目前，直序展頻分碼多工系統，除了應用在第二代行動通訊系統外，並且已被選為第三代無線網路系統設計上的一項重要技術。在直序展頻分碼多工系統的上鏈傳輸通道中，從傳統的接收器的情形可以明顯觀察出，多重存取干擾、遠近效應還有通道衰減效應的問題往往限制了整個系統的容量。為了有效地解決這些問題，在文獻上已有許多結合功率控制、多用戶偵測和錯誤更正碼的技術被提出來廣泛地討論著。為了達到優異的效能和保持較低的複雜度，在本篇碩士論文中，我們提出了結合功率控制與空時域迭代式多用戶接收機，並應用在建置了渦輪編碼之直序展頻分碼多工系統中的架構。此接收機架構包含了一組單用戶二維犁耙式接收機、一個空時域渦輪式部分平行干擾消除偵測器和一組渦輪解碼器。首先，我們利用空時域信號處理技術來抑制多重存取干擾，然後藉由渦輪式信號處理技術從多用戶偵測器和渦輪解碼器的訊息交流中提取出穩定可靠的軟式訊息。我們根據同步多用戶直序展頻分碼多工系統的信號模型，在納入路徑損失、遮蔽和多重路徑衰減效應的無線單細胞環境下執行電腦程式的模擬。結果顯示，相較於同樣複雜度的結合空時域信號處理之部分平行干擾消除的功率控制技術，本論文所提出的方法明顯可以獲得較佳的系統效能。

Direct sequence code division multiple access (DS-CDMA) is an important scheme for the current second generation (2G) Interim Standard (IS-95) and third generation (3G) wireless network. In DS-CDMA uplink channel, the capacity is greatly limited by multiple access interference (MAI), near-far effect, and channel fading effect. To overcome those problems, there have been many power control schemes with multiuser detection and error correcting code reported in the literature. In this thesis, a power control scheme with a space-time iterative multiuser receiver for turbo-coded DS-CDMA systems is proposed. The proposed receiver structure consists of a bank of single-user 2D-RAKE receivers, a space-time turbo partial parallel interference cancellation detector, which is presented by Shih and Wang, and a bank of single-user turbo decoders, where is the number of active users. We exploit the space-time processing to first suppress MAI and then extract reliable soft information from the exchange between multiuser detector and turbo decoders by the way of turbo processing. Based on the synchronous multiuser DS-CDMA model, the computer simulation results are carried out in the single cell environment with path loss, shadowing, and multipath fading. As compared with the same complicated power control method using space-time partial parallel interference cancellation technique, the proposed approach provides better performance.

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