Frequency-domain estimation of multiple access ultra-wideband signals

In a time-hopping ultra-wideband (UWB) system, a receiver is required to operate over a large bandwidth. Conventional receivers consist of sliding correlators to correlate received signal with a template signal. Such a time-domain waveform detection scheme is essentially a single-user detection method, whose performance has been observed to degrade in a multiple access environment. In this paper, estimation of all users' signals is carried out in the frequency domain. First, Fourier transform (FT) is applied to the received time-domain signal. Then users' information in terms of modulation delays is estimated by frequency-domain multiuser detection (MUD) methods. Frequency diversity at the receiver can be explored for performance enhancement by generating multiple sinusoidal waveforms at different frequencies and processing transformed data in parallel. Its promising feature for combating narrow band interference is expected.