對單載波區塊傳送系統而言，多路徑時變通道不止會產生符元間干擾，同時還會產生虛擬的載波間干擾。直接使用過去非時變通道下的頻域等化器錯誤率非常之高，因此時變通道下的等化多採用時域下的線性最小均方誤差等化器，然其錯誤率低但複雜度相當高。針對這項缺點文獻中提出了利用傳送區塊大小與多路徑通道長度差異的低複雜度最小均方誤差等化器，其中加入序列化及利用外部資訊遞迴的概念使複雜度降低的同時正確率進一步提高。
本論文中將該等化器從循環首字單載波區塊傳送系統轉移至加入訓練序列的單載波區塊傳送系統，利用訓練序列使傳送接收的正確率更加提高。並提出在不增加複雜度的情況下，可以使該等化器效能額外提升的一些方法。本論文的最後將該等化演算法從二位元相位偏移調變延伸至四位元相位偏移調變。

In doubly selective channels, single-carrier block transmission (SCBT) suffers from not only inter-symbol interference (ISI) but also virtual inter-carrier interference (ICI). The detection performance deteriorates considerably when a linear time-invariant (LTI) equalizer is employed. Therefore, equalization algorithms that cope with time-varying channels mostly used the time-domain minimum mean square error linear equalizer (MMSE-LE). However, the complexity of the MMSE-LE equalizer is fairly high. Aiming at the downside of the MMSE-LE, the low-complexity MMSE (LC-MMSE) equalizer was proposed in the literature that took advantage of the sparse nature of the channel matrix. In addition, with sequential processing and iteration with extrinsic information, the LC-MMSE equalizer not only lowers the complexity but also improves the detection performance over MMSE-LE.
In this thesis, we apply the LC-MMSE equalizer, originally developed for cyclic prefix SCBT (CP-SCBT) systems, to training sequence-aided SCBT (TA-SCBT) systems. We investigate methods that exploit the training sequence to enhance the detection performance without adding additional complexity. Finally, we extend the iterative method from binary phase-shift keying (BPSK) to quadrature phase-shift keying (QPSK).

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