在運作於毫米波頻段的IEEE 802.11ad單載波頻域等化系統中，由於接收端使用的直接轉換接收器存在頻率相依之實虛部不平衡，造成接收訊號受到鏡像干擾的影響，導致系統效能降低。本論文採用基於訓練序列的方法估計實虛部不平衡參數與多路徑通道。首先，根據系統訊號模型推導出概似函數，並且針對待估計的參數偏微分得出求解之方程式。接下來透過迭代的方法更新參數之估計值，直到概似函數收斂為止。根據估計的結果，接收訊號得以在頻域進行鏡像干擾的抑制以及多重路徑通道的等化。由模擬結果得知，無論實虛部不平衡在近似頻率獨立或頻率相依的情況下，相較於未進行補償的錯誤率曲線，接收訊號在經補償後的錯誤率皆有明顯下降，故可以推論論文中所使用之演算法能夠有效的估計實虛部不平衡與多路徑通道。

In IEEE 802.11ad single-carrier frequency-domain equalization (SC-FDE) systems that operate in the millimeter-wave band, frequency-dependent I/Q imbalance at the direct- conversion receiver leads to image interference and results in performance degradation.
In this thesis, we estimate the I/Q imbalance parameters and multipath channel using a training-sequence-based approach. First, we derive the likelihood function based on the frequency-dependent I/Q imbalance model. We then set the gradient with respect to each parameter to zero to obtain the set of equations that relate each one of the parameter with the remaining. Using this set of equations, the estimated value of each parameter is updated iteratively till convergence. With these estimates the image interference is suppressed and the multipath channel is equalized in the frequency domain. Simulation results demonstrate a significant performance improvement over the case of no compensation, showing that the algorithm used in the thesis effectively estimates and compensates for the frequency-dependent I/Q imbalance and multipath channel.

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