(7,K) GIRTH-8 QC-LDPC CODES WITH AN EXPLICIT CONSTRUCTION

Recently, for each row weight K and column-weight J, 3≤J K, several classes of (J,K) quasi-cyclic (QC) low-density parity-check (LDPC) codes with girth 8 have been constructed explicitly such that their corresponding lower-bounds on the size of circulant permutation matrices (CPMs) have been considered small as possible. In this paper, for J=7, a class of (7,K) QC-LDPC codes with girth 8 is generated by an explicit method such that the lower-bounds of the constructed codes remarkably are better than the state-of-the-art bound (K−1)(K²+K)+1.