臺灣博碩士論文加值系統

摘　　要

傳統的耙型接受器（RAKE receiver）利用了分集（diversity）的技巧收集不同延遲信號的能量並以提昇訊雜比（signal to noise ratio：SNR）並降低位元錯誤率（Bit Error rate：SNR），但其效能會飽和而使得分集效果不彰。定模數法則耙型接收器（CMA RAKE receiver）已經證明其在BER之效能確實比D-RAKE較為佳。然而，CMA RAKE接收器卻由於其演算法的影響而容易在衰落的通道環境下造成了錯誤的收斂。因此本論文提出應用最小輸出能量法則之定模遞迴最小平方耙型接收器（CMOE-initialized CMRLS RAKE receiver）使用限制最小輸出能量法則（constrained minimum output energy：CMOE）來做為濾波器估測子的初始設計並結合定模數法則與遞迴最小平方演算法（recursive least-squares algorithm：RLS）應用在耙型接收器上。多重路徑衰落的環境下比較CMOE-initialized CMRLS RAKE接收器和CMA-RAKE接收器，前者不僅擁有收斂快速的優點且於位元錯誤率上有進步，另一方面更不會因為環境的影響而造成錯誤的收斂。經模擬證實本論文提出之CMOE-initialized CMRLS RAKE接收器確實在訊雜比與位元錯誤率的效能上優於CMA-RAKE接收器。

關鍵字：定模數法則、限制最小輸出能量法則、耙型接收器

Abstract

Conventional RAKE receiver exploits the diversity technique to gather signal energies at different delays to improve the signal to interference plus noise ratio (SINR), but its performance is poor. The bit error rate (BER) performance of constant modulus algorithm RAKE (CMA RAKE) receiver is shown to be better than that of the decorrelating RAKE (D-RAKE) receiver. However, the CMA RAKE receiver is susceptible to misconvergence in the fading channel environment due to its multimodal cost surface. In this paper, we propose a RAKE receiver with an initialization scheme for the CMA RAKE receiver by using the solution form the minimization of the constrained minimum output energy (CMOE) criterion, and which combined with constant modulus recursive least square (CMRLS) algorithm called CMOE-initialized CMRLS RAKE receiver. The RAKE receiver we proposed owns faster convergence speed and better BER performance, furthermore it is not susceptible to misconvergence. Simulations confirm the CMOE-initialized CMRLS RAKE receiver we proposed is superiority over the CMA RAKE receiver in terms of the performance of SINR and BER.
Keyword：CMA、CMOE、RAKE Receivers.

第一章 序論……………………………………………………… 1
1.1. 引言………………………………………………… 1
1.2. 各章節內容概述…………………………………… 3

第二章 分碼多重進接系統與時變多重路徑衰弱通道……… 4
2.1. 分碼多重進接系統簡介…………………………… 4
2.2. 時變多重路徑衰弱通道…………………………… 8
2.2.1. 通道衰落效應的分類………………………… 9
2.2.2. 通道統計模型………………………………… 16

第三章 適應性濾波技術………………………………………… 20
3.1. 線性適應性濾波技術……………………………… 20
3.2. 盲蔽式適應性濾波技術…………………………… 21
3.3. 最小均方演算法…………………………………… 22
3.4. 遞迴最小平方演算法……………………………… 24
3.5. 定模數演算法則…………………………………… 27
3.5. 限制最小輸出能量法則的應用…………………… 30

第四章 盲蔽式適應性耙型接收器……………………………… 32
4.1. 定模數法則耙型接收器…………………………… 33
4.2. 限制最小輸出能量法則初始化之定模遞迴最小平方耙型接收器……………………………………… 36

第五章 模擬結果與分析………………………………………… 41
5.1. 參數與環境設定…………………………………… 41
5.2. 實驗模擬與結果分析……………………………… 46

第六章 結論與未來展望………………………………………… 54

參考文獻…………………………………………………………… 55

參考文獻

[1] T. S. Rappaport, “Wireless Communications Principles and Practice, “Prentice-Hall, New Jersey, Jul. 1999.
[2] H. Liu and K. Li, “A Decorrelating RAKE Receiver for CDMA Communications over Frequency-Selective Fading Channels,” IEEE Trans. Commun., vol. 47, no. 7, pp. 1036-1045, July. 1999.
[3] Yuvapoositanon, P. and Chambers, J.A., “A CMOE-CMA RAKE receiver structure for near-far frequency selective fading CDMA channels,” IEEE Trans. Signa Processing, vol. 2, pp. 418-421, Aug. 2001.
[4] R. Price and P. E. Green, “A Communication Technique for Multipath Channel,” Proceedings of the IRE, pp. 555-570, March 1958.
[5] M. Torlak and B. L. Evans, “A self-recovering RAKE receiver for asynchronous CDMA systems,” in Proc. Int. Conf. Acoustics, Speech and Signal Processing, Istanbul, Turkey, 2000, vol. 5, pp. 2869-2872.

[6] D. J. Devasirvatham, M. J. Krain and D. A. Rappaport, “Radio propagation measurements at 850 MHz, 1.7 GHz, nad 4.0 GHz inside two dissimilar office buildings,” Electronics Letters, vol. 26, no. 7, pp. 445-447, 1990.
[7] S. Y. Seidel, et.al., “The Impact or Surrounding Buildings on Propagation for Wireless Inbuilding Personal Communications System Design,” IEEE Vehicular Technology Conference, Denver, pp. 814-818, May 1992.
[8] Lee, C. Y. William, “Mobile Communications Engineering,” McGraw-Hill, New York, 1998.
[9] M. K. Tsatsanis, “Inverse filtering criteria for CDMA systems,” IEEE Trans.Signal Processing, vol. 45, no. 1, pp102-112, 1997.
[10] R. Prasad, H. S. Misser and A. Kegel, “Performance Analysis of Direct Sequence Spread Spectrum Multiple Access Communication in an Indoor Rician Fading Channels with DPSK Modulation,” IEEE Electronics Letters, vol. 26, pp.1366-1367, Sep. 1990.
[11] J. G.. Proakis, “Digital Communications,” New York: McGraw-Hill, 1995.
[12] W. C. Jakes, “New Techniques for Mobile Radio,” Bell Laboratory Rec., pp. 326-330, Dec. 1970.
[13] J. F. Lemieux, M. Tanany and H. M. Hafez, “Experimental Evaluation of Space/Frequency/Polarization Diversity in the Indoor Wireless Channel,” IEEE Trans. on Vehicular Technology, vol. 40, no. 3, pp. 569-574, Aug. 1991.

[14] L. Kanh, “Ratio Squarer,“ Proceedings of IRE (Correspondence), vol. 42, pp. 1074, Nov. 1954.
[15] R. Price and P. E. Green, “A Communication Technique for Multipath Channel,” Proceedings of the IRE, pp. 555-570, March 1958.
[16] G. L. Turin, “Introduction to Spread-Spectrum Antimultipath Techniques and Their Application to Urban Digital Radio,” Proceedings of The IEEE, Vol. 68, No. 3, pp. 328-353, Mar 1980.
[17] L-X. Wang and J. M. Mendel, “Fuzzy Adaptive Filters, with Application to Nonlinear Channel Equalization,” IEEE Trans. on Fuzzy Systems, vol. 1, no. 3, pp. 161-170, Aug., 1993.
[18] V. Kaasila and A. Mammela, “Bit Error Probability of a Matched Filter in a Rayleigh Fading Multipath Channel in the Presence of Interpath and Intersymbol Interference,” IEEE Trans. Commun., vol. 47, no. 6, pp. 809-812, Jun. 1999.
[19] M. L. Honig, U. Madhow, and S. Verdú, “Blind adaptive multiuser detection,” IEEETrans. Inform. Theory, vol. 41, pp. 944-966, 1995.
[20] K. Cheun, “Performance of Direct-Sequence Spread-Spectrum RAKE Receivers with Random Spreading Sequences,” IEEE Trans. Commun., vol. 45, no. 9, pp. 1130-1143, Sep. 1997.


[21] K. Hwang and K. Lee, “Performance Analysis of Low Processing Gain DS-CDMA Systems with Random Spreading Sequences,” IEEE Commun. Letters, vol. 2, no. 12, pp. 315-317, Dec. 1998.
[22] Vucetic, “Adaptive Receiver Structures for Asynchronous CDMA Systems,” IEEE J. Selected Areas Commun., vol. 12, pp.685-697, May 1994.
[23] S. L. Miller, “An Adaptive Direct-Sequence Code-Division Multiple-Access Receiver for Multiuser Interference Rejection,” IEEE Trans. Commun., vol. 43, pp.1746-1755, Feb./Mar./Apr. 1995.
[24] A. N. Barbosa and S. L. Miller, “Adaptive Dection of DS-CDMA Signals in Fading Channels,” IEEE Trans. Commun., vol. 46, pp.115-124, Jan. 1998.
[25] S. R. Kim, Y. G. Jeong and I. K. Choi, “A Constrained MMSE Receiver for DS-CDMA Systems in Fading Channels,” IEEE Trans. Commun., vol. 48, pp.1793-1796, Nov. 2000.
[26] D. N. Kalofonos and J. G. Proakis, “On the Performance of Coded Low Spreading Gain DS-CDMA Systems with Random Spreading Sequences in Multipath Rayleigh Fading Channels,” Global Telecommun. Conference, GLOBECOM '01. IEEE, vol. 6, pp.3247 -3251, 2001.
[27] S. R. Kim, Y. H. Jung, J. Choi and Y. H. Lee, “A Consideration on Adaptive RAKE Receivers for Single-User MMSE Detection,” Vehicular Technology Conference, VTC 2001 Spring. IEEE VTS 53rd, vol. 4, pp.2426 -2430, 2001.

[28] J. Choi, S. R. Kim, Y. H. Jung, S. C. Hong and Y. H. Lee, “Adaptive LMMSE receivers for CDMA Systems over Time-Varying Multipath Fading Channels,” Commun., 2001. ICC 2001. IEEE International Conference on, vol. 6, pp. 1955 -1958, 2001.
[29] D. N. Godard, “Self-recovering Equalization and Carrier Tracking in Two-dimensional Data Communication Systems,” IEEE Trans. Commun., vol. 28, no. 11, pp.1867-1875, Nov. 1980.
[30] S. Haykin, “Adaptive Filter Theory,” Prentice Hall, 3rd Ed., 1996.
[31] S. Bellini, “Bussgang Techniques for Blind Equalization,” in Proceeding IEEE GLOBE-COM, Houston, Tex., pp.1634-1640, 1986.
[32] S. Haykin, Ed., “Blind Deconvolution,” Prentice Hall, 1994.
[33] R. Johnson, P. Schniter, T. J. Endres, J. D. Behm, D. R. Brown and R. A. Casas, “Blind Equalization Using the Constant Modulus Criterion: A Review,” Proceeding IEEE, vol. 86, pp.1927-1950, Oct. 1998.