Effect of Bandwidth on UWB Ranging Error

In this paper, the authors analyze the effects of system bandwidth, transmitter-receiver (TX-RX) separation distance and line-of-sight (LOS) blockage on the ranging error in realistic ultra-wideband (UWB) channels. Data collected from extensive UWB indoor propagation channel measurements conducted in various types of apartments with bandwidth of 7 GHz are used to study the above effects. Here, a threshold-based time-of-arrival (ToA) estimator is employed to estimate the ToA of the first arriving path. An optimum threshold value is set for each measurement data set according to the channel operating conditions by adapting the thresholding technique proposed in Dardari and Win, 2006, Analysis of the measurement results show that the ranging error is independent of the TX-RX separation distance. However, the presence of LOS blockage increases the ranging error due to the positive bias introduce by different materials that block the LOS path. We then develop a model to quantify the effect of bandwidth on the ranging error due to multipath dispersion, which is found to be well-modeled by an exponential function.