An Opportunistic Cooperation Scheme in Wireless Networks: When to Cooperate with the Relay?

In the paper, an opportunistic cooperationscheme is proposed to make an effcient use of the cooperative relay, where whether the cooperative transmissionwill be adopted depends on the channel quality from thesource to the relay, as opposed to the deterministic cooperation regardless of the relay channel conditions. Closedform expressions of the Bit error rate (BER) and the outage probability are derived over Rayleigh fading channelsto evaluate the performance of the proposed cooperativediversity scheme. For the purpose of comparison, the performance of the coded cooperation is also analyzed, withnumerical results justifying the merits of our opportunistic cooperation scheme. From the numerical results, theproposed opportunistic scheme outperforms the coded cooperation across the whole SNR range in terms of the BERand the outage probability and moreover, it is less sensitive to relay-destination channel conditions compared withthe coded cooperation, further showing the superiority ofour scheme.