Power Efficient Multi-relay Cooperative Diversity in Wireless Network Using Hybrid Relaying Protocol

Abstract

Cooperative diversity technique using relays can improve the reliability of the network as well as improve the performance in the event of fading. For systems employing such cooperative diversity technique, outage probability and transmission power are very important performance measure. This paper uses multiple relays employing both Amplify-and-forward (AF) and decode-and-forward (DF) as a relaying protocol to compute the outage probability of the network and formulates an optimization problem to minimize the overall transmit power of the network. Since the cooperation can be costly for the nodes which act as the relay node, it is very important that the transmission power of the relay nodes are also within the bound. The results show that using both AF and DF are advantageous over using only AF or DF as a relay protocol in a multi-relay cooperative network. The overall transmit power of the HDAF network is 17% and 4% less as compared to that with only AF or DF protocols, respectively. Similarly, the transmit power of the source node decreases by 14% and 6.4% as compared to that with only AF or DF protocols, respectively.