基于高阶统计量的OFDM信号检测技术的研究
摘要
正交频分复用(OFDM)技术是一种具有很强抗多径干扰、码间干扰和窄带干扰以及很高频谱利用率的高效数据传输技术,已经广泛应用在非对称用户环路(ADSL)、数字音频广播(DAB)、高清晰度数字电视(HDTV)、无线局域网(WLAN)等系统中。未来的无线移动通信要求能够提供高速数据传输和宽带多媒体业务,因而正交频分复用技术将受到越来越多的关注,并将成为下一代移动通信的核心技术之一。
通信信号的自动识别和调制参数的估计是非协作通信和认知无线电中的关键问题。本文首先简要的介绍了移动信道的特性及OFDM的基本原理,并对OFDM的循环前缀的作用、OFDM的均衡及OFDM的信道估计方法等关键技术作了简要的介绍。
然后研究了基于高阶累积量的OFDM信号的识别算法。首先对检测信号进行了采样、Hilbert变换、归一化等预处理工作。其次利用OFDM信号具有高斯渐进性的特点,采用4阶累积量对OFDM信号识别,经理论推导和仿真分析表明该方法有很好的识别效果。
最后针对单载波信号通过Rayleigh信道后也会呈现高斯渐进性的特点,利用基于高阶矩的识别方法进行了仿真分析。同时研究了一种可变长自相关算法对OFDM信号的时域参数进行盲检测,在Matlab中对该算法进行仿真,结果分析表明该算法可行、有效。
Orthogonal Frequency Division Multiplexing (OFDM) technique is a efficienct data transmission techique with good immunity for the effects of multi-path channel propagation, intersymbol interference, narrowband interference.and higth frequency using ratio. Wide used in Asymmetrical Digital Subscriber Line( ADSL), Digital Audio Broadcasting (DAB) , Hign Definition Television(HDTV), Wireless Local Area Network (WLAN) and etc.systems.The future Radio Mobile Communication System requires high speed data transmission and multimedia in wireless networks,so Orthogonal Frequency Division Multiplexing will be more and more attented,and will become one of key technologis in the next mobile communication generation.
Communication signal auto identify and modulate parameter estimation are key technologis in non-cooperative communication and software radio.In this paper,the mobile fading channel characteristic and the fundament of OFDM are discussed firstly,and then briefly introduces the the OFDM key techniques such as cyclic prefix, Equalizer equalizer and Channel Estimation.
Secondly,research the algorithm to detect the OFDM based on four order cumulants.above all accomplished signal sampling, Hilbert transform, signal normalization work.Then using the fact that the OFDM is asymptotically Gaussian, introduce four order cumulants to detect the OFDM singal, after formula derivation and Simulation indicate that this method has good effect.
Finally, because the signal-carrier modulated signals after the Rayleigh fading channel also have the asymptotically Gaussian,using a more practical algorithm based on higher order moment. At the same time research the OFDM signal time-domain parameter the blind mode detection using variable length auto-correlation algorithm, The results indicate that the algorithm has beautiful identification defection, have quite theory and practicality value.
通信信号的自动识别和调制参数的估计是非协作通信和认知无线电中的关键问题。本文首先简要的介绍了移动信道的特性及OFDM的基本原理,并对OFDM的循环前缀的作用、OFDM的均衡及OFDM的信道估计方法等关键技术作了简要的介绍。
然后研究了基于高阶累积量的OFDM信号的识别算法。首先对检测信号进行了采样、Hilbert变换、归一化等预处理工作。其次利用OFDM信号具有高斯渐进性的特点,采用4阶累积量对OFDM信号识别,经理论推导和仿真分析表明该方法有很好的识别效果。
最后针对单载波信号通过Rayleigh信道后也会呈现高斯渐进性的特点,利用基于高阶矩的识别方法进行了仿真分析。同时研究了一种可变长自相关算法对OFDM信号的时域参数进行盲检测,在Matlab中对该算法进行仿真,结果分析表明该算法可行、有效。
Orthogonal Frequency Division Multiplexing (OFDM) technique is a efficienct data transmission techique with good immunity for the effects of multi-path channel propagation, intersymbol interference, narrowband interference.and higth frequency using ratio. Wide used in Asymmetrical Digital Subscriber Line( ADSL), Digital Audio Broadcasting (DAB) , Hign Definition Television(HDTV), Wireless Local Area Network (WLAN) and etc.systems.The future Radio Mobile Communication System requires high speed data transmission and multimedia in wireless networks,so Orthogonal Frequency Division Multiplexing will be more and more attented,and will become one of key technologis in the next mobile communication generation.
Communication signal auto identify and modulate parameter estimation are key technologis in non-cooperative communication and software radio.In this paper,the mobile fading channel characteristic and the fundament of OFDM are discussed firstly,and then briefly introduces the the OFDM key techniques such as cyclic prefix, Equalizer equalizer and Channel Estimation.
Secondly,research the algorithm to detect the OFDM based on four order cumulants.above all accomplished signal sampling, Hilbert transform, signal normalization work.Then using the fact that the OFDM is asymptotically Gaussian, introduce four order cumulants to detect the OFDM singal, after formula derivation and Simulation indicate that this method has good effect.
Finally, because the signal-carrier modulated signals after the Rayleigh fading channel also have the asymptotically Gaussian,using a more practical algorithm based on higher order moment. At the same time research the OFDM signal time-domain parameter the blind mode detection using variable length auto-correlation algorithm, The results indicate that the algorithm has beautiful identification defection, have quite theory and practicality value.
引文
[1]尹长春,罗涛,佟学俭.正交频分复用技术[J].中兴通信技术,2003,1:50-53页.
[2]王文博,郑侃.宽带无线通信OFDM技术[M].第1版.北京:人民邮电出版社,2003,8-33页.
[3]张贤达.现代信号处理(第二版).北京:清华大学出版社,2002 281页.
[4]韩钢,李建东,张文红,陈晨.基于多尺度小波分解和支撑矢量机的调制识别研究西安电子科技大学学报,Dec,2003 Vol.30 No.7 19-23页。
[5]韩钢.自适应单载波、多载波调制中信号盲检测技术研究西安电子科技大学博士学位论文,2003.
[6]陈卫东.数字通信信号调制识别算法研究,西安电子科技大学博士学位论文,2001.
[7]Swami,A.;Sadler,B.M."Hierarchical digital modulation classification using cumulants"IEEE Transactions on Communications March 2000Vol.48 No.3 p141-144.
[8]Le martret,C.J.,Boiteau D.M.Modulation classification by means of different ordersstatistical moments MILCOM'97 Monterey CA vol.3p1387-1391 1997
[9]吕铁军.调制信号的分形特征研究,中国科学(E),2001 31(6)508-513页.
[10]闫继业,谢泽斌.OFDM信号调制类型的自动识别研究,现代电子技术.2006.3第218期
[11]郭双冰.混沌时间序列预测及其混沌理论在通信信号调制识别中的应用电子科技大学学报,2002.
[12]HenryL.Bertoni,现代无线通信系统电波传播,电子工业出版社,200 1.33页
[13](美)拉帕波特.无线通信原理与应用,电子工业出版社,2001.4页
[14]张海滨.正交频分复用的基本原理与关键技术[M].北京:国防工业出版社,2006.10页
[15]谭泽富,聂祥飞,王海宝.OFDM的关键技术及应用.西南交通大学出版社.2005.13页
[16]苏鹏程,孙军.上海交通大学学报,第38卷增刊,2004年10月.122页
[17]佟学俭,罗涛。OFDM移动通信技术原理与应用.北京:人民邮电出版社.2003,3:1.8,30-36页
[18]Jenn-Kaie Lain,Dept.of Electronic Engineering National Yunlin University of Science & Technology,2006
[19](意)贝尼迪特吉安卡拉葛利嘉,超宽带无线电基础,电子工业出版社,2005
[20]樊龙飞.通信信息截获中的盲均衡技术.
[21]冯熳,廖桂生.恒模算法:进展与展望.信号处理.2003.(19).441-447页.
[22]孙守宇,郑君里,张琪.瑞利衰落电离层信道的自适应盲均衡.电波科学学报.2003.Vol.18.138-142页.
[23]A.Peled,A.Ruiz.Frenquency domain data transmission using reduced computational complexity algorithms.IEEE Signal Processing.1980.Pages:964-967.
[24]徐伯勋,白旭滨,傅孝毅编著.信号处理中的数学变换和估计方法[M].北京:清华大学出版社,2004.192-210页.
[25]陆根源,陈孝桢.信号检测与参数估计[M].第1版.北京:科学出版社,2004,210-240页.
[26]张更新等.通信工程丛书—卫星移动通信系统.北京.人民邮电出版社, 2001.
[27]张贤达.非平稳信号分析与处理.北京.国防工业出版社.1998.
[28]A.K.Nandi,E.E.Azzouz.Algorithms for Automatic recognition of communication signals.IEEE.Trans.Comun.1998,46(4).Pages:431-436.
[29]陈怀新.基于统计特征主分量的信号调制识别[J].电子科技大学学报,2004-06.
[30]Akmouche W.Detection ofmuhicarrier modulations using 4~(th)-order eumulants[C]//Proc of IEEE MII-COM 99.Atlantic City,NJ,USA:IEEE,1999:432-436.
[31]Dai Wei,Wang Youzheng,Wang Jing.Joint power estimation and modulation classification using second-and-higher statistics[C]//Proc of WCNC2002.Orlando,Florida,USA:IEEE,2002:135-158.
[32]张贤达.现代信号处理[M],北京:清华大学出版社,2002:282页.
[33]Proakis J G.Digital communications[M].3~(rd) ed.New York:McGraw-Hill,1995:47.
[2]王文博,郑侃.宽带无线通信OFDM技术[M].第1版.北京:人民邮电出版社,2003,8-33页.
[3]张贤达.现代信号处理(第二版).北京:清华大学出版社,2002 281页.
[4]韩钢,李建东,张文红,陈晨.基于多尺度小波分解和支撑矢量机的调制识别研究西安电子科技大学学报,Dec,2003 Vol.30 No.7 19-23页。
[5]韩钢.自适应单载波、多载波调制中信号盲检测技术研究西安电子科技大学博士学位论文,2003.
[6]陈卫东.数字通信信号调制识别算法研究,西安电子科技大学博士学位论文,2001.
[7]Swami,A.;Sadler,B.M."Hierarchical digital modulation classification using cumulants"IEEE Transactions on Communications March 2000Vol.48 No.3 p141-144.
[8]Le martret,C.J.,Boiteau D.M.Modulation classification by means of different ordersstatistical moments MILCOM'97 Monterey CA vol.3p1387-1391 1997
[9]吕铁军.调制信号的分形特征研究,中国科学(E),2001 31(6)508-513页.
[10]闫继业,谢泽斌.OFDM信号调制类型的自动识别研究,现代电子技术.2006.3第218期
[11]郭双冰.混沌时间序列预测及其混沌理论在通信信号调制识别中的应用电子科技大学学报,2002.
[12]HenryL.Bertoni,现代无线通信系统电波传播,电子工业出版社,200 1.33页
[13](美)拉帕波特.无线通信原理与应用,电子工业出版社,2001.4页
[14]张海滨.正交频分复用的基本原理与关键技术[M].北京:国防工业出版社,2006.10页
[15]谭泽富,聂祥飞,王海宝.OFDM的关键技术及应用.西南交通大学出版社.2005.13页
[16]苏鹏程,孙军.上海交通大学学报,第38卷增刊,2004年10月.122页
[17]佟学俭,罗涛。OFDM移动通信技术原理与应用.北京:人民邮电出版社.2003,3:1.8,30-36页
[18]Jenn-Kaie Lain,Dept.of Electronic Engineering National Yunlin University of Science & Technology,2006
[19](意)贝尼迪特吉安卡拉葛利嘉,超宽带无线电基础,电子工业出版社,2005
[20]樊龙飞.通信信息截获中的盲均衡技术.
[21]冯熳,廖桂生.恒模算法:进展与展望.信号处理.2003.(19).441-447页.
[22]孙守宇,郑君里,张琪.瑞利衰落电离层信道的自适应盲均衡.电波科学学报.2003.Vol.18.138-142页.
[23]A.Peled,A.Ruiz.Frenquency domain data transmission using reduced computational complexity algorithms.IEEE Signal Processing.1980.Pages:964-967.
[24]徐伯勋,白旭滨,傅孝毅编著.信号处理中的数学变换和估计方法[M].北京:清华大学出版社,2004.192-210页.
[25]陆根源,陈孝桢.信号检测与参数估计[M].第1版.北京:科学出版社,2004,210-240页.
[26]张更新等.通信工程丛书—卫星移动通信系统.北京.人民邮电出版社, 2001.
[27]张贤达.非平稳信号分析与处理.北京.国防工业出版社.1998.
[28]A.K.Nandi,E.E.Azzouz.Algorithms for Automatic recognition of communication signals.IEEE.Trans.Comun.1998,46(4).Pages:431-436.
[29]陈怀新.基于统计特征主分量的信号调制识别[J].电子科技大学学报,2004-06.
[30]Akmouche W.Detection ofmuhicarrier modulations using 4~(th)-order eumulants[C]//Proc of IEEE MII-COM 99.Atlantic City,NJ,USA:IEEE,1999:432-436.
[31]Dai Wei,Wang Youzheng,Wang Jing.Joint power estimation and modulation classification using second-and-higher statistics[C]//Proc of WCNC2002.Orlando,Florida,USA:IEEE,2002:135-158.
[32]张贤达.现代信号处理[M],北京:清华大学出版社,2002:282页.
[33]Proakis J G.Digital communications[M].3~(rd) ed.New York:McGraw-Hill,1995:47.