Cramer-Rao Bound for Clock Drift in UWB Ranging Systems.

This correspondence computes the Cramer-Rao lower bound on the variance of frequency drift estimates in oscillators for UWB ranging applications. An indoor multipath channel is assumed but, unlike previous investigations, the received pulses are not taken as separate from each other. Overlaps are possible and are accounted for. A simple formula is derived for the bound, which neatly shows its dependence on the channel parameters and the pulse shape. Comparisons are made with the case of separable pulses.