Performance analysis of Decode-and-Forward cooperative networks with best relay selection

The Decode-and-Forward (DAF) relay strategy is the most popular cooperative diversity scheme due to its performance. Selection DAF (SDAF), relaying single or multiple relay selection, has recently been proven to achieve the same diversity order with lower power consumption than all-participate (AP) networks. Most SDAF methods assume constant power for the best relay, regardless of channel conditions. In the SDAF method, the relay decodes the received signal and re-encodes it to forward it to its destination. We propose a single relay selection strategy for two-hop relay networks. We specify a factor for each relay based on their outage probability criterion and the relay with the lowest probability of outage is selected for further cooperation for DAF scheme. In this paper, we suggest a method to select the best relay, where the destination node decides to cooperate with the relay nodes according to it is own the lowest outage probability for each link between destination-relays nodes. In particular, we derive an expression for Cumulative Distribution Function (CDF) for the total SNR for SDAF. Our simulation results show that this method outperforms AP-DAF method, and can keep a full diversity order.