Localization Algorithms In Wireless Sensor Networks

Being a new research field, WSN has received more and more people's attention in recent years. Many specialized magazines and reviews regard this technology as the most influential one in the future. Related researches have been started in the USA at the end of the last century and by now the technology has been applied to military and other fields. Many scientific research institutions and universities in China are involved in WSN these years, and great progresses have been made.WSN is a multi-hop and self-organized system that organized by wireless communication technique,which is composed of a large number of sensors in the monitor region.By combining physical perceptual information in objective world with network technology, it brings great changes to the life style of us.As a research direction of multi-disciplinary integration, WSN involves lots of technology, in which the localization scheme is one of the most important. Centroiding algorithm is a typical range-free localization scheme. On the basis of centroiding algorithm, this paper, first of all, proposes the beacon-scalable centroiding algorithm, which enables the unknown node to receive more beacon messages from a wider range to improve its localization accuracy. Then, from another perspective, combining geometrical and statistical analysis, the paper proposes a beacon judgment-based algorithm to infer the region of the unknown node from amount and content of the beacons it received in order to locate it with an optimal position. From the perspective of beacon placement and message collection, the beacon judgment-based algorithm is as simply as centroiding algorithm, but it performs better than centroiding algorithm in localization accuracy according to both geometrical analysis and simulation.