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。
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.
引文
[1]Maria-Gabridla等著,葛利嘉,朱林等译,超宽带无线电基础,北京,电子工业出版社,2006
[2]葛利嘉,曾凡鑫,刘郁林等,超宽带无线通信,北京,国防工业出版社,2006
[3]佘静,超宽带信号模型及调制方式的研究与仿真,[学位论文],武汉,武汉理工大学,2006
[4]周薛雪,超宽带(UWB)通信技术的特点及应用,西部广播电视,2005,12,12-15
[5]Moe Z.Win,Impulse Radio:How It Works,IEEE Communications Letters,1998,VOL.2,NO.2,36-38
[6]刘婕,陈伟,UWB无线通信关键技术研究,武汉理工大学学报·信息与管理工程版,2005,27(5),237-240
[7]胡君萍,UWB技术及其应用探讨,武汉理工大学学报·信息与管理工程版,2005,27(5),261-264
[8]李熹,王治国,费元春等,超宽带无线电系统跳时技术的研究,微计算机信息,2006,22(2),172-174
[9]高远,齐本胜,石春燕,基于MATLAB的UWB信号仿真模型,河海大学常州分校学报,2004,18(4),30-32
[10]刘己斌,赵惠昌,PPM伪随机码及其应用,现代雷达,2004,26(2),23-26
[11]Sylvain Chaillou,Didier Helal,Chiara Cattaneo,Timed Simulator for UWB Communication Systems,IEEE Conference on Ultra Wideband System and Technologies,2002,0-7803-7496-7/02,7-11
[12]Hiroyuki Torikai,Toshimichi Saito,Wolfgang Schwarz,Synchronization via Multiplex Pulse Trains,IEEE Transactions On Circuits And Systems-I:Fundamental Theory And Applications,1999,VOL.46,NO.9,1072-1085
[13]欧阳永艳,超宽带通信信道模型,桂林电子工业学院学报,2003,23(3),18-20
[14]段吉海,郑继禹,仇洪冰等,UWB通信系统的TH-PPM信号的产生与接收处理, 桂林电子工业学院学报,2005,25(3),20-24
[15]R.A.Scholtz,Multiple Access with Time-Hopping Impulse Modulation,IEEE Military Communications Conference,1993,0-7803-0953-7/93,447-450
[16]郑霖,欧阳缮,UWB信道下的TH-PPM多径多址解调性能分析,系统工程与电子技术,2005,27(10),1676-1680
[17]邹卫霞,房玉东,周正,跳时超宽带无线电的性能分析,电路与系统学报,2005,10(6),69-72
[18]Moe Z.Win,Robert A.Scholtz,Ultra-Wide Bandwidth Time-Hopping Spread-Spectrum Impulse Radio for Wireless Multiple-Access Communications,IEEE Transactions On Communications,2000,VOL.48,NO.4,679-691
[19]吴斌,于东海,邹采荣,超宽带跳时扩频调制技术研究,江苏通信技术,2004,20(1),9-13
[20]Santosh S.Kolenchery,J.Keith Townsend,James A.Freebersyser,A Novel Impulse Radio Network For Tactical Military Wireless Communications,IEEE Military Communications Conference,1998,0-7803-4506-1/98,59-65
[21]高志英,郑国莘,超宽带跳时扩频通信系统性能分析,上海大学学报(自然科学版),2004,10(3),225-229
[22]赵立昕,蔡志坚,周正,超宽带信号的时频分析,高技术通讯,2006,16(2),133-135
[23]李旭光,仇洪冰,赵静,跳时超宽带信号的功率谱分析,现代电子技术,2004,6,33-36
[24]肖要强,混沌序列及其在通信系统中的应用研究,[学位论文],长沙,湖南师范大学,2005
[25]赵春明,尤肖虎,程时昕,混沌序列的数字发生及其在通信中的应用,东南大学学报,1995,25(4),137-142
[26]李辉,混沌数字通信,北京,清华大学出版社,2006
[27]张勇,混沌序列在扩频通信应用中的研究,[学位论文],合肥,合肥工业大学,2003
[28]张晓伟,王玫,一种基于Tent映射量化的二值混沌序列的设计,桂林电子工业学 院学报,2006,26(2),85-88
[29]刘健,徐耀群,秦红磊,平面帐篷映射的研究,哈尔滨商业大学学报(自然科学版),2002,18(4),450-451
[30]Toni Stojanovski,Ljupco kocarev,Chaos-Based Random Number Generators-Part I:Analysis,IEEE Transactions On Circuits And Systems-I:Fundamental Theory And Applications,2001,VOL.48,NO.3,281-288
[31]白薇,混沌序列在CDMA中的应用,[学位论文],哈尔滨,哈尔滨工程大学,2004
[32]Gian Mario MAGGIO,David LANEY Frederic LEHMANN,A Multi-Access Scheme For UWB Radio Using Pseudo-Chaotic Time Hopping,IEEE Conference on Ultra Wideband System and Technologies,2002,0-7803-7496-7/02,225-229
[33]Gian Mario Maggio,Pseudo-Chaotic Time Hopping For UWB Impulse Radio,IEEE Transactions On Circuits And Systems-I:Fundamental Theory And Applications,2001,VOL.48,NO.12,1424-1435
[34]徐耀群,刘健,秦红磊,平面帐篷映射二进制混沌序列分析,哈尔滨商业大学学报(自然科学版),2003,19(1),47-51
[35]蒋国平,万冬东,薛龙,超宽带通信中一种新的伪混沌编码器及其解码方法,通信学报,2005,26(10),72-77
[36]孙华明,周正,一种新的超宽带多用户调制方式:伪混沌编码跳时调制,无线电工程,2005,35(3),3-7
[37]李振强,王勇,张水莲,基于Gold码的跳时序列在超宽带系统中的应用,移动通信,2004(3月增刊),9-11
[38]张振宇,曾凡鑫,葛利嘉,超宽带无线电中跳时序列相关性能的研究,电子与信息学报,2004,26(8),1257-1261
[39]刘健,徐耀群,秦红磊,平面帐篷映射输出序列的相关性分析,哈尔滨商业大学学报(自然科学版),2003,19(2),147-148
[40]张振宇,曾凡鑫,葛利嘉,跳时序列与跳频序列的性能分析,通信技术,2003,1.85-88
[41]Ghobad Heidari-Bateni,Clare D.McGillem,A Chaotic Direct-Sequence Spread-Spectrum Communication System,IEEE Transactions On Communications, 1994,VOL.42,NO.2/3/4,1524-1527
[42]薛龙,万冬东,蒋国平,基于混沌扩频序列的超宽带通信系统多址性能,东南大学学报(自然科学版),2005,35(增刊Ⅱ),22-25
[43]张振宇,曾凡鑫,葛利嘉,跳时序列对UWB系统多址性能的影响,电讯技术,2003,4,15-19
[44]Mikhail Sushchi,Jr.,Nikolai Rulkov,Chaotic Pulse PositioModulation:A Robust Method of Communicating with Chaos,IEEE Communication Letters,2000,VOL.4,NO.4,128-130
[45]仇洪冰,郑霖,脉冲超宽带TH-PPM多址通信的误比特率计算方法,通信学报,2005,26(10),133-137
[46]马龙,王庭昌,基于混沌映射的UWB-IR抗截获性能分析,通信学报,2005,26(10),138-142
[47]岳光荣,葛利嘉,超宽带无线电抗干扰性能研究,电子与信息学报,2002,24(11),1544-1550
[48]Douglas R.Frey,Chaotic Digital Encoding:An Approach to Secure Communication,IEEE Transactions On Circuits And Systems-Ⅱ:Analog And Digital Signal Processing,1993,VOL.40,NO.10,660-666
[49]岳光荣,李川,李少谦,超宽带跳时PPM信号在多径环境下的误码率性能优化,通信学报,2005,26(10),7-12
[50]陈怀琛,吴大正,高西全,MATLAB及在电子信息课程中的应用,北京,电子工业出版社,2003