A Generalized Signal Flow Graph Approach for Hybrid Acquisition of Ultra-Wideband Signals

Joint TOA and DOA estimation compliant with IEEE 802.15.4a Standard

“…Most localization techniques for UWB signals are based on time domain approaches. Optimal correlation based TOA estimator is proposed in [4] but it suffers from high sampling constraints. To cope with these sampling requirements a viable alternative is proposed in [5] where an energy-based TOA estimator is developed using sub-Nyquist sampling rates.…”

Coarse synchronization of UWB signals in the dense multipath channel based on the golden section

“…To this end, all the different possibilities for the timing offset have to be tested, so that the problem can be modelled as a hypothesis testing one [5], in which the region of uncertainty for the parameter to estimate is divided into a discrete number of cells, so that the identification of the correct cell provides a coarse estimate of the parameter. One of the most usual ways to test the hypotheses is to compare a certain decision metric related to the correlation between the received signal and the local reference with a prescribed threshold [5][6][7][8][9][10][11][12].…”

“…Since a fully parallel search (simultaneous testing of all the cells) would usually imply a prohibitive cost, the serial search has become very popular [5][6][7][8][9][10][11][12]. When the cells are tested serially, a hypothesis is considered only after the previous one has been discarded, thus increasing the mean acquisition time (MAT) with respect to the parallel search.…”

“…These cells are usually clustered, so an intelligent search strategy based on the assumption of consecutive correct cells can influence the MAT critically, and for this reason the identification of appropriate strategies has attracted some research attention lately [11,12,14].…”

A Low Complexity and Effective Rapid Channel Tracking Scheme for UWB Multiple-Access Systems

“…Most of them are based on time domain approaches. Under the assumption of known undistorted received pulses, optimal correlation-based TOA estimators [20] and a simplified version of the generalized ML criterion [13] are known. Also, energy based TOA estimation schemes have received considerable attention as a viable alternative to correlation-based methods [21,22] due to their reduced complexity implementation at sub-Nyquist sampling rates.…”