A coverage-preserving scheme for wireless sensor network with irregular sensing range

Coverage is an important issue related to WSN quality of service. Several centralized/decentralized solutions based oil geometry information and under the assumption of disk sensing range have been introduced in the literature. However, disk sensing range assumption is too strong in the real world and cannot be held in scenarios requiring high accuracy, such as the emergency preparedness class of applications. This paper proposes a new intersection point method (IPM) that extends the disk sensing range assumption to an irregular simple polygon assumption. A unit circle test method has also been devised in order to provide a controllable degree of accuracy in the determination of fully covered nodes. By adjusting the radius r(u) of this unit circle test, the algorithm can be made tolerant to holes of a certain size which makes the solution flexible when the degree of accuracy must be controlled. IPM performance was evaluated through a set of simulation experiments implemented in the NS-2 simulator, which were compared to the results obtained using the central angle method (CAM) proposed by D. Tian and N.D. Georganas, and the association sponsors method (ASM) proposed by A. Boukerche, X. Fei and Regina B. Araujo. The results show that under the simple polygon sensing range assumption, our solution can efficiently identify fully covered sensors, discover holes (blind points) and archive better quality results than CAM and ASM. The performance and flexibility of IPM makes it a potential solution for applications that require a high rate of coverage with controllable hole tolerance. (C) 2007 Elsevier B.V. All rights reserved.