Effective path planning by mobile anchor for localization in wireless sensor network

Abstract

The impressive developments in VLSI, MEMS, wireless communication and embedded systems continue to produce tiny and inexpensive wireless sensors. Networks of thousands of wireless sensor nodes are already deployed in many applications to monitor, to track, to forecast and to control the physical quantities. These are Wireless Sensor Networks (WSNs). These sensor nodes possess limited sensing, processing, storage and communication. Sensor nodes communicate with each other and also with the Base Station (BS) wirelessly, to disseminate their data processing, analysis and storage. Each sensor node communicates with BS via single hop or multi hop communication. WSNs are subjected to various challenges and constraints.Accurate position information is needed for various applications like monitoring, tracking and controlling. Localization is the task of determining the physical coordinates. GPS is the good location sensing system. But it is not feasible in WSNs because of its more cost and poor coverage in indoor applications. Anyhow few nodes may be fitted with GPS, called as anchor nodes. All other nodes perform localization with the help of these anchors. This is called as anchor based localization. Many anchor based methods rely on the range measurements, called as range based localization techniques. Some of the techniques are signal propagation time, signal strength or angle of arrival. Some of the range based localization methods are triangulation, trilateration, multi- lateration, GPS based localization. These require additional hardware. In contrast range, free localization estimates the location based on the connectivity information. Some are Ad Hoc positioning system, Approximate point in triangulation, Multi-dimensional scaling. Range-free algorithm uses the mobile anchors for localization. Range-free algorithm does not require any measurement like distance, angle etc. newline newline newline