CO-OFDM系统中利用阈值功率点改进的后向传输补偿算法  

Improved backward propagation compensation algorithm using threshold power point in CO-OFDM systems

作　　者：刘剑飞[1] 刘帅民[1] 曾祥烨[1] 王蒙军[1] 卢嘉[1] 胡贵军[2] 

机构地区：[1]河北工业大学信息工程学院,天津300401 [2]吉林大学通信工程学院,吉林长春130012

出　　处：《光电子．激光》2014年第5期881-886,共6页Journal of Optoelectronics·Laser

基　　金：国家自然科学基金(61077054);河北省自然科学基金(F2014202036);天津市高等学校科技发展基金(20120715);河北省高层次人才(C2013001048)资助项目

摘　　要：采用后向传输(BP)补偿算法补偿相干光正交频分复用(CO-OFDM)通信系统的非线性损伤是一种具有应用前景的方法。本文针对后向传输(BP)补偿算法计算复杂度高的问题,根据相干光正交频分复用(CO-OFDM)系统中非线性损伤与光功率的关系,通过选取合适的阈值功率点降低BP补偿算法的高计算复杂度。仿真结果表明,提出的方法可以大大降低BP补偿算法的计算复杂度,同时克服了传统算法过补偿的缺点,系统性能也得到提升。在100Gbit/s的CO-OFDM系统中,采用衰减因子为0.2dB/km的零色散光纤,信号传输3 200km(32×100km),光信噪比(OSNR)为16dB时,在选取合适的阈值功率点后,所需的BP补偿步骤数目由传统算法N=61降低为N=13,计算复杂度仅为原来的13/61。此外,采用改进的BP补偿算法补偿之后,系统的Q因子增加了0.204dB。In coherent optical orthogonal frequency division multiplexing （CO-OFDM） communication system,backward propagation （BP） compensation algorithm is put forward to compensate the nonlinear damage. However, in engineering application, the BP compensation algorithm has high computational complexity. In this paper, an improved algorithm is proposed to reduce the complexity of BP compensa- tion algorithm. An appropriate threshold power point is found according to the relationship between the nonlinearity and the optical power. When the light power transmitted in fiber drops to threshold power point, the effect of nonlinearity in fiber can be ignored and the unnecessary BP computation can be omit- ted,thus the computational complexity can be largely reduced. We apply the improved method to a 100 Gbit/s CO-OFDM system based on VPI simulation platform. In the simulation, the zero dispersion fiber with 0. 2 dB/km attenuation factor is used,the optical signal noise ratio （OSNR） of system is 16 dB and the transmission distance is 3 200 krn. The simulation results indicate that the number of BP compensa- tion steps is decreased from 61 to 13 ,and the Q-factor of the system enhanced by 0. 204 dB.

关 键 词：光纤通信 后向传输(BP) 相干光正交频分复用(CO-OFDM) 非线性损伤 

分 类 号：TN911.5[电子电信—通信与信息系统]