The Probabilistic Analysis of Distance Estimators in Wireless Sensor Network

It is well known that localization plays an important role in wireless sensor network applications. There are two categories of localization approaches, such as range-based and range-free. RSSI (received signal strength indicator)-based method is in the first category. Three RSSI-based distance estimators, biased estimator (BE), unbiased estimator (UE) and maximal likelihood estimator (MIE), are presented to calculate the distance. The biased estimator is the existing method which is used extensively in the literatures, while the unbiased estimator and maximal likelihood estimator are two new estimators developed in this paper. The probabilistic analysis of those estimators is done to compare the performance among them. The probabilistic analysis and simulations show that under some condition we should choose unbiased estimator and under some other condition we should choose MIE.