在無線通訊系統中，多輸入多輸出技術已被廣泛用來增加傳輸量與改善傳輸品質。在這些多輸入多輸出的技術中，塊狀時空編碼透過結合空間分集和通道編碼來提升訊號在衰減通道的可靠度。近年來，為了在接收端有效率地解回傳送端的編碼資訊，塊狀時空碼偵測器是一種備受關注的方式。此外，軟式輸出偵測器亦被提出來提供軟式資訊給軟式輸入錯誤更正解碼器以改善系統的效能。不幸的是，塊狀時空碼偵測器的演算法在快速時變衰減通道的環境可能會導致效能損失。因此，適用於快速衰減通道的有效率塊狀時空碼的偵測器設計在通訊系統的議題上是一大挑戰。
在本篇論文中，一種具有軟式資訊的改良式強迫歸零-最大可能偵測器演算法將被探討於快速衰減通道上的渦輪多輸入多輸出系統。基於疊代偵測及解碼的處理程序，所提出之塊狀時空碼偵測器與渦輪解碼器的共同設計可遞迴地交換彼此的軟式資訊來改善系統整體效能。進一步地，採用一些軟式結合技術來合併從渦輪解碼器的事後機率資訊所得出之符元資訊和強迫歸零的解以提升所輸出之軟式資訊的可靠度。根據模擬結果，所提出之塊狀時空碼偵測器具有可接受的複雜度，並可改善在快速時變衰減通道下的系統效能。

In wireless communication systems, multiple-input multiple-output (MIMO) technique has been widely exploited to improve the transmission capacity and quality. In these of MIMO techniques, space-time block codes is a technique by combining the spatial diversity and channel coding to improve the reliability of transmission over fading channels. To recover efficiently the transmitted signals, the STBC detectors are deserved more and more attentions in recent years. In addition, the soft STBC detectors are also proposed to provide soft information for soft-decision forward error correction (FEC) decoders to improve system performance. Unfortunately, these STBC detector algorithms may cause performance loss due to fading channel with large time-selective decay. Therefore, a design of efficient STBC detector over time selective fading channel is one of challenge in future communication systems.
In this thesis, a modified ZF-ML STBC detector scheme with soft information is investigated in turbo-MIMO systems over time-varying channels. Based on an iterative detection and decoding process, the proposed STBC detector and turbo decoder can exchange soft information to iteratively improve system performance. Furthermore, some soft combining technique are applied to combine the soft symbol derived from a posteriori information of turbo decoder and ZF solution to enhance the reliability of soft information. According to simulation results, the proposed STBC detector with acceptable computational complexity can improve the system performance over time-selective channels.

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