基于导频辅助法,对相干光正交频分复用系统中采样时钟频率偏差进行估计和补偿, 并研究了导频的插入位置对该算法补偿效果的影响, 通过对五种不同的导频插入位置进行分析和比较, 得到最优导频插入位置.仿真结果表明: 本文算法即使在较大的频率偏移情况下也有较好的补偿效果, 并且采用该方法得到的光信噪比损耗不到1 dB, 可以有效地降低系统成本;不同导频插入位置对算法的补偿效果会产生影响, 在较小采样频率偏移范围内时, 导频平均插入方式为最优.如果采样频率偏移量较大, 在导频平均插入不能很好地补偿的情况下,导频应尽量插在低频位置.

The pilot-aided method was adopted for estimation and compensation of sampling clock frequency offset in CO-OFDM systems to improve the system′s performance .And the pilot arrangements were simulated and discussed by comparing with five different location of pilots inserted,the optimal location of pilot inserted was obtained.The simulated results show that the method can work quite effectively even with large sampling clock frequency offsets,and the loss of optical signal-to-noise ratio is less than 1 dB.Therefore,it can reduce the cost of system;the location of pilots will impact the performance of the algorithm,the average insertion of pilots is optimal.With increasing sampling frequency offset,if the method can not work well,the pilots should be inserted at the low frequency sub-carriers.