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Sparse Construction of Joint Viterbi Detector Decoder (JVDD) Codes

Authors:
Ashish James
Kheong Sann Chan
Sari Shafidah Binte Shafee

Keywords: JVDD; Iterative detector; ISI Channel; Sparse construction of JVDD Codes.

Abstract:
The Joint Viterbi detector decoder (JVDD) has been proposed as an alternative to the iterative detector, performing both detection and decoding in two stages on a trellis. The first stage estimates and retains a set of survivors, while the second stage performs a parity check on these to compute the minimum metric legal codeword (MMLC). With this structure, near optimal maximum-likelihood decoding (MLD) performance can be achieved but at the cost of complexity especially at long codeword lengths (CWL). JVDD codes have been introduced with the explicit target of reducing this complexity. Further, lower rate codes with more parity checks leads to reduced number of survivors in the JVDD trellis resulting in lower complexity. However, it has been observed that JVDD code performance degrades at low-rates while operating in the low SNR region through an error-floor. This aspect is analyzed in this paper and this performance can be attributed to the JVDD code structure where a constant number of ones are placed to the left of the main diagonal. This results in a dense region of ones at the top left corner where the entire rows are filled with ones. In this paper, a modification to the JVDD code construction is proposed by adjusting the number of ones placed in those rows where the row weight of JVDD codes is less than the available row width. It has been found that such sparse construction results in reducing JVDD complexity, as well as eliminates the error-floor problem. This has been verified through extensive simulation studies.

Pages: 29 to 33

Copyright: Copyright (c) IARIA, 2015

Publication date: June 21, 2015

Published in: conference

ISSN: 2308-4030

ISBN: 978-1-61208-411-4

Location: Brussels, Belgium

Dates: from June 21, 2015 to June 26, 2015