Power Control in UWB Position-Location Networks

In this paper, we discuss the use of power control in Ultra-Wideband (UWB) Position-Location Networks (PoLoNets)1, where the goal is to periodically estimate the locations of mobile nodes that move through a network of location-aware reference nodes. The reference nodes provide Time-of-Arrival (TOA) based range estimates that are used to estimate the locations of mobile nodes at regular intervals. We examine the accuracy of location-estimation through the Cramer-Rao lower bound (CRLB) and show that the localization accuracy fluctuates or "fades" as a mobile node moves through the network of reference nodes. The use of power control is shown to improve the robustness of location-estimates and provide higher localization accuracy. Two power control approaches are presented and compared with the empirically-obtained optimal solutions.