数字微波通信中的自适应均衡算法及实现
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摘要
在移动通信及高速无线数据通信中，由于多径效应和信道带宽的有限性以及信道特性的不完善性而产生的码间干扰(ISI)成为影响通信质量的重要因素，信道的均衡技术是克服码间干扰的主要手段，而自适应均衡器能够跟踪信道变化而获得广泛应用。
本文主要通过算法和在结构两个角度研究自适应均衡技术在高速无线数据通信中的应用。在算法上主要分析了实际常用的三种自适应均衡算法：LMS算法，RLS算法和Kalman算法，说明了它们之间的联系，进行了仿真；提出一种修正的将来状态滤波算法，并给出了性能仿真比较结果。在结构上，讨论了分数间隔判决反馈均衡器的性能，着重讨论了其局部收敛性和误差传播。
最后分析了分数间隔判决反馈均衡器的FPGA具体的实现过程，对实现过程中遇到的问题进行了分析并加以解决。
In mobile communication and high-speed wireless digital communication, inter symbol interference(ISI) introduced by multi-path effect, the limited channel bandwidth and the imperfectness of the channel, becomes a key factor that degrades the performance of communication. However channel equalization technique can overcome the influence of ISI. And adaptive equalizers have found wide applications for they can trace the variation of the channel.
This thesis studies the adaptive equalization problems by focusing on the algorithm and the structure aspects. A thorough analysis is made on the three wildly used adaptive equalization algorithm of LMS,RLS and Kalman, and the relationships among them as well as their performance evaluation are given. A modified future coefficient filtering algorithms in the least mean squares (LMS) algorithm is proposed and the performance is evaluated. In the structure aspsect, analysis of the performance of the fractionally spaced adaptive decision-feedback equalizer is made by putting emphases on its local convergence property and error propagation.
The implementation of the fractionally spaced adaptive decision-feedback equalizer with FPGA is also presented in the last of this thesis .
本文主要通过算法和在结构两个角度研究自适应均衡技术在高速无线数据通信中的应用。在算法上主要分析了实际常用的三种自适应均衡算法：LMS算法，RLS算法和Kalman算法，说明了它们之间的联系，进行了仿真；提出一种修正的将来状态滤波算法，并给出了性能仿真比较结果。在结构上，讨论了分数间隔判决反馈均衡器的性能，着重讨论了其局部收敛性和误差传播。
最后分析了分数间隔判决反馈均衡器的FPGA具体的实现过程，对实现过程中遇到的问题进行了分析并加以解决。
In mobile communication and high-speed wireless digital communication, inter symbol interference(ISI) introduced by multi-path effect, the limited channel bandwidth and the imperfectness of the channel, becomes a key factor that degrades the performance of communication. However channel equalization technique can overcome the influence of ISI. And adaptive equalizers have found wide applications for they can trace the variation of the channel.
This thesis studies the adaptive equalization problems by focusing on the algorithm and the structure aspects. A thorough analysis is made on the three wildly used adaptive equalization algorithm of LMS,RLS and Kalman, and the relationships among them as well as their performance evaluation are given. A modified future coefficient filtering algorithms in the least mean squares (LMS) algorithm is proposed and the performance is evaluated. In the structure aspsect, analysis of the performance of the fractionally spaced adaptive decision-feedback equalizer is made by putting emphases on its local convergence property and error propagation.
The implementation of the fractionally spaced adaptive decision-feedback equalizer with FPGA is also presented in the last of this thesis .
引文
[1] Lok-Kee Ting, Colin F. N. Cowan, Roger F. Woods,"LMS Coefficient Filtering for Time-Varying Chirped Signals"IEEE Trans Signal Processing, vol. 52, NO. 11, Nov 2004, pp.3160-3169
[2] Lucky,R.W., "Automatic equalization for digital communication, "Bell Syst.Tech.J.,vol.44,pp.547-588.
[3] Caraiscos,C.and Liu,B., "A Roundoff Error Analysis of the LMS Adaptive Algorithm," IEEE Trans.Acoust.,Speech,Signal Processing,vol.ASSP-32,January.pp.34-41.
[4] Proakis,J.G.,and J.H.Miller, "An adaptive receiver for digital signaling through channels with intersymbol interference, "IEEE Trans.Information Theory ,vol.IT-15,pp.484-497.
[5] Satorius,E.H.,and S.T.Alexander, "Channel equalization using adaptive lattice algorithms, "IEEE Trans.Commun.,voI.COM-27,pp.899-905.
[6] G. Kubin, "Time-varying coefficient tracking and noise suppression properties of a class of adaptive algorithm," in Proc. ICASSP, 1988, pp. 1542-1545.
[7] Satorius,E.H.,and J.D.Pack."Application of least squares lattice algorithms to adaptive equalization, " IEEE Trans.Commun.,vol.COM-29,pp.136-142.
[8] Brady,D.M.,"An adaptive coherent diversity receiver for data transmission through dispersive media, "in Conf.Rec.ICC70,pp.21-35-21-40.
[9] Tong,L.,and S.Perreau, "Multichannel blind identification:From subspace to maximum likelihood methods, "Proc.IEEE,vol.86,pp. 1951-1968.
[10] Ungerboeck,G., "Theory on the speed of convergence in adaptive equalizers for digital communication, "IBM J.Res.Dev,vol.16,pp.546-555.
[11] Godard,D.N., "Channel equalization using a Kalman filter for fast data transmission, "IBM J.Res.Dev,vol.18,pp.267-273.
[12] Falconer,D.D.,and L.Ljung. "Application of fast Kalman estimation to adaptive equalization, "IEEE Trans.Commun.,vol.COM-26,pp. 1439-1446.
[13] Monsen,P., "Feedback equalization for fading dispersive channels, "IEEE Trans.Information Theory,vol.IT-17,pp.56-64.
[14] Sato Y., "A method of self-recovering equalization for multiple amplitude modulation schemes, " IEEE Trans. Commun.,1975.pp.679-682.
[15] Benveniste A. "Blind equalizers, " IEEE Trans. Commun.,1984,pp.871-883.
[16] Godard,D.N.. "Self-recovering equalization and carrier tracking in two-dimensional communication systems,"IEEE Trans. Commun., 1980,pp. 1867-1875.
[17] Price,R, "Nonlinearly Feedback-Equalized PAM vs.Capacity, "Proc. 1972 IEEE Int.Conf.on Commun.Philadelphia,PA,June.pp.22.12-22.17.
[18] R.A.Kennedy,B.D.O.Anderson,and R.R.Bitmead, "Blind adaptation of decision feedback equalizers:gross convergence properties",International Journal of Adaptive Control and Signal Processing,Vol.7,pp.497-523,1993.
[19] C.B.Papadias and A.Paulraj, "Decision-feedback equalization and identification of linear channels using blind algorithms of bussgang type, Proceedings of the 29th Annual Asilomar Conference on Signal,Systems,and Computers,Pacific Grove,CA,November 1995.pp.335-340.
[20] S.Marcos,S.cherif, M.Jaidane, "Blind cancellation of intersymbol interference in decision feedback equalizers," Proceedings of the International Conference on Acoustics,Speech and Signal Processing,Detroit,MI,May 1995.pp. 1073-1076.
[21] T.J.Endres,S.N.Hulyalkar,T.A.Schaffer,C.H.Strolle, "A constant modulus decision feedback equalizer, "United States Patent no.60,148,983,filed August 14,1999.
[22] B.P.Paris,H.Chen, "Nonlinear blind channel equalization via ring decision feedback, "Proceedings of the 1998 IEEE International symposium on Information Theory,Cambridge,MA,August 1998.pp.452
[23] P.Mannion, "VSB/QAM receiver cracks the code to indoor and mobile reception, "Electronic Design,August 23,1999.pp.35-42.
[24] Haykin．S．著，郑宝玉等译，自适应滤波器原理(第四版)，北京：电子工业出版社，2003。
[25] John G．Proakis著，张力军等译，数字通信(第四版)，北京：电子工业出版社，2003。
[26] Georgios B．Giannakis等著，刘郁林等译，无线通信与移动通信中信号处理研究的新进展。北京：电子工业出版社，2004。
[27] Dimitris G．Manolakis等著，周正等译，统计与自适应信号处理，北京：电子工业出版社，2003。
[28] William H．Tranter等著，肖明波等译，通信系统仿真原理与无线应用，北京：机械工业出版社，2005。
[29] 张贤达、保铮著，通信信号处理，北京：国防工业出版社，2000。
[30] 曹达仲、王尤翠，数字移动通信中的自适应均衡技术。通信技术，1997．2．pp．24-29．
[31] 姚庆栎等著，数字无线传输，杭州：浙江大学出版社，1992。
[32] 吴继华、王诚编著，Altera FPGA／CPLD设计(高级篇)，北京：人民邮电出 版社，2005。
[33] 侯伯亨、顾新著，VHDL硬件描述语言与数字逻辑电路设计，西安：西安电子科技大学出版社，1999。
[34] 褚振勇、翁木云著，FPGA设计与应用，西安：西安电子科技大学出版社，2002。
[35] 张志涌等编著，精通MATLAB 6.5版，北京：北京航空航天大学出版社，2003。
[2] Lucky,R.W., "Automatic equalization for digital communication, "Bell Syst.Tech.J.,vol.44,pp.547-588.
[3] Caraiscos,C.and Liu,B., "A Roundoff Error Analysis of the LMS Adaptive Algorithm," IEEE Trans.Acoust.,Speech,Signal Processing,vol.ASSP-32,January.pp.34-41.
[4] Proakis,J.G.,and J.H.Miller, "An adaptive receiver for digital signaling through channels with intersymbol interference, "IEEE Trans.Information Theory ,vol.IT-15,pp.484-497.
[5] Satorius,E.H.,and S.T.Alexander, "Channel equalization using adaptive lattice algorithms, "IEEE Trans.Commun.,voI.COM-27,pp.899-905.
[6] G. Kubin, "Time-varying coefficient tracking and noise suppression properties of a class of adaptive algorithm," in Proc. ICASSP, 1988, pp. 1542-1545.
[7] Satorius,E.H.,and J.D.Pack."Application of least squares lattice algorithms to adaptive equalization, " IEEE Trans.Commun.,vol.COM-29,pp.136-142.
[8] Brady,D.M.,"An adaptive coherent diversity receiver for data transmission through dispersive media, "in Conf.Rec.ICC70,pp.21-35-21-40.
[9] Tong,L.,and S.Perreau, "Multichannel blind identification:From subspace to maximum likelihood methods, "Proc.IEEE,vol.86,pp. 1951-1968.
[10] Ungerboeck,G., "Theory on the speed of convergence in adaptive equalizers for digital communication, "IBM J.Res.Dev,vol.16,pp.546-555.
[11] Godard,D.N., "Channel equalization using a Kalman filter for fast data transmission, "IBM J.Res.Dev,vol.18,pp.267-273.
[12] Falconer,D.D.,and L.Ljung. "Application of fast Kalman estimation to adaptive equalization, "IEEE Trans.Commun.,vol.COM-26,pp. 1439-1446.
[13] Monsen,P., "Feedback equalization for fading dispersive channels, "IEEE Trans.Information Theory,vol.IT-17,pp.56-64.
[14] Sato Y., "A method of self-recovering equalization for multiple amplitude modulation schemes, " IEEE Trans. Commun.,1975.pp.679-682.
[15] Benveniste A. "Blind equalizers, " IEEE Trans. Commun.,1984,pp.871-883.
[16] Godard,D.N.. "Self-recovering equalization and carrier tracking in two-dimensional communication systems,"IEEE Trans. Commun., 1980,pp. 1867-1875.
[17] Price,R, "Nonlinearly Feedback-Equalized PAM vs.Capacity, "Proc. 1972 IEEE Int.Conf.on Commun.Philadelphia,PA,June.pp.22.12-22.17.
[18] R.A.Kennedy,B.D.O.Anderson,and R.R.Bitmead, "Blind adaptation of decision feedback equalizers:gross convergence properties",International Journal of Adaptive Control and Signal Processing,Vol.7,pp.497-523,1993.
[19] C.B.Papadias and A.Paulraj, "Decision-feedback equalization and identification of linear channels using blind algorithms of bussgang type, Proceedings of the 29th Annual Asilomar Conference on Signal,Systems,and Computers,Pacific Grove,CA,November 1995.pp.335-340.
[20] S.Marcos,S.cherif, M.Jaidane, "Blind cancellation of intersymbol interference in decision feedback equalizers," Proceedings of the International Conference on Acoustics,Speech and Signal Processing,Detroit,MI,May 1995.pp. 1073-1076.
[21] T.J.Endres,S.N.Hulyalkar,T.A.Schaffer,C.H.Strolle, "A constant modulus decision feedback equalizer, "United States Patent no.60,148,983,filed August 14,1999.
[22] B.P.Paris,H.Chen, "Nonlinear blind channel equalization via ring decision feedback, "Proceedings of the 1998 IEEE International symposium on Information Theory,Cambridge,MA,August 1998.pp.452
[23] P.Mannion, "VSB/QAM receiver cracks the code to indoor and mobile reception, "Electronic Design,August 23,1999.pp.35-42.
[24] Haykin．S．著，郑宝玉等译，自适应滤波器原理(第四版)，北京：电子工业出版社，2003。
[25] John G．Proakis著，张力军等译，数字通信(第四版)，北京：电子工业出版社，2003。
[26] Georgios B．Giannakis等著，刘郁林等译，无线通信与移动通信中信号处理研究的新进展。北京：电子工业出版社，2004。
[27] Dimitris G．Manolakis等著，周正等译，统计与自适应信号处理，北京：电子工业出版社，2003。
[28] William H．Tranter等著，肖明波等译，通信系统仿真原理与无线应用，北京：机械工业出版社，2005。
[29] 张贤达、保铮著，通信信号处理，北京：国防工业出版社，2000。
[30] 曹达仲、王尤翠，数字移动通信中的自适应均衡技术。通信技术，1997．2．pp．24-29．
[31] 姚庆栎等著，数字无线传输，杭州：浙江大学出版社，1992。
[32] 吴继华、王诚编著，Altera FPGA／CPLD设计(高级篇)，北京：人民邮电出 版社，2005。
[33] 侯伯亨、顾新著，VHDL硬件描述语言与数字逻辑电路设计，西安：西安电子科技大学出版社，1999。
[34] 褚振勇、翁木云著，FPGA设计与应用，西安：西安电子科技大学出版社，2002。
[35] 张志涌等编著，精通MATLAB 6.5版，北京：北京航空航天大学出版社，2003。