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针对相干光正交频分复用(CO-OFDM)系统中相位噪声造成的严重影响,提出了一种采用线性插值和卡尔曼滤波相结合的相位噪声抑制算法。该算法在第一阶中对接收端的时域信号进行线性组合,之后利用线性插值算法对相位噪声进行初步抑制,在第二阶中采用卡尔曼滤波技术来抑制残余的相位噪声。分析和仿真表明:提出的二阶算法能够有效地抑制相位噪声对OFDM符号的影响,在相位噪声线宽较大时明显地降低错误平层,利用所提出的二阶算法可使误码率达到10~(-7)以下,有效地提高了系统的性能。
Aiming at the serious influence of phase noise in coherent optical frequency division multiplexing (CO-OFDM) system, a phase noise suppression algorithm based on linear interpolation and Kalman filter is proposed. In the first order, the algorithm linearly combines the received signals in the time domain and then uses the linear interpolation algorithm to suppress the phase noise. In the second stage, Kalman filtering is used to suppress the residual phase noise. Analysis and simulation show that the proposed second-order algorithm can effectively restrain the influence of phase noise on OFDM symbol. When the phase noise linewidth is large, the error leveling is significantly reduced. By using the proposed second-order algorithm, the bit error rate can be achieved 10 ~ (-7) the following, effectively improve the system performance.