无线通信系统中均衡器的研究与设计
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摘要
在无线通信系统中,由于多径效应常常引起信道衰落,直接结果是码间干扰非常严重。为了克服码间干扰所带来的信号畸变,必须在接收端增加均衡器,以补偿信道特性,正确恢复发送序列。盲均衡器由于不需要训练序列,仅利用接收信号的统计特性就能对信道特性进行补偿,消除码间干扰。因而,盲均衡技术在数字通信、雷达、地震和图像处理等领域获得了广泛的应用。
本文首先分析了无线通信信道的传输特性以及码间干扰产生的原因,接着概述了自适应均衡技术,对常用的Bussgang盲均衡算法进行了研究、分析和仿真。
在信道盲均衡器的计算机仿真部分,通过MATLAB建模仿真,分析了噪声和步长对恒模(CMA)算法的收敛性能的影响。然后利用Simulink仿真工具,构建QPSK调制系统平台,分别在高斯白噪声信道和多径信道的环境下,通过眼图、星座图和误码率对CMA算法的性能做了进一步的分析。
在信道盲均衡器的实现部分,本文探讨了以FPGA为平台,利用VHDL语言,使用TOP-DOWN的数字系统设计方法,实现了基于判决引导(DDLMS)算法的盲均衡器。本文详细阐述了基于FPGA的信道盲均衡器的设计思想,设计结构和VHDL设计实现,以及分别给出了各个模块的结构框图和验证结果。
本文所设计和实现的信道盲均衡器,为电子设计自动化(EDA)技术做了有益的探索性尝试,对今后无线通信系统中的单芯片可编程系统(SOPC)的设计应用有着积极的借鉴意义。
In wireless communication system, Inter-symbol Interference is serious and signal is distorted extremely because of fading channel resulted in by the effect of multipath.The adaptive equalizer should be used in order to compensate channel characteristic and recover received signal correctly.Blind equalizers can compensate channel characteristic and reduce Inter-symbol Interference without training sequence,so are used widely in many fields such as digital communication system,radar system,earthquake and image processing system and so on.
The characterization of the wireless communication channel and the appearance of ISI are discussed in this paper firstly.Then, the adaptive equalization technology are summarized. This paper analyses and simulates the common blind equalization algorithms based on Bussgang family.
In the computer simulation part of the channel equalizer, this paper simulate the CMA by the MATLAB software.The effect of noise and step-size to the convergence are discussed with the module.Then we establish the QPSK modulation plat with the Simulink tool.In the AWGN and multi-path channels,the eye diagram,the constellation diagram and the BER curve are discussed furtherly.
During the process of the implementation, we establish the FPGA hardware plat,and VHDL code had been coded to implement blind equalizer of DDLMS algorithm based on TOP-DOWN digital design methodology. Design principle,structures and VHDL implementations of modules in enhancement blind equalizer are described in detail in follow sections. Each section closed with the structure graph and the test results of module in verification.
This thesis investigates the design technologies of EDA (Electronic Design Automation) by means of designing and implementing blind equalizer. It provides preliminary study for large scale SOPC (System on Programmable Chip) in wireless communication system field.
本文首先分析了无线通信信道的传输特性以及码间干扰产生的原因,接着概述了自适应均衡技术,对常用的Bussgang盲均衡算法进行了研究、分析和仿真。
在信道盲均衡器的计算机仿真部分,通过MATLAB建模仿真,分析了噪声和步长对恒模(CMA)算法的收敛性能的影响。然后利用Simulink仿真工具,构建QPSK调制系统平台,分别在高斯白噪声信道和多径信道的环境下,通过眼图、星座图和误码率对CMA算法的性能做了进一步的分析。
在信道盲均衡器的实现部分,本文探讨了以FPGA为平台,利用VHDL语言,使用TOP-DOWN的数字系统设计方法,实现了基于判决引导(DDLMS)算法的盲均衡器。本文详细阐述了基于FPGA的信道盲均衡器的设计思想,设计结构和VHDL设计实现,以及分别给出了各个模块的结构框图和验证结果。
本文所设计和实现的信道盲均衡器,为电子设计自动化(EDA)技术做了有益的探索性尝试,对今后无线通信系统中的单芯片可编程系统(SOPC)的设计应用有着积极的借鉴意义。
In wireless communication system, Inter-symbol Interference is serious and signal is distorted extremely because of fading channel resulted in by the effect of multipath.The adaptive equalizer should be used in order to compensate channel characteristic and recover received signal correctly.Blind equalizers can compensate channel characteristic and reduce Inter-symbol Interference without training sequence,so are used widely in many fields such as digital communication system,radar system,earthquake and image processing system and so on.
The characterization of the wireless communication channel and the appearance of ISI are discussed in this paper firstly.Then, the adaptive equalization technology are summarized. This paper analyses and simulates the common blind equalization algorithms based on Bussgang family.
In the computer simulation part of the channel equalizer, this paper simulate the CMA by the MATLAB software.The effect of noise and step-size to the convergence are discussed with the module.Then we establish the QPSK modulation plat with the Simulink tool.In the AWGN and multi-path channels,the eye diagram,the constellation diagram and the BER curve are discussed furtherly.
During the process of the implementation, we establish the FPGA hardware plat,and VHDL code had been coded to implement blind equalizer of DDLMS algorithm based on TOP-DOWN digital design methodology. Design principle,structures and VHDL implementations of modules in enhancement blind equalizer are described in detail in follow sections. Each section closed with the structure graph and the test results of module in verification.
This thesis investigates the design technologies of EDA (Electronic Design Automation) by means of designing and implementing blind equalizer. It provides preliminary study for large scale SOPC (System on Programmable Chip) in wireless communication system field.
引文
[1]邹谋炎.反卷积和信号复原[M].北京:国防工业出版社,2001.
[2] J.G. Proakis.数字通信(第三版)[M].北京:电子工业出版社,2001.
[3] D. Boss, K. D. Kammeyer and T. Petermann,Is blind estimation feasible in mobile communication systems A study based on GSM[J],IEEE.JSAC, vol. 16, pp1479-1492, Oct 1998.
[4] Y.Sato. A method of self-recovering equalization for multiple amplitude modulation systems[J]. IEEE Trans. on Communication, 1975,Vo1.23. pp.679～682.
[5] Macchi, O. and Eweda, E., Convergence analysis of self-adaptive equalizers, Information Theory[J], IEEE Transactions on, vol. 30, no. 2, pp. 161-176, 1984.
[6] Albert Benveniste, Maurice Goursat. Blind Equalizers[J]. IEEE Trans. on Communication., 1984 32.(8) pp:871-878.
[7] G.Picchi , G.Prati. Blind equalization and carrier recovering using a“Stop-and-Go”Decision-Directed algorithm[J]. IEEETrans.on communication, 1987, Vol. 35, pp: 877-887.
[8] D. N. Godard. Self-Recovering Equalization and Carrier Tracking inTwo-Dimension Date Communication System[J]. IEEE Trans Commun. 1980,COM-28(11) 1867-1875.
[9] J. Treichler, B. Agee. A new approach to multipath correction of constant modulus signals[J]. IEEE Transactions on Acoustic ,speech, and Signal processing. 1983, Vol.ASSP-31 (2):459-472.
[10] C. J. Foschini .Eciualization Without Altering or Detesting Data[J].AT&Technical 1985, Journal, Vo1.64. Oct:1885-1893.
[11] Z Ding .Convergence of Godard Blind Equalizers in Data Communication Systems[J]. IEEE Trans. On Comm. 1991,Vol.SP-39(1): 1313-1320.
[12] C K.Chan. Stationary Points of the Constant Modulus Algorithm for Real Gaussian Signals[J] IEEE Trans. On signal processing, 1990, Vo1.38(3):2176-2187.
[13] Y. Li,Z.ding. Convergence Analysis of Finite Length Blind Adaptive Equalizers[J]. IEEE Trans. on signal processing,Vo1.43,No.9,P.2120-2129,1995.
[14] J.J.Shynk,A Comparative Performance Studv of Several Blind Equalization Algorithms[J] Adaptive Signal Processing 1991,1565:102-107.
[15] Zervas. Effects of Constellation Shaping on Blind Equalization[J]. Adaptive Signal Processing 1991,15:178-182.
[16]樊龙飞,查光明,黄顺吉,关于CMA盲均衡算法的稳态剩余误差的研究[J],信号处理,1998 ,14 (4 ) : 376-379.
[17]徐金标,葛建华,王新梅.一种新的盲均衡算法[J],通信学报, 1995,16(3):78-82.
[18]欧阳喜,葛临东.一种新的基于误差切换的盲均衡算法[J],数字通信, 2000,2: 10-11.
[19]赵雅兴,刘栋,张宁.一种适用于FPGA实现的盲均衡算法[J],通信学报, 2001, 22 ( 8 ): 108-111.
[20]雷旭,徐重阳,刘屹.多径FIR信道的盲和半盲识别与均衡[J].系统仿真学报.December 2002 ,14 (12 ) : 1606-1610.
[21] Kenji Ueda, Hiroshi Lchi, James Okello, Yoshio, Itoh. A High-Speed Arthitecture for CMA Blind Equalizer [J].A Advanced Signal Processing for Communication.2002
[22] Chris. H. Dick, Henrik M. Pederson. Designing FPGA signal-processing datapaths for SDR[J].ESC-China. Conference Proceedings.2002.pp301-307.
[23]张贤达,保铮.通信信号处理[M].北京:国防工业出版社, 2000.
[24]曹志刚,钱亚生.现代通信原理[M].北京:清华大学出版社, 1992.
[25] Tranter W.H,Shanmugan K.S,Rappaport T.S. Principles of communication systems simulation with wireless applications[M].China Machine Press,2005.6
[26]张贤达.现代信号处理[M],北京:清华大学出版社.第二版, 2002.
[27]樊昌信,张甫诩,徐炳祥,吴成柯.通信原理[M].北京:国防工业出版社.第5版, 2001.
[28]邱天爽,魏东兴,唐洪,张安清.通信中的自适应信号处理[M].北京:电子工业出版社, 2005.
[29]龚耀寰.自适应滤波(第二版)——时域自适应滤波和智能天线[M].北京:电子工业出版社.2003.
[30]曹达仲,侯春萍.移动通信原理、系统及技术[M].北京:清华大学出版社. 2004.
[31]吴禀圣,邹志永.一种DDLMS和CMA方法相结合的盲均衡算法[J].电路与系统学报,2003.2,Vol. 8,No.1.
[32]夏威,林水生,吴广玉.一种高速率基带正交均衡算法[A]. 2004年中国通信集成电路技术与应用研讨会, pp. 102-107, 2004.
[33]吴广玉,李广军,阎波.基于FPGA的基带正交盲均衡器的设计[A].四川通信年会, 2003.
[34]飞思科技产品研发中心编著. MATLAB7辅助信号处理技术与应用[M].北京:电子工业出版社.2005.
[35] Simon Haykin自适应滤波器原理[M].北京:电子工业出版社. 2003.
[36] Cheolwoo You, Daesik Hong. Nonlinear blind equalization scheme using complex-valued Multilayer feed forward neural networks[J]. IEEE Trans. on signal processing, Vol. 19, No. 6, pp. 1442-1455,1998.
[37]邓华. MATLAB通信仿真及应用实例详解[M].北京:人民邮电出版社, 2003.
[38]夏宇闻. Verilog数字系统设计教程[M],北京:北京航空航天大学出版社, 2003.
[39]王诚,吴继华,范丽珍等编著. Altera FPGA/CPLD设计(基础篇)[M].北京:人民邮电出版社,2006.
[40] Uwe Meyer-Baese.数字信号处理的FPGA实现[M].北京:清华大学出版社, 2006.
[41] Altera Corporation. Stratix Device Handbook[S]. 1995-2003.
[42]张建.短波数字通信中均衡技术研究[D].电子科技大学硕士学位论文, 2005.4.
[43]尹晓璐.基于FPGA的信道均衡器的设计与实现[D].电子科技大学硕士学位论文,2005.2.
[44]吴广玉.无线信道仿真和均衡器的FPGA设计与实现[D].电子科技大学硕士学位论文,2005.6.
[45]杨娇瑜.高速移动无线信道自适应均衡研究[D].北京交通大学硕士学位论文,2006.12.
[46]周强.均衡算法[D].上海交通大学硕士学位论文,2006.12.
[47]王珊珊.移动信道条件下MPCM接收机的同步与均衡[D].浙江大学硕士学位论文,2007.5.
[48]高鑫.无线通信系统中Bussgang族盲均衡算法的研究[D].大连海事大学硕士学位论文,2007.3.
[2] J.G. Proakis.数字通信(第三版)[M].北京:电子工业出版社,2001.
[3] D. Boss, K. D. Kammeyer and T. Petermann,Is blind estimation feasible in mobile communication systems A study based on GSM[J],IEEE.JSAC, vol. 16, pp1479-1492, Oct 1998.
[4] Y.Sato. A method of self-recovering equalization for multiple amplitude modulation systems[J]. IEEE Trans. on Communication, 1975,Vo1.23. pp.679～682.
[5] Macchi, O. and Eweda, E., Convergence analysis of self-adaptive equalizers, Information Theory[J], IEEE Transactions on, vol. 30, no. 2, pp. 161-176, 1984.
[6] Albert Benveniste, Maurice Goursat. Blind Equalizers[J]. IEEE Trans. on Communication., 1984 32.(8) pp:871-878.
[7] G.Picchi , G.Prati. Blind equalization and carrier recovering using a“Stop-and-Go”Decision-Directed algorithm[J]. IEEETrans.on communication, 1987, Vol. 35, pp: 877-887.
[8] D. N. Godard. Self-Recovering Equalization and Carrier Tracking inTwo-Dimension Date Communication System[J]. IEEE Trans Commun. 1980,COM-28(11) 1867-1875.
[9] J. Treichler, B. Agee. A new approach to multipath correction of constant modulus signals[J]. IEEE Transactions on Acoustic ,speech, and Signal processing. 1983, Vol.ASSP-31 (2):459-472.
[10] C. J. Foschini .Eciualization Without Altering or Detesting Data[J].AT&Technical 1985, Journal, Vo1.64. Oct:1885-1893.
[11] Z Ding .Convergence of Godard Blind Equalizers in Data Communication Systems[J]. IEEE Trans. On Comm. 1991,Vol.SP-39(1): 1313-1320.
[12] C K.Chan. Stationary Points of the Constant Modulus Algorithm for Real Gaussian Signals[J] IEEE Trans. On signal processing, 1990, Vo1.38(3):2176-2187.
[13] Y. Li,Z.ding. Convergence Analysis of Finite Length Blind Adaptive Equalizers[J]. IEEE Trans. on signal processing,Vo1.43,No.9,P.2120-2129,1995.
[14] J.J.Shynk,A Comparative Performance Studv of Several Blind Equalization Algorithms[J] Adaptive Signal Processing 1991,1565:102-107.
[15] Zervas. Effects of Constellation Shaping on Blind Equalization[J]. Adaptive Signal Processing 1991,15:178-182.
[16]樊龙飞,查光明,黄顺吉,关于CMA盲均衡算法的稳态剩余误差的研究[J],信号处理,1998 ,14 (4 ) : 376-379.
[17]徐金标,葛建华,王新梅.一种新的盲均衡算法[J],通信学报, 1995,16(3):78-82.
[18]欧阳喜,葛临东.一种新的基于误差切换的盲均衡算法[J],数字通信, 2000,2: 10-11.
[19]赵雅兴,刘栋,张宁.一种适用于FPGA实现的盲均衡算法[J],通信学报, 2001, 22 ( 8 ): 108-111.
[20]雷旭,徐重阳,刘屹.多径FIR信道的盲和半盲识别与均衡[J].系统仿真学报.December 2002 ,14 (12 ) : 1606-1610.
[21] Kenji Ueda, Hiroshi Lchi, James Okello, Yoshio, Itoh. A High-Speed Arthitecture for CMA Blind Equalizer [J].A Advanced Signal Processing for Communication.2002
[22] Chris. H. Dick, Henrik M. Pederson. Designing FPGA signal-processing datapaths for SDR[J].ESC-China. Conference Proceedings.2002.pp301-307.
[23]张贤达,保铮.通信信号处理[M].北京:国防工业出版社, 2000.
[24]曹志刚,钱亚生.现代通信原理[M].北京:清华大学出版社, 1992.
[25] Tranter W.H,Shanmugan K.S,Rappaport T.S. Principles of communication systems simulation with wireless applications[M].China Machine Press,2005.6
[26]张贤达.现代信号处理[M],北京:清华大学出版社.第二版, 2002.
[27]樊昌信,张甫诩,徐炳祥,吴成柯.通信原理[M].北京:国防工业出版社.第5版, 2001.
[28]邱天爽,魏东兴,唐洪,张安清.通信中的自适应信号处理[M].北京:电子工业出版社, 2005.
[29]龚耀寰.自适应滤波(第二版)——时域自适应滤波和智能天线[M].北京:电子工业出版社.2003.
[30]曹达仲,侯春萍.移动通信原理、系统及技术[M].北京:清华大学出版社. 2004.
[31]吴禀圣,邹志永.一种DDLMS和CMA方法相结合的盲均衡算法[J].电路与系统学报,2003.2,Vol. 8,No.1.
[32]夏威,林水生,吴广玉.一种高速率基带正交均衡算法[A]. 2004年中国通信集成电路技术与应用研讨会, pp. 102-107, 2004.
[33]吴广玉,李广军,阎波.基于FPGA的基带正交盲均衡器的设计[A].四川通信年会, 2003.
[34]飞思科技产品研发中心编著. MATLAB7辅助信号处理技术与应用[M].北京:电子工业出版社.2005.
[35] Simon Haykin自适应滤波器原理[M].北京:电子工业出版社. 2003.
[36] Cheolwoo You, Daesik Hong. Nonlinear blind equalization scheme using complex-valued Multilayer feed forward neural networks[J]. IEEE Trans. on signal processing, Vol. 19, No. 6, pp. 1442-1455,1998.
[37]邓华. MATLAB通信仿真及应用实例详解[M].北京:人民邮电出版社, 2003.
[38]夏宇闻. Verilog数字系统设计教程[M],北京:北京航空航天大学出版社, 2003.
[39]王诚,吴继华,范丽珍等编著. Altera FPGA/CPLD设计(基础篇)[M].北京:人民邮电出版社,2006.
[40] Uwe Meyer-Baese.数字信号处理的FPGA实现[M].北京:清华大学出版社, 2006.
[41] Altera Corporation. Stratix Device Handbook[S]. 1995-2003.
[42]张建.短波数字通信中均衡技术研究[D].电子科技大学硕士学位论文, 2005.4.
[43]尹晓璐.基于FPGA的信道均衡器的设计与实现[D].电子科技大学硕士学位论文,2005.2.
[44]吴广玉.无线信道仿真和均衡器的FPGA设计与实现[D].电子科技大学硕士学位论文,2005.6.
[45]杨娇瑜.高速移动无线信道自适应均衡研究[D].北京交通大学硕士学位论文,2006.12.
[46]周强.均衡算法[D].上海交通大学硕士学位论文,2006.12.
[47]王珊珊.移动信道条件下MPCM接收机的同步与均衡[D].浙江大学硕士学位论文,2007.5.
[48]高鑫.无线通信系统中Bussgang族盲均衡算法的研究[D].大连海事大学硕士学位论文,2007.3.