Method and apparatus for encoding and decoding digital signals

Details Method and apparatus for encoding and decoding digital signals Method and apparatus for encoding and decoding digital signals

1996-09-19

1999-02-09

Baker, Stephen M.

Excavating

371 374, H03M 1300, H03M 1312

Patent

active

058704140

ABSTRACT:
A method of encoding a digital signal comprising a sequence of digital words, each comprising a first portion and a second portion, comprises the steps of successively encoding respective first portions using a trellis code to produce a corresponding sequence of trellis-encoded words, using each of the trellis-coded words to select one of a plurality of subcodes of a block code, and using the selected subcode to encode the corresponding second portion of the digital word corresponding sequentially to the trellis-coded word used to select the subcode, thereby providing a sequence of codewords corresponding to the sequence of digital words. After transmission and/or storage, a sequence of codeword vectors comprising the codewords and noise may be decoded by operating upon each of the sequence of codeword vectors using a decoder for each of the subcodes to produce, for each subcode, an estimated decoded second portion and a metric representing the likelihood that the estimated decoded second portion is correct, given that the assumed subcode is correct; using a trellis decoder, operating upon the sequence of likelihood metrics and the associated estimated second portions to provide a sequence of estimated first portions; and associating with each of the estimated first portions the corresponding estimated second portion, thereby providing a sequence of output digital words corresponding to the sequence of digital words originally encoded. The block code may comprise a Kerdock code, the subcodes being cosets of the Reed-Muller code. The decoder may then comprise a Fast Hadamard Transform unit and a Viterbi algorithm decoder.

REFERENCES:
patent: 4295218 (1981-10-01), Tanner
patent: 4761778 (1988-08-01), Hui
patent: 4939555 (1990-07-01), Calderbank et al.
patent: 5142539 (1992-08-01), Dahlin et al.
patent: 5151919 (1992-09-01), Dent
patent: 5218619 (1993-06-01), Dent
patent: 5230003 (1993-07-01), Dent et al.
patent: 5321725 (1994-06-01), Paik et al.
patent: 5353352 (1994-10-01), Dent et al.
patent: 5651032 (1997-07-01), Okita
patent: 5742678 (1998-04-01), Dent et al.
Channel Coding with Multilevel/Phase Signals, Gottfried Ungerboeck, IEEE Transactions on Information Theory, vol. It-28, No. 1, Jan. 1982.
Comparison of Very Low Rate Coding Methods for CDMA Radio Communications System, Kari Rikkinen, third International Symposium on Spread-Spectrum Techniques and Applications, University of Oulu, Oulu, Finland Jul. 1994.
Very Low Rate Convolutional Codes for Maximum Theoretical Performance of Spread-Spectrum Multiple-Access Channels, Andrew J. Viterbi, IEEE Journal on Selected Areas in Communications, vol. 8, No. 4, pp. 641-649 May 1990.
A Class of Low-Rate Nonlinear Binary Codes, A.M Kerdock, Low-Rate Nonlinear Binary Codes, Information and Control 20, 182-187 (1972), Academic Press, Inc.
Throughput Analysis for Code Division Multiple Accessing of the Spread Spectrum Channel, Joseph Y.N. Hui, IEEE Journal on Selected Areas in Communications, vol. SAC-2, No. 4, Jul. 1984 pp. 482-486.
Spread Spectrum Communications--Myths and Realities, Andrew J. Viterbi IEEE Communications Magazine, May 17, 1979 pp. 11-18.
On New Classes of Orthogonal Convolutional Codes; Communications, Control and Signal Processing, E. Zehavi and A.J. Viterbi, Elsevier Science Publishers,1990, pp. 257-263.
A Comparison of Trellis-Coded Versus Convolutionally-Coded Spread Spectrum Multiple-Access Systems, G.D. Boudreau et al, IEEE Journal on Selected Areas in Communications vol. 8, No. 4, 1990.
Qualcomm's Interim Standard (IS 95) (Proposed EIA/TIA Wideband Spread Spectrum) pp. 6-8 to 6-20.
Combined Trellis/Reed-Muller Coding for CDMA. J.P. Chaib and H Leib, Sixth IEEE Symposium on Personal Indoor and Mobile Radio Communications (PIMRC 95) Toronto, Canada Sep. 1995, pp. 243-247.

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