A novel decoding algorithm based on the hierarchical reliable strategy for SCG-LDPC codes in optical communications  

作　　者：袁建国 仝青振 黄胜 王永 

机构地区：[1]Key Lab. of Optical Fiber Communication Technology,Chongqing University of Posts and Telecommunications

出　　处：《Optoelectronics Letters》2013年第6期469-472,共4页光电子快报（英文版）

基　　金：supported by the National Natural Science Foundation of China(Nos.61071117,61275077 and 61003256);the Natural Science Foundation of Chongqing CSTC(No.2010BB2409)

摘　　要：An effective hierarchical reliable belief propagation(HRBP)decoding algorithm is proposed according to the structural characteristics of systematically constructed Gallager low-density parity-check(SCG-LDPC)codes.The novel decoding algorithm combines the layered iteration with the reliability judgment,and can greatly reduce the number of the variable nodes involved in the subsequent iteration process and accelerate the convergence rate.The result of simulation for SCG-LDPC(3969,3720)code shows that the novel HRBP decoding algorithm can greatly reduce the computing amount at the condition of ensuring the performance compared with the traditional belief propagation(BP)algorithm.The bit error rate(BER)of the HRBP algorithm is considerable at the threshold value of 15,but in the subsequent iteration process,the number of the variable nodes for the HRBP algorithm can be reduced by about 70%at the high signal-to-noise ratio(SNR)compared with the BP algorithm.When the threshold value is further increased,the HRBP algorithm will gradually degenerate into the layered-BP algorithm,but at the BER of 10-7and the maximal iteration number of 30,the net coding gain(NCG)of the HRBP algorithm is 0.2 dB more than that of the BP algorithm,and the average iteration times can be reduced by about 40%at the high SNR.Therefore,the novel HRBP decoding algorithm is more suitable for optical communication systems.An effective hierarchical reliable belief propagation （HRBP） decoding algorithm is proposed according to the struc- tural characteristics of systematically constructed Gallager low-density parity-check （SCG-LDPC） codes. The novel decoding algorithm combines the layered iteration with the reliability judgment, and can greatly reduce the number of the variable nodes involved in the subsequent iteration process and accelerate the convergence rate. The result of simulation for SCG-LDPC（3969,3720） code shows that the novel HRBP decoding algorithm can greatly reduce the computing amount at the condition of ensuring the performance compared with the traditional belief propagation （BP） algorithm. The bit error rate （BER） of the HRBP algorithm is considerable at the threshold value of 15, but in the sub- sequent iteration process, the number of the variable nodes for the HRBP algorithm can be reduced by about 70% at the high signal-to-noise ratio （SNR） compared with the BP algorithm. When the threshold value is further increased, the HRBP algorithm will gradually degenerate into the layered-BP algorithm, but at the BER of 10-7 and the maximal iteration number of 30, the net coding gain （NCG） of the HRBP algorithm is 0.2 dB more than that of the BP algo- rithm, and the average iteration times can be reduced by about 40% at the high SNR. Therefore, the novel HRBP de- coding algorithm is more suitable for optical communication systems.

关 键 词：LDPC码 译码算法 光通信 阳离子 光学通信系统 BP算法 低密度奇偶校验 解码算法 

分 类 号：TN911.22[电子电信—通信与信息系统] TN929.1[电子电信—信息与通信工程]