Anycast Routing Protocol for Forest Monitoring in Rechargeable Wireless Sensor Networks

In rechargeable wireless sensor networks (R-WSNs), sensors have to adjust their duty cycles continuously owing to sporadic availability of energy and operate in a very low duty cycle because of current energy conversion technical limitations. Even though the network lifetime is not the main problem, packet delivery latency is critical because a sensor is in the dormant state most of the time in R-WSNs. These unique characteristics pose a new challenge for routing protocol design over traditional energy-static sensor networks. In this work, we introduce a routing protocol based on anycast communications technology, a novel design to minimize packet delivery latency for forest monitoring in R-WSNs. The key idea is to let a sender choose a closest neighbor to forward packets from forwarding candidates and a nearest sink node to accept the packet from all sinks. For multiple source nodes, we introduce an anycast technology based on Tabu search for each source establishing a minimal E2E delay routing path to reach anyone sinks. Through extensive simulation and experiments, we demonstrate that our anycast scheme based on Tabu search is efficient to provide smallest packets delivery latency in R-WSNs.