Girth analysis of Tanner's (3, 5) QC LDPC codes
Sunghwan Kim, Jong‐Seon No, Habong Chung, Dong‐Joon Shin · 2005
In this paper, the cycles of Tanner's (3,5) quasicyclic (QC) low-density parity-check (LDPC) codes are analyzed and their girth values are derived. The conditions for the existence of cycles of lengths 4, 6, 8, and 10 in Tanner's (3,5) QC LDPC codes of length 5p are expressed in terms of polynomial equations in a 15-th root of unity of the prime field Fp. By checking the existence of solutions for these equations over Fp, the girths of Tanner's (3,5) QC LDPC codes are derived