Range Free Localization in Wireless Sensor Network

Recent advancement in the wireless sensor network has contributed greatly to emerging of low-cost, low-powered sensor nodes. Even though deployment of large-scale wireless sensor network became easier, as the power consumption rate of individual sensor nodes is restricted to prolong the battery lifetime of sensor nodes, hence the heavy computation capability is also restricted. Localization of an individual sensor node in a large scale geographic area is an integral part of collecting information captured by the sensor network. Global Positioning System (GPS) is one of the most popular methods of localization of mobile terminals, however, the use of this technology in wireless sensor node greatly depletes the battery life. Therefore, a novel idea is coined to use few GPS enabled sensor nodes also known as anchor nodes in the wireless sensor network in a well-distributed manner. Distances between anchor nodes are measured and various localization techniques utilize this information. A novel localization scheme Intersecting Chord Based Geometric Localization Scheme (ICBGLS) is proposed for the wireless sensor network, which loosely follows the Geometric Constraint Based algorithm. Simulation of the proposed scheme is carried out for various communication ranges, beacon broadcasting interval, and anchor node traversal techniques using Omnet++ framework along with INET framework. The performance of the proposed algorithm (ICBGLS) along with SSU Scheme, Xiao Scheme, and GCB Scheme is evaluated and the results show the fact that the proposed algorithm outperforms the existing localization algorithms in terms of average localization error. The proposed algorithm is executed in a real-time indoor environment using Arduino Uno R3 and shows a significant reduction in average execution time than Geometric Constraint Based scheme and similar to that of the SSU scheme and Xiao scheme. Use of mobile anchor node requires traversal path optimization, so that average localization error as well the traversed path length is reduced. Specific localization algorithm is used in literature to measure average localization error, which results in different preference of traversal scheme. In order to encounter the problem and to make comparison among the traversal schemes more generalized, a novel evaluation metric namely Inverted Coverability, a variation of ANOVA, is proposed. Besides this, a novel traversing path scheme, LH (Linear-Hexagonal) traversal scheme is proposed. Mathematical analysis and the results show better performance of the proposed scheme with respect to the total path traversed, number of beacon points, Inverted Coverability, and average localization error over other geometric based deterministic path planning schemes such as DOUBLE SCAN, CIRCLES, Z-curve, and Polygon approach