Rapid acquisition of ultra-wideband signals in the dense multipath channel

Efficient serial search strategies are presented and shown to reduce drastically the mean acquisition time for UWB signals in a dense multipath environment. Inherent in traditional serial search problems is the assumption that only a single bin or a small number of consecutive bins can properly terminate the search. This assumption leads to search strategies which tend to be linear in nature, e.g., a linear sweep of the uncertainty region. Because of the dense multipath channel present in most UWB systems, this assumption is invalid as seen by the channel's relatively large delay spread. A generalized analysis of various search algorithms is presented based on a Markov chain model of a simple single-dwell serial search. The results from this analysis reveal that the linear search has a considerably larger mean acquisition time than the more efficient search strategy termed the bit reversal search.