一种光通信中基于LDPC码的新颖级联码

基于SCG(4,k)码的构造方法对SCG-LDPC码进行优化改进,构造一种适用于光通信系统的新颖LDPC(3969,3720)码,通过增大其码长,构造码率为95.1%的新颖SCG-LDPC(6561,6240)码,使其码率更符合光通信系统的高码率要求。并用SCG-LDPC(6561,6240)码与码率为94.5%的BCH(127,120)码进行级联,构造出一种新颖的BCH(127,120)+LDPC(6561,6240)级联码。仿真分析表明:在误码率为10-7时,新构造的BCH(127,120)+LDPC(6561,6240)级联码的净编码增益比已广泛应用于光通信系统的经典RS(255,239)码和SCG-LDPC(6561,6240)码分别提高了2.27dB和0.49dB。因而该级联码更适合于光通信系统。

A Novel Concatenated Code Based on LDPC Codes for Optical Communications

A novel SCG low density parity check SCG-LDPC(3969,3720) code for optical communication systems, based on the optimization and improvement for the construction method of Systematically Constructed Gallager(SCG)(4,k) code, was constructed. The novel SCG-LDPC(6561,6240) code with the code-rate of 95.1% was constructed by increasing the code-length of SCG-LDPC(3969,3720), so that the code-rate of LDPC codes can better meet the high code-rate requirements of optical communication systems. And then the novel BCH(127,120)+LDPC(6561,6240) concatenated code was constructed by concatenating SCG-LDPC(6561,6240) code and BCH(127,120) code with the code-rate of 94.5%. The simulation analysis shows that at the bit error rate(BER) of 10-7, the net encoding gain(NCG) of the BCH(127,120)+LDPC(6561,6240) concatenated code is respectively 2.27dB and 0.49dB more than those of the classic RS(255,239) code and SCG-LDPC(6561,6240) code. Therefore, the novel BCH(127,120)+LDPC(6561,6240) concatenated code can be better suitable for optical communication systems.