摘要
超宽带(UWB)通信技术是一种新兴的短距离无线通信技术,因具有高达GHz的带宽并能提供上百兆的高速率等优点,成为当前研究与开发的热点。但是,超宽带技术要走向成熟,还需要解决许多关键的技术问题。其中之一就是接收机的硬件实现,要求它不仅有良好的接收性能,还要有简单的结构。
本文首先论述了超宽带通信的发展动态、基本原理和信道模型。接下来讨论了几种UWB接收技术。然后着重围绕自适应最小均方误差(MMSE)的DS-UWB多用户检测方案展开论述并分析其在FPGA上的实现性能。通过分析比较不同自适应算法在FPGA实现接收方案中的效果,得出LMS算法的误码率和计算复杂度都较RLS算法低,所以选择它来调整权系数的结论。在此基础上,借助软件设计为硬件实现提供接收信号并利用FPGA实现了该接收过程,其中提出了一种利用SOPC开发的方法将接收数据烧写入Flash中。另外,为了协调Flash与FPGA时钟频率不同的问题,提出了一种使用FIFO以及互相反馈的方式来提高设计的性能和灵活性。
Ultra-Wideband (UWB) is a novel short-distance wireless communication technique, which has a wide bandwidth up to GHz and is able to provide a high data rate up to Mbps, thus it becomes a hot spot in current researches. However, there are some key problems must be solved before it is matured, one of which is the hardware implementation of its receiver. It requires not only a good performance, but also a simple structure.
In this paper, the develop trends, the basic theory and the multipath channel model of UWB communication are introduced at first. After that, we lay emphasis on the multiuser detection for DS-UWB receiver based on MMSE method and analyze the performance on FPGA. By comparing the receiver’s performances using different kinds of adapter algorithm on FPGA , we conclude that LMS algorithm has the lower error rate and simpler calculation than RLS algorithm, therefore, LMS algorithm is chosen to adjust the power in this design. Based on these, received signals are created with the aid of software and the whole receive process is implemented on FPGA. Hereinto a storage scheme which can programme the received data into Flash by the SOPC design method is advanced in this design. In addition, in order to coordinate the different clock frequency between Flash and FPGA, the way of utilizing FIFO and feedback mutually is put forward, which can provide better performance and flexibility for the design.
引文
[1] 王金龙,王呈贵,阚春荣,徐以涛. 无线超宽带(UWB)通信原理与应用. 北京:人民邮电出版社,2005.11:1-3, 35-40
[2] Foerster J., E. Green, Somayazulu V. S., and Leeper D., Ultra-wide Band Technology for Short or Medium-range Wireless Communications, Intel Tech. J,vol.5, no.2, May 2001
[3] Yoshiyuki Ishiyama, Tomoaki Ohtsuki, Performance Comparison of UWB-IR using Rake Receivers in UWB Channel Models,Ultra Wideband Systems, 2004. Joint with Conference on Ultrawideband Systems and Technologies. Joint UWBST & IWUWBS. 2004 International Workshop on, 18-21 May 2004 pp.226-230
[4] Christine Uhl, Christophe Le Martret, Jamming Assessment of Impulse UWB Signals on Galileo Receivers, Ultra Wideband Systems, 2004. Joint with Conference on Ultrawideband Systems and Technologies. Joint UWBST & IWUWBS. 2004 International Workshop on, 18-21 May 2004 pp.55-59
[5] Birgit Kull, Sven Zeisberg, UWB Receiver Performance Comparison, Ultra Wideband Systems, 2004. Joint with Conference on Ultrawideband Systems and Technologies. Joint UWBST & IWUWBS. 2004 International Workshop on, 18-21 May 2004 pp.21-25
[6] Qinghua Li and Leslie A.Rusch, Multiuser Detection for DS-CDMA UWB in the Home Environment, IEEE Journal on selected areas in communications, vol.20, no.9, Dec 2002.
[7] Freescale 的 UWB 芯片组得到 FCC 批准. http://www.cnexp.net/hangye_xinxi/dianzi/dianzihangqing/92936.html
[8] 国际电子商情. http://www.esmchina.com/ART_8800059982_617661.HTM.c2bf9ce3, 2005.1.30
[9] 东南大学成功研制我国第一套高速超宽带无线通信实验系统 http://forum.netbig.com/bbscs/read.bbscs?bid=1&id=6785405&page=524
[10] “首届中国超宽带无线技术论坛”在北京举行. http://www.uwbforum.org.cn/news/news20040924.htm, 2004.9
[11] 张新跃,崔琪楣,沈树群,大规模的 FPGA 超宽带系统设计. 电子技术,2004年第 11 期.
[12] 段吉海,郑继禺,仇洪冰,林基明,UWB 通信系统的 TH-PPM 信号产生与接收处理. 桂林电子工业学院学报,2005.6,pp.22-24
[13] 唐岚,王树勋,孙晓颖,胡封晔,超宽带无线传输技术. 吉林大学学报,2004.4,pp.332
[14] M.Z.winetal, impluse radio: How it works, IEEE communication letter, vol2, pp.36-38, 1998
[15] Maria-Gabriella Di Benedetto, Guerino Giancola, Understanding Ultra Wide Band Radio Fundamentals. 北京:电子工业出版社, 2005.5:19-21
[16] 亢洁,杨刚,应用传输参考信号改进的超宽带差分相关接收机. 陕西科技大学学报,2005.12,pp.101-103
[17] 郑军,TR-UWB 系统自相关接收机性能研究.华中师范大学硕士学位论文, pp.22-23
[18] J.Zhang, T. D. Abhayapala, R. A. Kennedy, performance of ultra wideband correlator receiver using gaussian monocycles, ICC 2003-IEEE International Conference on Communication, vol.26, no.1, May 2003, pp.2192-2196
[19] Dr.Jeffrey Reed, Dr.R.Michael Buehrer, Introduction to UWB: Impulse Radion for Radar and Wireless Communications. http://www.mprg.org
[20] 方旭明,何蓉,短距离无线与移动通信网络. 北京:人民邮电出版社,2004.8:223-224
[21] 李川,超宽带通信 Rake 接收技术研究. 电子科技大学硕士学位论文.
[22] Deqiang Wang, Danpu Liu, Performance Comparison of Two Kinds of UWB Rake Receiver, IEEE 6th CAS Symp. On Energing Technologies: Mobile and Wireless Comm. 2004, pp.329-332,
[23] 姚尚绩,郑继禺. 超宽带无线通信室内 Rake 接收机性能分析,桂林电子科技大学学报,2006.12,pp.425-426
[24] Qinghua Li, Leslie A.Rusch, multiuser receivers for ds-cdma UWB, 2002 IEEE conf.On ultra wideband systems and technologies, pp.163-168, 2002.
[25] 唐建锋,汪一鸣,基于自适应的 DS-UWB 多用户检测方案研究,微电子学与计算机,2005 第 22 卷,第 9 期,pp.127-131
[26] Qinghua Li, Leslie A.Rusch, Multiuser Detection for DS-CDMA UWB in the Home Environment, IEEE Journal on selected areas in communications, vol.20, no.9, Dec 2002.
[27] 潘松,黄继业. EDA 技术与 VHDL. 北京:清华大学出版社,2005.7:31-33
[28] EDA 先锋工作室,吴继华,王诚. Altera FPGA/CPLD 设计(基础篇). 北京:人民邮电出版社,2005.7:3-6
[29] 潘松,黄继业,曾毓. SOPC 技术实用教程. 北京:清华大学出版社,2005.3:3-10
[30] 任爱锋,初秀琴,常存,孙肖子. 基于 FPGA 的嵌入式系统设计. 西安:西安电子科技大学出版社,2004.10:197-198
[31] Altera Corporation, DE2 Altera Development and Education Board User Manual. pp.4-9 http://www.altera.com.cn/literature/lit-manual.jsp
[32] Altera Corporation, CycloneII Device Family Data Sheet,pp.9-14 http://www.altera.com.cn/literature/lit-cyc3.jsp
[33] 汪一鸣,朱洪波,基于自适应的 DS-UWB 同步捕获方法研究,2005 年全国超宽带无线通信技术学术会议
[34] 何振亚,自适应信号处理. 北京:科学出版社,2002.4:21-34
[35] 王晓雁,黄孜理,汪一鸣,基于 SOPC 的 Flash 数据烧写,装备制造技术,2007.3
[36] Altera Corporation, Nios II Flash Programmer User Guide, pp.9-15 http://www.altera.com.cn/literature/lit-nio2.jsp
[37] Altera Corporation, Implementing the Nios II Processor in SOPC Builder, pp.1-16 http://www.altera.com.cn/literature/lit-nio2.jsp
[38] Altera Corporation, Nios II Software Developer’s Handbook, pp.50-55 http://www.altera.com.cn/literature/lit-nio2.jsp
[39] Spansion, S29AL032D datasheet, pp.5-20 http://www.icpdf.com/pdf/S29AL032D.htm
[40] Altera Corporation, Single and Dual-clock FIFO Megafunctions User Guide, http://www.altera.com/literature/ug/ug_fifo.pdf
[41] Altera Corporation, Design Debugging Using the SignalTap II Embedded Logic Analyzer, pp.10-17 http://www.altera.com.cn/literature/quartus2/lit-qts-verification.jsp