摘要
多输入多输出(MIMO)技术是一项在3G和4G中有着广泛应用的无线通信技术,采用多个发射天线和多个接收天线的结构,通过增加发射端和接收端的天线数量可以显著提高频谱的利用率。
贝尔实验室的分层空时(BLAST)编码技术是由Foschini等人最早提出的一种空时编码方式。特别是垂直分层空时码(V-BLAST)的编码复杂度较低,这使得V-BLAST在高速无线通信中的应用有着非常大的优势。通过采用V-BLAST可以大幅度提高MIMO系统的频谱利用率。
本文主要基于Foschini的理论工作,讨论了无线信道的基本特征、MIMO系统的信号模型和信道容量。在此基础上讨论了三种空时编码技术,包括空时分组码、空时网格码和分层空时码。基于V-BLAST的检测算法,对串行干扰抵消方法进行了改进,使改进后算法的复杂度有一定程度的降低;并对几种算法的性能进行了仿真和比较;给出了不同算法在不同环境下的适用性。最后,论文研究了MIMO技术在3G演进系统中的应用。
Multiple-input multiple-output (MIMO) technology is a wireless communication technologie which has a broad application in 3G and 4G. It uses multiple transmit antennas and multiple receive antennas, by increasing the antenna number of transmitter and receiver can significantly improve the spectrum utilization.
Bell Labs Layered Space-Time (BLAST) coding technique is a space-time coding first proposed by Foschini. Particularly the coding complexity in the vertical layered space-time codes (V-BLAST) is low, which makes the V-BLAST a very large advantage in the application of high-speed wireless communications. By using V-BLAST can significantly improve the spectrum utilization of MIMO systems.
This paper is mainly based on the theoretical work of Foschini, the basic characteristics of wireless channel and the signal model and channel capacity of MIMO system has be discussed. On this basis, we discussed three kinds of space-time coding techniques, including space-time block codes, space-time trellis codes and layered space-time codes. We discuss the detection algorithm base on V-BLAST, the serial interference cancellation method has been improved, receive the results of reducing complexity; also the performance of several algorithms has been simulating and comparing; giving the applicability of different algorithms in different environments. Finally, we research the applications of the MIMO technology in the 3G system.
引文
[1] 3GPP TS 36.211.Physical Channels and Modulation[S].
[2]谢显中,雷维嘉.移动通信中的空时信号处理[M] .北京:电子工业出版社,2008.187-200.
[3] P.W.Wolniansky,G.J.Foschini.V-BLAST:an Architecture for Realizing Very High Data Rates Over the Rich-Scattering Wireless Channel [J]. Proc.IEEE 1998.295-300.
[4] G.J.Foschini.Layered Space-time Architecture for Wireless Communication in a Fading Environment When Using Multiple Antennas [J].Bell Labs Tech Journal.Vol.1, No.2,Autumn, 1996.41-59.
[5] Hamid Jafarkhani著,任品毅译.空时编码的理论与实践[M] .西安:西安交通大学出版社, 2007.
[6]罗涛,刘丹谱,乐光新.Rician衰落下空时分组编码信道的容量[J] .北京邮电大学学报,2004,Vol.27.94-98.
[7] A.Paulraj,R.Nabar and D.Gore.Introduction to Space-Time Wireless Communications[M].Cambridge University Press,2003.
[8] C.E.Shannon.A Mathematical Theory of Communication [J].Bell Syst,Tech.1948,Vol.27.379-423.
[9]黄有度,朱士信.矩阵理论及其应用[M] .合肥:合肥工业大学出版社,2005.
[10]谢显中.移动通信中的空时编码技术与接收机设计[D] .西安电子科技大学,2000.
[11]吴伟陵,牛凯.移动通信原理[M] .北京:电子工业出版社,2005.290-306.
[12]杜雪樵,惠军.随机过程[M] .合肥:合肥工业大学出版社,2006.
[13]黄韬,袁超伟.MIMO相关技术与应用[M] .北京:机械工业出版社,2007.
[14]李颖,王新梅.空时码综述[J].电子信息学报,2002,Vol.24.1973-1979.
[15] S.M. Alamouti.A Simple Transmitter Diversity Scheme for Wireless Communication [J].IEEE JSAC,1998,Vol.16(10).1451-1458.
[16] Branka Vucetic著,王晓海译.空时编码技术[M] .北京:机械工业出版社,2004.
[17] G.D.Goldern, G.J.Foschini,. Detection Algorithm and Initial Laboratory Results Using V-BLAST Space-Time Communication Architecture [J]. Electronics Letters, 1999,35(1).6-7.
[18]郑珊珊,陈霞,谈振辉.V-BLAST系统检测算法的比较[J].无线通信技术,2006,4.19-22.
[19] H.EI.Gamal, A.R.Hammons. The Layered Space-Time Architecture :A New Perspective [J].IEEE Trans. Information Theory,2001.Vol.47.2321-2334.
[20]刘宁,李颖,王新梅.分层空时码检测算法的研究[J].电子学报, 2003.Vol.31(11), 1754-1757.
[21]李卫,张小颖,叶培大.一种高效的V-BLAST最大似然检测算法[J] .吉首大学学报(自然科学版) ,2007,1.77-80.
[22]郑珊珊.无线多输入多输出系统关键技术的研究[D] .北京交通大学,2007年.
[23]郭治,昂志敏,靳红超.基于V-BLAST的检测算法的研究[J] .仪器仪表学报增刊,2009,Vol.30(10), 146-149.
[24] O.Damen,A.Chkeif and J.Belfiore.Lattice Code Decode for Space-Time Codes [J].IEEE Comm.Letters,2000,Vol.4(5):161-163.
[25] B.Hassibi and H.Vikalo.On Expected Complexity of Sphere Decoding[J]. IEEE Conf. on Signal, systems and computers.2001,Vol.2:1051-1055.
[26]张德丰. MATLAB仿真与应用[M].北京:电子工业出版社,2009.
[27]李世鹤,杨运年.TD-SCDMA第三代移动通信系统[M] .北京:人民邮电出版社,2009.
[28]肖扬.MIMO多天线无线通信系统[M].北京:人民邮电出版社,2009.
[29]周伯扬,耿淑芬.CDMA网络技术[M].北京:国防工业出版社,2006.
[30] Stefania Sesia著,马霓译.LTE:UMTS长期演进理论与实践[M].北京:人民邮电出版社,2009.
[31]沈嘉.3GPP长期演进(LTE)技术原理与系统设计[M].北京:人民邮电出版社,2008.
[32]张克平.LTE-B3G/4G移动通信系统无线技术[M].北京:电子工业出版社,2008.
[33] IEEE 802.16-2001 IEEE Standard for Local and metropolitan area networks Part 16: Air Interface for Fixed Broadband Wireless Access Systems[S].
[34] G.D. Golden, G.J. Foschini,Detection algorithm and initial laboratory results using V-BLAST spacetime communication architecture[J]. Electronics Letters 1999.1 Vol. 35(1).
[35] G.J. Foschini, G.D. Golden .Simplified processing for high efficiency wireless communication spectralemploying multi-element arrays[J]. IEEE Journal on Selected Areas in Communications, 1999,11 VOL17(11).
[36] Tsung-Hsien Liu. Efficient and Stable MMSE Detection of the V-BLAST System[C]. IEEE GLOBECOM 2006 proceedings.
[37] Gan Zheng. Improved MIMO-DFE Detection Algorithm For V-BLAST Overfrequency-selective channels[C]. CCECE 2004- CCGEI 2004, Niagara Falls, May/mai 2004.
[38] Zhang XiaoGe. A New OSIC Detection Algorithm for V-BLAST System[C]. IEEE 2007.
[39] Saif K. Mohammed, A. Chockalingam. A Low-Complexity Near-ML Performance Achieving algorithm for large mimo detection[C]. ISIT 2008, Toronto, Canada, July 6 - 11, 2008.
[40] Jianmin Gong, Liu Chongchun. A rigorous proof ofMIMO channel capacity's increase with antenna number[C].MIC-CCA 2008.