單載波區塊傳送系統於雙重選擇性衰減通道中的等化，除了需要處理通道多重路徑造成的符元間干擾，還須對抗通道的時變性所造成的虛擬載波間干擾，使得文獻中適用於非時變通道下的迭代式區塊決策回授等化器不再適用，近年來適用於時變通道下的迭代式區塊決策回授等化器設計方法因而被提出，與最小均方誤差線性等化器相比，僅須耗費少許額外複雜度即可大幅降低錯誤率。然而研究文獻並未考慮通道估計之影響。本論文中，我們首先提出適用於時變通道下的迭代式區塊決策回授等化器，可以兼容以往文獻中之方法，且在都普勒頻率較高的情況下，可以藉由多付出少許複雜度使錯誤率降低。另外，我們進一步採用基於基底擴展模型與訓練符元所估計之通道設計等化器。本論文提供了最小平方法的通道估測均方誤差理論值推導，並同時模擬完美已知通道與估測之通道下等化器的錯誤率。結果顯示，通道估測之均方誤差理論值與模擬值符合，且在兩種情況下，提出之方法之錯誤率在都普勒偏移較大的環境下與過往文獻相比，皆有一些改善。

In doubly-selective cannels, single-carrier block transmission (SCBT) suffers from not only the inter-symbol interference (ISI), but also the virtual inter-carrier interference (virtual ICI) in the frequency domain. As a consequence, the iterative block decision feedback equalizer (IBDFE) originally designed for time-invariant channel transmissions is no longer applicable. Recently, the conventional IBDFE had been modified for time-varying channels. It outperforms the minimum mean square error frequency domain linear equalizer (MMSE FD-LE) with only a slight increase of complexity. In this thesis, we propose a generalized IBDFE algorithm that includes the modified IBDFEs as special cases. In the high Doppler frequency case, the proposed algorithm slightly outperforms the modified IBDFE with a small increase on complexity. Unlike the previous works on IBDFEs, which assume perfect knowledge of channel state information, we consider the impact of estimated CSI in the thesis. Basis expansion model (BEM) and pilot symbol are adopted for channel estimation. We derive the theoretical mean square error (MSE) of least squares estimator (LSE) and also simulate the error rate of IBDFE designed by both perfect CSI and estimated CSI. Simulation results indicate that in both case, the proposed IBDFE gives a small improvement in high Doppler frequency case compared to the existing IBDFEs.

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