多輸入多輸出系統被視為下一代行動通訊的核心技術，有著大幅提升資料傳輸速率，以及有效地對抗多路徑衰減通道的特性。然而，由於多根天線同時傳輸，其代價包含: 嚴重的天線間干擾導致接收端複雜度提高，與使用多射頻鏈造成成本與功耗提高、同步須更嚴謹。空間調變系統之傳送端僅需使用一射頻鏈，因此可有效避免天線間干擾。本論文探討單載波區塊傳輸空間調變系統之樹狀搜尋偵測演算法。文獻中的樹狀搜尋演算法使用M-演算法，在星座點數較大或區塊長度增加之情況下，需要保留較大的分枝數，以達到可接受的效能。為了改善此問題，我們提出了結合前置濾波之樹狀搜尋演算法，以改善等效通道與雜訊之相對影響。我們首先根據最小平方誤差準則設計時域前置濾波器，但此做法所付出的複雜度過高；為了降低複雜度，我們進一步設計頻域前置濾波器。模擬結果顯示:與傳統的樹狀搜尋演算法相比，我們提出之頻域前置濾波之樹狀搜尋演算法，在天線數較少的空間調變系統下，能以較低的複雜度達到傳統樹狀搜尋演算法的效能。

Multiple-input multiple-output systems are regarded as the core technology of next-generation mobile communication systems; they achieve greatly improved transmission data rates, and are effective against multipath fading channels. However, the prices paid include increased receiver complexity due to inter-antenna interference arising from simultaneously activating multiple transmit antennas, more stringent requirements on synchronization, and greater cost and power consumption due to the use of multiple RF chains. In contrast, spatial modulation systems use only a single RF chain at the transmitter, and effectively avoid inter-antenna interference. In this thesis, we focus on tree-search based detection algorithms for spatial modulation aided single-carrier block transmission systems. The conventional tree-search detection algorithm uses the M-algorithm; it needs to retain a large number of branches to achieve an acceptable performance when the constellation size and/or the block length increase. To tackle this issue, we combine pre-filtering with the tree-search detector in order to condition the equivalent channel experienced by the detector. We first design the time-domain pre-filter based on the minimum mean square error criterion. However, the resulting complexity is significantly high. In order to reduce the complexity, we design the frequency-domain pre-filter. Simulation results show that, compared with the conventional tree-search algorithm, the proposed frequency-domain pre-filter achieves a similar performance with a lower complexity in spatial modulation systems of a small size.

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