CO-OFDM系统中基于维纳滤波的相位噪声ICI抑制算法

Phase noise ICI suppression algorithm based on Wiener filter in CO-OFDM systems

针对相干光正交频分复用(CO-OFDM)通信系统中相位噪声引起的载波间干扰(ICI)问题,提出一种基于维纳滤波的相位噪声ICI抑制算法。算法不需要改变OFDM符号原有的结构,只需要利用相位噪声预先得到的统计数据,通过相关计算,得到ICI的修正项。由于没有在OFDM符号中添加额外的辅助数据,所以与ICI自消除算法相比,所提出的ICI抑制算法具有较高的频谱利用率。仿真结果表明,在相位噪声比率为10-4级别时,基于迭代检测的ICI消除算法的误码率(BER)趋于10-4,出现错误平层;而本文所提出的ICI抑制算法能够有效地降低错误平层,改善BER性能。

A phase noise inter-carrier interfere nce （ICI） suppression algorithm based on the Wiener filter is proposed so as to solve the ICI problem caused by the phase noise in the coherent optical o rthog onal frequency division multiplexing （CO-OFDM） communication systems.The proposed algorithm can effectively suppress the effec t of the ICI at the condition of the large phase noise.This algorithm can be deduced and obtained by the structure principle of the Wiener filter and does not need to change the original structure of the OFDM symbol.Moreover,the algorithm just requires to us e the statistical data obtained by the phase noise in advance and can get the ICI correction term through the related calculation.Bec ause there is no additional auxiliary data in OFDM symbol,the proposed ICI suppression algorithm,compared with the ICI self-cancel lation algorithm,has higher spectrum utilization. The proposed algorithm is comparatively analyzed with the ICI cancellation algor ithm based on the iterative detection.The simulation results show that the proposed ICI suppression algorithm can effectively suppres s the ICI,reduce the error floor and improve the performance of the bit error rate （BER） while the bit er ror rate of the ICI cancellation algorithm based on the iterative detection tend s to 10^-4 and the error floor occurs at the phase noise rate of 10^-4.