Ultra-wideband Wireless Communication Systems And A Number Of Key Technology Research

Ultra Wideband (UWB) radio is a novel wireless communication technology, which has been speed up to develop in recent years. According to the Federal Communications Commission (FCC) UWB rulings, the signal is recognized as UWB if the -10dB fractional bandwidth of the signal is greater than 20% or the absolute bandwidth of the signal is greater than 500MHz. UWB system has many benefits, which made UWB the most potential physical layer technology for short distance and high or low speed wireless communication. Ultra Wideband wireless communication system has an extensive perspective of application, and will become an important part of future wireless ubiquitous network. At present, UWB has been an excellent candidate for a variety of applications such as commerce multimedia equipment, wireless sensor network, wireless positioning, wireless home or personal network, as well as intelligent traffic system. As a result, it's of all-important significance of science and reality to establish and consummate the basic theory of UWB wireless communication system and resolve the key techniques. This dissertation mainly discusses the key techniques and continuous evolution issues of UWB communication technology. The issues can be divided into three parts: optimal UWB pulse waveform design, system analysis and architecture design of Cognitive Ultra Wideband (CUWB) wireless communication system, and adaptive pulse waveform design for CUWB system.This dissertation includes 6 chapters. The main content and innovation can be summarized as following:Chapter 1 is the introduction. In the chapter, the notion, the characteristics, prospect of deployment, and the key techniques of UWB system are introduced. Then, the main research content and innovation of this dissertation are summarized.In chapter 2, the general issues of UWB pulse waveform design are described. The basic principle of UWB-IR system is introduced. The power spectrum analysis of classic pulse signal shows the importance of UWB pulse waveform design. Finally, the common requirement and estimate target of UWB shaping pulse design are summarized based on the work of pioneer researchers, moreover, several typical UWB shaping pulse are introduced.In chapter 3, a novel optimal UWB shaping pulse design algorithm based on prolate spheroidal wave functions (PSWFs) is described. Firstly, some shortage of UWB pulse design at present is pointed out. The theoretical groundwork of PSWFs related with the algorithm is introduced, including the definition, the characteristics and approximate numerical solution of PSWFs. Then, a novel UWB pulse design algorithm based on the complete orthogonality of PSWFs was presented to improve the spectrum utilization efficiency and conform the special emission mask constraint. UWB pulse could be obtained by orthogonal synthesis of finite number of PSWFs pulse basis, which matching FCC emission mask. The simulation results show the validity of this algorithm.In chapter 4, a novel intelligent wireless system which is called Cognitive Ultra Wideband (CUWB) wireless communication system is expatiated. Firstly, Cognitive radio is simply introduced, mainly including the concept, the typical cognitive cycle model and the main functional characteristics. Then, essentiality and feasibility of the research combined ultra wideband with cognitive radio is analysed. Furthermore, the chapter gives the notion of CUWB, expounds the operating fundament of CUWB, describes the system cognitive cycle, presents a simple system cognitive cycle processing model and analyzes the core functions and key techniques of CUWB system in detail. Finally, the architecture of CUWB system is established by applying the design methods combined ISO layer design with cross-layer design.In chapter 5, a novel adaptive pulse waveform design algorithm based on measurement of interference temperature for CUWB system is presented. Firstly, the concept and the power spectrum estimate method of interference temperature are introduced. Then, this chapter gives a scheme of dynamically obtaining adaptive emission mask based on measurement of interference temperature to adapt to spectrum environment and be compatible with FCC spectral mask. Finally, a method to generate adaptive CUWB shaping pulse is proposed based on weight combination of PSWFs matching UWB multiple sub-band spectral mask. The simulation results show that the pulse waveforms shaped by this method conform the spectral mask constraint for CUWB, adapt to dynamical variety of the spectral mask.In the last chapter, we conclude the whole dissertation and point out succeeding works in the future researches.