无线移动通信中的智能天线技术——信号波达方向DOA估计研究
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摘要
随着近年来移动用户数量的剧增和新型无线业务类型(语音、数据、图像)的出现，使得无线通信业务量迅速增加，移动通信系统中的同频干扰(CCI，Co-Channel Interruption)、多址干扰(MAI，Multiple Address Interruption)日趋严重，信号传输带宽和传输速率严重不足。同时，由于无线信号传输环境的复杂性和不确定性，使得无线信号在传输过程中产生多径衰落和损耗。这些因素严重的限制了移动通信系统的容量和性能。智能天线技术为解决频率资源不足、提高移动通信系统容量和系统服务质量提供了一个有效的解决途径。在1998年电信科学技术研究院代表我国电信主管部门向国际电联提交的TD-SCDMA RTT建议和现在成为国际第三代移动通信标准之一的CDMA TDD技术(低码片速率选项)，就是第一次提出以智能天线为核心技术的CDMA通信实施方案。在TD-SCDMA中，智能天线作为核心技术，可以大大提高系统性能。
其前身是自适应天线阵。自从1990年就开始了智能天线在蜂窝移动通信中的应用研究。随着数字信号处理技术(DSP)的发展和3G移动通信技术、宽带CDMA技术研究的兴起，智能天线在其中的应用也成了研究热点。智能天线引入了第4种多址方式：空分多址(SDMA)。
论文的研究工作是基于MATLAB软件仿真平台上实现的。首先介绍了智能天线技术出现的背景；其次介绍了智能天线的原理和相关概念；进而研究了利用智能天线进行用户信号波达方向DOA(Direction Of Arrival)估计的几种算法。所有的研究基于均匀直线阵列。论文的主要研究工作是：在MATLAB仿真软件平台上实现了DOA估计的传统算法(时延—相加算法和Capon最小方差算法)、多重信号分类算法MUSIC(Multiple Signal Classifieation)的仿真实现；并定性研究比较了三种算法的性能差别。重点研究了高斯随机噪声对MUSIC算法的影响；找到了问题所在；并在仿真研究中提出了一种创新性的解决方法。这种方法的使用，可以使MUSIC算法在无规律变化的高斯随机噪声环境中提高用户信号DOA估计的抗噪声能力，从而提高DOA估计的性能。
In these years, with the fast increase of the mobile users and the appearance of new type of wireless services, the wireless services become lager and lager. This results in too much serious Co-Channel Interruption and the Multiple Address Interruption. The band of the transported signals and the signal rate become restricted. At the same time, the transport environment of the wireless signals is complicated and uncertain. So the transported signals are declined and wear down. All this has strong bad effect on the capacity and performance of wireless communication system. The smart antenna technology is an effective solution to take good use of the frequency sources and to promote the capacity and the service quality of the communication system. As known to all, TD-SCDMA is one of the three world 3ird mobile communication standers. It is put forward by Datang Telecom Technology and Industry Group of China. The Smart Antenna technology is one of the key technologies of the TD-SCDMA. It can largely improve the performance of the wireless communication system.
The Smart Antenna technology is originally used in military phase-control radar. It's formally called adaptive antenna array. The application research of the Smart Antenna technology in mobile communication filed is from 1990. With the development of the Digital Signal Processing technology and with the rise of the third generation mobile communication and broad-band CDMA, the Smart Antenna technology become a hot research point. The Smart Antenna technology introduce the forth concept of multiple access method SDMA (Space Division Multiple Access).
All of the research work of this paper is based on the MATLAB software environment. In this paper, we make an introduction on the appearance background of the Smart Antenna technology and its relative theory and concept. After that, we do some research work on the estimation arithmetic of the signal DOA(Direction Of Arrival) using Smart Antenna Array. The research work is based on the ULA(uniform linear array) antenna. The advanced research work of this paper is: we realize two kinds of DOA estimation arithmetic on the MATLAB software environment. One arithmetic is traditional arithmetic, which include Time-delay method and Capon method. The other one is MUSIC(Multiple Signal Classification) arithmetic. Then we qualitatively compare the performance of these arithmetic with each other. On this basis, we investigate primarily the effects of the Gauss Random Noise caused by antenna array on the MUSIC arithmetic. And we find out the exiting problem. Through simulation of M-file on MATLAB, we innovatively bring forward a effective solution. With the adoption of this elicited solution, the effects of the Gauss Random Noise on the MUSIC arithmetic, which is use to estimate the user signal's DOA, is decreased in largely degree. Thus the DOA estimation performance of the MUSIC arithmetic under the background of Gauss Random Noise is improved.
其前身是自适应天线阵。自从1990年就开始了智能天线在蜂窝移动通信中的应用研究。随着数字信号处理技术(DSP)的发展和3G移动通信技术、宽带CDMA技术研究的兴起，智能天线在其中的应用也成了研究热点。智能天线引入了第4种多址方式：空分多址(SDMA)。
论文的研究工作是基于MATLAB软件仿真平台上实现的。首先介绍了智能天线技术出现的背景；其次介绍了智能天线的原理和相关概念；进而研究了利用智能天线进行用户信号波达方向DOA(Direction Of Arrival)估计的几种算法。所有的研究基于均匀直线阵列。论文的主要研究工作是：在MATLAB仿真软件平台上实现了DOA估计的传统算法(时延—相加算法和Capon最小方差算法)、多重信号分类算法MUSIC(Multiple Signal Classifieation)的仿真实现；并定性研究比较了三种算法的性能差别。重点研究了高斯随机噪声对MUSIC算法的影响；找到了问题所在；并在仿真研究中提出了一种创新性的解决方法。这种方法的使用，可以使MUSIC算法在无规律变化的高斯随机噪声环境中提高用户信号DOA估计的抗噪声能力，从而提高DOA估计的性能。
In these years, with the fast increase of the mobile users and the appearance of new type of wireless services, the wireless services become lager and lager. This results in too much serious Co-Channel Interruption and the Multiple Address Interruption. The band of the transported signals and the signal rate become restricted. At the same time, the transport environment of the wireless signals is complicated and uncertain. So the transported signals are declined and wear down. All this has strong bad effect on the capacity and performance of wireless communication system. The smart antenna technology is an effective solution to take good use of the frequency sources and to promote the capacity and the service quality of the communication system. As known to all, TD-SCDMA is one of the three world 3ird mobile communication standers. It is put forward by Datang Telecom Technology and Industry Group of China. The Smart Antenna technology is one of the key technologies of the TD-SCDMA. It can largely improve the performance of the wireless communication system.
The Smart Antenna technology is originally used in military phase-control radar. It's formally called adaptive antenna array. The application research of the Smart Antenna technology in mobile communication filed is from 1990. With the development of the Digital Signal Processing technology and with the rise of the third generation mobile communication and broad-band CDMA, the Smart Antenna technology become a hot research point. The Smart Antenna technology introduce the forth concept of multiple access method SDMA (Space Division Multiple Access).
All of the research work of this paper is based on the MATLAB software environment. In this paper, we make an introduction on the appearance background of the Smart Antenna technology and its relative theory and concept. After that, we do some research work on the estimation arithmetic of the signal DOA(Direction Of Arrival) using Smart Antenna Array. The research work is based on the ULA(uniform linear array) antenna. The advanced research work of this paper is: we realize two kinds of DOA estimation arithmetic on the MATLAB software environment. One arithmetic is traditional arithmetic, which include Time-delay method and Capon method. The other one is MUSIC(Multiple Signal Classification) arithmetic. Then we qualitatively compare the performance of these arithmetic with each other. On this basis, we investigate primarily the effects of the Gauss Random Noise caused by antenna array on the MUSIC arithmetic. And we find out the exiting problem. Through simulation of M-file on MATLAB, we innovatively bring forward a effective solution. With the adoption of this elicited solution, the effects of the Gauss Random Noise on the MUSIC arithmetic, which is use to estimate the user signal's DOA, is decreased in largely degree. Thus the DOA estimation performance of the MUSIC arithmetic under the background of Gauss Random Noise is improved.
引文
[1] Joseph C.Liberti, Theodore S.Rappaport. Smart Antennas for Wreless communications.IS-95 and Third Generation CDMA Applications. Prentice Hall, 1999. pp. 158-161, 187-204.
[2] 张贤达，保铮，通信信号处理.北京：国防工业出版社，2000.12.pp.154，351.
[3] 郭梯云，邬国扬，李建东，移动通信.西安：西安电子科技大学出版社，2000.5
[4] 李小文，李贵勇等，TD-SCDMA第三代移动通信系统、信令及实现.北京：人民邮电出版社，2003.1.pp.8.
[5] 何仁斌，MATLAB 6工程计算及应用.重庆：重庆大学出版社，2001.11
[6] HIDEKAZU TAOKA, SHINYA TANAKA et al." Adaptive Antenna Array Transmit Diversity In FDD Forward Link for W-CDMA and Broadband Packet Wireless Access,"IEEE Wireless Communication, TECHNOLOGIES FOR 4G MOBILE COMMUNICATION, April 2002, pp.36-38.
[7] 林华芳，徐明远，徐晟，均匀直线阵的波束形成，信息技术，2003，(5)：p.22-23.
[8] J. Cpon,"High Resolution Frequency-Wavenumber Spectral Analysis," Proc. of the IEEE, Vol. 57, No. 8, pp. 1408-1418, Aug. 1969.
[9] S. Haykin,Adaptive Filter Theory, Prentice Hall, NJ, 1991.
[10] J. Capon, "Maximum Likelihood Spectral Estimation," Nonlinear Methods of Spectral Analysis. Ed. By S. Haykin, Springier, NY, pp. 155-179, 1979.
[11] S. V. Scheilj, W.A. Gardner, "High Resolution Direction Finding," Chapter 17, K. Bose and C.R.Rao, pp. 755-817, 1993.
[12] R. O. Schmidt, "Multiple Emitter Location and Signal Parameter Estimation," Proc. Of RADC Spectrum Estimation Workshop, Griffiss AFB, NY, pp. 243-258, 1979.
[13] R. O. Schmidt, "Multiple Emitter Location and Signal Parameter Estimation," IEEE Trans. On Antennas and Propagation, Vol. AP-34, No.3, Mar. 1986.
[14] R. O. Schmidt, and R. E. Franks, "Multiple Source DF Signal Processing: An Experimental System," IEEE Trans. On Antennas and Propagation, Vol. AP-34, No.3, pp. 281-290, Mar. 1986.
[15] IoWave Inc. Smart Antenna. http://www.iowave.com/.
[16] Ivica Stevanovic, Anja Skrivervik and Juan R. Mosig. "Smart Antenna Systems for Mobile communications," FINAL REPORT. ECOLE POLYTECHNIQUE FEDERSLE DE LAUSANNE. pp.1-23, 90-101, January. 2003.
[17] J. H. Winters. WTEC Panel Report on Wireless Technologies and Information Networks, chapter 6. Smart Antennas. International Technology Research Institute, Baltimore, July 2000.
[18] 李小强 胡健栋，未来移动通信系统中的智能天线技术，移动通信，1999，1
[19] P.H. Lehne, O. Rostbakken, and M. Pettersen. Estimating Smart Antenna Performance from Directional Radio Channel Measurements. Proc. 50th IEEE Vehic. Tech. Conf. -VTC 99-Fall, pages 57-61, September 1999. Amsterdam, Netherlands.
[20] G. V. Tsoulos, M. A. Beach, and S. C. Swales. DS-CDMA Capacity Enhancement with Adaptive Antennas. Electronic Letters, 13(16):1319-20, August 1995.
[2] 张贤达，保铮，通信信号处理.北京：国防工业出版社，2000.12.pp.154，351.
[3] 郭梯云，邬国扬，李建东，移动通信.西安：西安电子科技大学出版社，2000.5
[4] 李小文，李贵勇等，TD-SCDMA第三代移动通信系统、信令及实现.北京：人民邮电出版社，2003.1.pp.8.
[5] 何仁斌，MATLAB 6工程计算及应用.重庆：重庆大学出版社，2001.11
[6] HIDEKAZU TAOKA, SHINYA TANAKA et al." Adaptive Antenna Array Transmit Diversity In FDD Forward Link for W-CDMA and Broadband Packet Wireless Access,"IEEE Wireless Communication, TECHNOLOGIES FOR 4G MOBILE COMMUNICATION, April 2002, pp.36-38.
[7] 林华芳，徐明远，徐晟，均匀直线阵的波束形成，信息技术，2003，(5)：p.22-23.
[8] J. Cpon,"High Resolution Frequency-Wavenumber Spectral Analysis," Proc. of the IEEE, Vol. 57, No. 8, pp. 1408-1418, Aug. 1969.
[9] S. Haykin,Adaptive Filter Theory, Prentice Hall, NJ, 1991.
[10] J. Capon, "Maximum Likelihood Spectral Estimation," Nonlinear Methods of Spectral Analysis. Ed. By S. Haykin, Springier, NY, pp. 155-179, 1979.
[11] S. V. Scheilj, W.A. Gardner, "High Resolution Direction Finding," Chapter 17, K. Bose and C.R.Rao, pp. 755-817, 1993.
[12] R. O. Schmidt, "Multiple Emitter Location and Signal Parameter Estimation," Proc. Of RADC Spectrum Estimation Workshop, Griffiss AFB, NY, pp. 243-258, 1979.
[13] R. O. Schmidt, "Multiple Emitter Location and Signal Parameter Estimation," IEEE Trans. On Antennas and Propagation, Vol. AP-34, No.3, Mar. 1986.
[14] R. O. Schmidt, and R. E. Franks, "Multiple Source DF Signal Processing: An Experimental System," IEEE Trans. On Antennas and Propagation, Vol. AP-34, No.3, pp. 281-290, Mar. 1986.
[15] IoWave Inc. Smart Antenna. http://www.iowave.com/.
[16] Ivica Stevanovic, Anja Skrivervik and Juan R. Mosig. "Smart Antenna Systems for Mobile communications," FINAL REPORT. ECOLE POLYTECHNIQUE FEDERSLE DE LAUSANNE. pp.1-23, 90-101, January. 2003.
[17] J. H. Winters. WTEC Panel Report on Wireless Technologies and Information Networks, chapter 6. Smart Antennas. International Technology Research Institute, Baltimore, July 2000.
[18] 李小强 胡健栋，未来移动通信系统中的智能天线技术，移动通信，1999，1
[19] P.H. Lehne, O. Rostbakken, and M. Pettersen. Estimating Smart Antenna Performance from Directional Radio Channel Measurements. Proc. 50th IEEE Vehic. Tech. Conf. -VTC 99-Fall, pages 57-61, September 1999. Amsterdam, Netherlands.
[20] G. V. Tsoulos, M. A. Beach, and S. C. Swales. DS-CDMA Capacity Enhancement with Adaptive Antennas. Electronic Letters, 13(16):1319-20, August 1995.