Title: Refining hop-count for localisation in wireless sensor networks

Authors: Xiaojun Zhu; Xiaobing Wu; Guihai Chen

Addresses: State Key Laboratory for Novel Software Technology, Nanjing University, Nanjing, Jiangsu 210093, China ' State Key Laboratory for Novel Software Technology, Nanjing University, Nanjing, Jiangsu 210093, China ' State Key Laboratory for Novel Software Technology, Nanjing University, Nanjing, Jiangsu 210093, China

Abstract: Distance estimation is a crucial component in localisation for wireless sensor networks. Among the estimation methods, hop-count is widely used in situations where only connectivity information is available. However, hop-count is integer-valued, implying crude distance estimation. In this paper, we refine hop-count to achieve better distance estimation. This is done by estimating neighbour distance and then approximating non-neighbour distance by the length of the shortest path. To estimate neighbour distance, we propose three estimators and show that they have negligible bias. We also show that the variance of the estimators is related to node density. The final refined hop-counts are further studied by simulations. Results verify the improvement on distance estimation and show that existing localisation methods can benefit from the improvement in various scenarios.

Keywords: wireless sensor networks; WSNs; range-free localisation; refined hop count; distance estimation; proximity estimation; distance estimation; simulation.

DOI: 10.1504/IJSNET.2012.051529

International Journal of Sensor Networks, 2012 Vol.12 No.4, pp.232 - 243

Received: 23 Apr 2012
Accepted: 16 Oct 2012
Published online: 20 Jan 2013 *

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