United States Patent  [ii] Patent Number: 5,159,608
Falconer et al.  Date of Patent: Oct. 27, 1992
"The Weight Spectra of Some Short Low-Rate Convolutional Codes", Jean Conan, IEEE Transactions on Communications, vol. COM-32, No. 9 (Sep. 1984), pp. 1050-1053.
Dixon, Robert C, Spread Spectrum Systems 2nd Ed., John Wiley & Sons, New York, NY, 1984 Chapters 1 & 2, pp. 1-55.
Sklar, Bernard, Digital Communications: Fundamentals
and Applications, Prentice Hall, Englewood Cliffs,
N.J., 1988, Chapters 5 & 6 p.m. 245-380.
"Two Classes of Convolutional Codes Over GF(q) for
Q-ary Orthogonal Signaling", William E. Ryan &
Stephen G. Wilson, IEE Transactions on Communica-
tions, vol. 39, No. 1 (Jan. 1988), pp. 30-40.
"Performance of Convolutional Codes with Interleav-
A method and apparatus is provided for encoding and decoding. In encoding, bits (202) are encoded (204) into symbols (206) such that maximum likelihood decoding is facilitated. Groups of symbols (206) are translated by either interleaving by group each group within a block (208) and subsequently deriving an orthogonal code from each group (212) or deriving an orthogonal code from each group and subsequently interleaving by code each code within a block.
In decoding, groups of samples (228, 229) are transformed by either generating metrics and index symbols (242) for each group of samples (232,234,236,238,240) are subsequently deinterleaving by group each group of metrics within a block (244) or deinterleaving by group each group of samples within a block and subsequently generating metrics and index symbols for each deinterleaved group of samples. Each metric represents the confidence that a group of samples is a particular orthogonal code. Subsequently, maximum likelihood decoding (266) generates an estimated bit (268) from the index symbols and metrics (260).
41 Claims, 3 Drawing Sheets