使用基地台陣列天線之可適性調變技術及其在CDMA系統之應用與性能分析

Performance Analysis of Basestation Antenna Array With Adaptive Modulation and its Applications to CDMA Systems

洪志宏(Zhi-Hong Hong)

指導教授 ： 趙耀庚 博士

元智大學/工程學院/電機工程學系/碩士(2000年)

摘要

在本篇論文中，基於最大雜訊比組合（Maximal Ratio Combining）的原理，分析了Adaptive Modulation in CDMA 經過雷氏衰減通道，由陣列天線接收之系統效能。在發射端我們是利用接收端迴授回來的通道參數，來判斷要使用的調變方式。當通道狀況不好時，我們降低傳輸率來減少錯誤率；當通道狀況良好時，我們提高傳輸率來增加傳送的資料量，也就是說我們可以在要求的錯誤機率之下增加傳送資料量，整體而言可使系統的傳輸率增加。在調變方法方面是使用BPSK、QPSK及8PSK來做可適性的變化。。

關鍵字

最大雜訊比組合 ； CDMA ； 可適性

並列摘要

In the thesis, the performance of a cellular CDMA system with a basestation antenna diversity and adaptive modulation on Rayleigh fading and log-normal shadowing channels is analyzed. The transmitter uses the feedback information on the channel estimate to decide the modulation levels, BPSK, QPSK, or 8PSK, depending on the channel condition. If the channel fading is lower, a higher modulation level is employed and the data rate is higher; while if the fading is deep, a lower level is used. With a pre-designed value of the probability of symbol errors, the data rate can be increased with optimal thresholds for the adaptive switching between BPSK, QPSK, and 8PSK.

並列關鍵字

performance ； CDMA ； adaptive modulation ； optimal thresholds

參考文獻

[2] W. C. Y. Lee ,"Overview of Cellular CDMA" ,IEEE Trans. veh. Technol. ,vol. 40 ,pp. 291-302 ,May 1991.

[3] A. F. Naguib ,A. Paulraj ,and T. Kailath ,"Capacity improvement with base-station antenna arrays in cellular CDMA" ,IEEE Trans. Veh. ,vol. 43 ,no. 3 ,Aug. 1994.

[4] Mo-Han Fong , Vijay K. Bhargava and Qiang Wang ,” Concatenated Orthogonal/PN Spreading Sequences and Their Application to Cellular DS-CDMA Systems with Integrated Traffic ” , IEEE Journal. Select. Areas Commun. , vol.14 , No.3 ,APRIL,1996.

[5] Aymam F. Naguib and Arogyaswami Paulraj ”Performance of Wireless CDMA with M-ray Orthogonal Modulation and Cell Site Antenna Arrays” IEEE Journal. Select. Areas Commun., vol.14 , No.9 , December,1996

[7] Richard B. Ertel, Paulo Cardieri, Virginia Polytechnic Institute . Overview of spatial Channel Models for Antenna Array Communication Systems IEEE Personal Communications., vol.5 , No.1 ,February,1998.