基于循环谱理论的超宽带定时估计研究

发布时间：2019-02-09 14:53

【摘要】：在军事、公共事业和商业通信系统等领域,超宽带由于具有发射功率低、穿透能力强、多径分辨能力强及处理增益高等优点而得到广阔应用。定时估计是超宽带信号处理中的一个重要课题。高度周期性的结构使得脉冲和基于多载波的超宽带信号表现出高度的循环平稳性,与此相关的循环谱特性可以用来进行超宽带信号的多种信号处理任务。二阶循环平稳中的两个数学工具:循环自相关函数以及谱相关密度函数使得循环谱理论应用于超宽带信号中的定时估计分析成为可能。本论文通过推导超宽带信号TH-PPM和DS信号的码片级和符号级延时的循环自相关函数和谱相关密度函数进而完成定时估计任务。本论文的超宽带定时估计包括循环谱定时估计和高阶矩定时估计两个部分的研究。其中,循环谱定时估计是针对码片级延时的超宽带信号定时估计,高阶矩定时估计则是针对符号级延时的定时估计。首先阐述超宽带信号中的高斯脉冲信号;脉冲位置调制、脉冲幅度调制、跳时扩频以及直接序列扩频等扩频调制方式;然后介绍超宽带系统中常用的三种定时估计方法。接着分析循环平稳理论中的一阶、二阶循环平稳以及谱估计的方法。然后进行超宽带信号的码片级延时定时估计,在建立TH-PPM和DS信号模型的基础上,推导其循环自相关函数以及谱相关密度函数的表达式,通过MATLAB仿真出这两种信号的谱相关密度函数三维图,由仿真结果、参数设置计算和推导结果进行码片级的超宽带信号定时估计。最后的符号级延时定时估计是在码片级延时定时估计的基础上,利用三阶统计量进行的推导、仿真和高阶矩定时估计。通过仿真计算,本论文完成了定时估计任务,并且利用本论文的研究成果,通过简单的改进,可以实现更高精度的定时估计。
[Abstract]:Ultra-wideband (UWB) has been widely used in military, public utility and commercial communication systems due to its advantages of low transmission power, strong penetration, high multipath resolution and high processing gain. Timing estimation is an important subject in UWB signal processing. The highly periodic structure makes the pulse and UWB signals based on multi-carrier have a high cyclic stationarity, and the related cyclic spectral characteristics can be used to deal with various signal processing tasks of UWB signals. Two mathematical tools in second order cyclic stationarity, cyclic autocorrelation function and spectral correlation density function, make it possible for the cyclic spectrum theory to be applied to the timing estimation analysis of UWB signals. In this paper, the cyclic autocorrelation function and spectral correlation density function of chip level and symbol level delay for TH-PPM and DS signals of UWB signal are derived to complete the task of timing estimation. The UWB timing estimation in this paper includes two parts: cyclic spectrum timing estimation and high order moment timing estimation. Among them, cyclic spectrum timing estimation is for chip level delay of UWB signal timing estimation, high order moment timing estimation is for symbol level delay timing estimation. In this paper, Gao Si pulse signal in UWB signal, pulse position modulation, pulse amplitude modulation, time-hopping spread spectrum and direct sequence spread spectrum modulation are introduced, and then three common timing estimation methods in UWB system are introduced. Then the first and second order cyclic stationary and spectral estimation methods in cyclic stationary theory are analyzed. Secondly, the chip level delay timing estimation of UWB signal is carried out. Based on the TH-PPM and DS signal models, the expressions of cyclic autocorrelation function and spectral correlation density function are derived. The spectral correlation density function of these two kinds of signals is simulated by MATLAB. The timing estimation of chip level UWB signals is carried out by simulation results, parameter setting calculation and derivation. Finally, the symbol level delay timing estimation is based on the chip level delay timing estimation, and the derivation, simulation and high-order moment timing estimation are carried out by using third-order statistics. Through simulation, the task of timing estimation is completed in this paper, and a more accurate timing estimation can be realized by simple improvement using the research results of this paper.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN911.23

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