單載波區塊傳輸系統在無線傳輸的環境下，影響系統偵測效能極重要的因素即是符元間干擾。雖然最大概似偵測器擁有最佳錯誤率效能，然其運算複雜度與傳輸的區塊大小呈指數成長。而運用適當之樹狀搜尋演算法，可以在錯誤率效能與複雜度間取得較佳之平衡。傳統樹狀搜尋演算法使用QR分解取得樹狀結構，將此方法運用在單載波區塊傳輸時，傳輸區塊的大小會造成QR分解的計算複雜度極高。近來文獻中有研究者提出利用通道結構特性，可在不執行QR分解下取得樹狀結構；並搭配頻域等化器，可達到與傳統樹狀搜尋法相近之錯誤率效能。本篇論文中，我們透過訊號前置處理，採用不同之頻域等化器設計準則，使錯誤率效能更貼近傳統樹狀搜尋。模擬結果顯示:我們提出的方法比傳統樹狀搜尋法有更低的運算複雜度。另外，我們提出的設計準則相較於先前不需QR分解的樹狀搜尋法需付出較高的複雜度，但錯誤率效能更貼近傳統樹狀搜尋演算法。

Intersymbol interference (ISI) is a major performance impairment to high-rate single-carrier block transmission (SCBT) systems in wireless environments. Although the maximum likelihood detector (MLD) is the optimal equalizer for such a system, its complexity is exponential in block size and constellation size. It was reported that equalizers that apply appropriate tree search algorithms are able to achieve a better performance-complexity tradeoff than the MLD. The conventional tree search algorithms (e.g., the QRD-M algorithm) use QR decomposition to generate the tree structure, but the block sizes in the typical systems make the complexity of the decomposition extremely high. Recently, a new approach was proposed to alleviate this problem by exploiting the block format of SCBT and the structure of the channel matrix. Furthermore, it applies frequency-domain pre-processing to achieve a performance that is close to that of the QRD-M algorithm. In this thesis, we extend this new approach by adopting a different criterion to design the frequency-domain prefilter. Simulation results show that, when compared to the new approach, the adopted criterion lead to a better error-rate performance at the cost of an increase in complexity. Furthermore, when compared to the QRD-M algorithm, our tree search equalizer achieves approximately the same performance with a significantly lower complexity.

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