M-ary NCFSK with S + N Selection Diversity in Correlated Rayleigh Fading

The performances of two signal-plus-noise (S + N) selection diversity receivers employing M-ary noncoherent frequency shift keying (NCFSK) in slow, flat, correlated Rayleigh fading channels are examined. The correlation model is more general than the equally correlated scenario and includes it as a special case. Analytical expressions are derived for the average symbol error rate (SER) and the average bit error rate (BER) of each receiver structure. Extensive Monte Carlo simulation results are presented to validate the analytical expressions. The performances of the S + N SC receivers are compared to the performance of the classical SC receiver. The effects of correlation, average fading power imbalance and diversity order on the performances of the S + N SC receivers are examined.