16QAM相干光接收相位恢复算法的研究
Research on phase recovery algorithm for 16QAM coherent optical systems
摘要
传统的16QAM(16进制正交幅度调制)相干光系统的相位估计算法主要采用QPSK(正交相移键控)分圈法,然而受放大器ASE(自发辐射)噪声的影响,星座点的径向移动将对相位恢复的准确度造成严重影响。文章针对星座点受噪声影响程度的不同,对QPSK分圈法中的分类幅值阈值进行详细分析,并引入不同权重。蒙特卡罗仿真结果表明,该改进方法不仅能有效提高16QAM的相位恢复精度,而且具有更低的误码率。
Abstract
The traditional 16QAM phase estimation algorithm for coherent optical systems chiefly employs QPSK partitioning. However, owing to the influence of amplifier ASE noise, the radial movement of the constellation point seriously affects the accuracy of the phase recovery. In view of the different extent of the effects, this paper makes a detailed analysis of the classified amplitude threshold in the QPSK partitioning and proposes an analytical model that takes the relationship of Optical SNR (OSNR), the length of summing window, and the threshold radius into account. The model also induces a group of weighted coefficients into phase estimation. Monte Carlo simulation results show that the improved method effectively increases the precision of phase recovery with still lower BER.
王安冬, 刘岚, 胡荣, 刘武. 16QAM相干光接收相位恢复算法的研究[J]. 光通信研究, 2013, 39(5): 5. Wang Andong, Liu Lan, Hu Rong, Liu Wu. Research on phase recovery algorithm for 16QAM coherent optical systems[J]. Study On Optical Communications, 2013, 39(5): 5.