在本論文, 我們發展出一套建構在Alamouti空間-時間區塊碼技術下的多
重輸入多重輸出的直序碼多工調變系統中之高效能交叉決策迴授廣義旁瓣消
除器的多使用者偵測器解調器。
為了提升傳統空間-時間區塊碼系統的多使用者偵測效能, 我們在根據最
小均方誤差的法則下, 提出了以廣義旁瓣消除器作為偵測器的接收系統, 此系
統優點為能夠有效率的擷取天線陣列系統的空間多樣性特質以及使用分碼多
工的時間特性。
為了更有效率的使用空間-時間區塊碼的傳輸訊號特性, 我們更進一步提
出了一個新的交叉迴授機制, 其可以藉著把估測出的訊號, 迴授到廣義旁瓣消
除器的輸出端, 這樣能使欲解調的訊號在經過廣義旁瓣消除器中的阻擋矩陣
的作用之後, 能夠再更進一步使得解調器輸出的訊號更貼近所欲得到的訊號,
因此能夠使得抑制干擾的能力做再進一步的提升。另外,我們對新型系統的效
能上做了理論上的分析, 所獲得的結果, 也能獲得新型的系統確實有著較好的
效能。
最後, 我們對所提出的交叉決策迴授的偵測系統, 進行電腦模擬與效能分
析, 而實驗的結果也顯示出我們所提出的新系統比原始的系統以及加上了決
策迴授後的系統, 有更好的效能以及更快的收斂速度。

This paper proposes a simple, yet effective generalized sidelobe canceller (GSC)-
based Capon multiuser receiver for the Alamouti space-time block coded (STBC)
multiple-input multiple-output code-division multiple-access (MIMO CDMA) systems.
The new receiver makes full use of the space diversity provided by the
antenna array and the time diversity provided by the decision feedback (DF) from
the outputs of both of GSCs employed along with the transmit diversity induced
in the Alamouti STBC to render superior performance . With an ingenious DF
scheme, refer to as the the cross DF (CDF), the desired signals will be blocked more
thoroughly after the blocking matrix so that the interference suppression capability
can be further enhanced. Performance analysis is also provided to show that that
the minimum mean squared error (MMSE) of the receiver using the CDF is indeed
lower than those with or without the classical DF scheme. Conducted simulations
show that the new receiver can not only provide superior performance compared
with previous works, but it can also render faster convergence characteristics.

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