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Convolutional encoding of self-dual codesThere exist almost complete convolutional encodings of self-dual codes, i.e., block codes of rate 1/2 with weights w, w = 0 mod 4. The codes are of length 8m with the convolutional portion of length 8m-2 and the nonsystematic information of length 4m-1. The last two bits are parity checks on the two (4m-1) length parity sequences. The final information bit complements one of the extended parity sequences of length 4m. Solomon and van Tilborg have developed algorithms to generate these for the Quadratic Residue (QR) Codes of lengths 48 and beyond. For these codes and reasonable constraint lengths, there are sequential decodings for both hard and soft decisions. There are also possible Viterbi-type decodings that may be simple, as in a convolutional encoding/decoding of the extended Golay Code. In addition, the previously found constraint length K = 9 for the QR (48, 24;12) Code is lowered here to K = 8.
Document ID
19940025159
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Solomon, G. (Solomon (G.) Pasadena, CA, United States)
Date Acquired
September 6, 2013
Publication Date
February 15, 1994
Publication Information
Publication: JPL, The Telecommunications and Data Acquisition Report
Subject Category
Computer Programming And Software
Accession Number
94N29662
Funding Number(s)
PROJECT: RTOP 310-30-71-83-02
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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