光通信系统中基于BIBD对QC-LDPC码的研究

Study on QC-LDPC Codes Based on BIBD for Optical Communication Systems

基于平衡不完全区组设计(BIBD),深入分析与研究了准循环低密度奇偶校验(QC-LDPC)码的一种新颖构造方法,并通过该构造方法构造了3种同码率不同码长的QC-LDPC码,通过对这3种QC-LDPC码的仿真分析表明,同码率下,码长越长性能越好。同时在BER=10-6时码率均为93.7%的情况下,所构造的BIBD-QC-LDPC(5392,5056)码的净编码增益(NCG)比已广泛应用于光通信系统中的经典RS(255,239)码和ITU-T G.975.1中的LDPC(32640,30592)码分别提高了约2.13dB和1.41dB。因而其纠错性能更强,更适用于高速长距离光通信系统。该新颖构造方法简单灵活且编译码更容易实现。

Based on the Balanced Incomplete Block Design（BIBD）,a novel construction method of Quasi-Cyclic Low-Density Parity-Check（QC-LDPC） codes is further analyzed and researched.And the three QC-LDPC codes with the same code-rate and different code-length are constructed by applying the proposed method.The simulation analysis shows that under the condition of the same code-rate,the QC-LDPC code with the longer code-length has better error-correction performance.Simultaneously,at the condition of the bit error rate（BER） of 10-6 and the same code rate of 93.7%,the net coding gain（NCG） of the constructed BIBD-QC-LDPC（5392,5056） code is respectively 2.13 dB and 1.41 dB higher than that of the classic RS（255,239） code widely used in optical communication systems and that of the LDPC（32640,30592） code in ITU-T G.975.1.Therefore,the BIBD-QC-LDPC（5392,5056） code has much superior error-correction performance and is better suitable for high-speed long-haul optical communication systems.