On the Energy Efficiency of Multihop Communication in Wireless Sensor Networks

In this work we consider the energy efficiency of multihop communication in a wireless sensor network scenario. The system incorporates some relaying schemes based on node cooperation and forward error correction to improve the communication reliability in the presence of fading, and power control to reduce the energy consumed for transmission. We investigate the basic tradeoffs among energy consumption, hop distance and robustness against fading by assuming that routing and multiple access algorithms have already set up a path between source and destination. We address the design of hop distance from the point of view of energy efficiency by introducing a new metric, the energy consumption rate, function of the source-destination distance, and by deriving the optimal hop length that minimizes it. In our numerical results we compare the proposed relaying schemes from the point of view of reliability and energy efficiency. We will show that the use of node selection improves reliability without increasing energy consumption and the use of coding, which usually requires energy consuming processing, is convenient if implemented in a energy adaptive scheme or when long hops are required in low node-density networks.