Performance enhancement of channel-phase precoded ultra-wideband (CPP-UWB) systems by rake receivers

We propose to use the Rake receiver to improve the system performance by collecting more signal power in an ultra-wideband (UWB) system precoded by the channel phase information, called the CPP-UWB system [1], in this work. The performance of the proposed system is determined by the selected channel taps and the corresponding combining schemes for those Rake fingers. Three combing schemes, i.e., the maximum ratio combining (MRC), the minimized mean square error (MMSE) and the zero-forcing (ZF), are proposed. When the MRC scheme is applied to the Rake receiver with M fingers, M channel taps can be easily found to maximize the averaged signal power at the receiver output by exploiting the property of the channel- phase-precoded channel. It is shown by simulation results that the proposed scheme significantly outperforms the precoding system using one matched filter as proposed in [1].