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研究生:古廷軒
研究生(外文):Ting-Shuan Ku
論文名稱:OFDM系統中時間同步方法之改進
論文名稱(外文):On the Improvement of Timing Synchronization in OFDM Systems
指導教授:吳國光吳國光引用關係
指導教授(外文):Kuo-Guan Wu
口試委員:溫志煜梁新潁
口試委員(外文):Chih-Yu WenHsin-Ying Liang
口試日期:2017-10-13
學位類別:碩士
校院名稱:國立中興大學
系所名稱:通訊工程研究所
學門:工程學門
學類:電資工程學類
論文種類:學術論文
論文出版年:2017
畢業學年度:106
語文別:中文
論文頁數:29
中文關鍵詞:正交分頻多工時間同步
外文關鍵詞:OFDMTiming Synchronization
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OFDM系統較傳統的多載波系統具有更優異的傳輸速率與頻譜使用率,但同時也必須克服同步敏感的問題,否則將嚴重影響通訊性能。本論文將探討OFDM系統中常用的時間同步方法,並將語音辨識處理中常使用的AMDF(平均振幅差函數)方法應用在OFDM系統中的同步處理,以提升同步估計的效能。經實驗結果顯示其方法能夠有效提升估測準確度。
OFDM systems has better spectrum efficiency than traditional FDM systems. However, they are sensitive to the problem of synchronization errors which seriously affects the performance. In this thesis, we discuss the commonly used timing synchronization method in OFDM system and apply the method of AMDF( Average magnitude difference function ), which is often used in the field of speech recognition to improve the accuracy of synchronization . Simulations results shows that through the combination of the AMDF method and the existing correlation method , the performance of timing synchronization can be effectively improved .
摘要..................i
Abstract.............ii
目次.................iii
圖目次................v
第一章、 簡介.......................1
第二章、OFDM系統原理與架構.............2
2.1 單載波與多載波原理.................2
2.2 OFDM系統架構...................4
2.2.1 調變(Modulation).............5
2.2.2 以FFT為基礎的離散OFDM系統.............6
2.2.3 循環字首(Cyclic Prefix)..............7
2.2.4 同步問題....................8
2.3 OFDM系統優缺點比較.............9
第三章、OFDM系統時間同步原理與方法.............11
3.1 S&C method..............................11
3.2 Sliding window method...................13
第四章、OFDM模擬系統.............14
4.1 Transmitter......................14
4.1.1. Preamble................15
4.1.2. OFDM Symbol.............16
4.1.3. Null Symbol.............16
4.2 Receiver......................16
4.2.1. Packet Detection(PD)............................18
4.2.2. Carrier Frequency Offset Estimation ....19
4.2.3. Symbol Timing detection(ST).....................20
4.2.4. Channel Estimation(CE)..........................20
第五章、時間同步方法改良與效能分析............22
5.1 AMDF方法應用..........................22
5.2 ACF與AMDF結合.........................25
第六章、結論...................27
參考文獻.......................28
[1] Manik Gadhiok and Joseph R. Cavallaro “Preamble-based Symbol Timing Estimation for Wireless OFDM Systems”, IEEE Conference Publications , 2007 Conference Record of the Forty-First Asilomar Conference on Signals, Systems and Computers , Pages: 1791 - 1794 , April 2008 .
[2] J.J. van de Beek, M. Sandell, P.O. Borjesson “ML estimation of time and frequency offset in OFDM systems”, IEEE Transactions on Signal Processing,Volume: 45, Issue: 7, Jul 1997 .
[3] T.M. Schmidl, D.C. Cox “Robust Frequency and Timing Synchronization for OFDM”, IEEE Transactions on Communications , Volume: 45, Issue: 12, Dec 1997.
[4] H. Minn, M. Zeng, V.K. Bhargava“On timing estimation for OFDM systems”, IEEE Communications Letters,Volume: 4, Issue: 7, July 2000
[5] Byungjoon Park, Hyunsoo Cheon, Changeon Kang, Daesik Hong “A Novel Timing estimation method for OFDM systems”, IEEE Communications Letters,Volume: 7, Issue: 5, May 2003
[6] Yunsi Ma, Sanwen Zhou, Chaoxing Yan, Tongling Liu, Lingang Fu “Design of OFDM Timing Synchronization Based on Correlations of Preamble Symbol”, Vehicular Technology Conference (VTC Spring), 2016 IEEE 83rd
[7] Hlaing Minn, V.K. Bhargava, K.B. Letaief “A Robust Timing and Frequency Synchronization for OFDM Systems”, IEEE Transactions on Wireless Communications ,Volume: 2, Issue: 4, July 2003.
[8] Adegbenga B. Awoseyila; Christos Kasparis; Barry G. Evans “ Improved Preamble-Aided Timing Estimation for OFDM Systems”, IEEE Communications Letters , Volume: 12, Issue: 11 , Pages: 825 – 827 , December 2008
[9] M. Ross; H. Shaffer; A. Cohen; R. Freudberg; H. Manley “ Average magnitude difference function pitch extractor”, IEEE Transactions on Acoustics, Speech, and Signal Processing , Volume: 22, Issue: 5 ,Pages: 353 – 362 , Oct 1974
[10] Yu-Min Zeng; Zhen-Yang Wu; Hai-Bin Liu; Lin Zhou “ Modified AMDF pitch detection algorithm”, Proceedings of the 2003 International Conference on Machine Learning and Cybernetics (IEEE Cat. No.03EX693) , Volume: 1, Pages: 470 - 473 Vol.1 , February 2004 .
[11]Kai Chen; Z. H. Yu; Yu Mei Huang; Yang Zhang “An Improved Timing Offset Estimation for OFDM System”,2007 International Conference on Wireless Communications, Networking and Mobile Computing , October 2007
[12] A. Fort; J. -W. Weijers; V. Derudder; W. Eberle; A. Bourdoux “ A performance and complexity of auto-correlation and cross-correlation for OFDM burst synchronization
Acoustics, Speech, and Signal Processing, 2003. Proceedings. (ICASSP ''03). 2003 IEEE International Conference on , Volume: 2 , Pages: II - 341-4 vol.2 , June 2003
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