Redundancy and coverage detection in wireless sensor networks in the presence of obstacles

In the real applications of wireless sensor networks (WSNs), a great number of sensors are distributed in the region of interest in order to monitor the environment. The area covered and the energy consumed by the sensors are two key problems of the WSNs. There are several efforts which tried to find the coverage percentage of the network, and eliminate the redundant sensors; however, none of them have considered the presence of obstacles in the region of interest. In this paper, we propose a new efficient algorithm to compute the area covered by the sensors in a region containing transparent and opaque obstacles, and study the problem of detecting and eliminating redundant sensors in order to improve energy efficiency, while preserving the network's coverage. The proposed algorithm uses computational geometry techniques and is applicable for both homogeneous and heterogeneous WSNs. Also, the obstacles can have arbitrary polygonal shapes which are placed in arbitrary locations.