Minimizing End-to-End Delay Routing Protocol for Rechargeable Wireless Sensor Networks

Due to sporadic availability of energy and limited energy storage capacity, sensor nodes have to operate in very low duty cycles and adjust their duty cycles continuously. These characteristics cause E2E delay for packet delivery which is more critical in Rechargeable WSNs than that of traditional WSNs. In this work, we analyze the relationship between E2E delay and sensor density, duty cycle, sensor' transmission range and energy harvesting rate. An approximate average E2E delay was concluded by settling with the average delay between two adjacent nodes and the number of sensors laying the routing path, which is affected by sensor density and communication distance. The transmission range is on the influence of energy harvesting rate, size of solar panel and energy conversion rate, which were considered in our work. Depending on the average E2E delay, we provide an algorithm for creating a routing path with the minimal sleep latency by adjusting the neighbor selection continually when the E2E delay is higher significantly than the average E2E delay value and achieve to reduce packet delivery latency finally. Through extensive simulation and experiments, we demonstrate that our algorithm is efficient to reduce E2E delay in rechargeable wireless sensor networks.