Power-aware range-free wireless sensor network localization using neighbor distance distribution.

In large-scale wireless sensor networks, cost-effective and energy-efficient localization of sensor nodes is an important research topic. In spite of their coarse accuracy, range-free (connectivity-based) localization methods are considered as cost-effective alternatives to the range-based localization schemes with specialized hardware requirements. In this paper, we derive closed-form expressions for the average minimum transmit powers required for the localization of sensor nodes, under deterministic path loss, log-normal shadowing, and Rayleigh fading channel models. The impacts of propagation environment and spatial density of anchor nodes on the minimum transmit power for node localization are evaluated analytically as well as through simulations. Knowledge of the minimum transmit power requirements for localizability of a sensor node enables improving energy efficiency and prolonging lifetime of the network. We also propose a novel distance metric for range-free localization in large-scale sensor networks. The target and anchor nodes are assumed to be positioned according to two statistically independent two-dimensional homogeneous Poisson point processes. Analytical expression for the average distance from a target node to its kth nearest neighbor anchor node is derived and is used for estimating the target-to-anchor node distances for localization. The Cramér-Rao lower bound on the localization accuracy for the new distance estimator is derived. Simulation results show the accuracy of the proposed distance estimate compared with some existing ones for range-free localization. The results of our investigation are significant for low-cost, energy-efficient localization of wireless sensor nodes. [ABSTRACT FROM AUTHOR]