CO-OFDM中基于线性插值的子载波间串扰盲抑制算法  

A Linearly Interpolated Blind ICI Suppression Algorithm for CO-OFDM System

作　　者：洪晓建 刘柳[1] 洪学智[1] 

机构地区：[1]华南师范大学华南先进光电子研究院,广州510006

出　　处：《华南师范大学学报（自然科学版）》2016年第1期52-57,共6页Journal of South China Normal University(Natural Science Edition)

基　　金：中国博士后科学研究基金面上项目(2013M531868);华南师范大学青年教师科研培育基金项目(13KJ04)

摘　　要：提出了一种高性能的基于线性插值的子载波间串扰盲抑制算法(LI-BL-ICI算法):盲估计出次符号间相位噪声差值,进行线性插值拟合以获得更加精确的相位噪声估计,将插值获得的相位噪声用于载波相位补偿,从而实现对子载波间串扰(ICI)的盲抑制,并利用少量导频对残余的共同相位噪声进行估计和补偿;推导了算法的数学模型,通过蒙特卡洛仿真分别分析了算法在背靠背和320 km光纤传输后系统的性能,与传统的共同相位噪声抑制算法(CPEC算法)和改进前的盲估计算法(BL-ICI算法)进行了横行对比.数值仿真结果表明,LI-BL-ICI算法能有效地抑制光相位噪声,其光源线宽的容忍度得到进一步提升.此外,LI-BL-ICI算法允许将次符号切割成任意块数,且在获取观测矩阵的过程中无需任何的角度相关运算.研究结果表明,LI-BL-ICI算法存在一个适中的次符号切割块数,使得其既能兼顾复杂度又能保证一定的系统性能,对于相干光正交频分复用(CO-OFDM)技术在采用廉价光源和采用高阶调制格式的光接入/光城域网中的应用具有重要的意义.A high-performance blind ICI suppression algorithm, LI-BL-ICI, based on linear interpolation is pro- posed for CO-OFDM systems. In the proposed algorithm, the difference of averaged optical phase noise between sub-symbols is estimated blindly and then linearly interpolated to get a more accurate estimation of the optical phase noise. The carrier phase is partially recovered with the linearly interpolated sub-symbol phase noise estimation, by which the inter-carrier-interference （ICI） is suppressed blindly. After ICI suppression, the common phase error of the residual optical phase noise is compensated with only a few pilot subcarriers. The theoretical derivation of the proposed algorithm is presented and the performance of the proposed algorithm in CO-OFDM systems for both back- to-back and 320 km fiber transmission scenarios is investigated through Monte-Carlo simulations. As demonstrated by numerical simulations, the impact of optical phase noise can effectively be mitigated with the linear interpolation based algorithm, and a laser linewidth tolerance larger than that of the BL-ICI algorithm is achieved. Compared with BL-ICI, an arbitrary number of sub-symbols are supported and angle-related operation is avoided when obtai- ning the observation-based matrix in the proposed algorithm. As shown in the simulation results, a moderate num- ber of sub-symbols can be chosen in the proposed algorithm to balance the performance and complexity. The pro- posed algorithm is of great importance for the application of CO-OFDM in optical access/metro networks with low- cost laser sources and high-order modulation formats.

关 键 词：光相位噪声抑制 相干光正交频分复用 ICI盲抑制 次符号 

分 类 号：TN929.1[电子电信—通信与信息系统]