A Distributed Sleep Scheduling Algorithm with Range Adjustment for Wireless Sensor Networks

The network coverage for wireless sensor networks is an important issue because the information may not be considered useful when the total coverage drops below a certain required level. One way to maintain good coverage and extend the network lifetime is to schedule some sensor nodes to sleep between active cycles, as well as dynamically adjust the sensing ranges of active sensors. In this paper, we propose an algorithm to determine if a sensor node should sleep based on its residual energy and the size of the overlap area between the sensor and its neighbors. For those sensors that remain active, we use our algorithm to compute the sensing range of each active sensor such that the total coverage is maintained above a user-specified requirement for as long as possible. Simulation results show that our proposed scheme achieves a better performance in providing the user-required coverage and extending the system lifetime than the Coverage-Aware and Random-Sleep methods.