光学学报, 2015, 35 (10): 1006003, 网络出版: 2015-10-08
基于自适应ICA的PDM-CO-OFDM系统信道均衡算法
Channel Equalization Using Independent Component Analysis with Adaptive Variable Step in PDM-CO-OFDM
光通信 正交频分复用 独立成分分析 信道均衡 自适应步长 optical communications orthogonal- frequency- division- multiplexing independent component analysis channel equalization adaptive variable step
摘要
基于独立成分分析法(ICA)能够实现偏振复用相干光正交频分复用(PDM-CO-OFDM)系统的盲信道均衡,与基于导频的信道均衡方法相比,能极大提高系统的频谱利用率。然而这种固定步长的ICA 算法对每个子载波采用迭代算法来计算信道频率响应分离矩阵, 需要经过几十次迭代才能收敛。为有效降低该算法的计算复杂度,提出一种基于自适应步长ICA 的盲信道均衡算法,采用自适应分离步长提高迭代算法的收敛速度。基于100 Gb/s 16进制正交振幅调制(16-QAM)PDM-CO-OFDM 系统,仿真实验表明该自适应算法的系统误码率性能优于固定步长ICA算法的结果,且收敛速度提高5倍以上,能够用于未来高速PDM-CO-OFDM 系统接收端进行高效信道均衡。
Abstract
Compared with the conventional training symbols-based channel equalization method, the blind channel equalization method based on the independent component analysis (ICA) improves considerably the spectral efficiency of the polarization-division-multiplexing coherent-optical orthogonal-frequency-division-multiplexing (PDM- CO- OFDM) systems. However, the blind channel estimation requires the computations of the channel frequency response on subcarrier basis and needs dozens of iterations to converge. To reduce its computational complexity, on the basis of the channel equalization using ICA, a blind channel equalization method is proposed. It is performed by using ICA with adaptive variable step, and the separation step method enhances the convergence rate of the iterative algorithm greatly. For 100 Gb/s PDM-CO-OFDM with 16 quadrature amplitude modulation (16 QAM), it is proved by the simulation results that its convergence rate improves more than five times, compared with the channel equation method by using ICA with fixed iterative step. This method can be used to realize high efficiency channel equalization in the future high speed PDM-CO-OFDM system receivers.
顾欣, 卢瑾, 任宏亮, 薛林林, 郭淑琴, 覃亚丽, 胡卫生. 基于自适应ICA的PDM-CO-OFDM系统信道均衡算法[J]. 光学学报, 2015, 35(10): 1006003. Gu Xin, Lu Jin, Ren Hongliang, Xue Linlin, Guo Shuqin, Qin Yali, Hu Weisheng. Channel Equalization Using Independent Component Analysis with Adaptive Variable Step in PDM-CO-OFDM[J]. Acta Optica Sinica, 2015, 35(10): 1006003.