Multiple Symbol Differential Detection and Optimization of Differentially Modulated (N,M)APSK

A decision-feedback multiple symbol differential detection of differentially modulated 16-order (N,M)APSK signal, that is N-PSK on the inner ring and M-PSK on the outer ring (N+M=16), is presented, as well as the optimization of constellation according to the minimum SER (symbol-error-rate). Here we have studied the detection performance, and derived the theoretical expression of SER. It can been seen that the optimal (N,M)APSK constellations is related to the detection. The simulation shows the improvement compared to 16DAPSK approaches 1.2 dB at BER=10^-3 over AWGN channel, and the optimal constellation also outperforms others over Rayleigh fading channel