臺灣博碩士論文加值系統

最近幾年無線通訊的使用者大量增加，這使得無線通訊服務的需求量直線上升，大量的需求也使得系統需要更大的涵蓋範圍、更多的容量、和更好的品質。而智慧型天線則是一種在無線通訊中能有效增進效能的技術。
切換波束型的智慧型天線系統在基地台上有固定數目的波瓣，基地台可選擇一個接收與發射性能較好也可降低干擾的波辦，來接收與發射對行動台的訊號。而使用動態切換波束天線系統的方法，可以建構出能調整扇形區域大小的智慧型扇形波束合成。透過這種改變可以達到負載平衡的效果，進而增加系統容量。
本論文在探討此種系統中引入一個波束構成方法，這是在1993年由M.H. Er所提出的，藉由可調整的主波瓣寬度以及降低平均旁波帶高度來製作陣列場型。我們在圓形天線上建立一組權重的資料庫，讓論文中所提出的智慧型天線可以在不均勻且高密度的使用者分布下可以調整出適當的扇形區域。模擬結果可驗證出所提出的技術可以有效改善傳統切換波束天線的效能。

Over the last few years‚ the number of subscribers of wireless services has increased at an explosive rate. This ever growing demand for wireless communications services is constantly increasing the need for better coverage‚ improved capacity and higher quality service. Smart antennas system is an effective technology for the performance improvement of wireless communications.
Switching-beam smart antennas use a number of fixed beams at an antenna site. The system provides a beam that offers the best signal enhancement and interference reduction. Using the approach of dynamic switching-beam antenna system‚ an intelligent sector beam synthesis of adjustable sector width can be established. By doing so‚ traffic load balancing can be achieved, and therefore, system capacity is increased.
In this thesis, a beam-pattern synthesis algorithm proposed by M.H. Er is applied to shape array patterns with an adjustable mainlobe width and average sidelobe level reduction. Using an established database of weighting for circular arrays, the proposed smart antennas can adjust suitable sectors for the high dense subscribers not uniformly distributed. Simulation results demonstrate the proposed technique can dramatically improve the performance of traditional switching-beam antennas.

感謝詞
中文摘要
英文摘要
目錄
圖表目錄
第一章緒言
1.1文獻探討
1.2研究動機
第二章智慧型天線與天線陣列訊號模型
2.1 智慧型天線技術
2.2 線性陣列訊號模式
2.3 圓性陣列訊號模式
第三章 陣列場型合成的最佳限制技術
3.1 問題描述
3.2方法
3.3 方法二
3.4 權重近似解
3.5 陣列場型模擬
3.6旁波帶特性
3.7 旁波帶相關模擬
第四章 具動態扇形波束合成之智慧型天線
4.1簡介動態扇形
4.2 實例探討
4.3系統架構
4.3.1 切換波束系統
4.3.2 結合演算法
4.4 彈性與容量
4.5 阻塞率模擬
4.6 錯誤率模擬
4.6.1 使用者角度分布
4.6.2 錯誤率
第五章 討論與建議
參考文獻

[1] M. Chryssomallis, “Smart antennas,” IEEE Antennas and Propagation, Vol.42, No.3, pp. 129-138, June 2000.
[2] S. Choi, D. Shim, and Tapan K. Sarkar, “A comparison of tracking-beam arrays and switching-beam arrays operating in a CDMA mobile communication channel,” IEEE Antennas and Propagation, Vol.41, No.6, pp.10-22, December 1999.
[3] Fuhi, J and Molisch, A.F, “Capacity enhancement and BER in a combined SDMA/TDMA system ” Vehicular Technology Conference, 1996. Mobile Technology for the Human Race., IEEE 46th , Volume: 3, 1996
[4] Mahmoudi, M.; Sousa, E.S.; Alavi, H. “Adaptive sector size control in a CDMA system using Butler matrix “ Vehicular Technology Conference, Vol.2 , pp.1355 — 1359 1999 IEEE 49th.
[5] D. Shim and S. Choi “Should the smart antenna be a tracking beam array or swithing beam array? “ Proc. IEEE Veh. Tech. Conf., Ottawa, May 1998
[6] M.H. Er, S.L.Sim and S.N. Koh “Application of constrained optimization techniques to array pattern synthesis ” Signal Processing 34 pp323-334 1993.
[7] R. O. Schmidt, “Multiple emitter location and signal parameter estimation,” IEEE Trans. On Antennas Propagation, Vol.AP-34, pp.276-281, March 1986
[8] R. Roy, A. Paulraj and T. Kailath, “Direction-of-arraival estimation by subspace rotation method-ESPRIT,” IEEE Proc. ICASSP, pp.2495-2498,1986.
[9] Barry D. Van Veen and Kevin M. Buckley, “Beamforming: A Verrsatile Approach to Spatial Filter, “ IEEE ASSP Magazine, APRIL 1988.
[10] W. Park, H. Um, J. Ahn and S. Lee, “Performance Analysis on Traffic Load Shedding Scheme for mobile Communication System, “ IEEE International conference on Universal Personal Communications, SanDiego, California, 1997.
[11] H. Alavi, A. Saadat and E.Sousa, “Forward Link Capacity of a CDMA Network with Non-Uniform Cellular Load Distribution,” Submitted for publication in International Journal of Wireless Personal Communications.
[12] K. Gilhousen, et al, “On the Capacity of a Cellular CDMA System,” IEEE Transactions on Vehicular Technology, Vol. 40, No. 2, May 1991.
[13] M. Mahmoudi and E. S. Sousa, “ Sectorized Antenna System for CDMA Cellular Networks,” Proc.IEEE Veh. Tech. Conf., Phoenix, May 1997
[14] B. Sheleg, “A Matrix-Fed Circular Array for Continuous Scanning ,” Proceedings of IEEE , Vol. 56, No. 11, November 1968.
[15] S. Choi and D. Shim, “A Novel Adaptive Beamforming Algorithm for A Smart Antenna System in A CDMA Mobile Communication Environment,” IEEE Trans. on Vehicular Technology, Vol. 49, No.5, Sep. 2000.
[16] S. Haykin, Communication Systems, New York﹕Wiley,1994
[17] J. S. Thompson, P. M. Grant, and B. Mulgrew, “Smart Antenna Arrays for CDMA Systems,” IEEE Personal Communications Vol.3, No.5, pp.16-25, Oct. 1996.
[18] J. E. Padgett, C. G. Gunther, and T. Hattori, “Overview of wireless personal communications,” IEEE Commun. Mag., vol. 33, pp. 28-41, Jan. 1995.
[19] W. C. Y. Lee, “Overview of cellular CDMA,” IEEE Trans. Veh Technology. Vol. 40, pp. 291-302, 1991.
[20] J. LI. Winters, “Smart antennas for wireless systems,” IEEE Personal Communications, Feb 1998, pp. 23-27
[21] H. J. Xing, J. R. Cruz, and Y. Wang. “Fixed multibeam antennas versus adaptive arrays for CDMA systems, “ IEEE VTC, 1999, pp. 27-31
[22] S. C. Swales, M. A. Beach, D. J. Edwards, and J. P. McGeehan, “The performance enhancement of multibeam adaptive base-station antennas for cellular land mobile radio systems,” IEEE Trans. Veh. Technol., vol. 39, pp. 56-67, 1990.
[23] P. Zettorberg and B. Ottersten. “ The spectrum efficiency of a base station antenna array system for spatially selective transmission.” IEEE Trans. Veh. Technol., vol. 44, pp. 651-660, 1995.
[24] K. S. Gilhousen, I. M. Jacobs, R. Padovani, A. J. Viterbi, L. A. Weaver, Jr., and C. E. Wheatley III, “ On the capacity of cellular CDMA system,” IEEE Trans. Veh. Technol., vol. 40, pp. 303-312, 1991
[25] A. Wacker, J. Laiho-Steffens, K. Heiska, The impact of the base station sectorisation on WCDMA radio network performance, Proc. VTC’99, pp.2611-2615, Sep. 1999, Amsterdam, The Netherlands.