正交分頻多工系統下自我消除載波間干擾最佳區段組合權重之研究

Abstract

本論文旨在推導在兩種會造成載波間干擾的情況下，自我消除載波間干擾最佳區段的組合權重。 兩種情況分別是相位雜訊及高車速環境。 在高車速的情況下，本論文證明所提出的的方法較其他組合區段的方法擁有較佳的錯誤率效能。 在提出最佳的組合權重後, 我們對此最佳組合權重做一些修正，使得在計算權重時不需利用都卜勒頻偏與雜訊功率等資訊。 模擬結果顯示，這樣的修正在效能上並無顯著的下降。 在相位雜訊的情況下，就我們所知本論文是第一個使用最佳區段組合權重這種方法來解決載波間干擾的研究。 此外因為最佳區段組合權重可事先計算，故複雜度低並實作容易。 無論在相位雜訊和高車速的情況，本論文提出的方法都可以低複雜度改善系統錯誤率。

We derived the optimum combining weight of the self-ICI cancellation method for two different ICI-inducing conditions, i.e., phase noise and high mobility environment. In the high mobility case, we show that our proposed method outperforms other existing works (with different combining weight). After deriving the optimum weight, we make a modification so that the knowledge of f_D as well as noise power is not required in computing the combining weight. Simulation results show that the performance of this modification is nearly identical to the optimum one. In the phase noise case, we are the first one considering this kind of self-ICI cancellation method, to the best of our knowledge. Since most of the computation can be executed off-line, our proposed method is a low-complexity and practical solution. In both phase noise and high mobility cases, the proposed method can considerably improve the BER performance.