A cross-layer strategy for energy-efficient cooperative communication in wireless sensor networks

Cooperative communication has been shown to provide significant performance gains over fading channels in wireless networks, as well as enhancement of the energy efficiency in sensor networks. However, the cross-layer optimization and Qos providing in cooperative networks has not received much attention yet. In this paper, we investigate the problem of minimizing the total power consumption for multi-hop wireless sensor networks, under the constraint of a target end-to-end transmission reliability. By utilizing a cross-layer optimization scheme, joint routing, relay selection and power allocation strategies are proposed for direct transmission, single-relay cooperation and multi-relay cooperation scenarios respectively. Taking into consideration the power consumption in receiving and processing circuitry, we demonstrate through simulations that an energy efficiency trade-off exists in cooperation, and the trade-off depends on several parameters such as the average inter-node distance, the required QoS, the number of relays, the receiving power and so on. Results also show the proposed cross-layer strategy achieves significant energy savings.