BER-based relay selection strategy for cooperative communication

In this paper, a bit error ratio (BER)-based relay selection strategy is investigated under opportunistic relay selection. The challenging problem is to design the relay selection rule so that the relay is able to measure the performance of the cooperative system at the destination exactly with low computation costs. This paper derives a closed-form expression of the end-to-end bit error rate firstly. Then, an approximate BER expression based on the relationship between the instantaneous signal-to-noise ratio (SNR) of the relay-to-destination link and the probability of error propagation is derived. Finally, a simplified relay selection formula is proposed. Simulation results prove that the proposed relay selection rule can reflect the BER of each relay properly as well.