【作者】 涂春江；

【导师】 陈弘毅； 刘伯安；

【作者基本信息】 清华大学 ， 电子科学与技术， 2005， 博士

【摘要】 本论文研究了超宽带脉冲收发机的一些关键问题,包括RAKE接收机、多用户检测、相关器和延时线电路设计。论文以M元双正交键控直接序列扩频为调制方式的脉冲超宽带通信做为研究对象,全面研究了该调制方式下的RAKE接收机的理论性能,并且进行了计算机仿真。由于这种传统的RAKE接收机在前端模拟电路中需要大量相关器单元,因此论文提出一种简化RAKE接收机。这种接收机在前端只需要较少模拟相关器单元,将RAKE接收与合并移至后端数字电路处理,从而降低对前端电路设计要求。分析和仿真证明,与传统RAKE接收机相比,简化RAKE接收机在误码率性能类似的情况下,能明显降低前端电路的复杂度。为提高在多用户环境下的接收性能,论文基于简化RAKE接收机结构,提出了多用户RAKE接收机和最小均方误差标准的多用户检测算法。仿真表明,这两种接收机在多用户条件下性能明显优于单用户RAKE接收机。论文对系统实现上所需要的关键电路模块也做了相应研究。相关器是一种专门用于超宽带脉冲通信信号检测的电路单元,它的功能是将输入脉冲与本地匹配脉冲进行相关运算。论文分别在SiGe BiCMOS工艺和CMOS工艺下设计了相关器电路。为对相关器的性能进行仿真和测试,我们提出双频模型。该模型解决了在没有高频脉冲源的情况下相关器的性能测试问题。由于应用于超宽带通信的相关器的两个输入端口分别为本地匹配脉冲信号和接收到的射频信号,因此它可以用一个周期时变系统描述。在此基础上,论文提出了适用于超宽带的相关器噪声模型。延时线在接收机中的作用是将本地匹配脉冲产生延时,以供不同相关器对信号进行捕获和跟踪。我们在CMOS工艺下设计了由基本放大单元加上源级反馈网络组成的延时单元。为对论文中的设计进行验证,我们采用SMIC 0.18μm射频和混合信号工艺对相关器和延时线进行了流片和测试。测试结果表明,电路能够进行信号相关和延时运算,基本满足设计要求。更多还原

【Abstract】 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更多还原