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研究生:黃志民
研究生(外文):Chih-Min Huang
論文名稱:用於OFDMA系統下結合多重接取干擾消除機制之載波頻偏估測器
論文名稱(外文):Window-Based Carrier Frequency Offsets Estimator with MAI Cancellation Scheme for OFDMA Systems
指導教授:鍾日龍
指導教授(外文):Rih-Lung Chung
學位類別:碩士
校院名稱:中原大學
系所名稱:電子工程研究所
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:2011
畢業學年度:99
語文別:中文
論文頁數:51
中文關鍵詞:正交分頻多工存取載波頻率偏移多用戶存取干擾視窗化
外文關鍵詞:multiple interference cancellation(MAI)carrier frequency offset (CFO)window-basedorthogonal frequency division multiple access (OFDMA)
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  • 被引用被引用:0
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本論文中,吾人提出適用於OFDMA系統中,結合多用戶干擾(MAI)消除機制的高精準度視窗化載波頻偏估測器,藉此達到更佳的載波頻率偏移(CFO)更正。首先,假設再多個不同的CFO情況下,建構出視窗化頻域訊號模型並且推導不同使用者的訊號對干擾雜訊比(SINR)下限,分析系統效能結果,發現較小的CFO會受到其他較大CFO所產生的MAI引響最為嚴重。接著根據理論分析,吾人提出兩階段的CFO估測器,第一階段利用視窗化估測器可得初始CFO估測值,其中最佳的視窗寬度藉由預先模擬結果擇定,第二階段利用MAI消除設計,改善CFO估測值的精準度。最後,觀察在OFDMA系統中此演算的電腦模擬結果,顯示只做一次MAI消除與單一使用者的均方誤差(MSE)只差2dB。


In this thesis, we propose a high accuracy window-based carrier frequency offsets (CFO) estimator with multiple access interference (MAI) cancellation scheme to achieve better CFO’s correction for the orthogonal frequency division multiple access (OFDMA) systems. First, under the assumption of multiple different CFOs, we construct the frequency-domain signal model with scalable window, and then derive the lower bound of signal to interference and noise ratio (SINR) for different users. The analysis result shows that the performance of small CFO significantly suffers from the effects of MAI from the large CFOs. Then, we propose two-stage CFO estimator according to the result of theoretical analysis. In the first stage, we use the window-based CFO estimator to obtain the initial CFO’s estimates, where the best window width can be found the lower bound of the SINR (/determined by the pre-simulation results). In the second stage, we adopt the multiple access interference (MAI) cancellation scheme to improve the accuracy of CFO estimation. Finally, we investigate the proposed CFO estimator algorithm for OFDMA systems by using computer simulations. Simulation results demonstrate that the mean-square errors of the proposed algorithm with one-iteration MAI cancellation deviates the single-user bound only within 2 dB.


目錄
摘要 I
Abstract II
誌謝 III
目錄 IV
圖目錄 VI
表目錄 VII
縮寫 VIII
第一章 緒論 1
1.1 研究動機 1
2.4 本文架構 2
第三章 OFDMA系統和通道模型 3
2.4 OFDM系統簡介 3
2.2 OFDMA系統簡介 5
2.3 上鏈路OFDMA系統 7
2.3.1 上鏈路OFDMA傳送端 7
2.3.2 上鏈路OFDMA接收端 9
2.4 通道模型 11
第三章 上鏈路OFDMA及載波頻率偏移估測 13
3.1 CFO形成原因與問題 13
3.2 OFDMA系統SINR下限推導 17
3.3 OFDM與OFDMA系統之CFO估測演算法 20
3.3.1 OFDM系統CFO估測演算法 20
A. 時域CFO估測演算法 21
B. 頻域CFO估測演算法 23
3.3.2 OFDMA系統CFO估測演算法 25
3.4 具有MAI視窗化載波頻偏估測器 28
3.4.1 視窗化載波頻偏估測器 29
A. 視窗濾波器 29
B. 訓練序列設計 29
3.4.2 具有MAI消除機制載波頻偏估測器 32
第四章 模擬結果 35
4.1 性能評估 35
4.2 複雜度分析 38
第五章 結論 39
參考文獻 40

圖目錄
圖2.1 FDM與OFDM頻譜示意圖 3
圖2.2 OFDM系統方塊圖 4
圖2.3 加上循環字首後的OFDM訊號 5
圖2.4 子載波配置設計(CAS) 6
圖2.5 上鏈路OFDMA系統方塊圖 7
圖3.1 具有CFO之上鏈路OFDMA系統CFO方塊圖 14
圖3.2 2-D干擾振幅分佈圖 16
圖3.3 3-D干擾振幅分佈圖 16
圖3.4 觀測(2N+L)樣本點區間示意圖 22
圖3.5 Preamble 執行交相關示意圖 23
圖3.6 文獻[13]接收端架構 26
圖3.7 CLJL scheme架構 27
圖3.8 H&L干擾消除及CFO補償區塊架構 27
圖3.9 具有MAI消除視窗化載波頻偏估測器架構圖 28
圖3.10上鏈路 OFDMA兩個用戶的訓練序列 29
圖3.11 不同視窗寬度下之CFO估測效能 31
圖3.12 具有MAI消除的載波頻偏估測器 33
圖4.1 不同MAI消除次數估測CFO之MSE比較 36
圖4.2 一次MAI消除估測不同用戶CFO之MSE比較 37

表目錄
表3.1 不同視窗寬度下之模擬參數 31
表4.1 不同MAI消除次數估測CFO之模擬參數 35
表4.2 一次MAI消除估測不同用戶CFO之模擬參數 36
表4.3 提出CFO演算法所需複數乘法數 38
[1]H. Rohling and R. Grunheid, “Performance of an OFDM-TDMA mobile communication system,” in Proceedings of the IEEE Semiannual Vehicular Technology Conference, 46th, May 1996, pp. 1589 –1593.
[2]J. Choi, C. Lee, H. W. Jung, and Y. H. Lee, “Carrier frequency offset compensation for uplink of OFDM-FDMA systems,” IEEE Commun. Lett., vol. 4, no. 12, pp. 414–416, December 2000.
[3]S. Hara and R. Prasad, “Overview of multicarrier CDMA,” IEEE Commun. Mag., vol. 35, no. 12, pp. 126–133, Dec. 1997.
[4]J. Li, H. Kim, Y. Lee, Y. Kim, “A Novel Broadband Wireless OFDMA Scheme for Downlink in Cellular Communications,” IEEE Wireless Communications and Networking, WCNC 2003, vol. 3, pp. 1907-1911, 16-20 March 2003.
[5]Koffman and V. Roman, “Broadband wireless access solutions based on OFDM access in IEEE 802.16,” IEEE Commun. Mag., pp. 96–103, Apr. 2002.
[6]A. M. Tonello, N. Laurenti, and S. Pupolin, “Analysis of the uplink of an asynchronous multi-user DMT OFDMA system impaired by time offsets, frequency offsets, and multi-path fading,” in VTC Conference Record, vol. 3, October 2000 Fall, pp. 1094–1099.
[7]M. Morelli, C.-C. Jay Kuo, M. O. Pun, “Synchronization Techniques for Orthogonal Frequency Division Multiple Access (OFDMA): A Tutorial Review,” Proceedings of the IEEE, pp. 1394-1427, 2007.
[8]R. J. Hung, “Carrier Frequency Offset Estimation and Compensation of OFDMA Uplink System,”Thesis of Master Degree, National Chiao Tung University, 2007.
[9]P. H. Moose, “A technique for orthogonal frequency division multiplexing frequency offset correction,” IEEE Trans. Commun., vol. 42, no. 10 pp 2908-2914, Oct. 1994.
[10]J. Terry and J. Heiskala, OFDM wireless LANs: A theoretical and practical guide, Indiana: SAMS, 2001.
[11]J. J. van de Beek, M. Sandell, and P. O. Borjesson, “ML estimation of time and frequency offset in OFDM systems,” IEEE Trans. Signal Process., vol. 45, no. 7, pp. 1800-1805, July. 1997.
[12]T.M. Schmidl and D.C. Cox, “Robust frequency and timing synchronization for OFDM,” IEEE Trans. Commun., vol.45, no. 12, pp. 1613-1621, Dec. 1997.
[13]J.J. Van de Beek, P.O.Borjesson, D. Landstram, J.M. Areans, P.Odling, C. Ostberg, M. Wahlqvist, S. K. Wilson, “A time and frequency synchronization scheme for OFDMA,”IEEE J. Select. Area Commun., vol. 17 pp.1900-1914, Nov.1999.
[14]J. Choi, C. Lee, H. W. Jung, and Y. H. Lee, “Carrier frequency offset compensation for uplink of OFDM-FDMA systems,” IEEE Commun. Lett., vol.4, no. 12, pp. 414–416, December 2000.
[15]D. Huang and K. B. Letaief, “An interference-cancellation scheme for carrier frequency offsets correction in OFDMA systems,” IEEE Trans. Commun., Vol. 53, No. 7, pp. 1155-1165, Jul. 2005.
[16]R. Fantacci, D. Marabissi, and S. Papini, “Multiuser interference cancellation receivers for OFDMA uplink communications with carrier frequency offset,” in Proc. IEEE GLOBECOM, Nov. 2004, pp. 2808-2812.
[17]Sergio Verdu, ”Multiuser Detection,” Combridge University Press, 1998.
[18]Robert M. Gray, “Toeplitz and Circulant Matrices: A review,” Department of Electrical Engineering Stanford University Stanford 94305, USA.
[19]Shalhav Zohor, “Toeplitz Matrix Inversion: The Algorithm of W.F. Trench,” Journal of the Association for Computing machinery, vol. 16, No.4, October 1969, pp.592-601.

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