- 學位論文
以模組化協變調整適應性陣列天線於CDMA無線通訊之及時性模擬
Real-Time Simulation of a Modular Covariance Adjustment Adaptive Array for CDMA Wireless Communications
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摘要
本論文主要目的在針對 "covariance adjustment adaptive array" 應用於 CDMA 無線通訊系統的及時產模擬。藉由模擬的結果，評估系統實現化的可行性、首先探討系統模擬時的結構，包含 signal input module, covariance adjustment module, LMS array module 等。在系統的模擬過程中，我們改變各種參數來檢視系統運行的效果，由模擬的結果顯示在完全功率控制下，無論是 single path 或 multiple path，系統都有比傳統系統更好的消除干擾能力，尤其是在不完全功率控制下，系統也可以有效的消除同一頻道下不同用戶的干擾。對於解決無線通訊中的 "near-far problem" 有很好的效果。
並列摘要
This thesis presents a novel approach for the performance improvement in a CDMA wireless system by employing a covariance adjustment adaptive array to solve the near-far problem. Specifically, it is combining additional covariance adjustment modules and a multi-weight LMS adaptive array in a base station for co-channel interference cancellation to a large number of system users. Following the previous results and the preparation for the actual implementation, we conduct the real-time simulation of the proposed system in various operation conditions. The results show that our system indeed achieves a far better performance than other comparable systems do.
參考文獻
Tsung-Ching Liu, `` The Modular Covariance Adjustment
Constrained Minimum Variance Beamforming, '' IEEE Trans. Acoust.,
Speech, Signal Processing, vol. ASSP-35, pp. 249-266, Mar. 1987.
Ralph T. Compton, ``An Adaptive Array in a
Spread-Spectrum Communication System, '' Proc. of IEEE, vol. 66,