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博碩士論文 etd-0823110-230434 詳細資訊
Title page for etd-0823110-230434
論文名稱
Title
在多重路徑衰退通道下OFDM系統之盲蔽式時間同步
Blind Timing Synchronization for OFDM Systems in Multipath Fading Channels
系所名稱
Department
畢業學年期
Year, semester
語文別
Language
學位類別
Degree
頁數
Number of pages
49
研究生
Author
指導教授
Advisor
召集委員
Convenor
口試委員
Advisory Committee
口試日期
Date of Exam
2010-07-08
繳交日期
Date of Submission
2010-08-23
關鍵字
Keywords
盲蔽式、符號同步、多重路徑衰退通道、時間同步、循環字首
symbol synchronization, timing synchronization, cyclic prefix, multipath fading channels, blind
統計
Statistics
本論文已被瀏覽 5666 次,被下載 2687
The thesis/dissertation has been browsed 5666 times, has been downloaded 2687 times.
中文摘要
在多重路徑衰退通道(multipath fading channel)的情形下,本篇論文針對正交分頻多工(Orthogonal Frequency-Division Multiplexing,OFDM)系統提出了一個利用循環字首(cyclic prefix)來進行盲蔽式(blind)符號時間同步(symbol timing synchronization)的演算法,它從通道延遲的特性設計出了適當的權重來找尋符號時間起始點的方法。傳統的最大概似(maximum likelihood,ML)演算法在多重路徑衰退通道下因為通道延遲展開的影響,估測會偏差而且變動性很大。所提出的指數權重方法不只解決了以上的問題,而且提升了符號時間的準確度,尤其是此方法不需要知道訊雜比以及通道的長度。電腦模擬的結果證明了所提出的方法比其他傳統演算法更佳,且可對抗多路徑衰退通道的影響。
Abstract
In this thesis, a blind symbol timing synchronization algorithm based on cyclic prefix for OFDM systems in multipath fading channels is proposed. It finds the starting point of symbol timing for using appropriate weights which are designed from channel delay spread characteristics. In multipath fading channels, the conventional ML (maximum likelihood) algorithm estimate is biased and has a large variance due to the effect of channel delay spread. The proposed exponential weighting methods not only solve the above problems but also improve the accuracy of symbol timing. Particularly, the proposed method does not require the information of SNR and channel length. From computer simulation results, the proposed method outperforms the other conventional algorithms and is also robust against the effect of multipath fading channels.
目次 Table of Contents
第一章 簡介 1
1.1 研究動機 1
1.2 論文簡介 1
1.3 論文架構 3
第二章 系統模型 5
2.1 正交分頻多工技術概念 5
2.2 循環字首 8
2.3 正交分頻多工之架構 9
2.4 同步之議題 11
2.5 傳統符號時間同步演算法 12
2.5.1 最大相關演算法 13
2.5.2 最大概似演算法 14
2.5.3 最小均方誤差演算法 17
2.5.4 傳統演算法之模擬比較 18
2.6 多重路徑衰退通道 19
第三章 權重之符號時間同步演算法 21
3.1 接收訊號分析 21
3.2 簡化方法 22
3.3 加入權重之符號時間同步演算法 23
3.4 具有通道資訊的權重 25
第四章 系統模擬 26
4.1 傳統符號時間演算法之模擬 26
4.1.1 簡化方法之模擬 28
4.2 指數衰退通道模型 29
4.2.1 加入權重之符號時間同步演算法 30
4.3 實際通道模擬 32
第五章 結論 36
參考資料 37
參考文獻 References
[1] M. Morelli, C.-C. Jay Kuo, and M. O. Pun, “Synchronization techniques for orthogonal frequency division multiple access (OFDMA): A tutorial review,” Proceedings of the IEEE, vol. 95, no. 7, pp. 1394 –1427, July 2007.
[2] T. M. Schmidl and D. C. Cox, “Robust frequency and timing synchronization for OFDM,” IEEE Trans. Commun., vol. 45, pp. 1613–1621, Dec. 1997.
[3] H. Minn, M. Zeng, and V. K. Bhargava, “On timing offset estimation for OFDM systems,” IEEE Commun. Lett., vol. 4, pp. 242–244, July 2000.
[4] K. Shi and E. Serpedin, “Coarse frame and carrier synchronization of OFDM systems: a new metric and comparison,” IEEE Transactions on Wireless Communications, vol. 3, no. 4, pp. 1271 – 1284, Jul. 2004.
[5] A. Filippi and S. Serbetli, “OFDM symbol synchronization using frequency domain pilot in time domain,” IEEE Transactions on Wireless Communications, vol. 8, no. 6, pp. 3240-3248, June 2009.
[6] J. J. van de Beek, M. Sandell, and P. O. Börjesson, “ML estimation of time and
frequency offset in OFDM systems,” IEEE Trans. Signal Processing, vol. 45, no.
7, pp. 1800-1805, July 1997.
[7] D. Lee and K. Cheun, “Coarse symbol synchronization algorithms for OFDM
systems in multipath channels,” IEEE Communications Letters, vol. 6, no. 10, pp.
446–448, 2002.
[8] C. C. Ko, R. Mo and M. Shi, “A new data rotation based CP synchronization
scheme for OFDM systems,” IEEE Trans. Broadcasting, vol. 51, no. 3, Sep.
2005
[9] J. H. Wen, S. H. Lee, G. R. Lee and J. T. Chang, “Timing and delay spread estimation scheme in OFDM systems,” IEEE Transactions on Consumer
Electronics, vol. 54, no. 2, May 2008.
[10] C. Williams, M. A. Beach and S. McLaughlin, “Robust OFDM timing
synchronization in multipath channels,” EURASIP Journal on Wireless
Communications and Networking, vol. 2008, article ID 675048, 12 pages.
[11] B. Su and P. P. Vaidyanathan, “New blind block synchronization for transceivers
using redundant precoders,” IEEE Trans. Signal Processing, vol. 56, no. 12, Dec.
2008.
[12] S. Ma, X. Pan, G. H. Yang and T. S. Ng, “Blind symbol synchronization based on
cyclic prefix for OFDM systems,” IEEE Trans. Vehicular Tech., vol. 58, no. 4,
May 2009
[13] T. S. Rapport, “Wireless Communications – Principles and Practice, “IEEE
Press, 1996
[14] T. Fusco and M. Tanda, “Blind synchronization for OFDM systems in multipath
channels,” IEEE Trans. Wireless Communications, vol. 8, no. 3, March 2009.
[15] 3rd Generation Partnership Project; Physical layer aspects for evolved
Universal Terrestrial Radio Access (UTRA) (Release 7), 3GPP TR 25.814
V7.1.0., Sep. 2006.
[16] 3rd Generation Partnership Project; Technical Specification Group Radio
Access Networks; Deployment aspects (Release 9), 3GPP TR 25.943 V9.0.0.,
Dec. 2009.
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