改进的基于数据辅助的MPSK信号信噪比估计

摘要

According to maximum likelihood sequential estimation criterion, a SNR estimation method for MPSK signal is proposed in the condition that the channel coefficient is complex to fight the fault that channel coefficient is supposed to be real in the existing data aided SNR estimation method According to data used, there are three forms, which are method only using training symbol, hard-decision aided method and soft-decision aided method. The performances of proposed methods and existing methods are compared through analysis and simulation. Also, on how the performances of every method changes with different phases of channel coefficient and priori information is analyzed. The results show that when the quality of priori information is high, soft-decision aided improved method gives very precise estimation values, also it can handle a very wide range of SNR. When the quality of priori information is low, the improved method only using training symbols also give exact estimation results%针对目前数据辅助的信噪比估计方法假设信道系数为实数这一问题,基于最大似然序列估计准则,给出了信道系数为复数时MPSK调制信号的信噪比估计方法.根据利用的数据不同,给出了3种形式,分别为只利用训练序列、硬判决辅助、软判决辅助的方法.通过理论分析和仿真结果比较了改进方法和原来方法的性能,分析了当信道系数的相位不同、先验信息不同时各种方法的性能.实验结果表明,当先验信息质量较高时,软判决辅助的改进方法的估计精度非常高,且适用的信噪比范围也较大；当先验信息质量较低时,只利用训练序列的改进方法也可以得到比较精确地估计结果.