Improved data aided SNR estimation algorithm for MPSK signal

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