UWB无线通信Rake接收技术的研究-通信与信息系统专业毕业论文.docx

摘 要
超宽带(UWB)通信作为一种新的短距离高速无线通信技术,以其频带极宽、功率谱密度极低、传输速率高、截获概率低、多径分辨率好、频谱共用等特点,在无线通信领域必将发挥重要作用。由于超宽带信号本身功率谱密度极低,并且传输中受到路径损耗、阴影效应、特别是多径衰落等因素的影响,作为超宽带通信接收机的关键技术之一:Rake 接收技术的研究对超宽带通信系统的设计研究显得尤为重要。
本文首先论述了超宽带通信系统的一些关键技术,包括频带方案设计、脉冲信号的设计与产生、调制、多址、同步与接收、信道估计和高
采样速率的实现。建立了超宽带室内信道模型,并进行了模型仿真。同
时给出了Rake接收的系统模型,比较了不同路径合并方式Rake接收对系统的性能影响。在采用最大比合并方式下,根据路径平均权值相等与不等的两种条件,分别推导了Rake接收的误码率性能。 信道模型下,对提出的ARake、SRake和PRake接收机的性能进行仿真分析,得出了在稀疏信道模型和密集信道模型环境下如何选择Rake接收机结构的结论。
关键词:多径衰落Rake接收信道估计UWB信道模型
ABSTRACT
Ultra-wideband(munication is a novel short—distance wireless eon'lmunication must have a great influence munication
field with extreme晰de bandwidth,lOW power spectral density(PSD),high
data rate,lOW probability of intercept,high multipath resolution,and sDectrnm reuse ct receiver of munication system plays the key role of the reception technology of UWB signal for the reason that it’S lOW PSD,impacted by path loss,shadowing,especially multipath fading
and SOon.
The key techniques of munication,such勰the design of
spectrum schemes,the shaping and producing of pulse signals,modulation, multiple access and reception techniques,channel
estimation and implementation of hi曲sampling rate are in灯oduced in the
paper the UWB indoor channel model is set up and analyzed,
and simulation ofwhich are ,the system model of
Rake receiver is proposed and the influence of different bined paRem on the performance of Rake receiver is BER performance of the Rake receiver is calculated for both equality and
inequality ofpath mean weight in the condition ofmaximum signal—.to..noise
ratio(bined the final,the performance of ARake,
SRake and PRake receiver are theoretically analyzed for the modified S-V
channel analytical results are verified puter simulations. As a result,it is deduced that how to select Rake receivers in the sparse channel model and dense channel model by the a