光传输系统中基于Bose第一类方法对QC-LDPC码的一种新颖构造方法

基于平衡不完全区组设计(BIBD)、循环矩阵分解和循环置换矩阵,提出了一种适用于光传输系统的新颖准循环低密度奇偶校验码(QC-LDPC)构造方法。利用Bose的第一类方法构造的低密度校验矩阵对其进行循环列分解得到相应的模板矩阵,再利用合适的循环置换矩阵对其进行扩展。采用该方法构造的QC-LDPC码具有良好的结构,且可根据实际需要来灵活地选择码长和码率。仿真结果表明:在误码率为10-6时其码率均为93.7%的情况下,该方法构造的novel-QC-LDPC(10992,10305)码比ITU-T G.975中RS(255,239)码的净编码增益(NCG)改善了约1.8d B。因此该构造方法所构造的QC-LDPC码具有更好的纠错性能,更适合高速长距离的光传输系统。

A Novel Construction Method of QC-LDPC Codes Based on the First Method of Bose for Optical Transmission Systems

Based on the balanced incomplete block design （ BIBD ） , the circulant decomposition and the cycle permutation matrix, a novel construction method of quasi-cyclic low density parity check （ QC-LDPC ） codes for optical transmission systems is proposed. The template matrix is formed by the first method of Bose＇ s BIBD and circulant decomposition. The template matrix is extended by the appropriate cycle permutation matrix. The QC-LDPC codes constructed by the proposed method have well structure and flexibility to choose the code length and code rate. The simulation results show that at the bit error rate of 10^-6 and the same code rate of 93.7%, the net coding gain （ NCG ）of the constructed noveI-QC-LDPC （ 10992,10305 ） code is 1.8dB more than that of RS （ 255,239 ） code which has used in ITU-T G.975. Therefore, the QC-LDPC code constructed by the proposed method has a better performance and is more suitable for high-speed long-haul Optical transmission systems.