在本篇論文中，我們提出一個盲蔽多用戶偵測演算法用於類同步改良式多載波-分碼多工接取系統之上傳模式。在上傳模式時，每個用戶都可以隨時的傳送訊號，這會造成某些使用者的訊號在接收端做訊號處理時會受到符際干擾的影響，在這樣的情況下很難將使用者的訊號擷取出來。而在我們所採用的類同步環境中，使用者的傳送訊號只會受到多用戶擷取干擾的的影響而不會有符際干擾的影響，因此我們可以利用我們所提出的演算法將用戶的訊號擷取出來。我們所提出的演算法包含了祁等人所提出的快速峰度最大化演算法(Fast Kurtosis Maximization Algorithm, FKMA)與使用者之鑑別演算法。所提出的盲蔽多用戶偵測演算法是一個疊代式演算法，並與快速峰度最大化演算法均具有超指數收斂速率。在本篇論文中，我們先將接收到的訊號建立成一個多輸入多輸出的平坦衰減的離散訊號模型。然後在此訊號模型下提出了一些假設，並將我們的盲蔽多用戶偵測演算法應用於所建立的訊號模型中。除此之外，我們將提出的盲蔽多用戶偵測演算法結合祁等人提出的盲蔽最大比例結合演算法，進而擴充至多接收天線用於類同步改良式多載波-分碼多工接取系統，我們將此演算法稱為盲蔽多用戶偵測-盲蔽最大比例結合演算法。在論文最後，我們以一些模擬結果來證實我們所提出的演算法之效能。

In this thesis, a blind multiuser detection algorithm (BMDA) for the uplink of quasi-synchronous modified MC-CDMA systems is proposed that comprises Chi and Chen’s fast kurtosis maximization algorithm (FKMA) and a user identification algorithm. As the FKMA, the proposed BMDA is an iterative algorithm with super-exponential convergence rate. Furthermore, the proposed BMDA in conjunction with Chi et al.’s blind maximization ratio combining (BMRC) algorithm, called BMDA-BMRC algorithm, is proposed for the quasi-synchronous modified MC- CDMA system with multiple receive antennas. Finally, some simulation results are presented to support the efficacy of the proposed BMDA and BMDA-BMRC algorithm.

[1] S. Hara and R. Prasad, “Overview of multi-carrier CDMA,” IEEE Commun. Mag., vol. 35, no. 12, pp. 126-133, Dec. 1997.

[2] S. Tsumura and S. Hara, “Design and performance of quasi-synchronous multi-carrier CDMA system,” Proc. IEEE Vehicular Technology Conference, Atlantic City, NJ, Oct. 7-11, 2001, vol. 2, pp. 834-847.

[3] Li Zexian and M. Latva-aho, ”Analysis of MRC receivers for asynchrouous MC-CDMA with channel estimation errors,” Proc. IEEE Workshop on Spread Spectrum Techniques and Applications, Oulu Univ., Finland, Sept. 2-5, 2002, vol. 2, pp. 343-347.

[4] N. Yee and J.-P Linnartz, “Wiener filtering of multi-carrier CDMA in Rayleigh Fading channel,” Proc. IEEE Workshop on Personal, Indoor and Mobile Radio Communications, Berkeley, CA, USA, Sept. 18-23, 1994, vol. 4, pp. 1344-1347.

[5] D. Darsena, G. Gelli, L. Paura and F. Verde, “Blind Multiuser Detection for MC-CDMA systems,” Proc. IEEE Workshop on Signals, Systems and Computers, Italy, Nov. 3-6, 2002, vol. 2, pp. 1419-1423.

[6] C. Li and S. Roy, “Subspace Based Detection in MC-CDMA over Dispersive Channel,” Proc. IEEE Workshop on Personal Wireless Communications, Seattle, USA, Dec. 17-20, 2000, pp. 98-103.

[7] P. A. Delaney and D. O. Walsh, “A bibliography of higher-order spectra and cumulants,” IEEE Signal Processing Magazine, vol. 11, no. 6, pp. 61-70, July 1994.

[8] J. M. Mendel, “Tutorial on higher-order statistics (spectra) in signal processing and system theory: Theoretical results and some applications,” Proceedings of the IEEE, vol. 79, no. 3, pp. 278-305, Mar. 1991.

[9] C. L. Nikias and J. M. Mendel, “Signal processing with higher-order spectra,” IEEE Signal Processing Magazine, vol. 10, no. 3, pp. 10-37, July 1993.

[10] C. L. Nikias and A. P. Petropulu, Higher-Order Spectra Analysis: A Nonlinear Signal Processing Framework. Englewood Cliffs, NJ: Prentice-Hall, 1993.

[11] Z. Ding and T. Nguyen, “Stationary Points of a Kurtosis Maximization Algorithm for Blind Signal Separation and Antenna Beamforming,” IEEE Trans. Signal Processing, vol. 48, no. 6, pp. 1587-1596, June 2000.

[12] J. K. Tugnait, “Identification and deconvolution of multichannel linear non- Gaussian processes using higher order statistics and inverse filter criteria,” IEEE Trans. Signal Processing, vol. 45, no. 3, pp. 658-672, Mar. 1997.

[13] C.-Y. Chi, C.-H. Chen and C.-Y. Chen, “Blind MAI and ISI suppression for DS/CDMA systems using HOS-based inverse filter criteria,” IEEE Trans. Signal Processing, vol. 50, no. 6, pp. 1368-1381, June 2002.

[14] C.-Y. Chi and C.-H. Chen, “Blind beamforming and maximum ratio combining by kurtosis maximization for source separation in multipath,” Proc. 3rd IEEE Workshop on Signal Processing Advances in Wireless Communication, Taoyuan, Taiwan, Mar. 20-23, 2001, pp. 243-246.

[15] C.-Y. Chi, C.-Y. Chen, C.-H. Chen and C.-C. Feng, “Batch processing algorithms for Blind equalization using higher-order statistics,” IEEE Signal Processing Magazine, vol. 20, no. 1, pp. 25-49, Jan. 2003.