Ensuring Area k-Coverage in Wireless Sensor Networks with Realistic Physical Layers

Wireless sensor networks are composed of hundreds of small and low power devices deployed over a field to monitor. Energy consumption is balanced by taking advantage of the redundancy induced by the random deployment of nodes. Some nodes are active while others are in sleep mode. Area coverage protocols aim at turning off redundant sensor nodes while preserving satisfactory monitoring by the set of active nodes. The problem addressed here consists in building k distinct subsets of active nodes (layers), in a fully decentralized manner, so that each layer covers the area. In our protocol, each node selects a waiting timeout, listening to messages from neighbors. Activity messages include the layer at which a node has decided to be active. Depending on the physical layer used for sensing modeling, any node can evaluate if the provided coverage is sufficient for each layer. If so, node can sleep, otherwise it selects a layer to be active. Here, we describe a localized area coverage protocol able to maintain an area k-covered under realistic physical layer assumptions for both sensing and communicating modules.