dependent Claims (20)
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21. Apparatus for transmitting a digital signal over a television channel, the apparatus comprising:
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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 convolutional encoder within an N-dimensional trellis encoder, said convolutional coder including a finite state machine which advances multiple states for each of a plurality of N-dimensional signaling intervals, where N>
N'"'"'≧
1;means for representing each of said symbols as a sequence of J P-dimensional signal points of a P-dimensional M-ary transmitter constellation, where J×
P=N and the number of bits in the Reed-Solomon encoded digital signal per each P-dimensional signal point is integral;means for generating a modulated signal which represents the resulting sequence of signal point representations; and means for applying said modulated signal to said television channel. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30)
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31. A method of processing a signal from a communication channel, said signal having been generated by encoding a digital signal using N-dimensional trellis coded modulation, wherein the encoding comprised the step of generating a sequence of N-dimensional symbols as a function of the digital signal using an N'"'"'-dimensional convolutional encoder, said encoder including a finite state machine which advances multiple states for each of a plurality of N-dimensional signaling intervals, where N>
- N'"'"'≧
1, the N-dimensional symbols comprising J P-dimensional signal points and the digital signal having an integer number of bits per each P-dimensional signal point, the method including the steps of;receiving said signal from said communication channel, and recovering said digital signal from said received communication channel signal. - View Dependent Claims (32, 33, 34, 45)
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35. A method of processing a signal from a television channel, said 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 convolutional encoder within an N-dimensional trellis encoder, said convolutional coder including a finite state machine which advances multiple states for each N-dimensional symbol interval, where N>
- N'"'"'≧
1, representing each of said symbols as a sequence of J P-dimensional signal points of a P-dimensional M-ary transmitter constellation, where J×
P=N and the number of bits in the Reed-Solomon encoded digital signal per each P-dimensional signal point is integral, generating a modulated signal which represents the resulting sequence of signal point representations, and applying said modulated signal to said television channel, the method including the steps of;receiving said signal from said television channel, and recovering said digital signal from said received television channel signal. - View Dependent Claims (36, 37, 38, 39, 40, 41, 42, 43)
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44. A method of processing a signal from a communication channel, said signal having been generated by concatenated encoding a digital signal using N-dimensional trellis coded modulation, wherein the encoding comprised the steps of Reed-Solomon encoding the digital signal and generating a sequence of N-dimensional symbols as a function of the Reed-Solomon encoded signal using an N'"'"'-dimensional convolutional encoder, where N>
- N'"'"'≧
1, said encoder being used to generate for each N-dimensional symbol interval a plurality of groups of outputs, each said group of outputs being a function of a respective different group of inputs, the N-dimensional symbols comprising J P-dimensional signal points and the Reed-Solomon encoded signal having an integer number of bits per each P-dimensional signal point, the method including the steps of;receiving said signal from said communication channel, and recovering said digital signal from said received communication channel signal.
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Specification