Trajectory-Based Forwarding Mechanisms for Ad-Hoc Sensor Networks

Routing in ad-hoc sensor networks is a complicated task because of many reasons. The nodes are low powered and they cannot maintain routing tables large enough for well-known routing protocols. Because of that, greedy forwarding at intermediate nodes is desirable in ad-hoc networks. Also, for traffic engineering, multipath capabilities are important. So, it is desirable to define routes at the source like in Source Based Routing (SBR) while performing greedy forwarding at intermediate nodes. We investigate Trajectory-Based Routing (TBR) which was proposed as a middle-ground between SBR and greedy forwarding techniques. In TBR, source encodes trajectory to be traversed and embeds it into each packet. Upon the arrival of each packet, intermediate nodes decode the trajectory and employ greedy forwarding techniques such that the packet follows its trajectory as much as possible. In this paper, we provide techniques to efficiently forward packets along a trajectory defined as a parametric curve. We use the well-known Bezier parametric curve for encoding trajectories into packets at source. Based on this trajectory encoding, we develop and evaluate various greedy forwarding algorithms. We also investigate various issues regarding implementation of TBR. Keywords— Ad-hoc Sensor Networks, Trajectory-Based Routing, Greedy Forwarding