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標題: 直序展頻分碼多工和正交分頻多工結合分碼多工中之適應性演算法在收斂行為的分析
On the Convergence Behavior of Adaptive Algorithms for DS/CDMA and OFDM-CDMA System
作者: 陳明昌
Chen, Ming-Chang
關鍵字: LMS;最小均方差;NLMS;CDMA;MC-CDMA;MC-DS-CDMA;LEARNING CURVE;STEP SIZE;正規化最小均方差;分碼多工多重存取;多載波分碼多工多重存取;多載波直序展頻分碼多重存取;收斂曲線;步階值
出版社: 電機工程學系所
引用: [1] Simon Haykin, Adaptive Filter Theory, Fouth Edition, Prentice-Hall, Inc., 2002. [2] D. S. Bernstein, Matrix Mathematics, Princeton University Press, 2005. [3] Simon Haykin and BernardWidow, Least-Mean-Square Adaptive Filters,Wiley,Inc., 2003. [4] Dirk T.M. Slock, “On the Convergence Behavior of the LMS and the Normalied LMS Algorithms,” IEEE Trans. Signal Processing, vol. 41, no. 9, pp. 2811-2825,Sep. 1993. [5] F. B. Ueng, L. D. Jeng, J. D. Chen, J. Y. Yang, “Adaptive Receiver for DS/CDMA Multiuser Communications in Multipath Fading Channels,” IEICE Trans. Commun., vol. e88-b, no. 2, pp. 687-697, Feb. 2005. [6] D. N. Kalofonos, M. Stojanovic, and J. G. Proakis, “Performance of Adaptive MC-CDMA Detectors in Rapidly Fading Rayleigh Channels,” IEEE Trans. on Commun., vol. 2, pp. 229-239, March 2003. [7] B. Widrow et al., “Stationary and nonstationary learning characteristics of the LMS adaptive filter,” Proc. IEEE, vol. 64, no. 8, pp.1151-1162, Aug. 1976. [8] N. J. Bershad, “Analysis of the normalized LMS algorithm with Gaussian inputs,”IEEE TRans. Acoust., Speech, Signal Processing, vol. ASSP-34, pp. 793-806, Aug. 1986. [9] M. Tarrab and A. Feuer, “Convergence and performance analysis of the normalized LMS algorithm with uncorrelated Gaussian data,” IEEE Trans. Inform. Theory, vol. IT-34, no. 4, pp. 680-691, June 1988. [10] Ali H. Sayed, Fundamentals of Adaptive Filtering, Wiley, Inc., 2003. [11] A. E. Albert and L. A. Gardner, Stochastic Approximation and Nonlinear Regression, Cambridge, MA: M.I.T. Press, 1967. [12] Mendel, Discrete Techniques of Parameter Estimation: The Equaltion Error Formulation, New York: Marcel Dekker, 1973. [13] L. Hanzo et al., Singla- and Milti-Carrier DS-CDMA: Multi-User Detection Space-Time Spreading Synchronisation and Standards, Wiley, Inc., 2003. [14] S. Hara, “Overview of Multicarrier CDMA,” IEEE Commun. Mag., pp. 126-133, Dec. 1997. [15] L. Hanzo, M. Munster, B.J. Choi, and T. Keller, “OFDM and MC-CDMA for Broadband Multi-user Communications, WLANs and Broadcasting, ” IEEE Commun. vol. 23, Issue 6, pp. 1276-1286, June. 2005. [16] M. Majmundar, N. Sandhu and J. H. Reed,”Adaptive single-user receivers for direct-sequence spread-spectrum CDMA systems,” IEEE Trans. on Vehicular Technology, vol. 49, No. 2, pp. 379-389, March 2000 [17] M. Abddulrahman, A. U. H. Sheikh, and D. D. Falconer,”Decision feedback equalization for CDMA in indoor wireless communications,” IEEE J. Select. Areas Commun., vol. 12, pp. 698-706, May 1994. [18] P. B. Rapajic and B. B. Vucetic,”Linear adaptive transmitter-receiver structures for asynchronous CDMA systems,” European Trans. Telecommun., vol. 6, no. 1, Jan./Feb. 1995. [19] M. Tahernezhadi and L. Zhu,”Performance evaluation of LMS-based adaptive suppression schemes in asynchronous CDMA,” Int. J. Electron., vol. 79, no. 5, pp. 541-550, 1995. [20] U. Madhow and M. L. Honig, “Minimum mean squared error interference suppression for direct-sequence spread-spectrum code-division multiple-access,” in Proc. 1st Int. Conf. Universal Personal Commun.,Dallas, TX, Sept. 28—Oct. 1,1992, pp. 273—277. [21] U. Madhow and M. L. Honig, “Error probability and near—far resistance of minimum mean squared error interference suppression schemes for CDMA,” in Proc. IEEE GLOBECOM, 1992, pp. 1339—1343.
暫態的行為分析,並分析此系統使用多載波調變機制下的接收機效能。本論文採用的三種多使用者存取的方法為: 直序展頻分碼多工多重存取(DS-CDMA)、多載波分碼多工多重存取(MC-CDMA)和多載波直序展頻分碼多重存取(MC-DS-CDMA)。本論文分析使用最小均方差(LMS)和正規化最小均方差(NLMS)演算法之適應性接收機的統計特性,並以數值模擬驗證分析的結果。同時為了簡化最小均方差(LMS)和正規化最小均方差(NLMS)接收機的分析起見,本論文使用一個簡單模型來表示輸入訊號的向量,收斂曲線是以平方估計誤差的整體平均來實現,並應用於在適應性展頻系統下來作收歛行為分析。分析結果可提供一個主要的最佳化步階值(step size),電腦模擬顯示分析和模擬結果一致;收斂行為的分析結果顯示:在正規化最小均方差(NLMS)接收機下使用一個時變的步階值可以使收斂速度顯著的提升。

This work aims to investigate code division multiple access the convergences and transient behaviors of adaptive Recivers for communication systems with/without
multi-carrier (MC) scheme. The multiple access methods considered are: direct sequence-code division multiple access (DS-CDMA), multi-carrier-code division multiple access (MC-CDMA) and multi-carrier-direct sequence-code division multiple access (MC-DS-CDMA). The adaptive receivers with least mean square (LMS) and normalized least mean square (NLMS) algorithms are analyzed and verified by simulation. For simplifying analysis of the LMS and NLMS receivers, a simple model is adopted for the input signal vectors. The learning curve, which is the ensemble average of the squared estimations error, is applied to analyze the convergences of adaptive multi-user receivers. Furthermore, the analyzed result provides a priori the optimal step-size sequence for the case of white input signals with arbitrary distribution. Computer simulation shows that the analytical results obtained in this work are consistent with imulation results. The convergence behavior of the NLMS receiver can be speeded up significantly by employing a time-varying optimal step-size derived in this work.
其他識別: U0005-0507200715185400
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