Construction of Quasi-Cyclic LDPC Codes and the Performance on the PR4-Equalized MRC Channel

In this paper, we constructed a type of parity-check matrices of QC-LDPC codes based on the progressive edge-growth (PEG) algorithm with suggested unreliable factors incorporated. The proposed algorithm can eliminate short cycles efficiently and gain low error-floors. With this method, we can avoid the unreliable information transferred in decoding as far as possible. The proposed QC-LDPC codes are hardware-friendly due to the benefit from the quasi-cyclic structure of such codes. Simulation results demonstrate that the codes constructed with the proposed algorithm have better performance than those constructed with the PEG algorithm over the additive white Gaussian noise (AWGN) channel and the PR4-equalized magnetic recording channel (MRC).