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研究生： 賴群嵐
Chun-lan Lai
論文名稱： 時變通道環境下LTE下形鏈路系統通道估測之FPGA實現
Design and Implementation of Channel Estimation for LTE Downlink System in Time-Varying Channel Environment with FPGA
指導教授： 陳逸民
Yih-min Chen
口試委員:
學位類別： 碩士
Master
系所名稱： 資訊電機學院 - 通訊工程學系
Department of Communication Engineering
論文出版年： 2013
畢業學年度： 101
語文別： 中文
論文頁數： 76
中文關鍵詞： 長期演進技術 、可程式化邏輯閘陣列 、正交分頻多重存取
外文關鍵詞： LTE, FPGA, OFDMA
相關次數： 點閱：12  下載：0 
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    • 長期演進技術(Long Term Evolution，LTE)為第四代行動通訊重要技術之一，此技術之下行鏈路為正交分頻多重存取(Orthogonal Frequency Division Multiple Access，OFDMA)系統，而它是以正交分頻多工(Orthogonal Frequency Division Multiplexing，OFDM)演進而來。OFDM技術可使頻譜效益增加，但它對於都卜勒效應頻率偏移相當敏感，因此OFDMA技術如同OFDM技術，將須解決因通道環境下，進而引起子載波間正交性遭到破壞以及載波間互相干擾(Inter-Carrier- Interference，ICI)的相關問題。
    此篇論文將利用可程式化邏輯閘陣列(Field-programmable gate array，FPGA)板實現，以LTE下行鏈路規格下所提出的兩種通道估測方法。其中，我們使資料直接決策(Decision Directed)與多項式模型(Polynomial Model Based)估測法來提升頻域方向通道估測的準確度，且透過模擬來說明通道估測之性能改善。

    LTE (Long Term Evolution) is important for fourth generation of mobile communication technologies. On the downlink transmission, the LTE system uses OFDMA (Orthogonal Frequency Division Multiple Access) technology, which is based on OFDM (Orthogonal Frequency Division Multiplexing). It increases spectrum efficiency, but it is sensitive to Doppler spread and frequency offset. Therefore, the problem that we want deal with is the one operating in time-varying environments where the orthogonality among the subcarriers is destroyed and inter-carrier interference (ICI) is thus created.
    In this thesis, we conduct design and implementation of channel estimation with FPGA (Field-programmable Gate Array). We propose two channel estimation ways. One of the improved methods is data-aided and decision-directed polynomial model based estimation by frequency domain. The performance improvement is demonstrated through matlab simulations.

    目錄 摘要 iv ABSTRACT v 目錄 vii 表目錄 ix 圖目錄 x 第一章 緒論 1 1.1 簡介 1 1.2 研究動機 2 1.3 章節提要 3 第二章 LTE下行鏈路系統簡介 4 2.1 正交分頻多工系統簡介 4 2.1.1 正交分頻多工調變介紹 4 2.1.2 正交分頻多重存取系統介紹 10 2.2 長期演進技術結構介紹 12 2.2.1 長期演進技術傳輸資源結構 13 2.2.2 長期演進技術分工模式 14 2.3 實體層下行鏈路系統簡介 16 2.3.1 長期演進技術之下行鏈路通道和下行信號簡介 16 2.3.2 長期演進系統下行實體鏈路 18 2.3.3 長期演進技術傳輸參數 21 2.3.4 長期演進技術常用的通道模型 21 第三章 長期演進技術規格下之通道估測與等化 22 3.1 非時變通道與時變通道簡介 22 3.2 可加性高斯白雜訊通道 24 3.3 通道估測與等化 26 3.3.1 通道頻率響應線性內插 26 3.3.2 直接決策通道估測 27 3.3.3 多項是模型化通道估測 28 3.3.4 時域通道取樣延遲估測法 30 第四章 長期演進技術下行鏈路通道估測之硬體架構 31 4.1 參考訊號通道響應 32 4.2 線性內插器(Linear Interpolator) 33 4.3 通道等化器(Channel Equalizer) 34 4.4 迫零等化直接決策器(Decision Directed Zero Forcing) 37 4.5 二次多項式模型(2nd Polynomial Model Based) 39 4.6 時域通道延遲與取樣(Sample and Hold)估測 40 4.7 時域通道線性內插(Linear Interpolator)通道估測 42 第五章 硬體設計與實現 44 5.1 通道估測之設計流程 44 5.2 時變通道下LTE下行鏈路通道估測之效能模擬 45 5.3 FPGA硬體實現 57 第六章 未來與展望 61 參考文獻 62

    [1] Ericsson, Nokia, Motorola, and Rohde & Schwarz, “R4-070572: Proposal for LTE Channel Models, www.3gpp.org, +3GPP TSG RAN WG4, meeting 43, Kobe, Japan, 2007(5).
    [2] W.C Jakes and D. C. Cox, eds., Microwave Mobile Communications. Wiley-IEEE, Press, 1994.
    [3] Y. Mostofi and D. Cox, “ICI Mitigation for Pilot-Aided OFDM Mobile Systems,” Wireless Communications, IEEE Transactions on, vol. 4, pp. 765–774, Mar. 2005.
    [4] 3GPP Technical Specification 36.211, “Physical Channel and Modulation (Release 10) ,”www.3gpp.org.
    [5] 3GPP Technical Specification 36.212, “Multiplex and Channel Coding (Release 10) ,”www.3gpp.org.
    [6] X. Wang and K. J. R. Liu, “Channel estimation for multicarrier modulation systems using a time-frequency polynomial model,” IEEE Trans. Commun., vol. 50, pp. 1045–1049, July 2002.
    [7] M.-X. Chang and Y. Su, “Model-Based Channel Estimation for OFDM Signals in Rayleigh Fading,” Wireless Communications, IEEE Transactions on, vol. 50, pp. 540–544, Apr. 2002.
    [8] X. Wang and K. J. R. Liu, “Model-based channel estimation framework for MIMO multicarrier communication systems, ” IEEE Trans. Wireless Commun., vol. 4, no. 3, pp. 1050-1063, May 2005.
    [9] D. K. Borah and B. D. Hart, “Frequency selective fading channel estimation with a polynomial time-varying channel model,” IEEE Trans. Commun., vol. 47, pp. 862–873, Mar. 1999.
    [10] P. Hoeher, S. Kaiser, and P. Robertson, “Two-dimensional pilot-symbol-aided channel estimation by Wiener filtering,” in Acoustics, Speech, and Signal Processing, 1997. ICASSP-97., 1997 IEEE International Conference on, vol. 3, pp. 1845 –1848 vol.3, Apr. 1997.
    [11] D. Divsalar and F. Pollara, “Turbo codes for deep-space communications,” JPLTDA Progress Report 42-120, Feb. 1995.
    [12] J.-J. van de Beek, O. Edfors, M. Sandell, S. K. Wilson, and P. O. Borjesson, “On Channel Estimation in OFDM System,” in Proc.VTC’1995,Vehicular Technology Conference (VTC 1995) (Chicago,USA), July 1995.
    [13] P. Hoher, S. Kaiser and P. Robertson, “Pilot-Symbol-Aided Channel Estimation in Time and Frequency” in Proc. Communication Theory Mini-Conf. (CTMC) within IEEE Global Telecommun. Conf. (Globecom 1997) (Phoenix, USA), July 1997.

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