在行動正交分頻多工通訊系統中以卡曼通道脈衝響應估計法之子載波干擾消除

An ICI Mitigation Method with Kalman Channel Impulse Response Estimation for Mobile OFDM Communications

王士康(Shih-Kang Wang)

指導教授 ： 張大中

國立中央大學/資訊電機學院/通訊工程學系/碩士(2008年)

摘要

在正交分頻多工系統中，多路徑時變通道將造成子載波間正交性失去，因而產生子載波間干擾(Inter-carrier Interference, ICI)。為了消除子載波間干擾效應，在這篇論文中我們提出一個可重複執行使效能提升之系統，此系統是由一個決策回授式子載波干擾消除等化器(Decision feedback interference cancellation equalizer)以及一個決策回授式通道估計系統(Decision feedback channel estimation scheme)所組成。其中決策回授式子載波干擾消除等化器是使用決策回授訊號以及估計之通道來得到等化器係數以執行消除子載波干擾，另外我們配合平滑化機制、決策錯誤偵測器以及錯誤補償機制去補償決策錯誤所產生之不穩定通道，以達到更好之效能。最後由模擬結果可顯示我們提出之系統在移動式無線通道中可有效地消除子載波干擾效應。

關鍵字

子載波干擾 ； 正交分頻多工系統 ； 卡曼濾波器

並列摘要

In orthogonal frequency division multiplexing (OFDM)systems, time-varying multipath fading leads to the loss of subcarrier orthogonality and the occurrence of inter-carrier interference (ICI). In order to mitigate ICI, we propose an iterative system composed of a decision feedback interference cancellation (DFIC) equalizer and a decision feedback channel estimation scheme in this thesis. The DFIC equalizer utilizes the decision feedback signal and channel estimation to get the coefficients of the equalizer for canceling ICI. In this algorithm, we apply a smoothing recursion, decision error detector, and error concealment to detect this unreliable channel estimates caused by decision errors, and then correct them. Simulation results show that the proposed scheme can efficiently reduce the ICI effect in mobile wireless channels.

並列關鍵字

OFDM ； Kalman Filter ； ICI

參考文獻

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