A Novel Threshold-Based Coherent TOA Estimation for IR-UWB Systems

Precise time-of-arrival (TOA) estimation is challenging in dense multipath environments because the leading-edge path of a received signal may not be the strongest path. In this paper, we propose a threshold-based coherent TOA estimation scheme for impulse radio-based ultrawideband (UWB) systems. The scheme uses a dedicated ranging sequence with a good cross-correlation property and a search-back process that considers the count of threshold crossings to find the leading edge of the received signal. We derive an approximate closed-form expression for the optimal threshold that restrains the mean absolute error. We show by simulations that high-precision short-distance ranging is achieved without introducing too much latency.