Comparison of carrier recovery methods for narrow-band polyphase shift keyed signals

Considers the problem of carrier phase recovery in narrowband M-ary phase-shift keying. A number of methods proposed in the literature are analyzed and their relative merits are pointed out. The various methods are contrasted using the phase error variance of the recovered carrier as a performance measure. The effect of timing errors is also shown for clock-aided schemes. The FMPL (Fujino Mth power loop), DDL (decision-directed loop) and VE (Viterbi estimator) are shown to exhibit better behavior than the Mth power loop in the narrowband case, provided that the clock recovery error is small and the signal-to-noise ratio is sufficiently high. Introduction of TCM (trellis code modulation) in the channel alphabet is also discussed. It has been found that it does not affect the performance of the DDL and VE methods, whereas it can have moderate effect on the other techniques