Carrier-independent NDA symbol synchronization for M-PSK, operating at only one sample per symbol

Feedback symbol synchronization in sampled receivers for M-PSK ( M-ary phase-shift keying) signals is addressed. A whole class of nondecision-aided (NDA) carrier-phase independent symbol synchronisation algorithms are introduced which operate on the complex-valued samples of the baseband matched filter output signal, taken at the estimated decision instants (i.e. at the symbol rate). The algorithms are free of self-noise, and can be used for very small rolloff factors. It is shown that the dominating term of the tracking error variance, at moderate to high E_S/N_O, is the same for each of these algorithms. A subclass of optimum algorithms that minimize the second largest term of the tracking error variance is identified