超宽带无线通信中信道模型及信道估计技术研究

发布时间：2018-05-29 09:46

本文选题：超宽带 + 信道模型　；参考：《成都理工大学》2017年硕士论文

【摘要】：随着半导体技术的发展和网络技术的普及,各种智能设备在大众生活中普及开来,消费者对短距无线通信小型化、低成本、节能化、高速化等多方面的需求在这样的背景下与日俱增,超宽带(Ultra-wideband,UWB)技术因具有一些独特的优势刚好可以满足人们对短距离无线通信的上述需求。虽然超宽带技术在本世纪初就已经开放到民用领域了,但到目前为止主要的成果还集中在基于UWB技术的室内定位,关于无线通信领域的进展相对较少,主要是因为UWB技术应用到无线通信中还面临着一些技术难题,如:UWB信号的检测接收技术、UWB系统收发端的同步技术、UWB系统信道建模及信道估计技术等。本文的研究主要是关于UWB系统中的信道模型及信道估计技术。回顾整个UWB技术的发展历程,其中关于UWB信号方案(信道模型及估计技术)的发展大致可以分为三个阶段。第一阶段是摸索阶段,在这一阶段,关于UWB信道模型的研究主要是基于当时已有技术的移植;第二个阶段可以称为统一标准阶段,因为UWB技术应用于无线通信领域具有较大的优势,各大企业和机构为了抢占先机,纷纷投入了大量的人力物力资源,这就推动了UWB无线领域的标准制定;第三个阶段是不断改进阶段,也是现在所处的阶段。首先介绍了UWB信号的传播特性,然后以传统无线通信中的信道模型为切入点,简述了超宽带无线系统中信道模型的发展历程,重点介绍了S-V/IEEE802.15.3a参考模型,分析比较了它的优缺点。和传统的窄带或宽带系统相比,超宽带系统的衰落特性和信道稀疏特性均有很大不同。针对S-V/IEEE802.15.3a参考模型所存在的一些缺陷介绍了两种在其基础上修正后的UWB室内系统模型,并利用现有的数据进行了分析比较。从时域、频域和结构化、非结构化几个方面详细介绍了UWB无线通信系统中的信道估计技术,并对几种常见的估计方法进行比较,着重介绍了一种对噪声有一定的抵抗能力的估计方法,即基于FOS的盲UWB信道估计方法。传统的超宽带信道估计算法有一个共性,即都需要对信号进行高速率的采样,但由于UWB信号带宽非常大(500MHz),目前的ADC技术很难在低成本的前提下支撑起这一技术,压缩感知理论的提出使低速率采样成为了可能。本文对压缩感知理论进行了详细的介绍,包括其理论框架、观测矩阵的设计和CS信号重构算法等;然后对基于CS理论的UWB系统建模,介绍一般的OMP信道估计算法并引入对OMP算法的改进,之后对两种算法进行仿真,结合性能及运算时间两个因素对两种算法进行了综合分析。
[Abstract]:With the development of semiconductor technology and the popularization of network technology, all kinds of intelligent devices are popularized in the public life. Consumers have miniaturized, low cost and energy saving for short distance wireless communication. With the increasing demand for high speed and so on, Ultra-wideband UWB (Ultra-wideband UWB) technology can meet the demand of short-range wireless communication because of its unique advantages. Although UWB technology has been open to civilian applications since the beginning of this century, so far the main achievements have been focused on indoor positioning based on UWB technology, and relatively little progress has been made in the field of wireless communications. The main reason is that the application of UWB technology to wireless communication also faces some technical difficulties, such as the detection and reception technology of the UWB signal, the synchronization technology of the transceiver of the UWB system, the channel modeling and channel estimation technology of the UWB system, and so on. The research of this paper is mainly about the channel model and channel estimation technology in UWB system. The development of UWB signal scheme (channel model and estimation technique) can be divided into three stages. The first stage is the groping stage, in which the research on the UWB channel model is mainly based on the transplantation of the existing technologies at that time; the second stage can be called the unified standard stage. Because the application of UWB technology in the field of wireless communication has a great advantage, in order to seize the opportunity, the large enterprises and institutions have invested a lot of human and material resources, which has promoted the establishment of standards in the field of UWB wireless; The third stage is the stage of continuous improvement and the stage in which we are now. In this paper, the propagation characteristics of UWB signal are introduced, and then the development of channel model in UWB wireless system is briefly introduced, the S-V/IEEE802.15.3a reference model is introduced, and its advantages and disadvantages are analyzed and compared. Compared with the traditional narrowband or wideband systems, the fading characteristics and channel sparsity characteristics of UWB systems are very different. Aiming at some defects of S-V/IEEE802.15.3a reference model, two modified UWB indoor system models are introduced, and the existing data are analyzed and compared. In this paper, the channel estimation techniques in UWB wireless communication systems are introduced in detail from time domain, frequency domain, structured and unstructured aspects, and several common estimation methods are compared. This paper mainly introduces a method of estimating the noise, that is, the blind UWB channel estimation method based on FOS. The traditional UWB channel estimation algorithms have a common feature, that is, it is necessary to sample the signal at high rate. However, because the bandwidth of UWB signal is very large, it is difficult for the current ADC technology to support this technology under the premise of low cost. The theory of compressed sensing makes low rate sampling possible. In this paper, the theory of compressed perception is introduced in detail, including its theoretical framework, the design of observation matrix and the algorithm of CS signal reconstruction, and then the modeling of UWB system based on CS theory. This paper introduces the general OMP channel estimation algorithm and introduces the improvement of the OMP algorithm. Then the two algorithms are simulated and the two algorithms are synthetically analyzed by combining the performance and the operation time.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN925

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