Performance analysis of decision-directed maximum-likelihood phase estimators for M-PSK modulated signals

We investigate performance of decision-directed maximum-likelihood carrier phase synchronizers for M-PSK signalling (M/spl les/8) on the AWGN channel. Decision-directed feedback (DD-FB) and feedforward decision feedback (FF-DFB) structures are analyzed and compared in detail. A new, accurate model for the FF-DFB synchronizer is presented. Open loop characteristics and closed loop performance, in terms of steady-state jitter and cycle slip rate, are presented in the same framework for both the DD-FB and FF-DFB synchronizers. Performance comparison between the two phase estimator architectures is finally made for each modulation scheme investigated.