ON THE GIRTH OF TANNER (3,7) QUASI-CYCLIC LDPC CODES

Abstract. S. Kim et al. have been analyzed the girth of some algebraically structured quasi-cyclic (QC) low-density parity-check (LDPC) codes, i.e. Tanner (3; 5) of length 5p, where p is a prime of the form 15m + 1. In this paper, by extension this method to Tanner (3; 7) codes of length 7p, where p is a prime of the form 21m+ 1, the girth values of Tanner (3; 7) codes will be derived. As an advantage, the rate of Tanner (3; 7) codes is about 0:17 more than the rate of Tanner (3; 5) codes.