Density-aware hop-count localization (DHL) in wireless sensor networks with variable density

Localization schemes using hop-counts to reference nodes of known positions have been proposed to localize nodes in a sensor network. However, these schemes usually work well only when the networks have uniform and dense node distribution. A novel density-aware hop-count localization (DHL) algorithm is described to improve the accuracy of location estimation when the node distribution is non-uniform. When the density is low, each hop traversed is not necessarily equivalent to the maximum range distance. A range ratio is used to adjust the accumulated hop-count and this effectively reduces distance overestimation. Simulations show that our algorithm improves the localization accuracy compared to the algorithms without density considerations. The overhead incurred by DHL is found to be lower than that incurred by conventional schemes.