A Modified Tracking Algorithm for UWB Pilot-Assisted Receivers

The satisfactory performance of classical tracking circuits presumes that acquisition (coarse synchronization) has provided a good estimate of the correct symbol or frame timing (typically within a fraction of the chip duration). This might not be a reasonable assumption for pilot-assisted UWB receivers in dense multipath, where initial acquisition of the LOS component is highly problematic, and coarse synchronization is more likely to detect an arbitrary multipath component. In this paper, we propose a tracking algorithm for pilot-assisted receivers based on a variant of the early-late gate approach, where the circuit's correlation template is matched to the received pulse shape rather than the transmit pulse shape. The algorithm is mathematically analyzed then tested by simulation, and it is shown that it can potentially correct timing errors much larger than the transmit pulse duration