Combinatorial Optimization for Improving QC LDPC codes performance

Irina Bocharova, Boris Kudryashov, Rolf Johannesson

Research output: Chapter in Book/Report/Conference proceedingPaper in conference proceedingpeer-review


Techniques for searching for good quasi-cyclic (QC) LDPC block codes of short and moderate lengths which are suitable for practical purposes are studied. To facilitate implementations only codes whose parity-check matrices having bidiagonal structure of their submatrices and consequently having low encoding complexity are considered. The problem of finding QC LDPC codes with the near-optimum frame or bit error rate performance is split into two independent steps: searching for the near-optimum column degree distribution of the parity-check matrix together with the best base matrix for this degree distribution and searching for the near-optimum labeling of the chosen base matrix. Sets of parameters and criteria for both steps are introduced and discussed. They allow further reduction of the search complexity without significant loss of the search optimality. New QC LDPC block codes of various code rates are obtained and their BER and FER performances are compared with those of the LDPC block codes as well as the turbo codes defined in the IEEE 802.16 WiMAX standard.
Original languageEnglish
Title of host publicationIEEE International Symposium on Information Theory (ISIT)
Number of pages5
Publication statusPublished - 2013
EventIEEE International Symposium on Information Theory, 2013 - Istanbul, Turkey
Duration: 2013 Jul 72013 Jul 12

Publication series

ISSN (Print)2157-8117
ISSN (Electronic)2157-8095


ConferenceIEEE International Symposium on Information Theory, 2013
Abbreviated titleISIT13

Subject classification (UKÄ)

  • Electrical Engineering, Electronic Engineering, Information Engineering


Dive into the research topics of 'Combinatorial Optimization for Improving QC LDPC codes performance'. Together they form a unique fingerprint.

Cite this