Energy-Efficient Coverage and Connectivity Maintenance for Wireless Sensor Networks

In this paper, we propose a density control algorithm for wireless sensor networks to keep as few as possible sensors in the active state to achieve a connected coverage of a specific area of interest. Inactive sensors can turn off sensing modules to save energy. Unlike other algorithms, the proposed one does not rely on position information or ranging information of sensors. It just requires each active sensor to periodically send two beacons of different transmission ranges. Sensors can then decide to stay active or inactive according to received beacons. The proposed algorithm is fault-tolerant in the sense that one or more inactive sensors can switch to the active state to take over the surveillance responsibility when any active sensor runs out of energy or fails. Under the assumption of sufficiently high density of sensors and the assumption of RC  2RS, the algorithm can approximate the optimal connected coverage, where RC and RS are the radio communication radius and the sensing radius of sensors, respectively. We also perform simulation experiments to demonstrate the algorithm’s performance.