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Improving the Thresholds of Generalized LDPC Codes With Convolutional Code Constraints

Farooq, Muhammad Umar LU ; Amat, Alexandre Graell I. and Lentmaier, Michael LU (2023) In IEEE Communications Letters 27(7). p.1679-1683
Abstract

CC-GLPDC codes are a class of generalized low-density parity-check (GLDPC) codes where the constraint nodes (CNs) represent convolutional codes. This allows for efficient decoding in the trellis with the forward-backward algorithm, and the strength of the component codes easily can be controlled by the encoder memory without changing the graph structure. In this letter, we extend the class of CC-GLDPC codes by introducing different types of irregularity at the CNs and investigating their effect on the BP and MAP decoding thresholds for the binary erasure channel (BEC). For the considered class of codes, an exhaustive grid search is performed to find the BP-optimized and MAP-optimized ensembles and compare their thresholds with the... (More)

CC-GLPDC codes are a class of generalized low-density parity-check (GLDPC) codes where the constraint nodes (CNs) represent convolutional codes. This allows for efficient decoding in the trellis with the forward-backward algorithm, and the strength of the component codes easily can be controlled by the encoder memory without changing the graph structure. In this letter, we extend the class of CC-GLDPC codes by introducing different types of irregularity at the CNs and investigating their effect on the BP and MAP decoding thresholds for the binary erasure channel (BEC). For the considered class of codes, an exhaustive grid search is performed to find the BP-optimized and MAP-optimized ensembles and compare their thresholds with the regular ensemble of the same design rate. The results show that irregularity can significantly improve the BP thresholds, whereas the thresholds of the MAP-optimized ensembles are only slightly different from the regular ensembles. Simulation results for the AWGN channel are presented as well and compared to the corresponding thresholds.

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author
; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
codes on graphs, convolutional codes, GLDPC codes, iterative decoding thresholds, LDPC codes
in
IEEE Communications Letters
volume
27
issue
7
pages
5 pages
publisher
IEEE - Institute of Electrical and Electronics Engineers Inc.
external identifiers
  • scopus:85159840715
ISSN
1089-7798
DOI
10.1109/LCOMM.2023.3274088
language
English
LU publication?
yes
id
55d639ef-ac00-4ea0-9cba-2a940c376f0d
date added to LUP
2023-09-25 09:21:55
date last changed
2023-11-21 23:04:17
@article{55d639ef-ac00-4ea0-9cba-2a940c376f0d,
  abstract     = {{<p>CC-GLPDC codes are a class of generalized low-density parity-check (GLDPC) codes where the constraint nodes (CNs) represent convolutional codes. This allows for efficient decoding in the trellis with the forward-backward algorithm, and the strength of the component codes easily can be controlled by the encoder memory without changing the graph structure. In this letter, we extend the class of CC-GLDPC codes by introducing different types of irregularity at the CNs and investigating their effect on the BP and MAP decoding thresholds for the binary erasure channel (BEC). For the considered class of codes, an exhaustive grid search is performed to find the BP-optimized and MAP-optimized ensembles and compare their thresholds with the regular ensemble of the same design rate. The results show that irregularity can significantly improve the BP thresholds, whereas the thresholds of the MAP-optimized ensembles are only slightly different from the regular ensembles. Simulation results for the AWGN channel are presented as well and compared to the corresponding thresholds.</p>}},
  author       = {{Farooq, Muhammad Umar and Amat, Alexandre Graell I. and Lentmaier, Michael}},
  issn         = {{1089-7798}},
  keywords     = {{codes on graphs; convolutional codes; GLDPC codes; iterative decoding thresholds; LDPC codes}},
  language     = {{eng}},
  month        = {{07}},
  number       = {{7}},
  pages        = {{1679--1683}},
  publisher    = {{IEEE - Institute of Electrical and Electronics Engineers Inc.}},
  series       = {{IEEE Communications Letters}},
  title        = {{Improving the Thresholds of Generalized LDPC Codes With Convolutional Code Constraints}},
  url          = {{http://dx.doi.org/10.1109/LCOMM.2023.3274088}},
  doi          = {{10.1109/LCOMM.2023.3274088}},
  volume       = {{27}},
  year         = {{2023}},
}