无线通信系统信道估计技术研究与实现
摘要
移动通信系统应用需求迅速增长,要求在更复杂的通信环境中提供给更多的用户以更好的通信服务质量,对通信技术的发展提出更高的要求。正交频分复用(OFDM)技术可以有效的抵抗多径衰落,具有非常高的频带利用率,可以很好的满足通信技术进一步发展的要求。对OFDM系统来说,需要进行相干解调,而进行相干解调需要知道信道的信息,因此信道估计具有重要的意义。
对OFDM传输系统中的关键技术信道估计技术进行研究。针对OFDM传输系统介绍了信道估计技术。信道估计技术分为非盲估计与盲估计两类,本文主要研究非盲信道估计中的数据辅助信道估计,首先介绍辅助数据分布需满足的一般原则,之后介绍三种具体的辅助数据信道估计算法,包括LS信道估计、变换域信道估计与LMMSE信道估计。
从实际应用的角度出发,在WiMAX标准与LTE标准单天线系统中仿真实现LS信道估计与变换域、线性插值方法。WiMAX下行链路仿真实现LS信道估计与线性插值法,分析权重因子对信道估计结果的影响;LTE下行链路中仿真实现在LS信道估计基础上同时使用变换域插值与线性插值,以及在LS估计基础上仅使用线性插值,比较这两种方式的系统性能差异;LTE上行链路中分析不同运动速率条件下LS信道估计的系统性能差异;比较LTE上行、下行链路LS信道估计系统性能差异,并对其原因进行理论分析;对MIMO-OFDM系统辅助数据分布进行分析并证明一种辅助数据取值可达到最佳信道估计条件。
With the development of the mobile telecommunication implementation, it is required that the telecommunication systems supply better communication service quality to more customers even in complicated environment. The communication technology development is highly required. Orthogonal frequency division multiplexing modulation technology, which effectively resists multi-path fading interference and being with high spectrum efficiency, perfectly satisfy the requirement of the telecommunication development. The coherent demodulation is used in the OFDM system and in this case the channel information is needed so the channel estimation technique is of great significance.
The channel estimation schemes are studied. The channel estimation schemes for OFDM based system are introduced in detail. Channel estimation technique for OFDM based systems can be grouped into two main categories: blind and non-blind. The non-blind channel estimation with aided data is studied. The basic principles of the aided data location are introduced, and three kinds of channel estimation schemes, the Least Squares (LS) channel estimation technology, transform domain technology and Linear Minimum Mean Square Error (LMMSE) channel estimation technology, are described.
From the point of view of practical implementation, the simulation of LS technology, transform channel estimation and linear interpolation technology are based on WiMAX and LTE single-input single-output systems. In the WiMAX downlink system the comparison of effect of the two kinds of aided data is simulated, and the weight factor's effect on the system performance is analysed. In the LTE downlink system the effect of the transform estimation with the LS estimation scheme to the system performance compaired with the linear interpolation with LS scheme is simulated and analysed. In the LTE uplink system the resistance of the LS estimation scheme against moving speed is simulated. And the performance difference of the LTE uplink and downlink system respectively with LS estimation scheme and ideal estimation scheme is analyzed both in simulation result and in theory. In the end a kind of aided data value is proved theoretically which can supply the best condition for channel estimation.
对OFDM传输系统中的关键技术信道估计技术进行研究。针对OFDM传输系统介绍了信道估计技术。信道估计技术分为非盲估计与盲估计两类,本文主要研究非盲信道估计中的数据辅助信道估计,首先介绍辅助数据分布需满足的一般原则,之后介绍三种具体的辅助数据信道估计算法,包括LS信道估计、变换域信道估计与LMMSE信道估计。
从实际应用的角度出发,在WiMAX标准与LTE标准单天线系统中仿真实现LS信道估计与变换域、线性插值方法。WiMAX下行链路仿真实现LS信道估计与线性插值法,分析权重因子对信道估计结果的影响;LTE下行链路中仿真实现在LS信道估计基础上同时使用变换域插值与线性插值,以及在LS估计基础上仅使用线性插值,比较这两种方式的系统性能差异;LTE上行链路中分析不同运动速率条件下LS信道估计的系统性能差异;比较LTE上行、下行链路LS信道估计系统性能差异,并对其原因进行理论分析;对MIMO-OFDM系统辅助数据分布进行分析并证明一种辅助数据取值可达到最佳信道估计条件。
With the development of the mobile telecommunication implementation, it is required that the telecommunication systems supply better communication service quality to more customers even in complicated environment. The communication technology development is highly required. Orthogonal frequency division multiplexing modulation technology, which effectively resists multi-path fading interference and being with high spectrum efficiency, perfectly satisfy the requirement of the telecommunication development. The coherent demodulation is used in the OFDM system and in this case the channel information is needed so the channel estimation technique is of great significance.
The channel estimation schemes are studied. The channel estimation schemes for OFDM based system are introduced in detail. Channel estimation technique for OFDM based systems can be grouped into two main categories: blind and non-blind. The non-blind channel estimation with aided data is studied. The basic principles of the aided data location are introduced, and three kinds of channel estimation schemes, the Least Squares (LS) channel estimation technology, transform domain technology and Linear Minimum Mean Square Error (LMMSE) channel estimation technology, are described.
From the point of view of practical implementation, the simulation of LS technology, transform channel estimation and linear interpolation technology are based on WiMAX and LTE single-input single-output systems. In the WiMAX downlink system the comparison of effect of the two kinds of aided data is simulated, and the weight factor's effect on the system performance is analysed. In the LTE downlink system the effect of the transform estimation with the LS estimation scheme to the system performance compaired with the linear interpolation with LS scheme is simulated and analysed. In the LTE uplink system the resistance of the LS estimation scheme against moving speed is simulated. And the performance difference of the LTE uplink and downlink system respectively with LS estimation scheme and ideal estimation scheme is analyzed both in simulation result and in theory. In the end a kind of aided data value is proved theoretically which can supply the best condition for channel estimation.
引文
[1]P.Chaudhury,W.Mohr,and S.Once,"The 3GPP proposal for IMT-2000",IEEE Comm.Mag.,Vol:37,No.12,Dec.1999,p:72-81.
[2]Suk Yu Hui,Kai Hau Yeung,"Challenges in the migration to 4G mobile systems",IEEE Communications Magazine,vol.41,No.12,Dec.2003,p:54-59.
[3]O.Benali,K.E1-Khazen,D.Garrec,M.Guiraudou,G.Martinez,"A framework for an evolutionary path toward 4G by means of cooperation of networks",IEEE communications Magazine,Vol.42,No.5,May 2004,p:82-89.
[4]A.Bria,EGessler,O.Queseth,R.Stridh,M.Unbehaun,Wu Jiang,J.Zander and M.Flament,"4~(th)-generation wireless infrastructures:scenarios and reaearch challenges",IEEE Personal Communication,Vol.8,No.6,Dec.2001,p:25-31.
[5]W.W.Lu,B.H.Walke,Xuemin Shen,"4G mobile communications:toward open wireless architecture",IEEE Wireless Communications,Vol.11,No.2,Apr 2004,p:4-6.
[6]王文博,郑侃,宽带无线通信OFDM技术,北京,人民邮电出版社,2003
[7]Hoeher P,Kaiser S,Robertson P."Two-dimensional pilot-symbol-aided channel estimation by Wiener filtering".IEEE Proc ICASSP-97,Munich,Germany,Apr.1997,p:1845-1849.
[8]Ye Li."Pilot-symbol-aided channel estimation for OFDM in wireless systems".IEEE Transactions on Vehicular Technology,2000,49(4),p:1207-1215.
[9]王建新、周鹏、花汉兵.OFDM系统中一种新的导频辅助信道估计算法.电子与信息学报.2004,26(11),p:1805-1811
[10]Ove Edfors,Jan-Jaap Van deBeek."OFDM Channel Estimation by Singular Value Decomposition".IEEE Transactions on Communications.1998,46(7),p:931-938.
[11]Moon J K,Choi S I."Performance of channel estimation methods for OFDM systems in a multipath fading channels".IEEE Transactions on Consumer Electronics,2000,46(1),p:161-170.
[12]Yuping Zhao,Aiping Huang."A novel channel estimation methods for OFDM mobile communication systems based on pilot signals and transform domain processing".Proc,IEEE 47th VIC,1997,3,p:2089-2093
[13]Baoguo Yang,Khaled Ben Letaief,Cheng R S."Windowed DFT based pilot-symbol-aided channel estimation for OFDM systems in multipath fading channels[A]".Proc IEEE VTC'2000,2000,p:1480-1484.
[14]Baoguo Yang,Cao zhigang,Letaief Khaled Ben."A nalysiso flow- complexity windowed MMSE channel estimator for OFDM systems[J]".IEEE Transactions on Communications,2001,49(11),p:1977-1987.
[15]张继东,郑宝玉.基于导频的OFDM信道估计及其研究进展.通信学报,2003,24(11),p:116-124.
[16]Wang X.W,K.J.Liu."OFDM channel estimation based on time-frequency polynomial model of fading multipath channels[A]".IEEE GLOBECOM'01[C],2001,p:212-216.
[17]黄爱萍,胡荣.基于导频和多项式模型的信道估计.电子学报,2002,30(4),p:584-586.
[18]Xiaowen Wang,K.J.Ray Liu."An adaptive Channel Estimation Algorithm Using Time-Frequency Polynomial Model for OFDM with Fading Multipath Channels".EURASIP Journal on Applied Signal Processing,2002,8,p:818-830.
[19]Ki-Yong Han,Sang-Wook Lee,Jun-Seok Lim,"Channel Estimation for OFDM with Fast Fading Channels by Modified Kalman Filter".IEEE Transactions on Consumer Electronics,2004,50(2),p:443-449.
[20]Dieter Schafhuber,Gerald Matz,Franz Hlawatsch."Adaptive Wiener Filters for Time-varing channel estimation in wireless OFDM Systems".Proc IEEE ICASSP-2003,2003(4),p:688-691.
[21]Ma X.Q,Kobayashi H,Schwartz S C."An EM-based estimation of OFDM signals".Wireless Communications and Networking Conference,2002,p:228-232.
[22]Jeon W G,Paik K H,CHO Y S."An efficient channel estimation technique for OFDM systems with transmitter diversirty".The 11~(th)IEEE International Symposium on Personal Indoor and Mobile Radio Communicaitons,2000,p:1246-1250.
[23]Li Ye,Chuang J C,Sollenberger N R."Transmitter diversity for OFDM systems and its impact on high-rate data wireless networks".IEEE Journal on Selected Areas in Communications,1999,17(7),p:461-470.
[24]B.M.Sadler,R.J.Kozick,T.Moore,"Bounds on MIMO Channel Estimation and Equalization with Side Information," Proc.IEEE Int'l.Conf.Acoust.,Speech,and Signal Processing,vol.4,Salt Lake City,UT,May 2001,p:2145-48.
[25]H.Z.Jafarian,M.J.Omidi,and S.Pasupathy,"Improved Channel Estimation Using Noise Reduction for OFDM Systems," Proc.IEEE Vehic.Tech.Conf.,vol.2,Jeju, Korea,Apr.2003,p:1308-12.
[26]O.Edfors et al.,"OFDM Channel Estimation By Singular Value Decomposition,"IEEE Trans.Commun.,vol.46,no.7,July 1998,p:931-39.
[27]M.K.Ozdemir,H.Arslan,and E.Arvas,"Towards Real-Time Adaptive Low-Rank Lmmse Channel Estimation of MIMO-OFDM Systems," IEEE Trans.Wireless Commun.,vol.5,no.10,Oct.2006,p:2675-78.
[28]Y.Li,L.J.Cimini,and N.R.Sollenberger,"Robust Channel Estimation for OFDM Systems with Rapid Dispersive Fading Channels," IEEE Trans.Commun.,vol.46,no.7,July 1998,p:902-15.
[29]Mehmet Kemal Ozdemir,"Channel Estimation For Wireless OFDM System",IEEE Communications Surveys & Tutorials,2nd Quarter,2007,p:18-48.
[30]W.G.Jeon,K.H.Paik,and Y.S.Cho,"An Efficient Channel Estimation Technique for OFDM Systems with Transmitter Diversity," Proc.IEEE Int'l.Symp.Personal,Indoor and MobileRadio Commun.,vol.2,London,UK,Sept.2000,p:1246-50.
[31]J.Siew et al.,"A Channel Estimation Method for MIMO-OFDM Systems," Proc.London Commun.Symp.,London,England,Sept.2002,p:1-4.
[32]IEEE Standard 802.16e-2005,Amendment to IEEE Standard for Local and Metropolitan Area Networks -Part 16:Air Interface for Fixed Broadband Wireless Access Systems- Physical and Medium Access Control Layers for Combined Fixed and Mobile Operation in Licensed Bands.
[33]3GPP TS 36.300 V8.3.0(2007-12),3GPP TS Group RAN;E-UTRA and E-UTRAN Overall description;Stage 2.
[34]3GPP TS 36.211 V8.1.0(2007-11),3GPP TSG RAN E-UTRA Physical Channels and Modulation(Release 8).
[35]Y.Li,N.Seshadri,and S.Ariyavisitakul,"Channel Estimation for OFDM Systems with Transmitter Diversity in Mobile Wireless Channels," IEEE JSAC,vol.17,no.3,Mar 1999,p:461-71.
[2]Suk Yu Hui,Kai Hau Yeung,"Challenges in the migration to 4G mobile systems",IEEE Communications Magazine,vol.41,No.12,Dec.2003,p:54-59.
[3]O.Benali,K.E1-Khazen,D.Garrec,M.Guiraudou,G.Martinez,"A framework for an evolutionary path toward 4G by means of cooperation of networks",IEEE communications Magazine,Vol.42,No.5,May 2004,p:82-89.
[4]A.Bria,EGessler,O.Queseth,R.Stridh,M.Unbehaun,Wu Jiang,J.Zander and M.Flament,"4~(th)-generation wireless infrastructures:scenarios and reaearch challenges",IEEE Personal Communication,Vol.8,No.6,Dec.2001,p:25-31.
[5]W.W.Lu,B.H.Walke,Xuemin Shen,"4G mobile communications:toward open wireless architecture",IEEE Wireless Communications,Vol.11,No.2,Apr 2004,p:4-6.
[6]王文博,郑侃,宽带无线通信OFDM技术,北京,人民邮电出版社,2003
[7]Hoeher P,Kaiser S,Robertson P."Two-dimensional pilot-symbol-aided channel estimation by Wiener filtering".IEEE Proc ICASSP-97,Munich,Germany,Apr.1997,p:1845-1849.
[8]Ye Li."Pilot-symbol-aided channel estimation for OFDM in wireless systems".IEEE Transactions on Vehicular Technology,2000,49(4),p:1207-1215.
[9]王建新、周鹏、花汉兵.OFDM系统中一种新的导频辅助信道估计算法.电子与信息学报.2004,26(11),p:1805-1811
[10]Ove Edfors,Jan-Jaap Van deBeek."OFDM Channel Estimation by Singular Value Decomposition".IEEE Transactions on Communications.1998,46(7),p:931-938.
[11]Moon J K,Choi S I."Performance of channel estimation methods for OFDM systems in a multipath fading channels".IEEE Transactions on Consumer Electronics,2000,46(1),p:161-170.
[12]Yuping Zhao,Aiping Huang."A novel channel estimation methods for OFDM mobile communication systems based on pilot signals and transform domain processing".Proc,IEEE 47th VIC,1997,3,p:2089-2093
[13]Baoguo Yang,Khaled Ben Letaief,Cheng R S."Windowed DFT based pilot-symbol-aided channel estimation for OFDM systems in multipath fading channels[A]".Proc IEEE VTC'2000,2000,p:1480-1484.
[14]Baoguo Yang,Cao zhigang,Letaief Khaled Ben."A nalysiso flow- complexity windowed MMSE channel estimator for OFDM systems[J]".IEEE Transactions on Communications,2001,49(11),p:1977-1987.
[15]张继东,郑宝玉.基于导频的OFDM信道估计及其研究进展.通信学报,2003,24(11),p:116-124.
[16]Wang X.W,K.J.Liu."OFDM channel estimation based on time-frequency polynomial model of fading multipath channels[A]".IEEE GLOBECOM'01[C],2001,p:212-216.
[17]黄爱萍,胡荣.基于导频和多项式模型的信道估计.电子学报,2002,30(4),p:584-586.
[18]Xiaowen Wang,K.J.Ray Liu."An adaptive Channel Estimation Algorithm Using Time-Frequency Polynomial Model for OFDM with Fading Multipath Channels".EURASIP Journal on Applied Signal Processing,2002,8,p:818-830.
[19]Ki-Yong Han,Sang-Wook Lee,Jun-Seok Lim,"Channel Estimation for OFDM with Fast Fading Channels by Modified Kalman Filter".IEEE Transactions on Consumer Electronics,2004,50(2),p:443-449.
[20]Dieter Schafhuber,Gerald Matz,Franz Hlawatsch."Adaptive Wiener Filters for Time-varing channel estimation in wireless OFDM Systems".Proc IEEE ICASSP-2003,2003(4),p:688-691.
[21]Ma X.Q,Kobayashi H,Schwartz S C."An EM-based estimation of OFDM signals".Wireless Communications and Networking Conference,2002,p:228-232.
[22]Jeon W G,Paik K H,CHO Y S."An efficient channel estimation technique for OFDM systems with transmitter diversirty".The 11~(th)IEEE International Symposium on Personal Indoor and Mobile Radio Communicaitons,2000,p:1246-1250.
[23]Li Ye,Chuang J C,Sollenberger N R."Transmitter diversity for OFDM systems and its impact on high-rate data wireless networks".IEEE Journal on Selected Areas in Communications,1999,17(7),p:461-470.
[24]B.M.Sadler,R.J.Kozick,T.Moore,"Bounds on MIMO Channel Estimation and Equalization with Side Information," Proc.IEEE Int'l.Conf.Acoust.,Speech,and Signal Processing,vol.4,Salt Lake City,UT,May 2001,p:2145-48.
[25]H.Z.Jafarian,M.J.Omidi,and S.Pasupathy,"Improved Channel Estimation Using Noise Reduction for OFDM Systems," Proc.IEEE Vehic.Tech.Conf.,vol.2,Jeju, Korea,Apr.2003,p:1308-12.
[26]O.Edfors et al.,"OFDM Channel Estimation By Singular Value Decomposition,"IEEE Trans.Commun.,vol.46,no.7,July 1998,p:931-39.
[27]M.K.Ozdemir,H.Arslan,and E.Arvas,"Towards Real-Time Adaptive Low-Rank Lmmse Channel Estimation of MIMO-OFDM Systems," IEEE Trans.Wireless Commun.,vol.5,no.10,Oct.2006,p:2675-78.
[28]Y.Li,L.J.Cimini,and N.R.Sollenberger,"Robust Channel Estimation for OFDM Systems with Rapid Dispersive Fading Channels," IEEE Trans.Commun.,vol.46,no.7,July 1998,p:902-15.
[29]Mehmet Kemal Ozdemir,"Channel Estimation For Wireless OFDM System",IEEE Communications Surveys & Tutorials,2nd Quarter,2007,p:18-48.
[30]W.G.Jeon,K.H.Paik,and Y.S.Cho,"An Efficient Channel Estimation Technique for OFDM Systems with Transmitter Diversity," Proc.IEEE Int'l.Symp.Personal,Indoor and MobileRadio Commun.,vol.2,London,UK,Sept.2000,p:1246-50.
[31]J.Siew et al.,"A Channel Estimation Method for MIMO-OFDM Systems," Proc.London Commun.Symp.,London,England,Sept.2002,p:1-4.
[32]IEEE Standard 802.16e-2005,Amendment to IEEE Standard for Local and Metropolitan Area Networks -Part 16:Air Interface for Fixed Broadband Wireless Access Systems- Physical and Medium Access Control Layers for Combined Fixed and Mobile Operation in Licensed Bands.
[33]3GPP TS 36.300 V8.3.0(2007-12),3GPP TS Group RAN;E-UTRA and E-UTRAN Overall description;Stage 2.
[34]3GPP TS 36.211 V8.1.0(2007-11),3GPP TSG RAN E-UTRA Physical Channels and Modulation(Release 8).
[35]Y.Li,N.Seshadri,and S.Ariyavisitakul,"Channel Estimation for OFDM Systems with Transmitter Diversity in Mobile Wireless Channels," IEEE JSAC,vol.17,no.3,Mar 1999,p:461-71.
© 2004-2018 中国地质图书馆版权所有 京ICP备05064691号 京公网安备11010802017129号 地址：北京市海淀区学院路29号 邮编：100083 电话：办公室：(+86 10)66554848；文献借阅、咨询服务、科技查新：66554700 |