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The max-log list algorithm (MLLA) - A list-sequence decoding algorithm that provides soft-symbol output

Leanderson, Carl Fredrik LU and Sundberg, CEW (2005) In IEEE Transactions on Communications 53(3). p.433-444
Abstract
We present a soft decoding algorithm for convolutional codes that simultaneously yields soft-sequence output, i.e., list sequence (LS) decoding, and soft-symbol output. The max-log list algorithm (MLLA) introduced in this paper provides near- optimum soft-symbol output equal to that of the max-log maximum a posteriori (MAP) probability algorithm. Simultaneously, the algorithm produces an ordered list containing LS-MAP estimates. The MLLA exists in an optimum and a suboptimum version that are different in that the optimum version produces optimum LS-MAP decoding for arbitrary list lengths, while the suboptimum low-complexity version only provides the MAP, the second-order MAP, and the third-order MAP sequence estimates. For lists with more... (More)
We present a soft decoding algorithm for convolutional codes that simultaneously yields soft-sequence output, i.e., list sequence (LS) decoding, and soft-symbol output. The max-log list algorithm (MLLA) introduced in this paper provides near- optimum soft-symbol output equal to that of the max-log maximum a posteriori (MAP) probability algorithm. Simultaneously, the algorithm produces an ordered list containing LS-MAP estimates. The MLLA exists in an optimum and a suboptimum version that are different in that the optimum version produces optimum LS-MAP decoding for arbitrary list lengths, while the suboptimum low-complexity version only provides the MAP, the second-order MAP, and the third-order MAP sequence estimates. For lists with more than three elements, MAP decoding is not guaranteed, but the LS decoding is close to the optimal. It is demonstrated that the suboptimum/optimum MLLA can be used to obtain the combination of soft-symbol and soft-sequence outputs at lower complexity than a previously published algorithm. Furthermore, the suboptimum MLLA is well suited for operation in an iterative list (turbo) decoder, since it is obtained by only minor modifications of the well-known Max-Log-MAP algorithm frequently used for decoding of the component codes of turbo codes. Another potential area of application for the suboptimum/optimum MLLA is joint source-channel LS decoding. Estimates of complexity and memory use, as well as performance evaluations of the suboptimum/optimum MLLA, are provided in this paper. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
list decoding, combined source-channel decoding, convolutional codes, soft symbol, turbo decoding
in
IEEE Transactions on Communications
volume
53
issue
3
pages
433 - 444
publisher
IEEE--Institute of Electrical and Electronics Engineers Inc.
external identifiers
  • wos:000228095000011
  • scopus:17644366134
ISSN
0090-6778
DOI
10.1109/TCOMM.2005.843427
language
English
LU publication?
yes
id
f8308f92-3f2c-46d9-81e5-048965bd686a (old id 246708)
date added to LUP
2007-09-28 12:43:12
date last changed
2017-01-01 06:37:38
@article{f8308f92-3f2c-46d9-81e5-048965bd686a,
  abstract     = {We present a soft decoding algorithm for convolutional codes that simultaneously yields soft-sequence output, i.e., list sequence (LS) decoding, and soft-symbol output. The max-log list algorithm (MLLA) introduced in this paper provides near- optimum soft-symbol output equal to that of the max-log maximum a posteriori (MAP) probability algorithm. Simultaneously, the algorithm produces an ordered list containing LS-MAP estimates. The MLLA exists in an optimum and a suboptimum version that are different in that the optimum version produces optimum LS-MAP decoding for arbitrary list lengths, while the suboptimum low-complexity version only provides the MAP, the second-order MAP, and the third-order MAP sequence estimates. For lists with more than three elements, MAP decoding is not guaranteed, but the LS decoding is close to the optimal. It is demonstrated that the suboptimum/optimum MLLA can be used to obtain the combination of soft-symbol and soft-sequence outputs at lower complexity than a previously published algorithm. Furthermore, the suboptimum MLLA is well suited for operation in an iterative list (turbo) decoder, since it is obtained by only minor modifications of the well-known Max-Log-MAP algorithm frequently used for decoding of the component codes of turbo codes. Another potential area of application for the suboptimum/optimum MLLA is joint source-channel LS decoding. Estimates of complexity and memory use, as well as performance evaluations of the suboptimum/optimum MLLA, are provided in this paper.},
  author       = {Leanderson, Carl Fredrik and Sundberg, CEW},
  issn         = {0090-6778},
  keyword      = {list decoding,combined source-channel decoding,convolutional codes,soft symbol,turbo decoding},
  language     = {eng},
  number       = {3},
  pages        = {433--444},
  publisher    = {IEEE--Institute of Electrical and Electronics Engineers Inc.},
  series       = {IEEE Transactions on Communications},
  title        = {The max-log list algorithm (MLLA) - A list-sequence decoding algorithm that provides soft-symbol output},
  url          = {http://dx.doi.org/10.1109/TCOMM.2005.843427},
  volume       = {53},
  year         = {2005},
}