在一般直序展頻分碼多重存取(DS-CDMA)中使用的時域犁耙式接收機
(rake receiver)，其運算複雜度和通道多路徑效應的路徑數量成比
例。使用頻域等化的單載波區塊傳輸直序展頻分碼多重存取(SCBT
DS-CDMA)可以解決這個問題。它可將複雜的時域等化轉變成閥(tap)
係數為一的頻域等化。在上鏈(uplink)或是下鏈(downlink)傳輸時，多用戶(MAI)及剩餘碼際干擾(residual ICI)會嚴重影響分碼多重存取的效能。在這篇論文中，我們先對於使用不同頻域等化方法的單載波區塊傳輸直序展頻分碼多重存取作討論。接著針對上鏈傳輸，我們提出了一種結合頻域等化的多階段連續干擾消除(MS-SIC)演算法。為了增加干擾消除演算法的效能，我們也提出了相對應的軟式決策(soft decision)法，來減少錯誤遞增(error propagation)的影響。而對應下鏈傳輸，我們提出一種結合了頻域等化、時空編碼、以及碼際干擾消除的系統。模擬結果證實我們所提出的系統在上鏈及下鏈傳輸中皆有強健的效能。

In conventional DS-CDMA systems, the computational complexity of time-domain rake receiver is proportioned to the number of fading paths. The single-carrier block
transmission (SCBT) DS-CDMA with frequency-domain equalization can solve this problem because it transforms the complex time-domain equalization to simple equalization in the frequency domain.
In uplink or downlink transmission, the BER performance of SCBT DS-CDMA is severely degraded by the multiple access interference (MAI) or residual interchip interference (ICI). In this thesis, we first compare different frequency-domain equalization methods. For uplink transmission, we propose a multistage successive interference cancellation(MS-SIC) algorithm with frequency-domain equalization for SCBT DS-CDMA.
We also adopt the soft decision which can reduce the effect of error propagation. For downlink transmission, we propose a system which combines the frequency-domain
equalization with space-time block coding (STBC) and ICI cancellation. The simulation results confirm that the proposed systems are robust in uplink or downlink transmission.

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