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標題: | 針對分層差分正交振幅調變編碼系統下的相位估測演算法 An Algorithm for the Phase Recovery of Multi-Level Differential QAM Coding Systems |
作者: | Jia-Jun Hung 洪嘉駿 |
指導教授: | 林茂昭(Mao-Chao Lin) |
關鍵字: | 分層差分正交振幅調變,有跌代解碼的元位分散編碼調變系統,非同步通訊,通道估測,四次方演算法,泰勒級數, hierarchical differential QAM BICM-ID,non-coherent communication,channel estimation,4th power algorithm,Taylor series, |
出版年 : | 2014 |
學位: | 碩士 |
摘要: | 在本論文中,我們將處理於高階調變系統下的相位不確定性問題。對一個高階調變系統而言,已有文獻在之前提出於非同步檢測下以分層差分正交振幅編碼的方式處理九十度相位模糊的問題。首先,我們將展示三種相位不確定性:初始相位,頻率偏差和相位雜訊對分層差分正交振幅編碼的影響。之後,再以眾所周知的四次方演算法為基礎,提出一個粗略的頻率偏差估測方法,為了增進此通道估測算法的精確度,我們再提出以泰勒展開近似法為基礎的內插演算法。以上提到的方法除了能準確估測出頻率偏差之外,還具有其結果精確度不會被初始相位及相位雜訊所影響的特性。其補償後之誤碼率表現將會非常接近我們同步環境下的結果。 In this thesis, we deal with the problem of phase uncertainty in the highorder modulation. For high-order modulation, it has been proposed that hierarchical differential QAM (HDQAM) to avoid the 90 degree phase ambiguity in the non-coherent detection. First, we will show the influence of phase uncertainty in HDQAM with BICM-ID that caused by three kind of phase channel model: initial phase, frequency offset and phase noise. Afterward, we purpose a coarse frequency offset estimation method based on the well-known 4th power algorithm. For improving the resolution of channel parameter that estimated by the manner mentioned above, we provide a novel interpolation algorithm according to the Taylor series expansion. In addition, either the channel with or without initial phase will not affects both coarse estimated and interpolation algorithm. The bit error rate (BER) after phase compensation can approach the performance of coherent HDQAM. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/56927 |
全文授權: | 有償授權 |
顯示於系所單位: | 電信工程學研究所 |
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