A Novel Range-Free Localization Scheme for Wireless Sensor Networks

This paper present a low-cost yet effective localization scheme for the wireless sensor networks. There aremany studies in the literature of locating the sensors in the wireless sensor networks. Most of them requireeither installing extra hardware or having a certain amount of sensor nodes with known positions. Thelocalization scheme we propose in this paper is range-free, i.e., not requiring extra hardware devices, andmeanwhile it only needs two anchor nodes with known position. Firstly, we install the first anchor node atthe lower left corner (Sink X) and the other anchor node at the lower right corner (Sink Y). Then wecalculate the minimum hop counts for each unknown node to both Sink X and Sink Y. According to theminimum hop count pair to Sink X and Sink Y of each node, we can virtually divide the monitored regioninto zones. We then estimate the coordinate of each sensor depending on its located zone. Finally, weadjust the location estimation of each sensor according to its relative position in the zone. We simulate ourproposed scheme and the well-known DV-Hop method. The simulation results show that our proposedscheme is superior to the DV-Hop method under both low density and high density sensor deployments.