Diversity Analysis of Smart Relaying with Equal Gain Combining

Cooperative relaying has been proposed as a way to create a virtual antenna array, hence providing spatial diversity in slow fading wireless environment. From the practical implementation perspective, one needs to design a relaying system that can achieve the maximum diversity order with a low system complexity. One promising candidate is to incorporate equal gain combining (EGC) technique into relaying systems and it is the main focus of this paper. In particular, the techniques of EGC and smart relaying are combined in the decode-and-forward (DF) relay processing method. It is shown that for a system with one relay and M phase-shift-keying (M-PSK) modulation, a maximum diversity order of 2m is achieved in Nakagami-m fading environment. With K relays, numerical results suggest that the diversity order is m(K + 1).