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International Journal of Distributed Sensor Networks
Volume 2013 (2013), Article ID 620248, 10 pages
Research Article

Range-Free Localization Scheme in Wireless Sensor Networks Based on Bilateration

Department of Information Engineering, I-Shou University, Kaohsiung 84001, Taiwan

Received 4 October 2012; Accepted 17 December 2012

Academic Editor: Long Cheng

Copyright © 2013 Chi-Chang Chen et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


A low-cost yet effective localization scheme for wireless sensor networks (WSNs) is presented in this study. The proposed scheme uses only two anchor nodes and uses bilateration to estimate the coordinates of unknown nodes. Many localization algorithms for WSNs require the installation of extra components, such as a GPS, ultrasonic transceiver, and unidirectional antenna, to sensors. The proposed localization scheme is range-free (i.e., not demanding any extra devices for the sensors). In this scheme, two anchor nodes are installed at the bottom-left corner (Sink ) and the bottom-right corner (Sink ) of a square monitored region of the WSN. Sensors are identified with the same minimum hop counts pair to Sink and Sink to form a zone, and the estimated location of each unknown sensor is adjusted according to its relative position in the zone. This study compares the proposed scheme with the well-known DV-Hop method. Simulation results show that the proposed scheme outperforms the DV-Hop method in localization accuracy, communication cost, and computational complexity.