光通信系统中低计算复杂度的载波相位估计方法

Algorithm for Low-Computational-Complexity Carrier-Phase Estimation in Optical Communication Systems

相干光通信系统中,传统的盲相位搜索(BSP)算法具有良好的激光线宽容忍度,但传统BSP算法的高计算复杂度限制了其应用场合。针对这一问题,提出了一种低复杂度的相位噪声估计方法。该方法基于激光线宽所产生的相位噪声缓变的特点,对相位测试范围进行限定,并在此范围内搜索最佳相位估计值,最终降低了相位搜索的数目,极大地降低了算法的复杂度。同时,由于该算法避免了传统BSP方法可能存在的少数相位误估计的问题,因此在性能上略优于传统的BSP方法。最后,在偏振复用相干光通信系统中验证了该新方法的正确性与有效性。

In the coherent optical communication system, the traditional blind phase search (BPS) algorithm has shown its excellent tolerance to laser linewidth, however its high-computational-complexity limits its practical applications. Thus a low-computational-complexity carrier phase estimation (CPE) algorithm is proposed, in which the phase-test range is defined based on the slow variance characteristic of noise phase produced by laser linewidth and the optimum phase angle is searched. Consequently, the number of phase searches is finally reduced and the computational complexity of this algorithm is also significantly reduced. Meanwhile, the proposed algorithm can avoid the problem of few phase mismatches existing in the traditional BPS algorithm and thus it is superior to the traditional BPS algorithm in performances. Finally, the correctness and validity of this algorithm are verified in the polarization multiplexing coherent optical communication system.