Trail-Based Location Service in Event-Driven Wireless Sensor and Actor Networks

In wireless sensor and actor networks, when events of interest are detected, the sensor nodes should transmit event reports to inform the actors. Due to the mobility of actors, their current locations are generally unavailable to the sensor nodes. Location service is a popular solution to solve this problem. However, the actor is required to periodically update its location to the location servers, which may waste considerable energy in the event-driven scenario. In this paper, we propose an algorithm named trail- based location service (TLS). The basic idea of TLS is that, the actor can leave its trail which is composed of continuous footprints. When a footprint is discovered during the event report transmission, the event report packet can be forwarded along the trail until it reaches the actor. With the help of trail information, TLS can prolong the period of location update and hence reduce the update overhead with guaranteed delivery. The theoretical analysis and simulation results are provided to prove the efficiency of TLS.