在單載波區塊傳送系統下，快速衰減通道的等化與處理是一項極具挑戰性的工作。因其通道的時變性，讓我們無法利用許多在處理緩慢衰減通道中的有效方法進行等化。已知文獻對快速衰減通道提出之線性等化器效能欠佳，依次干擾刪除演算法與其餘現有演算法相比複雜度較高。QRD-M樹狀搜尋為目前在此快速衰變環境下表現較佳的演算法，但其預處理階段之QR分解同樣有不小的複雜度。本篇論文以樹狀搜尋的訊號偵測為基礎，利用多階對角化方法，在接收端預處理階段對時變通道矩陣進行處理，形成不需經過QR分解即可使用樹狀搜尋之架構，並採取適當的準則減緩線性等化器諸如ZF等化器、MMSE等化器中產生之雜訊放大問題。模擬結果顯示，雖然多階對角化的複雜度與QRD-M演算法相比仍過高，但在錯誤率效能上已較QRD-M有所提昇。另外，我們提出的演算法和SIC相較也有著顯著的效能增長和複雜度節約。

In Single-carrier block transmission (SCBT), equalizing the fast fading channel, in which channel variation within a transmitted block is not negligible, is a challenging task because many existing efficient methods targeted for slow fading channels are no longer easily applicable. In the literature, the linear equalizer (LE) usually performs poorly; on the other hand, successive interference cancellation (SIC) has a very high complexity. The QRD-M algorithm is a tree-search-based detector that achieves a better error-rate performance than LE and SIC; however, the complexity of the QR decomposition in the preprocessing stage is high. In this thesis, we focus on the tree-search-based approach. We poly-diagonalize the channel matrix in the preprocessing stage, so that, by exploiting the block format of SCBT and the structure of the poly-diagonalized channel matrix, tree search can be executed without QR decomposition. Furthermore, we investigate the detection performance of several criteria of poly-diagonalization. Simulation results show that, compared to the QRD-M algorithm, the proposed tree-search detector has slightly improved error-rate performance, at the cost of a higher complexity. In addition, the proposed algorithms outperforms the SIC with a lower complexity.

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