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Sequential decoding

About: Sequential decoding is a research topic. Over the lifetime, 8667 publications have been published within this topic receiving 204271 citations.


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Patent
30 Jul 1990
TL;DR: In this paper, a convolutional decoder which assigns bit metrics to at least one bit of a symbol in a multilevel system is proposed, which uses soft-decision Viterbi decoding with channel state information.
Abstract: A convolutional decoder which assigns bit metrics to at least one bit of a symbol in a multilevel system. This decoder uses soft-decision Viterbi decoding with channel state information of a convolutionally-encoded communication transmitted using multilevel modulation.

57 citations

Proceedings ArticleDOI
08 Dec 2008
TL;DR: For decoding low-density parity-check (LDPC) codes on discrete memoryless channels, a method to quantize messages and to find message-passing decoding functions for the variable and check nodes is developed and noise thresholds close to those of belief propagation are obtained.
Abstract: For decoding low-density parity-check (LDPC) codes on discrete memoryless channels, a method to quantize messages and to find message-passing decoding functions for the variable and check nodes is developed. These are used to obtain noise thresholds by density evolution. The message-passing decoding alphabet is restricted to be discrete with a fixed maximum alphabet size. Discrete quantization is required to obtain this fixed alphabet size; a greedy algorithm which uses the mutual information between the code bit and message is presented. It is argued that using this message-passing decoding framework is more efficient for approaching channel capacity than simply quantizing the belief-propagation algorithm. This method is evaluated using regular LDPC codes on the binary symmetric channel. Using a maximum alphabet size of 16 (4 bits), noise thresholds close to those of belief propagation are obtained.

57 citations

Proceedings ArticleDOI
17 Nov 2002
TL;DR: The numerical calculations show that with one properly chosen parameter for each of these two improved BP-based decoding algorithms, performances very close to that of the BP algorithm can be achieved.
Abstract: In this paper, we analyze the performance of two improved BP-based decoding algorithms for LDPC codes, namely the normalized BP-based and the offset BP-based algorithms, by means of density evolution. The numerical calculations show that with one properly chosen parameter for each of these two improved BP-based algorithms, performances very close to that of the BP algorithm can be achieved. Simulation results for LDPC codes with code length moderately long validate the proposed optimization. Finite quantization effects on the BP-based and the offset BP-based decoding algorithms are evaluated.

57 citations

Journal ArticleDOI
TL;DR: When phase fluctuations are severe and when occasional large phase fluctuations exist, MAP phase-symbol sequence decoding on circles is superior to Ungerboeck's technique, which in turn are superior to decision-directed techniques.
Abstract: The problem of simultaneously estimating phase and decoding data symbols from baseband data is posed. The phase sequence is assumed to be a random sequence on the circle, and the symbols are assumed to be equally likely symbols transmitted over a perfectly equalized channel. A dynamic programming algorithm (Viterbi algorithm) is derived for decoding a maximum {\em a posteriori} (MAP) phase-symbol sequence on a finite dimensional phase-symbol trellis. A new and interesting principle of Optimality for simultaneously estimating phase and decoding phase-amplitude coded symbols leads to an efficient two-step decoding procedure for decoding phase-symbol sequences. Simulation results for binary, 8 -ary phase shift keyed (PSK), and 16-quadrature amplitude shift keyed (QASK) symbol sets transmitted over random walk and sinusoidal jitter channels are presented and compared with results one may obtain with a decision-directed algorithm or with the binary Viterbi algorithm introduced by Ungerboeck. When phase fluctuations are severe and when occasional large phase fluctuations exist, MAP phase-symbol sequence decoding on circles is superior to Ungerboeck's technique, which in turn is superior to decision-directed techniques.

57 citations

Journal ArticleDOI
TL;DR: The genie-aided algorithm is used as a tool in estimating the asymptotic behavior of the M-algorithm and the results conform closely to experience with convolutional codes due to the similar distance structure of the codes.
Abstract: Comparisons are made of a genie-aided sequential algorithm due to D. Haccoun and M.J. Ferguson (1975), the Viterbi algorithm, the M-algorithm, and the Fano algorithm for rate-1/2 and rate-2/3 trellis modulation codes on rectangular signal sets. The effects of signal-to-noise ratio and decoding-delay constraints on the choice of decoding algorithms for framed data are examined by computer simulation. Additionally, the genie-aided algorithm is used as a tool in estimating the asymptotic behavior of the M-algorithm. In general, the results conform closely to experience with convolutional codes due to the similar distance structure of the codes. The Fano algorithm produces good error performance with a low average number of computations when long decoding delay is permissible. The M-algorithm provides a savings in computation compared to the Viterbi algorithm if a small decoding delay is required. >

57 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202351
2022112
202124
202026
201922
201832