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Good trellises for IC implementation of viterbi decoders for linear block codesThis paper investigates trellis structures of linear block codes for the IC (integrated circuit) implementation of Viterbi decoders capable of achieving high decoding speed while satisfying a constraint on the structural complexity of the trellis in terms of the maximum number of states at any particular depth. Only uniform sectionalizations of the code trellis diagram are considered. An upper bound on the number of parallel and structurally identical (or isomorphic) subtrellises in a proper trellis for a code without exceeding the maximum state complexity of the minimal trellis of the code is first derived. Parallel structures of trellises with various section lengths for binary BCH and Reed-Muller (RM) codes of lengths 32 and 64 are analyzed. Next, the complexity of IC implementation of a Viterbi decoder based on an L-section trellis diagram for a code is investigated. A structural property of a Viterbi decoder called ACS-connectivity which is related to state connectivity is introduced. This parameter affects the complexity of wire-routing (interconnections within the IC). The effect of five parameters namely: (1) effective computational complexity; (2) complexity of the ACS-circuit; (3) traceback complexity; (4) ACS-connectivity; and (5) branch complexity of a trellis diagram on the VLSI complexity of a Viterbi decoder is investigated. It is shown that an IC implementation of a Viterbi decoder based on a non-minimal trellis requires less area and is capable of operation at higher speed than one based on the minimal trellis when the commonly used ACS-array architecture is considered.
Document ID
19960026759
Acquisition Source
Goddard Space Flight Center
Document Type
Contractor Report (CR)
Authors
Lin, Shu (Hawaii Univ. Manoa, HI United States)
Moorthy, Hari T. (Hawaii Univ. Manoa, HI United States)
Uehara, Gregory T. (Hawaii Univ. Manoa, HI United States)
Date Acquired
September 6, 2013
Publication Date
May 24, 1996
Subject Category
Computer Programming And Software
Report/Patent Number
NAS 1.26:201120
TR-96-002
NASA-CR-201120
Accession Number
96N28319
Funding Number(s)
CONTRACT_GRANT: NAG5-2938
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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