Research On The Coverage Control In Wireless Sensor Networks

Wireless sensor networks (WSNs) consist of low-cost, low-power tiny sensor nodes that can communicate with each other to perform sensing and data processing cooperatively. Network coverage and energy consumption are two primary problems in wireless sensor networks. The performance of a sensor network depends to a large extent on the sensor field coverage and its lifetime is determined by its energy consumption. While network coverage is closely related to network energy consumption, the deployment of sensor nodes is an important factor affecting the coverage of a sensor network. This thesis focuses on energy-efficient coverage control in wireless sensor networks and movement-assisted self-deployment of sensor nodes. It presents methods for energy-efficient node scheduling and self-organization, as well as techniques for coverage-centric sensor node deployment.The thesis first presents a localized, distributed coverage-preserving node scheduling scheme (CPNSS) to improve the energy efficiency and prolong the network lifetime of densely deployed random sensor networks. In such a wireless sensor network, the inherent node coverage redundancy will cause a large amount of unnecessary energy waste, which is harmful to the network lifetime. The CPNSS scheme tries to extend the network lifetime by deactivating some unnecessary redundant sensor nodes, thus reducing the number of active sensor nodes and the coverage redundancy. Combining the (α,β)-perimeter coverage based rule for detecting coverage redundancy and the node priority based method for resolving cyclic dependency, the CPNSS scheme can preserve the network coverage after turning off unnecessary sensor nodes. Extensive simulation results show that the CPNSS scheme can not only outperform the PEAS protocol, but also achieve longer FDL lifetime and α-CL lifetime of sensor network than the SITE algorithm.The thesis next considers the energy-efficient self-organization of wireless sensor networks. Query execution is a kind of frequent and important operation in wireless sensor networks. One promising energy-saving technique is to activate a subset of sensor nodes to respond the specific user query, while these active sensor nodes must cover the target region completely and form a connected communication network. The problem of calculating the minimum number of sensor nodes satisfying the coverage and connectivity requirements simultaneously is formulated as a minimal connected cover set (MCCS) problem, which is NP hard. A centralized approximation algorithm is proposed for the MCCS problem in this thesis. This algorithm tries to solve the MCCS problem by constructing the near optimal cover set firstly and then making the cover set connected if necessary. A centralized, Voronoi tessellation (CVT) based algorithm is proposed to...