【作者】 闫永梅；

【导师】 王华奎；

【作者基本信息】 太原理工大学 ， 信号与信息处理， 2008， 硕士

【摘要】 随着无线通信的发展,各种无线通信系统相继出现,无线局域网(WLAN)、自组网(Ad hoc)、无线个域网(WPAN)等概念的提出掀起了短距离无线通信研究的热潮。然而,人们对无线通信系统的要求仍在不断提高,希望其提供更高的数据传输速率、成本更低、功耗更小。而超宽带(UWB)可以满足这些需求,它将成为未来短距离无线通信的主流技术。超宽带技术无论是在美国还是欧洲,都得到了极大的关注。超宽带系统由于其低功耗、低截获率和抗多径衰落效益好等特点,特别适合应用在短距离无线通信领域中。对UWB技术的研究仅仅是近几年才引起人们的注意,其中一个研究方向涉及到调制方式。因为采用不同调制方案,对系统传输速率、抗多径干扰能力有很大影响。对它们进行分析比较,对系统调制信号的设计具有一定的参考意义。另外,对系统速率的不断提高也是人们不懈追求的目标。混沌动力学的发现为扩频序列研究提供了新的思路。混沌现象是在非线性动态系统中出现的确定性的,类似随机的过程,这种过程非周期,是一种貌似无规则的运动,不收敛但有界,且对初值具有及其敏感的依赖性,这些独具特色的性质使得混沌在通信应用领域尤其在伪随机码的产生方面有着很好的应用前景。本文针对超宽带系统进行了相关的介绍和研究,所做主要工作如下:1、从UWB通信的基本原理入手,分析了其系统的技术特点,了解了其广泛的应用领域,研究了UWB通信系统常用的调制方式,重点研究了常用的调制方式:脉冲位置调制(PPM)。2、研究了超宽带通信系统中,信号波形的选择、信号的产生以及调制信号的波形。3、讨论了在UWB系统中采用跳时码(TH码)与PPM调制技术结合后,信号的功率谱变化情况及TH码对信号功率谱的影响。4、重点研究了基于帐篷映射(Tent)映射产生的伪混沌码(PC码),比较了这种伪混沌码与常用的伪随机码的性能,并研究了在UWB系统中采用伪混沌码后的误码率性能。更多还原

【Abstract】 Along with the development of wireless communication, all kinds of wireless communication systems appeared, the advanceing of WLAN、Ad hoc、WPAN raise the upsurge on the short distance wireless communication. However, the people’s demands are increasing, hoping it to provide higher data rate、lower cost and power. And Ultra-WideBand (UWB) can meet these demands. It is becoming the main technique on short distance wireless communication in future. Whatever in America or in Europe, UWB technique gained great attention. The UWB system specially applies in short distance wireless communication because of its characteristics such as lower power、low capture rate and anti-multi-path decline ability.It is these years that UWB aroused the people’s attention, one of the research directions relating to the modulation. Different modulations give great effect to system transmission rate, anti-multi-path ability. To draw comparison of them will have certain reference meaning to the system’s modulation design. In addition, the improving on data rate of the systems is also our hanker goal.The discovery of chaotic dynamic system broad the way of study of PN sequence. Chaos is a convinced and random kind course that appears in the nonlinear system. It is an unperiod and an irregular course. It is not convergence but dose have a bound, while it is sensitive to its initial value. For all these special performance, chaos has a excellent outlook in the application of telecommunication, especially in the generation of PN sequence.This paper carries through correlative introduction and research on UWB system. The main researches and results are the following:1、Starting with the rationale of UWB, analyzed the technique characteristics of the system, known about its abroad applications fields, traversed the common modulation of UWB.2、Analyzed the choice of the waveform、the build of the signal and the waveform using the general modulation.3、Discussed on the changing complexion of the signal power spectrum and the influence of time hopping (TH) code, after combining the TH code with PPM.4、Reserached the generation of pseudo-chaotic (PC) code based on the Tent map, comparing the performance of the PC code with the PN code, also studing the Bit Error Ratio after adopting the PC code.更多还原