English  |  正體中文  |  简体中文  |  Items with full text/Total items : 43312/67235
Visitors : 2106404      Online Users : 11
RC Version 5.0 © Powered By DSPACE, MIT. Enhanced by NTU/NCHU Library IR team.
National Chung Hsing University Institutional Repository - NCHUIR > 工學院 > 通訊工程研究所 > 依資料類型分類 > 碩博士論文 >  適用於多輸入多輸出正交分頻多工系統之頻域渦輪等化技術

Please use this identifier to cite or link to this item: http://nchuir.lib.nchu.edu.tw/handle/309270000/153924

標題: 適用於多輸入多輸出正交分頻多工系統之頻域渦輪等化技術
Frequency-Domain Turbo Equalization for MIMO OFDM systems
作者: 鍾奇洋
Chung, Chi-Yang
Contributors: 翁芳標
Fang-Biau Ueng
通訊工程研究所
關鍵字: 軟式決策反饋等化器;正交分頻多工;多輸入多輸出;最小均方差;低密度查核碼;多階調變;渦輪等化器
SDFE;OFDM;MIMO;MMSE;LDPC;multilevel modulation;turbo equalization
日期: 2013
Issue Date: 2013-11-19 12:31:53 (UTC+8)
Publisher: 通訊工程研究所
摘要: 本文主要提出一個在多徑傳播(Multi-path propagation)環境影響下,適用於多輸入多輸出-正交分頻多工(Multi-input Multi-output Orthogonal frequency-division multiplexing;MIMO-OFDM)通訊系統之頻域(Frequency domain)迭代軟式決策反饋等化器(Iterative soft decision feedback equalizer;ISDFE)。因錯誤傳播(Error propagation)會嚴重的影響適應性決策反饋等化器(Adaptive decision feedback equalizer;ADFE)的效能,特別是等化器工作於符際干擾(inter symbol interference,ISI)存在的通道環境中,錯誤傳播對等化器的效能影響會更明顯。本文所提出的迭代軟式決策反饋等化器(SDFE)不僅適用在多階調變(Multi-level modulation)系統,亦可消除錯誤傳播。於迭代等化運算過程中,使用等化器所輸出的傳送符元預估值與傳送符元做最小均方誤差(Minimum Mean-Square Error, MMSE)運算,用以決定等化器係數。然而,事後資訊(a posterior information)對數似然機率(log-likelihood ratio;LLR)和外部資訊(extrinsic information )對數似然機率於多階調變下的推導之假設為事前資訊(a priori information)和軟式決策反饋等化器(SDFE)的輸出值近似為等效高斯通道之輸出值。此外,從模擬的結果可以看出,不規則低密度查核碼(irregular low-density parity-check;irregular LDPC)相較於渦輪碼(Turbo code),有較佳的效能表現;另外,在高階調變下,本文所提出的等化器相較於最小均方差線性等化器(MMSE-LE)有更好的效能。
The mainly idea of this paper, we using iterative soft decision feedback equalization (SDFE) in frequency-domain (FD) for multiple-input–multiple-output (MIMO) Orthogonal frequency division multiplexing (OFDM) communication system transmission over multi-path propagation channels. Error propagation can seriously affect the performance of an adaptive decision feedback equalization (ADFE), especially when operated in inter-symbol interference (ISI) channel environments. Error propagation on the performance of the equalizer effect will be more obvious. So we using iterative SDFE not only suitable for multilevel modulation systems employing turbo equalization, but also using SDFE algorithm offers a novel approach to combat error propagation. Its equalization coefficients are chosen to minimize the mean-squared error (MMSE) between the transmitted symbol and equalizer output, used to determine the equalizer coefficients. However, under a Gaussian approximation to the a priori information and the SDFE output. Both the output of an equivalent AWGN channel, expressions for the a posteriori log likelihood ratio (LLR) and the extrinsic LLR are derived for multilevel modulation. In addition, we used irregular low-density parity check codes (LDPC) compared with the turbo codes, the regular LDPC codes performance better than turbo codes of the iterative receivers. And results show the performance of the using equalization scheme significantly improves when higher order constellations are used for MMSE-LE
Appears in Collections:[依資料類型分類] 碩博士論文

Files in This Item:

File SizeFormat
index.html0KbHTML126View/Open


 


學術資源

著作權聲明

本網站為收錄中興大學學術著作及學術產出,已積極向著作權人取得全文授權,並盡力防止侵害著作權人之權益。如仍發現本網站之數位內容有侵害著作權人權益情事者,請權利人通知本網站維護人員,將盡速為您處理。

本網站之數位內容為國立中興大學所收錄之機構典藏,無償提供學術研究與公眾教育等公益性使用。

聯絡網站維護人員:wyhuang@nchu.edu.tw,04-22840290 # 412。

DSpace Software Copyright © 2002-2004  MIT &  Hewlett-Packard  /   Enhanced by   NTU/NCHU Library IR team Copyright ©   - Feedback