《Construction of protograph LDPC codes with circular generator matrices》.pdf

Construction of protograph LDPC codes with circular generator matricesKaiyao Wang1 Yang Xiao1, Kiseon Kim2 1. Institute of Information Science, Beijing Jiaotong University, Beijing 100044, P. R. China;2. Department of Information munications, Gwangju Institute of Science and Technology, Gwangju 500-712, KoreaAbstract: The application of protograph low density parity check (LDPC) codes involves the plexity problem. Since the generator matrices are dense, and if the positions of "1" s are irregularity, the encoder needs to store every "1" of the generator matrices by using huge chip area. In order to solve this problem, we need to design the protograph LDPC codes with circular generator matrices. A theorem concerning the circulating property of generator matrices of nonsingular protograph LDPC codes is proposed. The circulating property of generator matrix of nonsingular protograph LDPC codes can be obtained from the corresponding quasi-cyclic parity check matrix. This paper gives a scheme of constructing protograph LDPC codes with circulating generator matrices, and it reveals that the fast encoding algorithm of protograph LDPC codes has lower plexity under the condition of the proposed theorem. Simulation results in additive white Gaussian noise (AWGN) channels show that the bit error rate (BER) performance of the designed codes based on the