An optimal relay selection scheme for cooperative diversity

Cooperative diversity technology proposed in recent years can improve the system performance enormously by sharing different userspsila antennas, which has already widely been investigated by researchers. However, how to select the best relay for cooperative diversity in a dynamic network environment is still an open challenge. In this paper, two optimal criteria for the selection of the best cooperative relay are presented based on the A&F and D&F strategies, with which a heuristic distributed relay selection protocol is further proposed to implement the cooperative relay selection. In addition, computer simulations are conducted to validate the proposed relay selection criterion, showing that our relay selection scheme outperforms the conventional relay selection rules in terms of the BER.