Non-coherent code acquisition for UWB systems in dense multipath fading channels

The primary characteristic of the ultra-wideband (UWB) indoor radio channel is the large frequency diversity, which translates into a large number of resolvable paths and, consequently, in a low signal energy-per-path. Code acquisition is particularly difficult in such a hostile environment if the available diversity is not exploited. This paper deals with the initial code acquisition for an UWB impulse radio (IR) system in a dense multipath environment. In particular, we propose an approach based upon a non-coherent Rake detector (NCRD), which combines the energy collected from different paths in a non-coherent fashion. System performance of the NCRD is analyzed in multipath fading channels, showing that satisfactory performance is achievable with relatively low complexity.