Coverage analysis for wireless sensor networks

The coverage problem in wireless sensor networks (WSNs) is to determine the number of active sensor nodes needed to cover the sensing area. The purpose is to extend the lifetime of the WSN by turning off redundant nodes. In this paper, we propose a mathematical model for coverage analysis of WSNs. Based on the model, given the ratio of the sensing range of a sensor node to the range of the entire deployment area, the number of the active nodes needed to reach the expected coverage can be derived. Different from most existing works, our approach does not require the knowledge about the locations of sensor nodes, thus can save considerably the cost of hardware and the energy consumption on sensor nodes needed for deriving and maintaining location information. We have also carried out an experimental study by simulations. The analytical results are very close to the simulations results. The proposed method can be widely applied to designing protocols for handling sensor deployment, topology control and other issues in WSNs.