A Review on Energy Optimization Relay Selection Scheme for Wireless Sensor Networks

Author considered a wireless sensor network (WSN) with identically distributed nodes, and a two phase cooperative protocol where the source transmits and is overheard by multiple relays which in turn transmit to the destination or fusion center (FC). The Author introduces a selection scheme that will pick a subset of the relays that overhear the message and transmit to the FC. This scheme will aim at making the least number of relays active while minimizing the outage probability and sending the least amount of information enough to reconstruct the message at the FC. The reduced amount of information being transmitted through the network along with an even distribution of active relays leads to a more energy efficient system. The use of cooperative diversity, where neighboring stations may act as relay nodes to transfer the source data to the desired destination node through an independent relay channel, has shown to provide diversity gain and consequently improve the achievable bit rate. The network performance under the proposed settings is modeled using continuous Markov chains. The steady-state transmission blocking probability and the average network throughput are obtained by analyzing the derived Markov model. Author’s scheme first selects the best relay from a set of available relays and then uses this “best” relay for cooperation between the source and the destination. The outage probabilities of selection relaying protocols are analyzed and compared for cooperative wireless networks. These multiple relay selection schemes require the same amount of feedback bits from the receiver as single relay selection schemes.