传输参考超宽带接收机优化设计与抗干扰性能研究
摘要
超宽带通信技术是一种新兴的短距离无线通信技术,它利用纳秒至皮秒级的非正弦波窄脉冲传输数据,具有传输速率高,功耗低,安全性好,抗多径能力强以及成本低廉等许多优点,特别是它不需要占用额外的频谱,可与现有的无线通信系统在同一频带内共存这一特点,使它在频谱资源日益紧张的今天受到了广泛的注意。目前,超宽带通信技术已成为无线通信技术研究的热点之一。
超宽带系统采用纳秒级窄脉冲作为传输信号,其传统的接收机结构为Rake接收机。Rake接收机要达到理论上比较好的检测性能,就必须进行精确的信道参数估计,搜索出每个延迟分支的纳秒级精确延迟和增益系数,这是非常困难的;加之超宽带信道的密集多径特性,需要数量很大的延迟分支,成本很高;另外Rake接收机对定时和同步的要求严格,这在超宽带系统中实现难度非常大。因此Rake接收机难以在较低成本下实现较好的检测性能。也由于这些原因,传输参考超宽带通信技术越来越受到人们的关注。
从原理来看,传输参考超宽带系统的发射脉冲是成对发送的,第一个是参考脉冲,而第二个脉冲上面调制了有用的数据信息,经过信道传输,它们经过相同的信道变化,在解调时可以用第一个脉冲作为数据脉冲的参考。传输参考超宽带系统的优点主要在于不需要信道估计和降低了同步要求。但是,参考模板中携带的信道噪声(高斯白噪声或干扰)在自相关过程中产生噪声乘噪声项,它严重的影响系统性能。所以,消除信道噪声的影响成为TR-UWB接收机设计的一个关键问题,也是本文的研究重点。
本文的研究主要内容:
介绍了超宽带通信的基本概念及发展历史;介绍了TR-UWB的基本概念和研究情况以及建立了传统TR-UWB系统模型。
分析了传统TR-UWB接收机性能,提出了平均接收机、MRC加权接收机、MMSE加权接收机以及平均-加权接收几种结构。并在AWGN信道下进行了系统性能分析和比较。并在Matlab平台上进行了仿真。
建立了超宽带信道模型,对传统接收机、MMSE接收机和MRC接收机进行了抗多径性能分析和仿真,并确定了下一步的研究方向。
针对传统的TR-UWB接收机以及所提出的几种优化结构的接收机进行了抗单音干扰分析。发现不同频率的干扰对接收机有不同的影响,部分干扰的初始相位影响接收机性能;在自相关中产生干扰直流量,这些直流量使±1判决出现不平衡现象,容易造成对-1或+1完全误判。文章提出一种干扰直流量消除方法来消除判决不平衡现象,并分析了方法的有效性,确定了下一步的研究方向。
Ultra-wideband (UWB) communication is a novel short-distance wireless communication technique, in which data is transferred with non-sinusoidal pulses with very short duration. UWB has many advantages, such as high transmission rate, low power consumption, good security, immune to multi-paths and low cost. Especially, UWB systems can coexist with the existing wireless communication systems at the same frequency band, that UWB can achieve license free wideband wireless access system. It is attracted for nowadays limited frequency spectrum resource.
Ultra-wideband communication transmits information with a train of narrow pulse, and generally receives signals by Rake receiver. Rake receiver need exactly estimate the delay and gain of all multi-paths. But t is very difficult to obtain exact delays and gains for the dense multi-paths environment. Due to the narrow pulse, precise synchronization is needed for the UWB Rake receiver. Thus, the UWB Rake receiver becomes too complex to be implemented. For these reasons, transmitted reference UWB have regained popularity.
According to the TR-UWB scheme, a pair of pulses is transmitted where the first pulse is unmodulated and the second is modulated by data. Both pulses are distorted in the same way by the channel since the inter between the pulse pair is very shot. So the first pulse can be used as reference or pilot for the demodulation of the second pulse. The advantages of TR-UWB are simple receiver architecture and synchronization. But the performance of TR-receivers are sensitive to type of channel noise such as additive white Gaussian noise and narrowband interferences Thus, it is an important issues to design the TR-receiver with the ability to mitigate the impact of noise.
The main contributions of this paper are as follows:
The definition, development and application of UWB and TR-UWB are introduced in the first chapter. The background of our research product about TR-UWB system is also presented.
The receiver models about TR-UWB with MMSE weighted receiver, MRC weighted receiver, average receiver and averaged-weighted receiver are proposed. Then, the performances of these receivers are analyzed with the AWGN channel. It shows the simulation results with the Matlab model.
The performance analyses of proposed receivers are also performed with the UWB channel.
The anti-jamming algorithms for single tone and partial frequency band interference are studied and optimized in this dissertation. The simulation results show that performance of anti-jamming algorithms is sensitive to frequency or phase of the interference signals, and imbalance is also introduced by the correlation processing. A novel anti-jamming algorithm is proposed for the signal imbalance. The simulation results show it is effective.
超宽带系统采用纳秒级窄脉冲作为传输信号,其传统的接收机结构为Rake接收机。Rake接收机要达到理论上比较好的检测性能,就必须进行精确的信道参数估计,搜索出每个延迟分支的纳秒级精确延迟和增益系数,这是非常困难的;加之超宽带信道的密集多径特性,需要数量很大的延迟分支,成本很高;另外Rake接收机对定时和同步的要求严格,这在超宽带系统中实现难度非常大。因此Rake接收机难以在较低成本下实现较好的检测性能。也由于这些原因,传输参考超宽带通信技术越来越受到人们的关注。
从原理来看,传输参考超宽带系统的发射脉冲是成对发送的,第一个是参考脉冲,而第二个脉冲上面调制了有用的数据信息,经过信道传输,它们经过相同的信道变化,在解调时可以用第一个脉冲作为数据脉冲的参考。传输参考超宽带系统的优点主要在于不需要信道估计和降低了同步要求。但是,参考模板中携带的信道噪声(高斯白噪声或干扰)在自相关过程中产生噪声乘噪声项,它严重的影响系统性能。所以,消除信道噪声的影响成为TR-UWB接收机设计的一个关键问题,也是本文的研究重点。
本文的研究主要内容:
介绍了超宽带通信的基本概念及发展历史;介绍了TR-UWB的基本概念和研究情况以及建立了传统TR-UWB系统模型。
分析了传统TR-UWB接收机性能,提出了平均接收机、MRC加权接收机、MMSE加权接收机以及平均-加权接收几种结构。并在AWGN信道下进行了系统性能分析和比较。并在Matlab平台上进行了仿真。
建立了超宽带信道模型,对传统接收机、MMSE接收机和MRC接收机进行了抗多径性能分析和仿真,并确定了下一步的研究方向。
针对传统的TR-UWB接收机以及所提出的几种优化结构的接收机进行了抗单音干扰分析。发现不同频率的干扰对接收机有不同的影响,部分干扰的初始相位影响接收机性能;在自相关中产生干扰直流量,这些直流量使±1判决出现不平衡现象,容易造成对-1或+1完全误判。文章提出一种干扰直流量消除方法来消除判决不平衡现象,并分析了方法的有效性,确定了下一步的研究方向。
Ultra-wideband (UWB) communication is a novel short-distance wireless communication technique, in which data is transferred with non-sinusoidal pulses with very short duration. UWB has many advantages, such as high transmission rate, low power consumption, good security, immune to multi-paths and low cost. Especially, UWB systems can coexist with the existing wireless communication systems at the same frequency band, that UWB can achieve license free wideband wireless access system. It is attracted for nowadays limited frequency spectrum resource.
Ultra-wideband communication transmits information with a train of narrow pulse, and generally receives signals by Rake receiver. Rake receiver need exactly estimate the delay and gain of all multi-paths. But t is very difficult to obtain exact delays and gains for the dense multi-paths environment. Due to the narrow pulse, precise synchronization is needed for the UWB Rake receiver. Thus, the UWB Rake receiver becomes too complex to be implemented. For these reasons, transmitted reference UWB have regained popularity.
According to the TR-UWB scheme, a pair of pulses is transmitted where the first pulse is unmodulated and the second is modulated by data. Both pulses are distorted in the same way by the channel since the inter between the pulse pair is very shot. So the first pulse can be used as reference or pilot for the demodulation of the second pulse. The advantages of TR-UWB are simple receiver architecture and synchronization. But the performance of TR-receivers are sensitive to type of channel noise such as additive white Gaussian noise and narrowband interferences Thus, it is an important issues to design the TR-receiver with the ability to mitigate the impact of noise.
The main contributions of this paper are as follows:
The definition, development and application of UWB and TR-UWB are introduced in the first chapter. The background of our research product about TR-UWB system is also presented.
The receiver models about TR-UWB with MMSE weighted receiver, MRC weighted receiver, average receiver and averaged-weighted receiver are proposed. Then, the performances of these receivers are analyzed with the AWGN channel. It shows the simulation results with the Matlab model.
The performance analyses of proposed receivers are also performed with the UWB channel.
The anti-jamming algorithms for single tone and partial frequency band interference are studied and optimized in this dissertation. The simulation results show that performance of anti-jamming algorithms is sensitive to frequency or phase of the interference signals, and imbalance is also introduced by the correlation processing. A novel anti-jamming algorithm is proposed for the signal imbalance. The simulation results show it is effective.
引文
[1] M. Z. Win, R. A. Scholtz. Impulse radio: How it works. IEEE Commun. Lett, 1998, Vol. 2, pp.36~38.
[2] 王中杰, 刘治德. 超宽带(UWB)无线通信技术.山西电子技术, 2006 年 01 期
[3] 韩立锋 超宽带无线通信技术. 中国数据通信,2005 年 01 期
[4] 邹卫霞 周正超宽带无线通信技术介绍 世界电子元器件,2005 年 01 期
[5] Federal Communications Commission. Revision of Part 15 of the Commission’s Rules Regarding Ultra-Wideband Transmission Systems. Ultra-Wideband (UWB) First Report and order, 2002, USA. ET. Docket 98~1537
[6] 曹志刚,钱亚生.现代通信原理.北京:清华大学出版社,1992.20~24
[7] Federal Communications Commission, ‘In the matter of revision of the commission’s rules regarding ultra-wideband transmission systems,’ First report and order, adopted: February 14, 2002, released Apr, 22, 2002. http://www. fcc .gov
[8] Anywlan. UWB:值得关注的无线通信新技术.http://www.anywlan. com/ view. asp?id=593.
[9] M.Z.Win, R.A.Scholtz. Ultra-Wide Bandwidth Signal Propagation for Indoor Wireless Communications. In Proc. IEEE ICC, 1997, Vol. 1.pp 56～60
[10] M. Z. Win, F. Ramirez-Mireles, R. A. Scholtz, et al. Ultra-Wide Bandwidth Signal Propagation for Outdoor Wireless Communications.In Proc. IEEE VTC, 1997, Vol. 3:251～255
[11] M. Z. Win, R. A. Scholtz. On the Robustness of Ultra Wide Bandwidth Signals in Dense Multipath Environment.IEEE. Comm. Letters, 1998, Vol. pp.251～256
[12] H. Lee, B. Han, Y. Shin, et al. Multipath characteristics of impulse radio channels. In Proc.IEEE VTC, 2000, Vol. 23. pp.2487～2491
[13] 张陆, 勇周正. 超宽带无线通信 http://www.ptsn.net.cn/xueyuan/technic/mobile/ comment.php3?id=443
[14] 柴宇 罗进文 超宽带无线通信及其两大标准. 电信工程技术与标准化, 2006年 05 期
[15] Bartosz Mielczarek, Matts-Ola Wassman, Arne Svensson. Performance of Coherent UWB Rake Receivers with Channel Estimators. IEEE VTC., 2003, Vol. 3. pp.1880~1884.
[16] 朱林,超宽带定位测距技术研究,四川大学 优秀硕士论文,2005
[17] 黄文,Location Technique in UWB System, 电子科技大学 硕士论文 2006
[18] CHOI J,STARK W. Performance analysis of RAKE receivers for ultra-wideband communications with PPM and OOK in multipath channels[A].Proc IEEE ICC[C]. New York, USA, 2002, 1969-1973
[19] D.Cassioli, M.Z. Win, F. Vatalaro, and A. F. Molisch,”Performance of low -complexity Rake reception in a realistic UWB channel”, Proc. IEEE Int. Conf.on commun,pp.763-767
[20] R.A.Scholtz, ”The orgins of spread-spectrum communications”, IEEE Trans. Commun. Vol.30, No.5, pp.822-854, May 1982
[21] R. Hoctor and H. Tomlinson, “Delay-hopped transmitted-reference RF communications,” Proc. Conf. on Ultra Wideband Sys. and Technol., pp. 265–270, June 2002
[22] J. D. Choi and W. E. Stark, “Performance of ultra-wideband communications with suboptimal receivers in multipath channels,” IEEE J. Select. Areas Commun., vol. 20, no. 9, pp. 1754 –1766, Dec. 2002
[23] A.Spiridon, F.Dowla , F.Nekoogar , D. Benzel”, On the performance of ultra-wideband transmitted-reference receivers”, IEEE Trans. comm. (submitted to publication.)
[24] 杨刚,亢洁,施仁。 超宽带传输参考接收机的性能研究. 通信学报. 第 26 卷第 10 期.122 页~127 页.
[25] Y.-L.Chao and R.AScholtz ”Optimal and Suboptimal Receivers for Ultral-Wideband Transmitted Referenc Systems”, Globcom, December, 2003. PP. 759 - 763
[26] Stefan Franz, Urbashi Mitra.”On Optimal Data Detection for UWB Transmitted Reference Systems” Globcom Volume 2, Dec. 2003. PP:744 – 748
[27] J.Romme G.Gurisi,”Transmit Reference Implse Radio Systems using Weighted Correlation”, IEEE 2004,pp.141-145
[28] Romme, J.; Witrisal, K.. “Transmitted-reference UWB systems using weighted autocorrelation receivers” ,Microwave Theory and Techniques, IEEE Transactions on Volume 54, Issue 4,Part 2, June 2006 .pp:1754 – 1761
[29] Honglei Zhang; Goeckel, D.L.“Generalized transmitted-reference UWB systems”, Ultra Wideband Systems and Technologies, 2003 IEEE Conference on 16-19 Nov. 2003, pp.147 – 151
[30] Federal Commmunications Commissions Report and order, Oct. 26, 2001 http: // www. fcc. gov
[31] A.Spiridon, F.Dowla, F.Nekoogar, D.Benzel, ”On the performance of ultra wideband transtimitted-reference receivers”, IEEE Trans.comm.(submitted to publication.)
[32] Marco Pausini, Gerard J.M.Janssen”, On the Narrowband Interference in Transmitted Reference UWB Receivers”, Ultra-Wideband, 2005. ICU 2005. 2005 IEEE International Conference on 5-8 Sept. 2005 pp.:571 – 575
[33] Dowla.F, Nekoogar.F, Spiridon.A, “Interferencemitigation in transmitted-reference ultra-wideband (UWB) receivers”, Antennas and Propagation Society International Symposium, 2004. IEEE Volume 2, 20-25 June 2004 pp.1307 – 1310
[34] Lei Feng, Won Namgoong, “Oversampled channelized receiver for transmitted reference UWB system in the presence of narrowband interference”, Signal Processing Systems, 2004. SIPS 2004. IEEE Workshop on 2004 pp.48 – 52
[35] SUSHCHIK M.et al.”Performance analysis of correlation-based communication schemes utilizing chaos[J]”, IEEE Transactions on Circuits and Systems-I, 2000, 47(12) pp.1684-1691
[36] M.Z.Win and R.A.Scholtz,”Impulse radio:How it works”, IEEE commun.Lett, vol.2, No.2, pp.36-38, Feb.1998
[37] ---,”Ultra-wide bandwidthtime-hopping spread-spectrum impulse radio for wireless multiple-access communications”, IEEE Trans. Commun, vol.48, no.4,pp.679-691, Apr 2000
[38] M.Hamalainen, V.Hovinen, R.Tesi, J.H.Iinatti, and M.Latva-aho, “On the UWB system coexistence with GSM900, UMTS/WCDMA, and GPS”, IEEE J.Selet. Areas Commun. Vol.20, no.9, pp.1712-1721, Dec. 2002
[39] A.Saleh , R.Valenzuela., “A Statistical Model for Indoor Multipath Propagation”, IEEE JSAC, vol. SAC-5, no.2, FEB. 1987.128-37
[40] 陈小云,李巍 “超宽带(UWB)的信道模型”,2005 年全国超宽带无线通信技术学术会议 页码:241-142
[41] 郑军,李玲远,樊艳,李正强,徐雪慧,“一种 TR-UWB 系统的改进自相关接收机”,2005 年全国超宽带无线通信技术学术会议 页码:235-239
[42] Yi-Ling Chao,”Optimal Integration Time for UWB Transmitted Reference Correlation Receivers”, IEEE 2004 pp.647-651
[43] B.Basore,”Noise-like signals and their detection by correlation”, Ph.D. dissertation, MIT, Cambridge, MA, May 2003
[44] C.Rushforth, “Transmitted-reference techniques for random or unknown channels”, IEEE Trans. Inform Theory, vol. 10, pp 39-42, Dec 1964
[45] R.Galiardi, “A Geometrical study of transmitted reference communication system”, IEEE Trans. Commun, pp 118-123 Dec 1964
[46] TG4a channel modeling group, Andreas F. Molisch (Chairman), “802.15.4a Channel model subgroup final report”, Sept. 2004
[2] 王中杰, 刘治德. 超宽带(UWB)无线通信技术.山西电子技术, 2006 年 01 期
[3] 韩立锋 超宽带无线通信技术. 中国数据通信,2005 年 01 期
[4] 邹卫霞 周正超宽带无线通信技术介绍 世界电子元器件,2005 年 01 期
[5] Federal Communications Commission. Revision of Part 15 of the Commission’s Rules Regarding Ultra-Wideband Transmission Systems. Ultra-Wideband (UWB) First Report and order, 2002, USA. ET. Docket 98~1537
[6] 曹志刚,钱亚生.现代通信原理.北京:清华大学出版社,1992.20~24
[7] Federal Communications Commission, ‘In the matter of revision of the commission’s rules regarding ultra-wideband transmission systems,’ First report and order, adopted: February 14, 2002, released Apr, 22, 2002. http://www. fcc .gov
[8] Anywlan. UWB:值得关注的无线通信新技术.http://www.anywlan. com/ view. asp?id=593.
[9] M.Z.Win, R.A.Scholtz. Ultra-Wide Bandwidth Signal Propagation for Indoor Wireless Communications. In Proc. IEEE ICC, 1997, Vol. 1.pp 56～60
[10] M. Z. Win, F. Ramirez-Mireles, R. A. Scholtz, et al. Ultra-Wide Bandwidth Signal Propagation for Outdoor Wireless Communications.In Proc. IEEE VTC, 1997, Vol. 3:251～255
[11] M. Z. Win, R. A. Scholtz. On the Robustness of Ultra Wide Bandwidth Signals in Dense Multipath Environment.IEEE. Comm. Letters, 1998, Vol. pp.251～256
[12] H. Lee, B. Han, Y. Shin, et al. Multipath characteristics of impulse radio channels. In Proc.IEEE VTC, 2000, Vol. 23. pp.2487～2491
[13] 张陆, 勇周正. 超宽带无线通信 http://www.ptsn.net.cn/xueyuan/technic/mobile/ comment.php3?id=443
[14] 柴宇 罗进文 超宽带无线通信及其两大标准. 电信工程技术与标准化, 2006年 05 期
[15] Bartosz Mielczarek, Matts-Ola Wassman, Arne Svensson. Performance of Coherent UWB Rake Receivers with Channel Estimators. IEEE VTC., 2003, Vol. 3. pp.1880~1884.
[16] 朱林,超宽带定位测距技术研究,四川大学 优秀硕士论文,2005
[17] 黄文,Location Technique in UWB System, 电子科技大学 硕士论文 2006
[18] CHOI J,STARK W. Performance analysis of RAKE receivers for ultra-wideband communications with PPM and OOK in multipath channels[A].Proc IEEE ICC[C]. New York, USA, 2002, 1969-1973
[19] D.Cassioli, M.Z. Win, F. Vatalaro, and A. F. Molisch,”Performance of low -complexity Rake reception in a realistic UWB channel”, Proc. IEEE Int. Conf.on commun,pp.763-767
[20] R.A.Scholtz, ”The orgins of spread-spectrum communications”, IEEE Trans. Commun. Vol.30, No.5, pp.822-854, May 1982
[21] R. Hoctor and H. Tomlinson, “Delay-hopped transmitted-reference RF communications,” Proc. Conf. on Ultra Wideband Sys. and Technol., pp. 265–270, June 2002
[22] J. D. Choi and W. E. Stark, “Performance of ultra-wideband communications with suboptimal receivers in multipath channels,” IEEE J. Select. Areas Commun., vol. 20, no. 9, pp. 1754 –1766, Dec. 2002
[23] A.Spiridon, F.Dowla , F.Nekoogar , D. Benzel”, On the performance of ultra-wideband transmitted-reference receivers”, IEEE Trans. comm. (submitted to publication.)
[24] 杨刚,亢洁,施仁。 超宽带传输参考接收机的性能研究. 通信学报. 第 26 卷第 10 期.122 页~127 页.
[25] Y.-L.Chao and R.AScholtz ”Optimal and Suboptimal Receivers for Ultral-Wideband Transmitted Referenc Systems”, Globcom, December, 2003. PP. 759 - 763
[26] Stefan Franz, Urbashi Mitra.”On Optimal Data Detection for UWB Transmitted Reference Systems” Globcom Volume 2, Dec. 2003. PP:744 – 748
[27] J.Romme G.Gurisi,”Transmit Reference Implse Radio Systems using Weighted Correlation”, IEEE 2004,pp.141-145
[28] Romme, J.; Witrisal, K.. “Transmitted-reference UWB systems using weighted autocorrelation receivers” ,Microwave Theory and Techniques, IEEE Transactions on Volume 54, Issue 4,Part 2, June 2006 .pp:1754 – 1761
[29] Honglei Zhang; Goeckel, D.L.“Generalized transmitted-reference UWB systems”, Ultra Wideband Systems and Technologies, 2003 IEEE Conference on 16-19 Nov. 2003, pp.147 – 151
[30] Federal Commmunications Commissions Report and order, Oct. 26, 2001 http: // www. fcc. gov
[31] A.Spiridon, F.Dowla, F.Nekoogar, D.Benzel, ”On the performance of ultra wideband transtimitted-reference receivers”, IEEE Trans.comm.(submitted to publication.)
[32] Marco Pausini, Gerard J.M.Janssen”, On the Narrowband Interference in Transmitted Reference UWB Receivers”, Ultra-Wideband, 2005. ICU 2005. 2005 IEEE International Conference on 5-8 Sept. 2005 pp.:571 – 575
[33] Dowla.F, Nekoogar.F, Spiridon.A, “Interferencemitigation in transmitted-reference ultra-wideband (UWB) receivers”, Antennas and Propagation Society International Symposium, 2004. IEEE Volume 2, 20-25 June 2004 pp.1307 – 1310
[34] Lei Feng, Won Namgoong, “Oversampled channelized receiver for transmitted reference UWB system in the presence of narrowband interference”, Signal Processing Systems, 2004. SIPS 2004. IEEE Workshop on 2004 pp.48 – 52
[35] SUSHCHIK M.et al.”Performance analysis of correlation-based communication schemes utilizing chaos[J]”, IEEE Transactions on Circuits and Systems-I, 2000, 47(12) pp.1684-1691
[36] M.Z.Win and R.A.Scholtz,”Impulse radio:How it works”, IEEE commun.Lett, vol.2, No.2, pp.36-38, Feb.1998
[37] ---,”Ultra-wide bandwidthtime-hopping spread-spectrum impulse radio for wireless multiple-access communications”, IEEE Trans. Commun, vol.48, no.4,pp.679-691, Apr 2000
[38] M.Hamalainen, V.Hovinen, R.Tesi, J.H.Iinatti, and M.Latva-aho, “On the UWB system coexistence with GSM900, UMTS/WCDMA, and GPS”, IEEE J.Selet. Areas Commun. Vol.20, no.9, pp.1712-1721, Dec. 2002
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