NADS: Neighbor Assisted Deployment Scheme for Optimal Placement of Sensor Nodes to Achieve Blanket Coverage in Wireless Sensor Network

Abstract

Sensor Node (SN) is a vital component in any automated system. It is an electro-chemical or electro-mechanical device designed to observe the specific changes occurring in its vicinity. Wireless Sensor Network (WSN) is a system formed by the group of wirelessly connected SNs which are deployed at distinct geographical locations within a candidate region. Performance of any WSN in terms of connectivity, coverage and life mainly depends on the distribution of SNs. In this paper, we propose a Neighbor Assisted Deployment Scheme (NADS) to uniformly distribute the randomly spread Mobile Sensor Nodes (MSNs) within a candidate region. Entire candidate region is divided into Square Sub-Regions (SSRs) which are further divided into regular hexagons and center of these hexagons forms the Desired Locations (DLs) for placement of MSNs. NADS uses 3-phase incremental approach for optimal placement of MSNs. Resultant of each phase forms the infrastructure to assist the placement of remaining unplaced MSNs. In each phase MSNs communicate locally with each other to elect the most appropriate one among them to relocate to the nearest DL. Factors such as dropping height, wind speed, parachute size, battery size and MSN weight are considered to determine the area approachable by any dropped MSN. This limits the number of computations performed at each MSN, regardless of the size of the candidate region. The scheme is simulated and a comparative study is made with some existing systems. It is observed that NADS is realistic, scalable and yields better performance in terms of coverage, connectivity, setup-time and energy-efficiency with minimum number of MSNs as compared to existing schemes.