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.