Zhang, J.Kennedy, R. A.Abhayapala, T. D.2025-06-292025-06-290536-1486http://www.scopus.com/inward/record.url?scp=4143124612&partnerID=8YFLogxKhttps://hdl.handle.net/1885/733765364In this paper, we present the Cramér-Rao lower bounds (CRLBs) for the time delay estimation of UWB signals which could be tight lower bounds for the theoretical performance limits of UWB synchronizers. The CRLBs are investigated for both single pulse systems and time hopping systems in AWGN and multipath channels. Insights are given into the relationship between CRLBs for different Gaussian monocycles. It is found that larger number of multipath signals implies higher CRLBs and inferior performance of synchronizers, and multipath interference on CRLBs can not be eliminated completely except in very special cases. As every estimate of time delay could not be perfect, the least influence of the synchronization error on the performance of receivers is quantified.5en200410.1109/icc.2004.13131804143124612