Zhang Shaoliang, Arabaci Murat, Yaman Fatih, Djordjevic Ivan B, Xu Lei, Wang Ting, Inada Yoshihisa, Ogata Takaaki, Aoki Yasuhiro
NEC Laboratories America, Inc., Princeton, NJ 08540, USA.
Opt Express. 2011 Sep 26;19(20):19042-9. doi: 10.1364/OE.19.019042.
The performance of rate-0.8 4-ary LDPC code has been studied in a 50 GHz-spaced 40 Gb/s DWDM system with PDM-QPSK modulation. The net effective coding gain of 10 dB is obtained at BER of 10(-6). With the aid of time-interleaving polarization multiplexing and MAP detection, 10,560 km transmission over legacy dispersion managed fiber is achieved without any countable errors. The proposed nonbinary quasi-cyclic LDPC code achieves an uncoded BER threshold at 4×10(-2). Potential issues like phase ambiguity and coding length are also discussed when implementing LDPC in current coherent optical systems.
已经在采用偏振复用正交相移键控（PDM-QPSK）调制的50GHz间隔40Gb/s密集波分复用（DWDM）系统中研究了速率为0.8的四进制低密度奇偶校验（LDPC）码的性能。在误码率为10^(-6)时获得了10dB的净有效编码增益。借助时间交织偏振复用和最大后验概率（MAP）检测，在传统色散管理光纤上实现了10560km的传输且无任何可计数的错误。所提出的非二进制准循环LDPC码在4×10^(-2)时实现了未编码误码率阈值。在当前相干光系统中实现LDPC时，还讨论了诸如相位模糊和编码长度等潜在问题。
