Hybrid Geographic Routing for Flexible Energy—Delay Tradeoff

Several geographic (or position-based) routing protocols have been proposed for data dissemination in wireless sensor networks. In these protocols, routing is based on the positions of neighboring nodes. In particular, the next-hop node is selected according to either a distance-based strategy, which favors a neighbor with the largest distance progress toward the sink, or a direction-based strategy, which favors a neighbor with the lowest angle deviation toward the sink. In this paper, we propose a novel hybrid geographic routing (HGR) scheme that combines both distance- and direction-based strategies in a flexible manner. To further facilitate a tradeoff between energy consumption and end-to-end delay, we propose two dynamic HGR (DHGR) mechanisms based on the basic HGR scheme, which are designed to satisfy constraints on the average end-to-end delay of specific applications while minimizing energy consumption. Packet-delivery decisions are locally made, and the state at a node is independent of the number of nodes in the network; thus, DHGR has the inherent scaling property of geographic routing. The effectiveness of the proposed schemes is evaluated by analysis and extensive simulations.