Optimizing area coverage in Wireless Sensor Networks

Wireless Sensor Networks (WSNs) have inspired tremendous research interest in since the mid-1990s. Advancement in wireless communication and miniature electromechanical systems (MEMSs) have enabled the development of low-cost, low power, multi-functional, tiny sensor nodes that can sense the environment, perform data processing, and communicate with each other untethered over short distances. Most of the applications deployed over WSNs require strong coverage requirements, especially those related to the detection and tracking of distributed events. Moreover, these events are forwarded to the analysis center(s) through a set of sink nodes that locally gather data emanating from the elementary sensors. This paper proposes a coverage control scheme that adapts to the situation where multiple sink nodes are deployed within the monitored area. On the opposite to traditional coverage approaches that aim at guaranteeing a uniform density distribution, we place the sensor nodes in a manner that increases the coverage degree according to their proximity to a sink node. To reduce the complexity of the optimization process, we consider a discrete search space by structuring the monitored into a uniform grid. An evolutionary algorithm is then used to choose whether to activate or not sensor nodes within every cell of the grid. We conducted a set of simulations in order to evaluate the performance of the proposed strategy, mainly in ensuring multi-target tracking.