低密度奇偶校验码在光通信中的性能

低密度奇偶校验码(LDPC)不仅有逼近香农限的良好性能, 而且译码复杂度较低, 结构灵活, 是近年信道编码领域的研究热点, 在光通信系统中有广泛的应用前景。针对非规则Tanner图上构造的低密度奇偶校验长码具有良好的性能, 以及其在光通信系统中的应用, 构造了几种LDPC码, 并采用置信传播(BP)译码, 在加性高期白噪声(AWGN)信道、二相移相键空(BPSK)调制下进行了计算机仿真。根据规则LDPC码和非规则LDPC码的误码率(BER)和FER曲线, 对规则码和非规则LDPC码在编译码方面以及性能方面作了分析和比较, 进而对构造在光通信系统中具有实用价值的LDPC码提出了看法。通过理论分析与仿真结果表明LDPC 码型具有良好的性能, 可以节省硬件开销, 比较适用于光通信系统中, 可作为超强前向纠错码型的候选码。

Performance Analysis and Research of LDPC code in Optical Communication System

Low-density parity check code(LDPC)is a good approximation of the Shannon limit. It has decoding with low complexity and flexible structure. It was the hot-spot of channel coding field in recent years so that it has the widespread application prospect in the optical communication system. In the view of LDPC long code based on irregular Tanner graph which has good performance and its application in the optical communication system, this paper constructed several LDPC codes,and used BP algorithm to carry out computer simulation in the AWGN channel and under the BPSK modulation. According to the BER and the FER curve of regular and irregular LDPC code, not only coding and decoding but also performance are analyzed and compared.At last, the paper makes some suggestion as to the LDPC code with the practical value in the optical communication system. Through the theoretical analysis and simulation results show that the LDPC code has a good performance, and can save hardware costs so that it is suitable in optical communication system and can be used as a super-forward error correction candidate code.