Maximum likelihood sequence estimation of uncoded and coded PSK signals transmitted over Rayleigh flat-fading channels

The problem of maximum likelihood (ME) detection for uncoded and coded M-PSK signals on Rayleigh fading channels is investigated. It is shown that, if the received signal is sampled at baud rate, a ML receiver can be implemented. The error rate performance of this receiver is evaluated by means of computer simulations and its limitations are discussed. Moreover, it is shown that, on a fast fading channel, the error floor in the BER curve can be appreciably lowered if more than one received signal sample per symbol interval is processed by the receiver decoder. Finally, it is proved that, on fast fading channels, the use of PSK trellis-codes without the interleaving-deinterleaving subsystems can provide substantial gains over uncoded PSK systems with the same information rate