Synchronization for Differential Transmitted Reference UWB Receivers

This paper investigates timing recovery for differential transmitted reference (DTR) ultra-wideband receivers. In DTR systems the symbol energy is distributed over several time slots (frames) and a single pulse is transmitted per frame. The information is conveyed by differentially encoding the pulse polarities. Equal polarities correspond to a bit +1 while alternate polarities correspond to a bit -1. The detector computes the decision statistic by correlating pulses from adjacent frames and summing the contributions from all the frames of a symbol. Synchronization consists in providing accurate timing for the correlation computations. A timing algorithm is proposed requiring a limited amount of circuitry in addition to that needed for detection purposes. No training sequences are needed as the synchronizer operates in a blind mode. Two possible receiver architectures are envisioned, analog or digital. The effects of the timing errors on the receiver performance are investigated by simulation. In general, they are found to be negligible, except when the implementation is digital and the analog-to-digital converter resolution is limited to 1 bit.