Performance analysis of generalized selection combining of M-ary NCFSK signals in Rayleigh fading channels

In this paper, we propose and analyze the bit error performance of a generalized selection combining (GSC) receiver for M-ary noncoherent frequency shift keying (NCFSK) signals on i.i.d. Rayleigh fading channels with L antennas at the receiver. For each of the M hypotheses, the receiver combines the K largest outputs among the L available square-law detector outputs before proceeding to the bit detection process. We derive a closed-form expression for the bit error probability of the proposed (K, L) GSC receiver, and present numerical results to illustrate the bit error performance of this receiver for different values of M, K, and L. We also show that our generalized (K, L) GSC scheme and analysis encompass the previously reported schemes/analyses by Chyi et al and Hahn as special cases for K = 1 and K = L, respectively.