iterative construction of regular ldpc codes from independent.pdf

MUNICATIONS LETTERS, VOL. 15, NO. 3, MARCH 2011Iterative Construction of Regular LDPC Codes fromIndependent Tree-Based Minimum Distance BoundsEric Psota and Lance C. P′erezAbstract—An independent tree-based method for lower bound-ing the minimum distance of low-density parity-check (LDPC)codes is presented. This lower-bound is then used as the decisioncriterion during the iterative construction of regular new construction algorithm results in LDPC codes withgreater girth and improved minimum-distance bounds pared to regular LDPC codes constructed using the progres-sive edge-growth (PEG) construction and the approximate cycleextrinsic message degree (ACE)-constrained PEG results of codes constructed with the new methodshow improved performance on the additive white Gaussian noisechannel at moderate signal-to-noise Terms—LDPC codes, progressive edge-growth (PEG),girth, computation tree, minimum distance, iterative . INTRODUCTIONSINCE the rediscovery of low-density parity-check (LDPC)codes [1], several methods have been devised for con-structing codes that perform well with iterative decoders [2][3] [4] [5]. One such construction, known as progressive edge-growth (PEG), takes a set of variable node and check nodedegrees and attempts to maximize the girth of the resultantTanner graph [2]. Thegirthis the length of the shortest