光通信系统中QC-LDPC码的新颖构造方法

基于Richardson-Urbanke算法校验矩阵的结构,提出了一种适合光通信系统的具有更低编码复杂度的准循环低密度奇偶校验(QC-LDPC)码的构造方法,构造出码率高达93.7%的QC-LDPC(4288,4020)码.仿真结果表明,在误码率为10-7时,与广泛应用于光通信系统中的经典RS(255,239)码相比,QC-LDPC码可获得约1.7 dB的净编码增益,并比SCG-LDPC(3969,3720)码的净编码增益提高了约0.3 dB,距离香农限约1.3 dB,并低于随机构造的列重为3的LDPC(4288,4020)码的错误平层.

Construction Method of QC-LDPC Codes in Optical Communication Systems

To meet the increasing requirement on the transmission characteristics of optical communication systems, based on the structure of parity-check matrix of Richardson-Urbanke algorithm, a lower-complexity constructing method is proposed for the quasi-cyclic low-density parity-check (QC-LDPC) codes in the optical communication systems, and a QC-LDPC(4288,4020) code with 93.7% higher code-rate is also constructed. Simulation shows that the constructed QC-LDPC(4288,4020) code has net coding gain of about 1.7 dB over the classic RS(255,239) code which has been widely used for optical communication systems and 0.3 dB more than that of SCG-LDPC(3969,3720) code with the same 93.7% higher code-rate, and the NCG of the QC-LDPC(4288,4020) code is about 1.3 dB away from the Shannon limit at bit error rate BER of 10-7; furthermore, the error floor of QC-LDPC(4288,4020) code is lower than that of the randomly constructed LDPC(4288,4020) with the column weight of 3.