Routing in Duty-Cycled Surveillance Sensor Networks

In many surveillance sensor networks, sensors are scheduled to work in a duty-cycled mode (i.e., periodically switching between active states and sleeping states) in order to prolong the network lifetime. The duty-cycled mode saves sensors' energy but brings other issues. In surveillance applications (e.g., forest fire alarm or intruder detection), it is desired to report detected events to the sink node as soon as possible. However, the duty-cycled mode may increase the data delivery latency. In this paper, we study minimum-delay routing in duty-cycled surveillance sensor networks. As the minimum-delay routes are time dependent (i.e., they change with time) in duty-cycled sensor networks, routing becomes a challenging task. We propose a distributed routing algorithm to find the minimum-delay routes at any time from all nodes to the sink node. Further, all minimum-delay routes can be found in one execution of our routing algorithm. We further provide a distributed route maintenance algorithm for finding the minimum-delay routes when the network dynamically changes. We theoretically prove the correctness of the proposed algorithm, and extensive simulation results show that the performance of our algorithm outperforms other existing algorithms.