S+N-ESC Diversity in Nakagami and Rician Fading with MPSK and 16-QAM

Abstract

A signal-plus-noise ($S+N$) energy selection diversity combining ($S+N$-ESC) scheme for $M$-ary phase shift keying (MPSK) and 16-quadrature amplitude modulation (16-QAM) signaling in Nakagami-$m$ and Rician fading channels is studied. The $S+N$-ESC selects the branch with the maximum $S+N$ energy for detection. The advantage of the $S+N$-ESC scheme is that it requires no explicit channel estimation for diversity branch selection. We show that the symbol error probability (SEP) of the $S+N$-ESC is the same as that of classical selection combining (SC) for MPSK signaling in independent and identically distributed (i.i.d.) Rayleigh fading channels. Also, we show that the SEP of a weighted $S+N$-ESC scheme is the same as that of classical SC for MPSK signaling in independent and nonidentically distributed (i.n.d.) Rayleigh fading channels. It is shown that the $S+N$-ESC scheme provides a smaller SEP than classical SC for MPSK signaling in nondispersive fading channels such as Nakagami-m fading channels with Nakagami parameter $m>1$ and Rician fading channels with Rician parameter $K>0$. On the other hand, the $S+N$-ESC scheme is shown to have a larger SEP than classical SC for 16-QAM signaling in Nakagami-$m$ and Rician fading channels.