针对激光器产生的相位噪声会严重影响相干光正交频分复用(CO-OFDM)系统的性能问题, 提出了一种新颖容积卡尔曼滤波(CKF)相位噪声补偿算法。该算法利用导频信息, 先通过扩展卡尔曼滤波(EKF)和线性插值算法补偿公共相位误差(CPE)噪声, 然后对相位噪声粗补偿后的信号进行预判决, 在时域对预判决后的信号进行次符号处理的CKF实现对载波间干扰(ICI)相位噪声的精细补偿。对补偿后的信号进行二次迭代, 从而提高补偿效果。分析和仿真表明: 提出的新颖CKF算法能有效补偿相位噪声对信号的影响, 在相位噪声线宽较大时能有效增强对ICI相位噪声的补偿效果, 改善CO-OFDM系统对激光器线宽的容忍度, 有效提高系统的性能。

A phase noise compensation algorithm based on cubature Kalman filter (CKF) is proposed to solve the problem that the phase noise generated by laser will seriously affect the performance of CO-OFDM system. Using pilot information, the algorithm compensates the common phase error noise by extended Kalman filter and linear interpolation algorithm. Then the signal is prejudged after the phase noise is compensated, and the prejudged signal is subsymbolically processed in time domain by CKF to realize fine phase noise compensation of inter-carrier interference (ICI). The compensated signal is iterated twice to improve its compensation effect. The analysis and simulation results show that the novel CKF algorithm can compensate the influence of phase noise on the signal, largely enhance the compensation effect of ICI phase noise when the phase noise linewidth is large, improve the tolerance of CO-OFDM system to laser linewidth and effectively improve the performance of the system.