Geographic and Energy-Aware Routing in Sensor Networks

Typical communication patterns within a sensor network are data delivery from sensor nodes to one of selected information sinks, and information sinks requesting a certain physical phenomenon or requesting sensor nodes lying within a sensed area. In general, addressing is achieved by utilizing sensor locations. Geographic routing algorithms allow routers to be nearly stateless since packet forwarding is achieved by utilizing location information about candidate nodes in vicinity and the location of the final destination only. By their localized nature, geographic routing algorithms are highly scalable solutions which do not require any additional control overhead when network topology changes due to mobility or energy conserving sleep cycles. Recent work investigated that location information may be utilized to define new link metrics aiming on energy and physical layer optimized routing paths instead of only minimizing the number of hops needed to reach the desired destination. This chapter reviews geographic and energy aware routing algorithms for sensor networks. It includes simple heuristic greedy forwarding strategies, strategies which obtain guaranteed delivery by memorizing information about all ongoing routing task, memoryless recovery strategies, energy aware link metrics and routing strategies aiming on increased network lifetime, and routing without information about their neighbor nodes. The majority of geographic routing protocols assume a simplified network model which does not take into account random variations in correct message receipt. This chapter also discusses physical