Feed-forward decision-feedback carrier phase synchronizer for M-PSK signals

Coherent phase shift keying (C-PSK) represents an efficient modulation scheme for satellite communications. In such systems, carrier phase synchronizers often implement maximum likelihood (ML) estimation algorithms, the reason for this being the need of robust modem operations at low signal-to-noise ratios and the availability of digital technology. In this paper, performance of a feed-forward decision-feedback (FF-DFB) ML carrier phase synchronizer for M-PSK signals (M/spl les/18) on the AWGN channel is investigated. Open loop characteristics are analytically derived. A novel equivalent model for the FF-DFD synchronizer is presented and used to derive synchronizer tracking performance.