Invited Paper: Cooperative Communication And Routing Over Fading Channels In Wireless Sensor Networks

The dense deployments of wireless sensor networks offer the opportunity to develop novel communication techniques based on multi-node cooperation that can perform efficiently even over harsh fading channels. Several key contributions in the development and analysis of such techniques are provided. First, prior studies on cooperative communication and routing are extended by explicitly considering fading channels and relaxing synchronization requirements. It is demonstrated that significant asymptotic spatial diversity gains are achievable with K-cooperation even if error propagation is considered. Second, power-optimal cooperative communication strategies are derived and a low complexity near-optimal algorithm is provided that selects the number of cooperating transmitters based on observed channel conditions, and several power distribution strategies over links are compared. Finally, it is shown that multi-hop cooperative routing can be highly energy efficient in realistic settings.