下一代移动通信系统中自适应调制算法的研究
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摘要
多输入多输出—正交频分复用(Multiple-Input Multiple-OutputOrthogonalFrequency Division Multiplexing,MIMO-OFDM)系统因其能大幅度提高系统容量而成为下一代移动通信的推荐系统,而自适应调制技术作为提高系统性能的一项重要技术也逐渐被人们所关注。本论文在此背景下,对自适应调制技术在下一代移动通信系统中从理论和实际应用两方面进行了深入细致的研究。
本文首先简单介绍了MIMO和OFDM系统中的关键技术,简述了自适应调制的基本知识,并且对传统的也是非常被重视的贪婪(Greedy)算法进行了详细的介绍。然后,针对现有自适应调制算法复杂度过高而不利于系统实现的问题,提出了两种低复杂度的自适应调制算法,并且对基于正交三角(quadrature rectangle,QR)分解的自适应调制算法进行了性能分析。本文完成的主要工作及创新点包括:
1.提出了一种在误比特率(bit error ratio,BER)和传输速率受限的情况下最小化发送功率的自适应调制算法。与Greedy算法相比,两者在性能上差别微小,但是所提出算法的复杂度却大大降低。
2.提出了一种在误比特率和传输功率受限的情况下最大化系统信息传输速率的自适应调制算法。比较最大化信息传输速率的Greedy算法,这种算法也可以显著降低实现复杂度,并且几乎没有性能损失。
3.提出了一种最大化传输速率的自适应调制算法,并且对这种自适应调制算法的性能进行理论分析。一方面,所提算法可以大幅度提高系统性能(信息传输速率、误比特率两方面),另一方面,理论分析结果和仿真实现结果几乎完全一致,从而验证了分析结果的正确性。
本文所提出的前两种算法都可以大幅度地降低自适应调制算法的实现复杂度,对于自适应调制算法在现实系统中的推广具有重要的意义。创新点3中的所提出的算法可以有效改善系统性能,而所给出的性能分析结果对自适应调制算法的设计具有重要的理论指导意义。
Multiple-Input Multiple-Output (MIMO) Orthogonal Frequency Division Multiplexing (OFDM) system can be one of the nominated systems for beyond the third generation (B3G) mobile communication systems because of its high capacity. Adaptive modulation (AM) technology is also paid more attention by many scholars for its high data transmission rate. So we do some research work about AM algorithm for MIMO-OFDM systems in theory and practical applications.
In this thesis, we firstly introduce the knowledge about MIMO and OFDM simply, and then the basic knowledge of adaptive technology is depicted later. The traditional algorithm Greedy which is well known for good performance is introduced. The AM algorithms with low complexity under some constraints are proposed to minimize the transmit power and maximize the transmission rate, respectively. Besides that, the AM algorithm using Quadrature Rectangle (QR) decomposition is given and the performance analysis in theory is deduced too. The innovations about the thesis are given as following:
Firstly, the adaptive algorithm with the goal of minimizing the transmit power under the constraint of certain bit error ratio (BER) and transmission rate is proposed in the thesis. Comparing with the Greedy algorithm, the new AM algorithm can achieve almost the same performance but with much lower complexity.
Secondly, we give out one new AM algorithm to maximize the transmission rate under the constraint of BER and transmit power with in this thesis. The AM algorithm can lower the complexity and the performance is almost the same performance with that of using Greedy algorithm to maximize the data transmission rate.
Lastly, we propose one AM algorithm to maximize the transmission rate and give out the performance analysis result in theory. The system performance can be improved greatly (in the field of data transmission rate and BER) with the AM algorithm. The theorical result and the simulation result are almost the same, so the theorical deduction is correct.
The first two AM algorithm proposed in the thesis can lower the complexity greatly, so they can be widely used in practical systems. The last AM algorithm can improve the system performance effectively, and the performance analysis result is of important theorical guide in AM design field.
本文首先简单介绍了MIMO和OFDM系统中的关键技术,简述了自适应调制的基本知识,并且对传统的也是非常被重视的贪婪(Greedy)算法进行了详细的介绍。然后,针对现有自适应调制算法复杂度过高而不利于系统实现的问题,提出了两种低复杂度的自适应调制算法,并且对基于正交三角(quadrature rectangle,QR)分解的自适应调制算法进行了性能分析。本文完成的主要工作及创新点包括:
1.提出了一种在误比特率(bit error ratio,BER)和传输速率受限的情况下最小化发送功率的自适应调制算法。与Greedy算法相比,两者在性能上差别微小,但是所提出算法的复杂度却大大降低。
2.提出了一种在误比特率和传输功率受限的情况下最大化系统信息传输速率的自适应调制算法。比较最大化信息传输速率的Greedy算法,这种算法也可以显著降低实现复杂度,并且几乎没有性能损失。
3.提出了一种最大化传输速率的自适应调制算法,并且对这种自适应调制算法的性能进行理论分析。一方面,所提算法可以大幅度提高系统性能(信息传输速率、误比特率两方面),另一方面,理论分析结果和仿真实现结果几乎完全一致,从而验证了分析结果的正确性。
本文所提出的前两种算法都可以大幅度地降低自适应调制算法的实现复杂度,对于自适应调制算法在现实系统中的推广具有重要的意义。创新点3中的所提出的算法可以有效改善系统性能,而所给出的性能分析结果对自适应调制算法的设计具有重要的理论指导意义。
Multiple-Input Multiple-Output (MIMO) Orthogonal Frequency Division Multiplexing (OFDM) system can be one of the nominated systems for beyond the third generation (B3G) mobile communication systems because of its high capacity. Adaptive modulation (AM) technology is also paid more attention by many scholars for its high data transmission rate. So we do some research work about AM algorithm for MIMO-OFDM systems in theory and practical applications.
In this thesis, we firstly introduce the knowledge about MIMO and OFDM simply, and then the basic knowledge of adaptive technology is depicted later. The traditional algorithm Greedy which is well known for good performance is introduced. The AM algorithms with low complexity under some constraints are proposed to minimize the transmit power and maximize the transmission rate, respectively. Besides that, the AM algorithm using Quadrature Rectangle (QR) decomposition is given and the performance analysis in theory is deduced too. The innovations about the thesis are given as following:
Firstly, the adaptive algorithm with the goal of minimizing the transmit power under the constraint of certain bit error ratio (BER) and transmission rate is proposed in the thesis. Comparing with the Greedy algorithm, the new AM algorithm can achieve almost the same performance but with much lower complexity.
Secondly, we give out one new AM algorithm to maximize the transmission rate under the constraint of BER and transmit power with in this thesis. The AM algorithm can lower the complexity and the performance is almost the same performance with that of using Greedy algorithm to maximize the data transmission rate.
Lastly, we propose one AM algorithm to maximize the transmission rate and give out the performance analysis result in theory. The system performance can be improved greatly (in the field of data transmission rate and BER) with the AM algorithm. The theorical result and the simulation result are almost the same, so the theorical deduction is correct.
The first two AM algorithm proposed in the thesis can lower the complexity greatly, so they can be widely used in practical systems. The last AM algorithm can improve the system performance effectively, and the performance analysis result is of important theorical guide in AM design field.
引文
[1]胡捍英、杨峰义,“第二代移动通信系统”,人民邮电出版社,2001.8,pp10-83.
[2]3GPP TR25.848,"Physical layer aspects of UTRA High Speed Downlink Packet Access(Release 4)",2001.03.
[3]3 GPP TS 25.858 v5.0.0,"High speed downlink packet access(HSDPA):physical layer aspect",March 2002
[4]A Bria,et al,4~(th)-Generation Wireless Infrastructures:Scenariosand Research Challenges[J],IEEE Personal Communications Magazine,2001,8(6).
[5]3 GPP TR 25.835,"Report on Hybrid ARQ Type Ⅱ/Ⅲ," Sep.2000
[6]吴伟陵,牛凯,“移动通信原理”,电子工业出版社,2005,pp250-293.
[7]杨大成,“移动传播环境:理论基础·分析方法和建模技术”,2006,pp.159-179.
[8]Liu R.W.,"Blind signal processing:an introduction",IEEE International Symposium on Circuits and Systems 1996,vol.2,May 1996,pp.81-84,
[9]E.de Carvalho and D.T.M.Slock,"Blind and semi-blind FIR multichannel estimation:(Global)identifiability conditions," IEEE Trans.Signal Process.,vol.52,Apr.2004,pp.1053-1064.
[10]Q.Sun,D.C.Cox,H.C.Huang,and A.Lozano,"Estimation of Continuous Flat Fading MIMO Channels," IEEE Trans.on Wireless Commun.,vol.1,No.4,Oct.2002,pp.549-553.
[11]樊吕信、詹道庸、徐炳祥等,“通信原理”,第四版,国防工业出版社,1995.10,pp150-201.
[12]Boynton Beach,"Decimation-in- time -frequency FFT Algorithm",Vol.3,April 1994,pp 453-456.
[13]H.C.Lin and C.S.Lee,"Enhanced FFT-based Parametric Algorithm for Simultaneous Multiple Harmonics Analysis",IEEE Trans.on Proceeding Vol.148,No.3,May 2001,pp209-214.
[14]S.Ohmori,Y.Yamao,and N.Nakajima,"The Future Generations of Mobile Communications Based on Broadband Access Technologies",IEEE Commun.Mag.,vol.38,no.12,Dec.2000,pp.134-142
[15]Theodore S.Rappaport "Wireless Communication Principle and Practice" Second Edition,Publishing House of Electronics Industry,2004,pp64-99.
[16]Hamid Jafarkhani,"Space-Time Coding Theory and Practice",Electronic Industry Press,2003,pp59-120.
[17]程云鹏,“矩阵论”,西北工业大学出版社,2005,pp135-175.
[18]Branka Vucetic,Jinhong Yuan,"Space-Time Coding",Equipment Industry Press,2004,pp28-76.
[19]I.E.Telatar,"Capacity of Multi-antenna Gaussian Channels" European Trans.Telecommun.Related Technol.,vol.10,1999,pp.585-595.
[20]G.J.Foschini,M.J.Gans," On limits of Wireless Communications in a Fading Environment when Using Multiple Antennas",Wireless Personal Commu.,vol.6,March 1998,pp.311-335.
[21]罗涛等,“OFDM移动通信技术原理与运用”,人民邮电出版社,2003,pp.106-130.
[22]Hanyu Li,Yu-Dong Yao,Jin Yu,"Outage probabilities of wireless systems with beamforming",WCNC 2005,April.2005,pp.268-272.
[23]Li Ping'an,Sun Qin,"A Simple and Efficient Approach for Space-Frequency Channel Estimation and Beamforming in OFDM Systems",Volume2,June 2006,pp1077-1080.
[24]Thomas Schonhoff,Arthur A.Giorano "Detection and Estimation Theory and Its Application"Electronic Industry Press,2005,pp350-375.
[25]Yu Guan-ding;Zhang Zhao-yang;Qiu Pei-liang,"Bit and power allocation algorithm for OFDM system",Journal of Electronics &.Information Technology,vol.27,No.9,2005,pp.1479-1482.
[26]T L.Piazzo,"Fast algorithm for power and bit allocation in OFDM systems," Electronics Letters,vol.35,no.25,1999,pp.2173 -2174.
[27]Jiho Jang,Kwang Bok Lee,and Yong-Hwan Lee,"Transmit Power and Bit Allocations for OFDM Systems in a Fading Channel," Proc.IEEE GLOBECOM'03,San Francisco,2003,pp.510-515.
[28]Steven M.Ray,"Fundamentals of Statistical Signal Processing(Volume1:Estimation Theory,Volume2:Detection Theory",Electronic Industry Press,pp.54-104.
[29]Myung-sun Baek,Mu-jeong Kim,Young-Hwan You,"Semi-blind channel estimation and PAR reduction for MIMO-OFDM system with multimple antennas" IEEE Trans.On Broadcasting,Dec.2004,pp414-424.
[30]A.D.S.Jayalath,C.R.N.Athaudage,"On the PAR Reduction of OFDM Signals Using Multiple Signal Representation" IEEE Communication Letter,Voi.8,No.7,July 2004,pp425-427.
[31]Qi Lu,Lin Gui,Xiang-Zhong Fang,"A New Scheme to Mitigate the OFDM High PAR Problem by Minimizing the Signals Nonlinear Distortion Caused by HPA",IEEE Trans.On Broadcasting,Vol.52 No.4,Dec.2006,pp576-578.
[32]Shin.c.Heath,Powers.E.J,"Blind Channel Estimation for MIMO-OFDM systems",Vehicular Tech.IEEE Trans.Feb.2007,pp670-685.
[33]王文博,郑侃,宽带无线通信OFDM技术,人民邮电出版社,2003,pp.50-80.
[34]刘毅,“MIMO-OFDM功率分配算法研究”,万方数据库,2005,pp25-30.
[35]余官定、张朝阳、仇佩亮等“OFDM系统功率利比特分配算法研究”,电子与信息学报,第27卷第9期,2005年9月,pp140-142
[36]胡乐明、夏辉林、熊尚坤等“OFDM系统中一种自适应比特分配算法”,科学技术与工程,第6卷第16期,006年8月,pp.54-58
[37]罗军会、罗勇江等,“MATLAB7.0在数字信号处理中的应用”,机械工业出版社 2005pp22-60.
[38]Stuber.G.L,Barry.J.R,Mclaughlin.S.W," Broadband MIMO-OFDM Wireless Communications",IEEE Trans.On Proceedings,Feb.2004,pp.271-294.
[39]Ya-Han Pan;Letaief,K.B.;Zhigang Cao;" Dynamic spatial subchannel allocation with adaptive beamforming for MIMO-OFDM systems," IEEE Transactions on Wireless Communications,Vol.3,No.6,2004,pp.2097-2107。
[40]Jung Min Choi;Kwak,J.S.;Ho Seok Kim;Jae Hong Lee;"Adaptive subcarrier,bit,and power allocation algorithm for MIMO-OFDMA system",Proc.IEEE VTC Spring,Vol.3,2004,pp.1801-1805.
[41]P.Xia,S.Zhou,and G.B.Giannakis,"Adaptive MIMO-OFDM with Partial Channel State Information," IEEE Transactions on Signal Processing,vol.52,no.1,2004,pp.202-213.
[42]Liu Min,Xu Dazhuan,"A Practical Bit and Power Allocation Algorithm for MIMO-OFDM System in Time Varying Wireless Channels",IEEE 2007 International Symposium on Microwave,Antenna,Propagation,and EMC Technologies For Wireless Communications,Aug.2007 pp61-65.
[43]P.J.Smith,M.Shaft,and L.M.Garth,"Performance analysis for adaptive MIMO SVD transmission in a cellular system",Proc.of the 7th Australian Commun.Theory Workshop,2006,pp.49-54.
[44]S.Zhou and G.B.Giannakis,"How accurate channel prediction needs to be for transitbeamforming with adaptive modulation over Rayleigh MIMO channels," IEEE Trans.on Wireless Commun.,vol.3,2004,pp.1285-1295.
[45]Aimin Yang and Ranran Zhang,"Low Complexity Bit and Power Allocation for MIMOOFDM Systems" FTC 2007,2007,pp.140-143.
[46]Antonia M.Tulino,Sergio Verdu,"Random Matrix Theory and Wireless Communications"Vol.1 Issue 2004,2004,pp315-320.
[47]A.J.Goldsmith,and P.P.Varaiya,"Capacity of fading channels with channel side information," IEEE Trans.on Infor.Theory,vol.43,1997,pp.1986-1992.
[48]Aimin Yang,Gang Xie,Ranran Zhang,"Performance Analysis for AM in MIMO-OFDM Systems",ISCIT 2007,2007,pp290-295.
[49]Z.Zhou,B.Vucetic,M.Dohler and Y.Li "MIMO Systems with adaptive modulation," IEEE Trans on Vehic.Technology,vol.54,2005,pp.1828-1842.
[50]Zhou Xiaolin,Liu Zhaowei,Zong Xin,"Capacity Analysis for Distributed MIMO-OFDM system in composite Spatially Correlated Channels" Chinacom 2007,2007,pp 1116-1120.
[51]R.Negi,J.M.Cioffi,"Blind OFDM symbol synchronization in ISI channels",IEEE Trans.,Commun.Vol.50,Sept.2002,pp.1525-1534.
[2]3GPP TR25.848,"Physical layer aspects of UTRA High Speed Downlink Packet Access(Release 4)",2001.03.
[3]3 GPP TS 25.858 v5.0.0,"High speed downlink packet access(HSDPA):physical layer aspect",March 2002
[4]A Bria,et al,4~(th)-Generation Wireless Infrastructures:Scenariosand Research Challenges[J],IEEE Personal Communications Magazine,2001,8(6).
[5]3 GPP TR 25.835,"Report on Hybrid ARQ Type Ⅱ/Ⅲ," Sep.2000
[6]吴伟陵,牛凯,“移动通信原理”,电子工业出版社,2005,pp250-293.
[7]杨大成,“移动传播环境:理论基础·分析方法和建模技术”,2006,pp.159-179.
[8]Liu R.W.,"Blind signal processing:an introduction",IEEE International Symposium on Circuits and Systems 1996,vol.2,May 1996,pp.81-84,
[9]E.de Carvalho and D.T.M.Slock,"Blind and semi-blind FIR multichannel estimation:(Global)identifiability conditions," IEEE Trans.Signal Process.,vol.52,Apr.2004,pp.1053-1064.
[10]Q.Sun,D.C.Cox,H.C.Huang,and A.Lozano,"Estimation of Continuous Flat Fading MIMO Channels," IEEE Trans.on Wireless Commun.,vol.1,No.4,Oct.2002,pp.549-553.
[11]樊吕信、詹道庸、徐炳祥等,“通信原理”,第四版,国防工业出版社,1995.10,pp150-201.
[12]Boynton Beach,"Decimation-in- time -frequency FFT Algorithm",Vol.3,April 1994,pp 453-456.
[13]H.C.Lin and C.S.Lee,"Enhanced FFT-based Parametric Algorithm for Simultaneous Multiple Harmonics Analysis",IEEE Trans.on Proceeding Vol.148,No.3,May 2001,pp209-214.
[14]S.Ohmori,Y.Yamao,and N.Nakajima,"The Future Generations of Mobile Communications Based on Broadband Access Technologies",IEEE Commun.Mag.,vol.38,no.12,Dec.2000,pp.134-142
[15]Theodore S.Rappaport "Wireless Communication Principle and Practice" Second Edition,Publishing House of Electronics Industry,2004,pp64-99.
[16]Hamid Jafarkhani,"Space-Time Coding Theory and Practice",Electronic Industry Press,2003,pp59-120.
[17]程云鹏,“矩阵论”,西北工业大学出版社,2005,pp135-175.
[18]Branka Vucetic,Jinhong Yuan,"Space-Time Coding",Equipment Industry Press,2004,pp28-76.
[19]I.E.Telatar,"Capacity of Multi-antenna Gaussian Channels" European Trans.Telecommun.Related Technol.,vol.10,1999,pp.585-595.
[20]G.J.Foschini,M.J.Gans," On limits of Wireless Communications in a Fading Environment when Using Multiple Antennas",Wireless Personal Commu.,vol.6,March 1998,pp.311-335.
[21]罗涛等,“OFDM移动通信技术原理与运用”,人民邮电出版社,2003,pp.106-130.
[22]Hanyu Li,Yu-Dong Yao,Jin Yu,"Outage probabilities of wireless systems with beamforming",WCNC 2005,April.2005,pp.268-272.
[23]Li Ping'an,Sun Qin,"A Simple and Efficient Approach for Space-Frequency Channel Estimation and Beamforming in OFDM Systems",Volume2,June 2006,pp1077-1080.
[24]Thomas Schonhoff,Arthur A.Giorano "Detection and Estimation Theory and Its Application"Electronic Industry Press,2005,pp350-375.
[25]Yu Guan-ding;Zhang Zhao-yang;Qiu Pei-liang,"Bit and power allocation algorithm for OFDM system",Journal of Electronics &.Information Technology,vol.27,No.9,2005,pp.1479-1482.
[26]T L.Piazzo,"Fast algorithm for power and bit allocation in OFDM systems," Electronics Letters,vol.35,no.25,1999,pp.2173 -2174.
[27]Jiho Jang,Kwang Bok Lee,and Yong-Hwan Lee,"Transmit Power and Bit Allocations for OFDM Systems in a Fading Channel," Proc.IEEE GLOBECOM'03,San Francisco,2003,pp.510-515.
[28]Steven M.Ray,"Fundamentals of Statistical Signal Processing(Volume1:Estimation Theory,Volume2:Detection Theory",Electronic Industry Press,pp.54-104.
[29]Myung-sun Baek,Mu-jeong Kim,Young-Hwan You,"Semi-blind channel estimation and PAR reduction for MIMO-OFDM system with multimple antennas" IEEE Trans.On Broadcasting,Dec.2004,pp414-424.
[30]A.D.S.Jayalath,C.R.N.Athaudage,"On the PAR Reduction of OFDM Signals Using Multiple Signal Representation" IEEE Communication Letter,Voi.8,No.7,July 2004,pp425-427.
[31]Qi Lu,Lin Gui,Xiang-Zhong Fang,"A New Scheme to Mitigate the OFDM High PAR Problem by Minimizing the Signals Nonlinear Distortion Caused by HPA",IEEE Trans.On Broadcasting,Vol.52 No.4,Dec.2006,pp576-578.
[32]Shin.c.Heath,Powers.E.J,"Blind Channel Estimation for MIMO-OFDM systems",Vehicular Tech.IEEE Trans.Feb.2007,pp670-685.
[33]王文博,郑侃,宽带无线通信OFDM技术,人民邮电出版社,2003,pp.50-80.
[34]刘毅,“MIMO-OFDM功率分配算法研究”,万方数据库,2005,pp25-30.
[35]余官定、张朝阳、仇佩亮等“OFDM系统功率利比特分配算法研究”,电子与信息学报,第27卷第9期,2005年9月,pp140-142
[36]胡乐明、夏辉林、熊尚坤等“OFDM系统中一种自适应比特分配算法”,科学技术与工程,第6卷第16期,006年8月,pp.54-58
[37]罗军会、罗勇江等,“MATLAB7.0在数字信号处理中的应用”,机械工业出版社 2005pp22-60.
[38]Stuber.G.L,Barry.J.R,Mclaughlin.S.W," Broadband MIMO-OFDM Wireless Communications",IEEE Trans.On Proceedings,Feb.2004,pp.271-294.
[39]Ya-Han Pan;Letaief,K.B.;Zhigang Cao;" Dynamic spatial subchannel allocation with adaptive beamforming for MIMO-OFDM systems," IEEE Transactions on Wireless Communications,Vol.3,No.6,2004,pp.2097-2107。
[40]Jung Min Choi;Kwak,J.S.;Ho Seok Kim;Jae Hong Lee;"Adaptive subcarrier,bit,and power allocation algorithm for MIMO-OFDMA system",Proc.IEEE VTC Spring,Vol.3,2004,pp.1801-1805.
[41]P.Xia,S.Zhou,and G.B.Giannakis,"Adaptive MIMO-OFDM with Partial Channel State Information," IEEE Transactions on Signal Processing,vol.52,no.1,2004,pp.202-213.
[42]Liu Min,Xu Dazhuan,"A Practical Bit and Power Allocation Algorithm for MIMO-OFDM System in Time Varying Wireless Channels",IEEE 2007 International Symposium on Microwave,Antenna,Propagation,and EMC Technologies For Wireless Communications,Aug.2007 pp61-65.
[43]P.J.Smith,M.Shaft,and L.M.Garth,"Performance analysis for adaptive MIMO SVD transmission in a cellular system",Proc.of the 7th Australian Commun.Theory Workshop,2006,pp.49-54.
[44]S.Zhou and G.B.Giannakis,"How accurate channel prediction needs to be for transitbeamforming with adaptive modulation over Rayleigh MIMO channels," IEEE Trans.on Wireless Commun.,vol.3,2004,pp.1285-1295.
[45]Aimin Yang and Ranran Zhang,"Low Complexity Bit and Power Allocation for MIMOOFDM Systems" FTC 2007,2007,pp.140-143.
[46]Antonia M.Tulino,Sergio Verdu,"Random Matrix Theory and Wireless Communications"Vol.1 Issue 2004,2004,pp315-320.
[47]A.J.Goldsmith,and P.P.Varaiya,"Capacity of fading channels with channel side information," IEEE Trans.on Infor.Theory,vol.43,1997,pp.1986-1992.
[48]Aimin Yang,Gang Xie,Ranran Zhang,"Performance Analysis for AM in MIMO-OFDM Systems",ISCIT 2007,2007,pp290-295.
[49]Z.Zhou,B.Vucetic,M.Dohler and Y.Li "MIMO Systems with adaptive modulation," IEEE Trans on Vehic.Technology,vol.54,2005,pp.1828-1842.
[50]Zhou Xiaolin,Liu Zhaowei,Zong Xin,"Capacity Analysis for Distributed MIMO-OFDM system in composite Spatially Correlated Channels" Chinacom 2007,2007,pp 1116-1120.
[51]R.Negi,J.M.Cioffi,"Blind OFDM symbol synchronization in ISI channels",IEEE Trans.,Commun.Vol.50,Sept.2002,pp.1525-1534.