Improved localisation method based on multi-hop distance unbiased estimation

Range-free, distributed localisation method is a challenging issue in wireless sensor networks (WSN). Typical hop count-based localisation methods assume that the Hopsize for different hop count is the same. However, many observations in WSN indicate that this assumption does not always correspond to the practical situation. In this study, the authors propose an approximate distribution of k-hop node distance and derive the expectation of k-hop node distance under the above distribution. Furthermore, the authors propose a novel range-free localisation method based on the multi-hop distance unbiased estimation (MDUE), and the simulation results demonstrate that more accurate distance and localisation can be obtained by MDUE than the state-of-the-art methods.