IPSD: New Coverage Preserving and Connectivity Maintenance Scheme for Improving Lifetime of Wireless Sensor Networks

In many applications it is necessary to have some guarantees on the coverage, connectivity and lifetime of the Wireless Sensor Networks(WSN). Coverage problem is regarding how to ensure that each of the points in the region to be monitored is covered by the sensors. In maximizing coverage, the sensors need to be placed not too close to each other so that the sensing capability of the network is fully utilized and at the same time they must not be located too far from each other to avoid the formation of coverage holes. On the other hand from connectivity point of view, the sensors need to be placed close enough so that they are within each other communication range thus connectivity is ensured. Once coverage and connectivity are ensured, the overall lifetime of the network gets increased thereby improving the quality of service (QoS) of the Wireless Sensor Network (WSN). The concept of Integer Programmed Sensor Deployment (IPSD) scheme is being proposed, with a set of relay nodes a triangular lattice is formed by the grid based approach thus providing maximum coverage and connectivity. Integer Linear Programming (ILP) is brought into existence for eliminating the unused relay nodes thereby enhancing the coverage and connectivity with minimum number of relay nodes. Simulation is performed using NS-2 and the results shows that the proposed scheme provides better results in large scale WSN with improved coverage and connectivity. Key-Words:WSN,ILP, relay node, coverage, connectivity.