電機資訊學院: 電信工程學研究所指導教授: 曹恆偉; 錢膺仁游皓鈞Yu, Hao-ChunHao-ChunYu2017-03-062018-07-052017-03-062018-07-052016http://ntur.lib.ntu.edu.tw//handle/246246/276474電力線通訊中，電力迴路不但存有多重路徑(Multipath)效應，且還受到脈衝式雜訊(Impulsive noise) 干擾之影響。這兩種效應會使得接收端之通道估測準確度下降與資料錯誤率提升，嚴重影響整個系統之資料傳輸效能，因此提升通道估測之性能與消除脈衝式雜訊為提升電力線通訊品質之關鍵。 本論文參考IEEE P1901規格中的小波轉換(Wavelet Transform) 之正交多工(Orthogonal Frequency-Division Multiplexing, OFDM)收發機技術 (Wavelet-based OFDM)為平台，提出一遞迴式接收機架構。本論文所提出之接收機會遞迴地改進通道估測以及脈衝干擾消除的效能。傳統的通道估測演算法有可能因為脈衝式干擾導致收斂效果不佳。所提出之脈衝式雜訊消除演算法的效果取決於通道估測的精準度，我們運用對於脈衝式干擾更為強健的演算法 Variable Step-Size Affine Projection Algorithm (VSS-APA) 來進行通道估測。 會在接收端的Discrete Wavelet Transform(DWT)方塊之前先進行零化法(Blanking)，以消除較強的脈衝式雜訊；在Discrete Wavelet Transform(DWT)方塊之後進行遞迴式雜訊消除，同時也進行通道估測及等化器訓練。而遞迴式雜訊消除則會持續估計殘餘的脈衝式雜訊以及進行通道估測，這種結構將使得通道估測以及殘餘脈衝式雜訊消除處於互利互助之狀態。 而遞迴式雜訊消除則會持續估計殘餘的脈衝式雜訊以及進行通道估測，這種結構將使得通道估測以及殘餘脈衝式雜訊消除處於互利互助之狀態。 模擬結果顯示，傳統的零化法(Blanking)雖可消除部分脈衝式雜訊，但其效果不佳。然而，我們提出之遞迴式通道估測與脈衝式雜訊消除演算法不僅可提升通道估測之效能，同時也可有效消除脈衝式雜訊，因此使得整體系統性能大幅提升。The multipath effect and impulsive noise (IN) of a power-line channel may affect the performance of power-line communications. Specifically, these two impairments reduce the accuracy of the channel estimation and increase the bit error rate (BER). In this thesis, we focus on the Discrete Wavelet Transform based orthogonal frequency division multiplexing (Wavelet-based OFDM) receiver, which is defined in IEEE P1901 standard, and propose an iterative receiver architecture. Moreover, we devise an associated iterative channel estimation and IN cancellation algorithm for this receiver. Due to IN, the conventional channel estimation algorithm may diverge or a poor estimated channel response. Therefore, an accurate channel estimation becomes more challenging. In our proposed iterative receiver, the resulting performance heavily depends on the quality of the channel estimation. We apply a variable step-size affine projection algorithm (VSS-APA) to estimate the channel response while avoiding the affect of IN. Before the DWT operation, we pre-mitigate the IN by a blanking device to cancel the strong part of the IN sources. On the other hand, after the DWT operation, we iteratively post-mitigate the residual IN. The post-IN mitigation block iteratively cancel the residual IN and update the estimated channel impulse response, so that the channel estimation and IN mitigation are in a mutually beneficial status. Simulation results show that the proposed iterative receiver not only increases the accuracy of the channel estimator, but also effectively cancel IN sources.3947758 bytesapplication/pdf論文公開時間: 2021/8/25論文使用權限: 同意有償授權(權利金給回饋學校)小波轉換正交分頻多工電力線系統脈衝式雜訊等化器Wavelet-OFDMPowerlineImpulsive NoiseEqualizationthesis10.6342/NTU201603432http://ntur.lib.ntu.edu.tw/bitstream/246246/276474/1/ntu-105-R03942098-1.pdf