A new interconnection structure method for QC-LDPC codes

A new technique for constructing the Quasi Cyclic Low density Parity Check (QC-LDPC) codes based on splitting rows into sub rows method is proposed. The proposed QC-LDPC code, at BER of 10^-6 achieves 0.1dB coding gain over the PEG-LDPC codes. Moreover, in the high E_b / N₀ region, the proposed code with girths 16 and 20 respectively, achieve 0.056 dB and 0.27 dB at a BER of 10^-5 over the randomly constructed code. Simulation results portray that large girth QC-LDPC codes achieve a 0.1dB coding gain over randomly constructed codes and perform 1.3dB from the Shannon-limit at a BER of ^-6 with a code rate of 0.89 for block length of 1332.