單載波分頻多重存取系統在多重路徑通道的環境下，會因為符元間的干擾而導致系統效能變差，為了解決這個問題，我們參考原本使用在單載波區塊傳送系統上等化的方法，並且將它應用在單載波分頻多重存取系統上。由於線性等化器的效能不佳，所以本論文以探討非線性的迭代式區塊決策回授等化器為主。硬式迭代區塊決策回授等化器是藉由回授前次已偵測的資料，來消除殘餘的符元間干擾，但這有可能讓錯誤的資料進入回授，反而降低效能；而軟式迭代區塊決策回授等化器則限制只讓可靠度高的符元進入回授，它不僅彌補了硬式迭代區塊決策回授等化器的缺點，還降低了參數估測的複雜度，模擬結果也顯示其效能確實比硬式的好。除此之外，為了瞭解軟式迭代區塊決策回授等化器在非完美通道估測下的效能，我們參考文獻的方法做通道估測；模擬結果效能最好的是最小均方誤差通道估測法，但它的複雜度最高，所需通道的統計資訊也最多。

The single-carrier frequency-division multiple access (SC-FDMA) system suffers from severe inter-symbol interference (ISI) in multi-path channels. In order to mitigate this problem, we apply the equalization methods that are originally developed for the single-carrier block transmission (SCBT) systems to the SC-FDMA system. Because of the poor performance of the linear equalizers, we focus on the non-linear iterative block decision feedback equalizer (IBDFE) in this thesis. The IBDFE with hard detection (HD-IBDFE) eliminates the residual ISI by using the hard detected data from previous iteration as the input of the feedback filter, but using the wrongly detected data for feedback might result in performance degradation. To overcome this drawback, the IBDFE with soft detection (SD-IBDFE) feeds back only the detected data that are deemed reliable. Simulation results show that SD-IBDFE not only improves the performance of HD-IBDFE, but also reduces the complexity of parameter estimation. In the thesis, we also investigate the effect of imperfect channel estimation on the performance of IBDFE. Simulation results show that the minimum mean square error (MMSE) channel estimator leads to the best bit-error-rate performance; however, the drawbacks of MMSE estimator include the higher complexity and requiring the knowledge of the channel statistics.

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