光传输系统中LDPC码的新颖随机构造方法

A Novel Random Construction Method of the LDPC Code for Optical Transmission System

摘要:

分析光传输系统的传输特性与规则LDPC码的随机构造方法之后, 提出LDPC码的一种新颖随机构造方法。基于该构造方法构造了一种新颖的码率为93.7%、冗余度为6.69%的规则SCG-LDPC(3969,3720)码, 该规则LDPC码在将来的硬件实现中可相对地节省硬件存储空间和减少计算量。仿真分析表明: 该新颖的SCG-LDPC(3969,3720)码在BER为10-8时, 与同码率同冗余度的ITU-T G.975建议中RS(255,239)码和ITU-T G.975.1建议中LDPC(32640,30592)码相比, 其净编码增益(NCG)和距离Shannon限都分别改善了约1.92dB和0.97dB。因而该规则LDPC码的纠错性能更为优越, 更适用于光传输系统。

Abstract:

A novel random construction method of low density parity check(LDPC) codes is proposed by analyzing the transmission characteristics of optical transmission systems and the random construction methods of regular LDPC codes. Based on the novel random construction method, a novel regular Systematically Constructed Gallager(SCG)-LDPC(3969,3720) code with the code rate of 93.7% and the redundancy of 6.69% is constructed. The novel regular LDPC code has some advantages such as saving storage space and reducing computation complexity in the hardware realization. The simulation result shows that both the net coding gain(NCG) and the distance from the Shannon Limit of the novel SCG-LDPC(3969,3720) code, compared with those of the classic RS(255,239) code in ITU-T G.975 recommendation and the LDPC(32640,30592) code in ITU-T G.975.1 recommendation with the same code rate and the same redundancy, can separately be improved approximately by 1.92dB and 0.97dB at the bit error rate(BER) of 10-8.