WSN04-4: A Coverage-Preserving and Hole Tolerant Based Scheme for the Irregular Sensing Range in Wireless Sensor Networks

Coverage is an important issue related to WSN quality of service. Several centralized/decentralized solutions based on the geometry information of sensors and under the assumption of the disk sensing range have been introduced in the literature. However, the disk sensing range assumption is too strong for applications in the real world and cannot be held in required high accurate scenarios, 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 was also devised in order to provide a controllable degree of accuracy in the determination of fully covered nodes. By adjusting the radius "r" of this unit circle test the algorithm can be made tolerant to holes of a certain size. This 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. Those results were compared to the results for the Central Angle Method (CAM)-part of the C-PNSS scheme[6], and the Association Sponsors Method (ASM)-part of the OCoPS solution[1]. 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 coverage rate with controllable hole tolerance.