Studies On The Transceivers For Ultra Wideband Communications

This dissertation focuses on some key issues in the transceivers for Pulsed Ultra-Wideband (UWB) Communications, including RAKE receiver, multiuser detection,correlator and delay line.The research work in the paper is based on MBOK DS-CDMA Pulsed-UWB. Thetheoretical performance of the RAKE receivers for MBOK UWB communications isanalyzed, and computer simulation is also taken. Considering that a large number ofcorrelators are necessary in the front-end circuit for traditional RAKE receivers, a newsimplified RAKE receiver is presented. It needs much fewer correlators in the front-end, and finger reception and combination are moved to the back-end digital circuits,which will release the requirements for front-end RF circuit. Simulation results showthat compared with traditional RAKE receivers with similar BER performance, thesimplified RAKE receiver can greatly reduce the hardware complexity of the front-endcircuit.Multiuser RAKE receiver and Multiuser detection algorithm are also presented inthe dissertation. Simulation results show that the performance of these two receiversare much better than single user RAKE receivers in multiuser environment.Some key circuit blocks are also researched in the dissertation. Correlator is aspecial block for UWB signal detection, which correlates the received pulses with thelocal template pulses. The correlator is designed using both SiGe BiCMOS and CMOStechnologies. Two-Tone model is developed for simulation and test of the correlator.It can measure the performance of the correlator at the lack of high frequency pulsesources. When the correlator is used for UWB receivers, the signals feed into the twoinput ports are local template pulses and RF pulses respectively, therefore it can betreated as periodical linear time varying system. Based on it, a new noise model for thecorrelator is also presented.Delay line is used to generator local template pulses with different time delay.It can be used for signal acquisition and tracking. A delay line, constructed by basic...