ToA ranging using subsample peak estimation and equalizer-based multipath reduction

In the presence of multipath propagation received signals are composed of multiple echoes which are correlated to the direct signal. When using bandlimited signals for time-of-arrival (ToA) locating in indoor environments, the radio bandwidth is often not sufficient to decompose the received signal and to identify the first arriving path. This paper presents a ToA estimation approach based on a high-resolution correlation receiver with subsample interpolation. It is combined with a multipath error estimator based on the inverse channel impulse response determined by an equalizer. Simulation results confirm that the proposed approach can reduce the multipath error by a factor of 3.42 compared to matched filtering. Finally, measurements using an FPGA-based prototype implementation for wireless LAN show the applicability of the proposed approach for real-time locating systems.