應用於合作式通訊環境之頻率偏移與通道檢估器研究

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研究生：	陳品仲 Ping-chung Chen
論文名稱：	應用於合作式通訊環境之頻率偏移與通道檢估器研究 Estimations of Frequency offset and channel Response in Cooperative Communication Environments
指導教授：	林嘉慶 Jia-chin Lin
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：	2014
畢業學年度：	102
語文別：	中文
論文頁數：	54
中文關鍵詞：	通道估測
相關次數：	點閱：6 下載：0
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對於無線通訊系統來說，正交分頻多工(Orthogonal Frequency Division Multiplexing, OFDM)技術是現行最流行且較優異的技術，由於OFDM子載波間的正交性讓頻寬可以有效的運用，循環字首(Cycle prefix, CP)的運用可以抵抗多重路徑通道的衰減。頻率偏移會破壞子載波間的正交性，會降低系統效能；通道估測在通訊系統架構中是很重要的步驟，估測的準確度大大地影響訊號錯誤率，在合作式通訊這種較複雜的環境下，通道估測就更為重要。
本篇論文同時考慮頻率偏移和通道這兩個影響系統的因素，利用最大事後機率法(Maximum a posteriori) 推導出聯合估計器，並期望能運用在合作式通訊環境中，比較在放大並傳送和解碼並傳送的傳輸協定下的估測效能比較，甚至將此擴展到分時多工的並列式多中繼站的合作通訊環境。

Up to now, orthogonal frequency division multiplexing (OFDM) was a current and outstanding technique of wireless communication. Bandwidth can be used effectively through orthogonality of OFDM subcarriers. The usage of CP can resist multipath effect. The CFOs can destroy orthogonality of OFDM subcarriers and degrade system performance; Channel estimation is very important step in communication system structure. The accuracy of channel estimation influences bit error rate (BER) significantly. Channel estimation is highly significant in complex cooperative communication system.
CFOs and channel estimation are considered to the factors for communication system. We derived the joint estimator by maximum a posteriori method. We expect that it can be applied in cooperative communication environment with comparison of estimation performance based on amplify and forward as well as decode and forward transmission protocol, even in TDM parallel multiple relays cooperative communication environment.

摘要………………………………………………………………………………...I
致謝………………………………………………………………………………III
目錄………………………………………………………………………………IV
圖目錄……………………………………………………………………………VII
表目錄……………………………………………………………………………VIII
第一章    緒論………………………………………………………………………1
   1-1 研究背景…………………………………………………………………1
   1-2 研究動機…………………………………………………………………1
   1-3 論文大綱…………………………………………………………………2
第二章    無線移動通道特性………………………………………………………3
   2-1 前言……………………………………………………………………….3
   2-2 多重路徑………………………………………………………………….3
       2-2.1 多重路徑衰減的成因…………………………………………… .3
       2-2.2 大尺度與小尺度衰減……………………………………………. 3
   2-3 大尺度衰減……………………………………………………………….4
       2-3.1 自由空間傳播模型………………………………………………. 4
       2-3.2對數距離路徑損耗模型………………………………………… ..5
       2-3.3哈他模型………………………………………………………….. 6
       2-3.4 對數高斯遮蔽模型………………………………………………..7
  2-4 小尺度衰減……………………………………………………………….7
       2-4.1 多重路徑效應……………………………………………………..8
       2-4.2 延遲擴展………………………………………………………… .8
       2-4.3 時散參數…………………………………………………………. 9
       2-4.4 同調頻寬…………………………………………………………10
       2-4.5 寬頻系統與窄頻系統…………………………………………10
       2-4.6 都普勒偏移……………………………………………………11
       2-4.7 都普勒偏移及同調時間………………………………………12
       2-4.8 緩慢衰減與快速衰減…………………………………………13
   2-5 瑞雷分布……………………………………………………………....13
   2-6 萊斯分布………………………………………………………………13
第三章    合作式中繼通訊系統………………………………………………...15
   3-1 合作式通訊簡介………………………………………………………15
   3-2 中繼網路………………………………………………………………15
       3-2.1 中繼傳輸協定………………………………………………….16
       3-2.2 雙工…………………………………………………………….17
       3-2.3 分時多工存取………………………………………………….17
第四章    載波頻率偏移及通道估測……………………………………………19
   4-1 載波頻率偏移………………………………………………………….19
       4-1.1 OFDM系統中載波頻率偏移的數學分析……………………..20
   4-2 通道估測……………………………………………………………….21
       4-2.1 引航訊號的放置方式…………………………………………..21
第五章    頻率偏移及通道聯合估測……………………………………………22
   5-1 傳統點對點通訊系統模型…………………………………………….25
      5-1.1 訊號模型…………………………………………………………25
      5-1.2 聯合估測器………………………………………………………26
   5-2 延伸到合作式通訊環境……………………………………………… 27
   5-3 並列多中繼站的合作式通訊環境…………………………………….29
第六章    模擬與結論……………………………………………………………32
   6-1 模擬結果……………………………………………………………….32
   6-2 結論…………………………………………………………………….39
參考文獻………………………………………………………………………. 40
圖2.1 大尺度與小尺度衰減………………………………………………………….4
圖2.2 都普勒偏移示意圖……………………………………………………………11
圖3.1 合作式通訊網路示意圖………………………………………………………16
圖4.1 頻率偏移示意圖………………………………………………………………19
圖4.2 塊狀排列法示意圖……………………………………………………………22
圖4.3 梳狀排列法示意圖……………………………………………………………23
圖4.4 二維網格排列法示意圖………………………………………………………24
圖5.1 並列式多中繼示意圖…………………………………………………………30
圖5.2 並列式多中繼的分時多工時槽排程…………………………………………31
表2-1 各種環境的 值列表………………………………………………………..6
表3.1 三種協定的分類表…………………………………………………………18
表6.1 參數設定表…………………………………………………………………32

                                

[1] O.Amin, B. Gredik and M. Uysal, “Channel estimation for amplify-and-forward relaying : cascaded against disintegrated estimators,” IET Communication, vol. 4, pp 1207-1216 , Jan. 2010.
[2] Choo W. R. Chiong, Y. Rong and Y. Xiang, “Robust channel estimation algorithm for dual-hop MIMO relay channels,” in Proc. IEEE PIMRC, pp. 2347-2352, 2012.
[3] L. C. Velasquez, H. N. Le and T. L. Ngoc, ”Cascaded doubly-selective channel estimation in multi-relay AF OFDM transmissions,” in Proc. IEEE ICC, Signal Processing for Communications Symposium. pp.3836-3840, 2012.
[4] K. C. Fu, S. H. Chiu and Y. F. Chen, “Joint maximum likelihood estimation of carrier frequency offsets and channels in OFDM systems,” in Proc. ITS Telecommunications. pp.710-715, 2012.
[5] J. Chen, Y. C. Wu and S. C. Chen, “Joint maximum-likelihood CFO and channel estimation for OFDMA uplink using importance sampling,” IEEE Transcations on Vehicular Technology, vol. 57, no. 6, Nov. 2008.
[6] D. Hung and K. B. Letaief, “Carrier Frequency offset estimation for OFDM systems using null subcarriers,” IEEE Transcations on Communications, vol. 54, no. 5, May 2006.
[7] http://web.ee.ccu.edu.tw/~wl/ofdm/class/class%20pdf/Channel%20model.pdf
[8] M. Zimmermann and K. Dostert, “A multipath model for the powerline channel,”IEEE Transactions on Communication, vol. 50, no. 4, Apr 2002.
[9] J. Salo, H. M. El-Sallabi and P. Vainikainen, “The distribution of the product of independent Rayleigh Random Variables,” IEEE Transactions on Antennas and Propagation, vol. 54, no. 2, Feb. 2006.
[10] J. Sijbers, A. J. Dekker, P. Scheunders and D. V. Dyck. “Maximum-likelihood estimation of Rician distribution parameters” IEEE Transactions on Medical Imaging, vol. 17, no. 3, Jun 1998.
[11] 林高洲，「無線通信系統發展新趨勢-智慧型合作式通信網路」，中華民國電子零件認證委員會，pp. 44-49
[12] R. U. Nabar, H. Bolcskei and F. W. Kneubuhler, “Fading relay channels: performance limits and space-time signal design,” IEEE Journal on Selected Areas in Communications, vol. 22, no. 6, Aug. 2004.
[13]http://read.pudn.com/downloads67/ebook/241606/ofdm%20book/Chapter5%20final%20version.pdf
[14] J. C. Lin, “A frequency offset estimation technique based on frequency error characterization for OFDM communications on multipath fading channels,” IEEE Transactions on Vehicular technology, vol. 56, no. 3, May 2007.
[15] J. C. Lin, “Coarse frequency-offset acquisition via subcarrier differential detection for OFDM communications,” IEEE Transactions on Vehicular technology, vol. 54, no. 8, Aug. 2006.
[16] 賴彥亨，”正交多重存取以共同向載波頻率偏移補償以達到最小均方誤差之方法”，國立中央大學通訊工程學系碩士論文，民國97年7月。
[17] J. C. Lin, “Least-squares channel estimation for mobile OFDM communication on time-varying frequency-selective fading channels,” IEEE Transactions on Vehicular technology, vol. 57, no. 6, Nov. 2008.
[18] J. S. Sheu, J. K. Lain and W. H. Wang, “On channel estimation of orthogonal frequency-division multiplexing amplify-and-forward cooperative relaying systems,” IET Communications, vol. 7, no. 4, pp. 325-334, 2013.
[19] S. Coleri, M. Ergen, A. Puri and A. Bahai. “Channel estimation techniques based on pilot arrangement in OFDM systems,” IEEE Transactions on Broadcasting, vol. 48, no. 3, Sep. 2002.
[20] Y. Li, “Pilot-symbol-aided channel estimation for OFDM in wireless systems,” IEEE Transactions on Vehicular Technology, vol. 49, no. 4, July 2000.
[21] D. D. Lin, R. A. Pacheco, T. J. Lim and D. Hatzinakos. “Joint estimation of channel response, frequency offset, and phase noise in OFDM,” IEEE Transaction on Signal Processing, vol. 54, no. 9, Sep. 2006.
[22] H. Nguyen-Le and T. Le-Ngoc, “Pilot_aided joint CFO and doubly-selective channel estimation for OFDM transmissions,” IEEE Transaction on Broadcasting, vol. 56, no. 4, Dec 2010.

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