Energy-efficient forwarding strategies for Wireless Sensor Networks in fading channels

International audienceIn the context of geographic routing in wireless sensor networks linked by fading communication channels, energy efficient transmission is important to extend the network lifetime. To this end, we propose a novel method to minimize the energy consumed by one bit of information per meter and per second towards the destination in fading channels. Using the outage probability as a measure to maximize the amount of information delivered within a given time interval we decide energy efficient geographic routing between admissible nodes in a wireless sensor network. We present three different approaches, the first is optimal and is obtained by varying both transmission rate and power, the other two are sub-optimal since only one of them is tuned. Simulation examples comparing the energy costs for the different strategies illustrate the theoretical analysis in the cases of log-normal and Nakagami shadow fading. With the method proposed it is possible to obtain a significant energy savings (up to ten times) with respect to fixed transmission rate and power