带宽受限QPSK相干光侦听接收机最佳性能分析  

Optimum Performance of Optical Coherent Eavesdropping Receiver with Bandwidth Limitation in QPSK Systems

作　　者：马兆慧[1] 陈健[1] 王萍[1] 刘雪[1] FENG Tian-ping 

机构地区：[1]南京邮电大学通信与信息工程学院,南京210003

出　　处：《光子学报》2016年第10期86-92,共7页Acta Photonica Sinica

基　　金：国家自然科学基金(No.61271239)资助~~

摘　　要：在带宽受限情况下建立了相干光侦听接收机模型并给出了带宽受限的等效滤波器模型.给出了带宽受限下的接收信号数学模型,利用星座图详细阐述并总结了其它符号对当前符号的干扰规律.重新定义了符号信噪比,推导了基于辅助判决式最大似然式相位估计的带宽受限的侦听接收机的误码率性能,并分析了接收机的最佳采样判决时刻和最佳带宽.仿真结果表明,不同带宽下定义的最大信噪比对应系统的最小误码率;不同滤波器类型对应的最佳采样判决时刻和最佳带宽是不同的,但都可以找到一个最佳点;随着信噪比的增加,带宽受限会降低辅助判决式最大似然式相位估计算法的性能.Optical coherent eavesdropping receiver model with limited bandwidth is established in Quadrature Phase Shift Keying（QPSK）system.And equivalent filter model about bandwidth limitation is given.The received signal model is present in the presence of limited bandwidth.The interferences of other symbols on current symbol are analyzed in detail with received signal constellation.Signal-to-noise ratio（SNR）is redefined and Bit Error Rate（BER）performance of receiver with limited bandwidth is derived based on Decision Aided Maximum Likelihood（DAML）phase estimation.The optimum sampling timing offset and bandwidth are also analyzed.Simulation results show that the maximum SNRs per bit we defined correspond to the minimum BER under different bandwidth.The optimum sampling timing offset and bandwidth are different with different type of filter,but the optimum ones can be found by SNR we defined.And with Optical Signal-to-Noise Ratio（OSNR）increasing,the performance of DAML phase estimation receiver is degraded by bandwidth limitation.

关 键 词：相干光通信 带宽限制 光纤侦听 辅助判决式最大似然式 码间干扰 误码率 信噪比 

分 类 号：TN911.4[电子电信—通信与信息系统]