Modified Price and Green's rake receiver for ultra-wideband system

Ultra-Wideband (UWB) system mostly works in a dense multipath environment. It has been proved that good diversity gain can be obtained by a rake receiver over this kind of channel to resist multipath fading. In this paper, the Price and Green's rake receiver which is well known in CDMA system is used for UWB system with some necessary modifications. The channel information can be estimated by this receiver without a pilot when M-ary orthogonal modulation is used. So Ms orthogonal short impulse waveforms is used as the transmitted waveforms to implement the M-ary orthogonal modulation. This method has low complexity and processing delay. In particular, it is much fit for fast time-varying channel.