Performance analysis of multi-branch cooperative diversity networks over Nakagami-m fading channels

Adaptive decode and forward (DF) relay are studied over independent non-identical (i.n.d.) flat Nakagami-m fading channels. Taking advantage of the moment generating function (MGF), the closed-form expression for the bit error rate (BER) is derived. The behaviors of Space-Time Block Coding (STBC) have also been investigated over the same channel with DF. Taking BER as a metric, cooperation parameter is proposed to conjecture DF cooperative region by comparing with BER of STBC and directive communication. Simulation results show that, under the same channel information, the performances of DF is far superior to directive transmission and better than amplify and forward (AF) strategy, but poorer than STBC strategy. Also, the results indicate that its behavior will be better than STBC strategy when channel performs well, as long as SD and RD channel can reach certain prerequisite.