直扩信号码序列恢复算法及系统性能仿真研究
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摘要
直扩信号由于具有工作信噪比低、强抗干扰性、低截获概率、能够抑制多径效应等优点,已经在军事和民用通信领域得到广泛应用。因而与之对应的直扩通信对抗技术也成为通信对抗领域急需解决的研究主题。直扩通信对抗包括直扩信号的盲检测、参数估计和扩频码序列恢复等内容。在检测到直扩信号和估计出直扩信号的参数后,要恢复原始信息,就需要恢复出扩频码序列,因而对直扩信号PN码序列的估计研究就具有迫切性和重要意义。本文正是针对上述问题,以恢复扩频码序列为主要研究对象,对码序列恢复方法做了创新性和探索性研究,核心工作和创新点主要体现在以下几个方面:
1.建立了同步和非同步的基带信号模型,介绍了码序列估计及解扩的两种方案,研究了基于主特征向量的码序列恢复原理,对基于特征值分解的码序列恢复算法进行了计算机仿真实验。
2.研究了码同步技术,包括延迟相乘法和改进滑动窗法,重点研究的是改进滑动窗法进行码同步,结合码序列恢复算法对同步和非同步情况做了大量仿真。
3.研究了短码调制直扩信号的码序列恢复算法,包括基于神经网络的码序列恢复算法、基于投影逼近子空间跟踪的码序列恢复算法、基于新息准则的神经网络码序列恢复算法。通过大量的计算机仿真实验,分析了在同步和非同步两种信号模型下算法的可行性,比较了算法在恢复码序列的相关性和收敛性方面的性能。
4.针对更低信噪比下的直扩信号码序列恢复问题,研究了利用小波去噪的方法先将直扩信号进行预处理,然后再进行码序列的恢复,进行了去噪前后的比较。
5.研究了基于快速逼近功率迭代的码序列恢复算法,该算法通过迭代,快速提取主特征向量,实现码序列的恢复。大量的仿真和算法分析表明,该算法能够在低信噪比下,迅速提取出主特征向量,使码序列恢复能够实时实现。
6.针对长码调制直扩信号码序列恢复问题,研究了基于分段的码序列恢复方法,大量的仿真表明该方法能使码序列恢复算法工作在较低的信噪比下,而且性能也能达到一定的要求。
7.研究了DSSS/BPSK信号参数估计的基本方法,建立了对DSSS/BPSK信号进行检测、参数估计和码序列恢复的联合处理系统,并对系统进行仿真和分析。
Direct sequence spreading spectrum signal has been widely used both in military and commercial telecommunication area, owing to the ability of working at low signal-to-noise ratio (SNR), strong anti-jamming, lower probability interception and mitigating the effects of multi-path fading effects. So the DSSS communication antagonism technology becomes an urgent research topic in the communication field. The blind detection, parameters estimation and recovery of spreading sequences are the main contents of DSSS communication antagonism. After having estimated some signal parameters, it need to recover the spreading sequences before de-spreading the DSSS signal and recovering the primitive information. Therefore the research on blind estimation of PN sequences shows the vital urgency and significance at present. This paper focuses on the blind code synchronization approach and the spreading sequences estimation algorithm. In this thesis, the spreading sequence restoration has been analyzed. The methods of code sequences restoration are explored and investigated, and the key work and innovations of the thesis mainly include:
1. Set up the synchronous and non-synchronized base-band signal model, introduced the two programs of code sequence estimation and despreading, researched the principle of restoring the code sequence based on the principal eigenvector and computer simulation based on eigen-value decomposition algorithm.
2. Studied the code synchronization technology, including delayed multiplication and modified sliding window, modified sliding window method is researched for code synchronization, combining algorithm of restoring code sequence a lot of simulations are done in synchronous and non-synchronous cases.
3. Studied the code sequences restoration algorithm of the short-code modulation DSSS signal, including code sequences restoration algorithm based on neural network algorithm, code sequences restoration algorithm based on the projection approximation subspace tracking, code sequences restoration algorithm based on neural network by a novel information criterion. Through many computer simulation experiments, analysis of the feasibility of algorithms in the synchronous and asynchronous two signal models,the relevance of sequences and convergence performance are compared by the algorithms.
4. For the problem of code sequences restoration in the lower SNR DSSS signal, researched pre-processing of DSSS signal by the use of wavelet denoising method, then we will proceed to restore code sequences and compare before and after denoising.
5. Researched the code sequences restoration algorithm based on fast approximated power iteration, rapid extraction of the principal eigenvector achieves recovery of PN code sequences. Many simulation and algorithm analysis show that the algorithm can quickly extract the principal eigenvector at low SNR, so that spreading sequences can restore real-time implementation.
6. For the problem of code sequence restoration of long-code modulation DSSS signal, researched the recovery method based on the subsection technique, many simulations show that this method can restore the code sequences at low SNR, and the performance can also achieve the request.
7. Studied the basic ways of parameter estimation in the DSSS/BPSK signal, builded on the union processing system including the DSSS/BPSK signal detection, parameter estimation and code sequences restoration, and a lot of simulation and analysis are done for this system.
1.建立了同步和非同步的基带信号模型,介绍了码序列估计及解扩的两种方案,研究了基于主特征向量的码序列恢复原理,对基于特征值分解的码序列恢复算法进行了计算机仿真实验。
2.研究了码同步技术,包括延迟相乘法和改进滑动窗法,重点研究的是改进滑动窗法进行码同步,结合码序列恢复算法对同步和非同步情况做了大量仿真。
3.研究了短码调制直扩信号的码序列恢复算法,包括基于神经网络的码序列恢复算法、基于投影逼近子空间跟踪的码序列恢复算法、基于新息准则的神经网络码序列恢复算法。通过大量的计算机仿真实验,分析了在同步和非同步两种信号模型下算法的可行性,比较了算法在恢复码序列的相关性和收敛性方面的性能。
4.针对更低信噪比下的直扩信号码序列恢复问题,研究了利用小波去噪的方法先将直扩信号进行预处理,然后再进行码序列的恢复,进行了去噪前后的比较。
5.研究了基于快速逼近功率迭代的码序列恢复算法,该算法通过迭代,快速提取主特征向量,实现码序列的恢复。大量的仿真和算法分析表明,该算法能够在低信噪比下,迅速提取出主特征向量,使码序列恢复能够实时实现。
6.针对长码调制直扩信号码序列恢复问题,研究了基于分段的码序列恢复方法,大量的仿真表明该方法能使码序列恢复算法工作在较低的信噪比下,而且性能也能达到一定的要求。
7.研究了DSSS/BPSK信号参数估计的基本方法,建立了对DSSS/BPSK信号进行检测、参数估计和码序列恢复的联合处理系统,并对系统进行仿真和分析。
Direct sequence spreading spectrum signal has been widely used both in military and commercial telecommunication area, owing to the ability of working at low signal-to-noise ratio (SNR), strong anti-jamming, lower probability interception and mitigating the effects of multi-path fading effects. So the DSSS communication antagonism technology becomes an urgent research topic in the communication field. The blind detection, parameters estimation and recovery of spreading sequences are the main contents of DSSS communication antagonism. After having estimated some signal parameters, it need to recover the spreading sequences before de-spreading the DSSS signal and recovering the primitive information. Therefore the research on blind estimation of PN sequences shows the vital urgency and significance at present. This paper focuses on the blind code synchronization approach and the spreading sequences estimation algorithm. In this thesis, the spreading sequence restoration has been analyzed. The methods of code sequences restoration are explored and investigated, and the key work and innovations of the thesis mainly include:
1. Set up the synchronous and non-synchronized base-band signal model, introduced the two programs of code sequence estimation and despreading, researched the principle of restoring the code sequence based on the principal eigenvector and computer simulation based on eigen-value decomposition algorithm.
2. Studied the code synchronization technology, including delayed multiplication and modified sliding window, modified sliding window method is researched for code synchronization, combining algorithm of restoring code sequence a lot of simulations are done in synchronous and non-synchronous cases.
3. Studied the code sequences restoration algorithm of the short-code modulation DSSS signal, including code sequences restoration algorithm based on neural network algorithm, code sequences restoration algorithm based on the projection approximation subspace tracking, code sequences restoration algorithm based on neural network by a novel information criterion. Through many computer simulation experiments, analysis of the feasibility of algorithms in the synchronous and asynchronous two signal models,the relevance of sequences and convergence performance are compared by the algorithms.
4. For the problem of code sequences restoration in the lower SNR DSSS signal, researched pre-processing of DSSS signal by the use of wavelet denoising method, then we will proceed to restore code sequences and compare before and after denoising.
5. Researched the code sequences restoration algorithm based on fast approximated power iteration, rapid extraction of the principal eigenvector achieves recovery of PN code sequences. Many simulation and algorithm analysis show that the algorithm can quickly extract the principal eigenvector at low SNR, so that spreading sequences can restore real-time implementation.
6. For the problem of code sequence restoration of long-code modulation DSSS signal, researched the recovery method based on the subsection technique, many simulations show that this method can restore the code sequences at low SNR, and the performance can also achieve the request.
7. Studied the basic ways of parameter estimation in the DSSS/BPSK signal, builded on the union processing system including the DSSS/BPSK signal detection, parameter estimation and code sequences restoration, and a lot of simulation and analysis are done for this system.
引文
[1]田日才.扩频通信.清华大学出版社,2007,11.
[2]何世彪,谭晓衡.扩频技术及其实现.电子工业出版社,2007,1:1-28,41-50.
[3]查光明,熊贤祚.扩频通信.西安:西安电子科技大学出版社,2002,1-118.
[4] Bouder C, Azou S, Burel G. Blind estimation of the pseudo-random sequence of a direct sequence spread spectrum signal. IEEE-MILCOM, 2000, 2(10): 967-970.
[5] Bouder C, Azou S, Burel G. A robust synchronization procedure for blind estimation of the symbol period and the timing offset in spread spectrum transmissions. Spread Spectrum Techniques and Applications, 2002 IEEE Seventh International Symposium on, 2002, 1: 238-241.
[6]詹亚峰,曹志刚,马正新.DSSS信号的扩频序列估计.电子与信息学报,2005,27(2): 169-172.
[7]杨小牛.直接序列扩频码的截获与干扰技术初探.通信对抗,1991,(3):78-83.
[8]谈满堂,朱德君.谱相关理论用于直接序列扩谱信号的检测与估计.电子对抗,1995,(4): 53-59.
[9] Hill P C J, Ridley M E. Blind Estimation of direct-sequence spread spectrum M-sequence chip codes. IEEE International Symposium on Spread Spectrum Techniques and Applications, 2000, 1: 305-309.
[10] Bouder C, Azou S, Burel G. Performance analysis of a spreading sequence estimator for spread spectrum transmissions. Journal of The Franklin Institute, 2004, 341(7): 595-614.
[11] Afshin Haghighat, Soleymani M R. A MUSIC-based algorithm for spreading sequence discovery in multiuser DS-CDMA. IEEE Vehicular Technology Conference, 2003, 58(2): 978-981.
[12] Afshin Haghighat, Soleymani M R. Blind spreading sequence discovery for DS-CDMA signal interception. IEEE Military Communications Conference MILCOM, 2003, 2: 1115-1119.
[13]张天骐,周正中.直扩信号的谱检测和神经网络估计.系统工程与电子技术,2001, 23(12):12-15.
[14] Zhang Tianqi, Lin Xiaokang, Zhou Zhengzhong. A neural network approach to blind-estimation of PN spreading sequence in lower SNR DSSS signals. ICSP’04 Proceedings, 1: 1735-1738.
[15]张天骐,周正中,郭宗祥.一种DS/SS信号PN码序列估计的神经网络方法.信号处理, 2001,17(6):533-537.
[16] Zhang Tianqi, Zhang Chuanwu, Lin Xiaokang, et al. Algorithms for period and sequence estimation of the PN code in DS-SS in signals [J]. Systems Engineering and Electronics, 2005, 27(8): 1365-1368.
[17]张天骐,周正中,邝育军,田增山.低信噪比长伪码直扩信号伪码周期的估计方法.系统工程与电子技术,2007,29(1):12-16.
[18] Bin Yang. Projection Approximation Subspace Tracking. IEEE Transactions on Signal Processing. 1995, 43(1): 95-107.
[19] Bin Yang. Convergence analysis of the subspace tracking algorithms PAST and PASTd. IEEE International Conference on Acoustics, Speech and Signal Processing– Proceedings, 1996, 3: 1759-1762.
[20] Bin Yang. Asymptotic convergence analysis of the profection approximation subspace tracking algorithms. Signal Processing, 1996, 50(1): 123-136.
[21] Yongfeng Miao, Yingbo Hua. Fast Subspace Tracking by a Novel Information Criterion. Conference Record of the Asilomar Conference on Signals, Systems & Computers, 1997, 2: 1312-1316.
[22] Yongfeng Miao, Yingbo Hua. Fast subspace tracking and neural network learning by a novel information criterion. IEEE International Conference on Acoustics, Speech and Signal Processing, 1998, 2: 1197-1200.
[23]朱孝武,唐斌.基于DS-SS信号相位特性的参数估计.电子与信息学报,2005, 27(9):1425-1428.
[24] Robert C D. Spread spectrum systems. New York. John Wiley & Sons, 1984, 15-79.
[25] Viterbi A J. Spread spectrum communications-myths and realities. IEEE Communications Magazine, 1979, 17(3): 11-18.
[26]张贤达.矩阵分析与应用.北京:清华大学出版社,2004,255-653.
[27]张红波,吕明.基于子空间跟踪的扩频码盲估计算法.系统工程与电子技术,2006,28:1470-1472.
[28] Bouder C, Burel G. Spread spectrum codes identification by neural networks. System andControl: Theory and Applications, 2000: 257-262.
[29] Dominique F, Reed J H. Simple PN code sequence estimation and synchronization technique using the constrained Hebbian rule. Electronics Letters, 1997, 33(1): 37-38.
[30] Dominique F, Reed J H. Subspace based PN code sequence estimation for direct sequence signals using a simplified Hebb rule. Electronics Letters, 1997, 33(13): 1119-1120.
[31] Wang Chen, Wei Ping. PN code acquisition of DS/SS signals based on neural network methods [J]. Electronic Warfare, 2006, 3: 6-12.
[32] P.Baldi and K.Homik. Learning in linear neural networks. IEEE Trans. Neural Networks, 1995, 6: 837-858.
[33] Ou Yang Congxing, Zhou Jian, Yue Guangxin. A novel principal component analysis subspace tracking algorithm [J]. Journal of Beijing University of Posts and Telecommunications, 2000, 23(2): 38-42.
[34]潘泉等.小波滤波方法及应用[M].北京:清华大学出版社,2005.
[35]赵瑞珍,宋国乡.一种基于小波变换的白噪声消噪方法的改进[J].西安电子科技大学学报(自然科学版),2000,27(5):619-622.
[36] Mallat S, Hwang W L. Singularity Detection and Processing with Wavelets [J]. IEEETrans on IT, 1992, 38 (2): 617-643.
[37] R.Badeau, B.David, and G.Richard. Approximated power iterations for fast subspace tracking [J]. Proc.7th Int.Symp. Signal Process, 2003, 2: 583-586.
[38] R.Badeau, B.David, and G.Richard. Fast Approximated Power Iteration Subspace Tracking [J]. IEEE Trans on Signal Processing, 2005, 53 (8): 2931-2941.
[39] Xu H, Huang Z, Zhou Y. Blind estimation of the symbol period of a long-code DSSS signal. 5th Int. Conf. Microwave and Millimeter Wave Technology, Gui Lin, China, 2007, 2: 820-823.
[40] P.-Y. Qui, Z.-T. Huang, W.-L. Jiang. Improved blind-spreading sequence estimation algorithm for direct sequence spread spectrum signals. IET Signal Processing, 2008, 2(2): 139-146.
[41]徐海源,黄知涛,周一宇.长码直扩信号的伪码参数及序列的估计方法[J].西安电子科技大学学报(自然科学版),2007,34:51-54.
[42] Miao Y. F, Hua Y. B. Fast subspace tracking and neural network learning by a novel information criterion. IEEE Trans. Signal Processing, 1998, 46: 1967-1979.
[43] Douglas A.Hill, John B.Bodie. Carrier detection of PSK signals. IEEE Trans. Communication, 2001,49(3): 487-496.
[44]谭舒,吕明,成昊.DS/BPSK信号载频估计方法的研究[J].信息技术,2006,7:117-119.
[45] Kuehls, J.F. Evaggelos Geraniotis. Presence Detection of Binary-Phase-Shift-Keyed and Direct Sequence Spread Spectrum Signals Using a Prefilter-Delay-and-Multiply Device. IEEE Journal on SAIC, June 1990, 8 (5).
[46] Reed, D.E. and Wickert, M.A. Minimization of Detection of Symbol-Rate Spectral Lines by Delay and Multiply Receivers. IEEE Trans. On Communicaions, January, 1988, 36(1): 118-120.
[2]何世彪,谭晓衡.扩频技术及其实现.电子工业出版社,2007,1:1-28,41-50.
[3]查光明,熊贤祚.扩频通信.西安:西安电子科技大学出版社,2002,1-118.
[4] Bouder C, Azou S, Burel G. Blind estimation of the pseudo-random sequence of a direct sequence spread spectrum signal. IEEE-MILCOM, 2000, 2(10): 967-970.
[5] Bouder C, Azou S, Burel G. A robust synchronization procedure for blind estimation of the symbol period and the timing offset in spread spectrum transmissions. Spread Spectrum Techniques and Applications, 2002 IEEE Seventh International Symposium on, 2002, 1: 238-241.
[6]詹亚峰,曹志刚,马正新.DSSS信号的扩频序列估计.电子与信息学报,2005,27(2): 169-172.
[7]杨小牛.直接序列扩频码的截获与干扰技术初探.通信对抗,1991,(3):78-83.
[8]谈满堂,朱德君.谱相关理论用于直接序列扩谱信号的检测与估计.电子对抗,1995,(4): 53-59.
[9] Hill P C J, Ridley M E. Blind Estimation of direct-sequence spread spectrum M-sequence chip codes. IEEE International Symposium on Spread Spectrum Techniques and Applications, 2000, 1: 305-309.
[10] Bouder C, Azou S, Burel G. Performance analysis of a spreading sequence estimator for spread spectrum transmissions. Journal of The Franklin Institute, 2004, 341(7): 595-614.
[11] Afshin Haghighat, Soleymani M R. A MUSIC-based algorithm for spreading sequence discovery in multiuser DS-CDMA. IEEE Vehicular Technology Conference, 2003, 58(2): 978-981.
[12] Afshin Haghighat, Soleymani M R. Blind spreading sequence discovery for DS-CDMA signal interception. IEEE Military Communications Conference MILCOM, 2003, 2: 1115-1119.
[13]张天骐,周正中.直扩信号的谱检测和神经网络估计.系统工程与电子技术,2001, 23(12):12-15.
[14] Zhang Tianqi, Lin Xiaokang, Zhou Zhengzhong. A neural network approach to blind-estimation of PN spreading sequence in lower SNR DSSS signals. ICSP’04 Proceedings, 1: 1735-1738.
[15]张天骐,周正中,郭宗祥.一种DS/SS信号PN码序列估计的神经网络方法.信号处理, 2001,17(6):533-537.
[16] Zhang Tianqi, Zhang Chuanwu, Lin Xiaokang, et al. Algorithms for period and sequence estimation of the PN code in DS-SS in signals [J]. Systems Engineering and Electronics, 2005, 27(8): 1365-1368.
[17]张天骐,周正中,邝育军,田增山.低信噪比长伪码直扩信号伪码周期的估计方法.系统工程与电子技术,2007,29(1):12-16.
[18] Bin Yang. Projection Approximation Subspace Tracking. IEEE Transactions on Signal Processing. 1995, 43(1): 95-107.
[19] Bin Yang. Convergence analysis of the subspace tracking algorithms PAST and PASTd. IEEE International Conference on Acoustics, Speech and Signal Processing– Proceedings, 1996, 3: 1759-1762.
[20] Bin Yang. Asymptotic convergence analysis of the profection approximation subspace tracking algorithms. Signal Processing, 1996, 50(1): 123-136.
[21] Yongfeng Miao, Yingbo Hua. Fast Subspace Tracking by a Novel Information Criterion. Conference Record of the Asilomar Conference on Signals, Systems & Computers, 1997, 2: 1312-1316.
[22] Yongfeng Miao, Yingbo Hua. Fast subspace tracking and neural network learning by a novel information criterion. IEEE International Conference on Acoustics, Speech and Signal Processing, 1998, 2: 1197-1200.
[23]朱孝武,唐斌.基于DS-SS信号相位特性的参数估计.电子与信息学报,2005, 27(9):1425-1428.
[24] Robert C D. Spread spectrum systems. New York. John Wiley & Sons, 1984, 15-79.
[25] Viterbi A J. Spread spectrum communications-myths and realities. IEEE Communications Magazine, 1979, 17(3): 11-18.
[26]张贤达.矩阵分析与应用.北京:清华大学出版社,2004,255-653.
[27]张红波,吕明.基于子空间跟踪的扩频码盲估计算法.系统工程与电子技术,2006,28:1470-1472.
[28] Bouder C, Burel G. Spread spectrum codes identification by neural networks. System andControl: Theory and Applications, 2000: 257-262.
[29] Dominique F, Reed J H. Simple PN code sequence estimation and synchronization technique using the constrained Hebbian rule. Electronics Letters, 1997, 33(1): 37-38.
[30] Dominique F, Reed J H. Subspace based PN code sequence estimation for direct sequence signals using a simplified Hebb rule. Electronics Letters, 1997, 33(13): 1119-1120.
[31] Wang Chen, Wei Ping. PN code acquisition of DS/SS signals based on neural network methods [J]. Electronic Warfare, 2006, 3: 6-12.
[32] P.Baldi and K.Homik. Learning in linear neural networks. IEEE Trans. Neural Networks, 1995, 6: 837-858.
[33] Ou Yang Congxing, Zhou Jian, Yue Guangxin. A novel principal component analysis subspace tracking algorithm [J]. Journal of Beijing University of Posts and Telecommunications, 2000, 23(2): 38-42.
[34]潘泉等.小波滤波方法及应用[M].北京:清华大学出版社,2005.
[35]赵瑞珍,宋国乡.一种基于小波变换的白噪声消噪方法的改进[J].西安电子科技大学学报(自然科学版),2000,27(5):619-622.
[36] Mallat S, Hwang W L. Singularity Detection and Processing with Wavelets [J]. IEEETrans on IT, 1992, 38 (2): 617-643.
[37] R.Badeau, B.David, and G.Richard. Approximated power iterations for fast subspace tracking [J]. Proc.7th Int.Symp. Signal Process, 2003, 2: 583-586.
[38] R.Badeau, B.David, and G.Richard. Fast Approximated Power Iteration Subspace Tracking [J]. IEEE Trans on Signal Processing, 2005, 53 (8): 2931-2941.
[39] Xu H, Huang Z, Zhou Y. Blind estimation of the symbol period of a long-code DSSS signal. 5th Int. Conf. Microwave and Millimeter Wave Technology, Gui Lin, China, 2007, 2: 820-823.
[40] P.-Y. Qui, Z.-T. Huang, W.-L. Jiang. Improved blind-spreading sequence estimation algorithm for direct sequence spread spectrum signals. IET Signal Processing, 2008, 2(2): 139-146.
[41]徐海源,黄知涛,周一宇.长码直扩信号的伪码参数及序列的估计方法[J].西安电子科技大学学报(自然科学版),2007,34:51-54.
[42] Miao Y. F, Hua Y. B. Fast subspace tracking and neural network learning by a novel information criterion. IEEE Trans. Signal Processing, 1998, 46: 1967-1979.
[43] Douglas A.Hill, John B.Bodie. Carrier detection of PSK signals. IEEE Trans. Communication, 2001,49(3): 487-496.
[44]谭舒,吕明,成昊.DS/BPSK信号载频估计方法的研究[J].信息技术,2006,7:117-119.
[45] Kuehls, J.F. Evaggelos Geraniotis. Presence Detection of Binary-Phase-Shift-Keyed and Direct Sequence Spread Spectrum Signals Using a Prefilter-Delay-and-Multiply Device. IEEE Journal on SAIC, June 1990, 8 (5).
[46] Reed, D.E. and Wickert, M.A. Minimization of Detection of Symbol-Rate Spectral Lines by Delay and Multiply Receivers. IEEE Trans. On Communicaions, January, 1988, 36(1): 118-120.