Abstract:The key to improving the performance of QC LDPC codes is how to construct a parity-check matrix H with a girth distribution as good as possible. In this paper, a novel algorithm for constructing QC LDPC codes, GirthOpt-DE algorithm, is proposed, which achieves a good girth distribution based on the differential evolution. Simulation results show that the performance of the QC LDPC codes constructed with the proposed algorithm is superior to Array codes and Tanner codes in both BER and the minimum distance. Besides, the proposed algorithm is more flexible for designing the QC LDPC codes with desired block length and rate as well as good girth.