QoS-based geographic routing for event-driven image sensor networks

We investigate the use of distributed image sensing for network localization, dynamic routing, and load balancing in wireless sensor networks. In particular, the image sensors are first used to obtain angular bearing information between each network node and a set of other nodes, mobile agents, or targets. This data is used to construct the relative geographic topology of the network. The image sensors are then employed to make periodic measurements, which are reported to the destination via multihop routing. Nodes may also infrequently detect an event from which a set of image frames need to be reported. These high-bandwidth event reports may cause packet queues to develop at the routing nodes along paths to the destination. We propose a distributed routing scheme that employs a cost function based on location data, in-node queue sizes, and energy levels at neighboring nodes. Our scheme also implements a set of relative priority levels for the event-based and periodic data packets. Simulation results are presented and indicate improved network lifetime, lower end-to-end average and maximum delays, and significantly reduced buffer size requirements for the network nodes.