Optimal Receiver for MPSK Signaling with Imperfect Channel Estimation

The authors derive the structure of the optimal receiver for MPSK signaling over a correlated Rayleigh fading channel. The channel is estimated using the minimum mean square error criterion by means of pilot symbols. For the case of high signal-to-noise ratio, an approximate expression for the symbol error probability (SEP) of this scheme is obtained as an integral, and compared with the SEP of a suboptimal receiver which uses maximal-ratio combining. Numerical results show that the performance gap between the optimal and sub-optimal receivers increases with increase of the channel correlation and the number of diversity branches, whereas it decreases with increase of pilot-to-signal ratio.