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研究生:李元鈞
研究生(外文):Yuan-Chin Lee
論文名稱:以自互補碼符元模組組成的訓練碼來達成OFDM碼框同步之系統設計
論文名稱(外文):System Design of Frame Synchronization with Symbol Module Using Auto-Complementary Code in OFDM System
指導教授:廖和恩
指導教授(外文):Ho-En Liao
學位類別:碩士
校院名稱:逢甲大學
系所名稱:通訊工程所
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:2005
畢業學年度:93
語文別:中文
論文頁數:63
中文關鍵詞:頻率位移時間延遲定長度完全互補碼正交分頻多工
外文關鍵詞:OFDMTime DelayFrequency ShiftPeriodic Complete Complementary Code
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正交分頻多工(OFDM)系統已在數位音訊廣播、數位影像廣播及無線區域網路等領域被廣泛的使用,因為它對多重路徑造成的影響能有效的克服及有效運用頻寬和降低子載波傳輸速率等優點,將來勢必被更加重視。
由於時間延遲和頻率位移對於OFDM系統影響很大,同步機制便格外重要,因此本篇論文即探討同步機制如何解決時間延遲與頻率位移的問題。此論文所探討的同步架構有兩個,第一個是利用參考符元作初步的時間延遲與頻率位移估測,並由資料符元估測殘餘的頻率位移,而第二個是用自互補碼組成的訓練符元估測時間延遲,並由資料符元估測頻率位移。
The OFDM system has been adopted widely in applications such as DAB ,DVB and wireless LAN. Because it is recognized as superior in combating multipath fading effects, and it has the advantages of using the frequency bandwidth efficiently and reducing the subcarriers transmitting rate. So it will be valued more in the future.
Because of the effects induced by time delay and frequency shift to the OFDM system are serious. So the synchronization scheme is very important. This thesis is for probing into that how do the synchronization scheme reducing the effects induced by time delay and frequency shift. And there are two synchronization schemes investigated in this thesis. First, using the reference symbol to estimate the time delay and frequency shift initially, and then, using the data symbol to estimate the remnant frequency shift. And second, using the training symbol which is composed of the auto complementary code to estimate the time delay, and then, doing the estimation of frequency shift with the data symbol.
中文摘要 i
英文摘要(ABSTRACT) ii
目錄 iii
圖目錄 vi
第一章 緒論 1
1.1 研究動機 1
1.2 研究目的 2
第二章 OFDM系統 3
2.1 OFDM簡介   3
2.2 ISI效應與guard interval的應用 6
2.2.1 ISI效應 6
2.2.2 guard interval--減緩ISI效應 6
2.3 ICI效應與cyclic extension的應用 8
2.3.1 ICI效應     8
2.3.2 循環延伸(cyclic extension) 8
第三章 同步估測 10
3.1 時間延遲與頻率位移 10
3.1.1 時間延遲 10
3.1.2 頻率位移 10
3.2 同步演算法與架構 13
3.2.1 OFDM系統的傳輸信號結構 13
3.2.2 碼框同步(frame synchronization) 14
3.2.3 頻率位移初估(frequency shift acquisition)15
3.2.4 符元同步與殘存頻率位移的估測 17
3.2.5 信號失真造成的影響 19
第四章 定長度完全互補碼與訓練符元 22
4.1 簡介定長度完全互補碼 22
4.2 運用碼的特性降低雜訊對同步估測的影響 26
4.2.1 將定長度自互補碼編入參考符元 26
4.2.2 訓練符元對時間延遲的估測 27
4.2.3 頻率位移對訓練符元估測效果的限制 30
第五章 模擬結果的分析與比較 33
5.1 模擬架構的建立 33
5.2 模擬結果與分析 36
5.2.1 QPSK mapping 及較低頻率位移 36
5.2.2 QPSK mapping 及較高頻率位移 39
5.2.3 QAM mapping 及較低頻率位移 43
5.2.4 QAM mapping 及較高頻率位移 46
第六章 結論 50
[1].S. B. Weinstein and P. M. Ebert, “Data transmission by frequency-division multiplexing using the discrete fourier transform,” IEEE Transactions on Communication Technology, Vol. 19, no. 5, pp.628-634, May 1971.
[2].Richard van Nee, and Ramjee Prasad ”OFDM wireless multimedia communications,” Artech House.
[3].Thomas Keller, Lorenzo Piazzo, Paolo Mandarini, and Lajos Hanzo “Orthogonal frequency division multiplex synchronization techniques for frequency-selective fading channels,” IEEE Journal on Selected Areas in Communications , vol. 19, June 2001, pp. 999-1008.
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[5].Meng-Han Hsieh, and Che-Ho Wei, Fellow “A low-complexity frame synchronization and frequency offset compensation scheme for OFDM systems over fading channels,” IEEE Trans. Vehicular Technology, vol. 48, September 1999, pp. 1596-1609.
[6].J.-J van de Beek, M. Sandell, M. Isaksson, and P. O. , “Low-complex frame synchronization in OFDM systems,” in Proc. IEEE Int. Conf. Universal Personal Commun., Toronto, Canada, Sept. 27-29,1995, pp. 982-986.
[7].Hideyuki Torii, Naoki Suehiro, Makoto Nakamura “General Construction of Periodic Complete Complementary Codes Composed of Expanded Modulatable Orthogonal Sequences,” IEEE 2000.
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[9].Hideyuki Torii and Naoki Suehiro “Expansion of modulation for modulatable orthogonal sequences,” ISIT 1998, Cambridge, MA, USA, August 16 – August 21.
[10].Liru Lu, Student Member, and V. K. Dubey, senior Member “Extended orthogonal polyphase codes for multicarrier CDMA system,” IEEE COMMUNICATIONS LETTERS, VOL.8, NO. 12, DECEMBER 2004.
[11].Jan-Jaap van de Beek, Magnus Sandell, and Per Ola “ML estimation of time and frequency offset in OFDM systems,” IEEE Trans. Signal Processing ,vol. 45, July 1997, pp.1800-1805.
[12].Jia-Chin Lin, Member “Maximum-likelihood frame timing instant and frequency offset estimation for OFDM communication over a fast rayleigh-fading channel,” IEEE transactions on vehicular technology, vol.52, NO. 4, July 2003.
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