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Student Number 965203009
Author Shiue-Ru Wang(王學儒)
Author's Email Address 965203009@cc.ncu.edu.tw
Statistics This thesis had been viewed 1046 times. Download 399 times.
Department Communication Engineering
Year 2008
Semester 2
Degree Master
Type of Document Master's Thesis
Language zh-TW.Big5 Chinese
Title Channel Tracking in MIMO OFDM Systems by Utilizing Constant Modulus Algorithms
Date of Defense 2009-07-01
Page Count 84
Keyword
  • channel tracking
  • MIMO
  • Abstract The combination of multiple input and multiple output (MIMO) technology and orthogonal frequency division multiplexing (OFDM) to combat multipath and mobile channels is widely used in wireless communications. For example, in wireless network applications with limited number of pilots, channel tracking is an important scheme to deal with time-varying channels. Here, the Alamouti space-time block code is applied to a two-by-two MIMO OFDM system in which we explore a new channel tracking algorithm that can alternatively operate between the constant modulus algorithm (CMA) and the decision feedback algorithm based on the proposed mechanism. The proposed algorithm is also further verified in an intercarrier interference cancellation algorithm that can solve the time-varying channel with changed status even between two consecutive OFDM symbols. Simulation results show that the proposed algorithm can achieve better performance than the method employing only the CMA method or the decision feedback method.
    Table of Content 章節目錄
    第一章 序論1
    1.1 前言1
    1.2章節架構介紹2
    第二章 多輸入多輸出正交分頻多工系統(MIMO-OFDM)簡介3
    2.1 OFDM系統介紹3
    2.2 MIMO-OFDM系統介紹4
    2.3 MIMO-OFDM STBC系統介紹5
    2.4 通道模組9
    2.4.1 傑克斯通道模組10
    2.4.2 自迴歸通道模型13
    第三章 多輸入多輸出正交分頻多工之通道追蹤15
    3.1 使用Preamble預估 MIMO-OFDM通道值16
    3.2 MIMO-OFDM STBC 之通道追蹤演算法18
    3.3 頻域通道追蹤利用平滑化決策迴授機制20
    3.3.1決策迴授法20
    3.3.2 平滑化通道估測23
    3.4 半盲目式通道追蹤法24
    3.4.1 CMA與相位回復演算法25
    3.4.2 Modified CMA與相位回復演算法33
    3.5 Normalized CMA36
    3.6 半盲目通道追蹤與直接決策迴授機制之切換法則39
    3.7 Interference Cancellation Detector44
    第四章 模擬與分析48
    4.1 系統及通道模型參數設定48
    4.2 NCMA 與遞迴次數之模擬與分析50
    4.3 NCMA 與決策迴授機制切換之模擬與分析51
    4.3.1 不同 值切換對系統影響之模擬與分析51
    4.3.2 不同 值切換對系統影響之模擬與分析54
    4.3.3 滑動視窗大小切換對系統影響之模擬與分析57
    4.3.4 不同步階大小對系統影響之模擬與分析60
    4.4 通道追蹤演算法效能與位元錯誤率之模擬與分析64
    4.5 IC detector69
    第五章 結論與未來展望71
    參考文獻72
    圖目錄
    圖 2.1 OFDM 系統架構圖4
    圖 2.2 MIMO-OFDM STBC系統架構圖5
    圖 2.3 2x2 Alamouti 傳送分集架構6
    圖 2.4 2x2 STBC Block Index示意圖7
    圖 2.5 時變通道中振幅值之機率分佈情形11
    圖 2.6 時變通道中相位之機率分佈情形11
    圖 2.7 COST 207功率延遲數據圖13
    圖 3.1 MIMO-OFDM STBC 上行系統傳送架構方塊圖18
    圖 3.2 MIMO-OFDM STBC 通道追蹤架構圖19
    圖3.3 頻域通道追蹤利用決策迴授機制之方塊圖20
    圖3.4 加入平滑化之頻域通道追蹤架構圖24
    圖3.5 MIMO-OFDM STBC利用CMA追蹤通道架構圖25
    圖3.6 MIMO-OFDM STBC利用MCMA追蹤通道架構圖34
    圖 3.7 預設區間切換之自動切換示意圖41
    圖 3.8 預設區間自動切換可靠區間示意圖41
    圖 3.9 4-ASK 之決策區間示意圖42
    圖 3.10 滑動視窗模組示意圖43
    圖 3.11交干擾項消除之通道估測流程圖45
    圖 3.12交干擾項消除方塊圖47
    表 4.1 系統模擬參數表48
    表 4.2 自迴歸模組之模擬參數設定值49
    表 4.3 傑克斯模組之模擬參數設定值49
    圖 4.1 各種通道環境下,不同遞迴次數對系統效能影響50
    圖 4.2 固定通道環境下,不同MSE大小對系統效能影響52
    (step size= )52
    圖 4.3 AR通道環境下,不同MSE大小對系統效能影響52
    (step size= )52
    圖 4.4 情況下,不同MSE大小對系統效能影響(step size= )53
    圖 4.5 情況下,不同MSE大小對系統效能影響(step size= )53
    圖 4.6 固定通道環境下,不同 大小對系統效能影響54
    (step size= )54
    圖 4.7 AR通道環境下,不同 大小對系統效能影響55
    (step size= )55
    圖 4.8 情況下,不同 大小對系統效能影響(step size= )55
    圖 4.9 情況下,不同 大小對系統效能影響(step size= )56
    圖 4.10 固定通道環境下,不同滑動視窗大小對系統效能影響(step size= )58
    圖 4.11 AR通道環境下,不同滑動視窗大小對系統效能影響58
    (step size= )58
    圖 4.12 情況下,不同滑動視窗大小對系統效能影響(step size= )59
    圖 4.13 情況下,不同滑動視窗大小對系統效能影響(step size= )59
    圖 4.14 固定通道環境下,不同步階大小對系統效能影響61
    圖 4.15 AR通道環境下,不同步階大小對系統效能影響61
    圖 4.16 情況下,不同步階大小對系統效能影響62
    圖 4.17 情況下,不同步階大小對系統效能影響62
    圖 4.18不同步階大小在各個通道環境下對系統效能影響63
    圖 4.19 固定通道環境下,不同通道追蹤演算法對系統效能影響(step size= , )65
    圖 4.20 固定通道環境下,不同通道追蹤演算法之MSE 性能比較圖 (step size= , )65
    圖 4.21 AR通道環境下,不同通道追蹤演算法對系統效能影響(step size= , )66
    圖 4.22 AR通道環境下,不同通道追蹤演算法之MSE 性能比較圖(step size= , )66
    圖 4.23 情況下,不同通道追蹤演算法對系統效能影響(step size= , )67
    圖 4.24 情況下,不同通道追蹤演算法之MSE 性能比較圖(step size= , )67
    圖 4.25 情況下,不同通道追蹤演算法對系統效能影響(step size= , )68
    圖 4.26 情況下,不同通道追蹤演算法之MSE 性能比較圖(step size= , )68
    圖 4.27 情況下,不同決策演算法對系統效能比較圖(step size= )69
    圖 4.28 情況下,不同決策演算法對系統效能比較圖(step size= )70
    表目錄
    表 2.1 STBC 編碼方式6
    表 2.2 四種地區功率延遲數據之數學模型12
    表 2.3 不同的環境下 的設定值14
    表 4.1 系統模擬參數表48
    表 4.2 自迴歸模組之模擬參數設定值49
    表 4.3 傑克斯模組之模擬參數設定值49
    Reference 參考文獻
    [1]“Orthogonal Frequency Division Multiplexing,” U.S Patent No.3 488, 4555, filed Nov.14, 1966, issued Jan.6, 1970.
    [2]S. M. Alamouti, “A simple transmit diversity scheme for wireless communications, ” IEEE Journal on Select. Areas in Commun., vol. 16, pp. 1451-1458, Oct. 1998.
    [3]D.N. Godard, “Self recovering equalization and carrier tracking in two dimensional data communications systems, ” IEEE Trans. Commun., vo1. 28, no. 11, pp. l867-1875, Nov. 1980.
    [4]P. Y. Tsai and T. D. Chiueh, “Frequency-domain interpolation-based channel estimation in pilot-aided OFDM systems,” in Proc. IEEE Vehicular Technology Conf., pp. 420-424, 2004.
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    [6]J. Zhu and W. Lee, “Channel estimation with power-controlled pilot symbols and decision-directed reference symbols, ” in Proc. IEEE Vehicular Technology Conf., pp. 1268-1272, Oct. 2003.
    [7]S. Balasubramanian, B. B. Farhang, and V. J. Mathews, “Pilot embedding for channel estimation and tracking in OFDM systems, ” in Proc. IEEE Global Telecommunications Conf., pp. 1268-1272. Nov. 2004
    [8]Jie Wu and Gary J. Saulnier, “Orthogonal space-time block code over time-varying flat-fading channels:channel estimation, detection, and performance analysis, ” IEEE Trans. Commun., vol. 55, NO. 5, pp. 1077-1087. MAY 2007.
    [9]V. Tarokh, N. Seshadri, and A. R. Calderbank, “Space-time codes for high data rate wireless communication: performance criteria and code construction, ” IEEE Trans. Inform. Theory., vol. 44, NO. 2, pp. 744-765. Mar. 1998.
    [10]COST 207 Management Committee, COSE 207: Digital Land Mobile Radio Communications (Final Report), commission of the European Communities, 1989.
    [11]W. C. Jakes, Microwave Mobile Communications, New York: John Wiley, 1974.
    [12]E. Baddour and C. Beaulieu, “Autoregressive modeling for Fading channel simulation, ” IEEE Trans Wireless Commun., vol. 4, NO. 4, JULY 2005.
    [13]C.C Cheng and D.C. Chang, “Improved time-domain channel tracking algorithms for mobile OFDM applications, ” in IEEE 4th VTS Asoa Pacific Wireless Communication Symposium(APWCS 2007), Hsinchu, Aug. 2007.
    [14]Z.-S. Lin, T.-L. Hong, and D.-C. Chang, “Design of an OFDM system with long frame by the decision-aided channel tracking technique, ” in IEEE International Conf. on Electro/information Technology, MA, pp. 330-333, May. 2006.
    [15] I. Chahed, J. Belzile and A. B. Kouki, “Blind decision feedback equalizer based on high order MCMA, ” in Proc. IEEE Canadian Conference on Electrical and Computer Engineering., vol. 4, pp. 2111-2114, May. 2004.
    [16]J.-W Kim and A.D Poularikas, “Performance analysis of the adjusted step size NLMS algorithm” IEEE Proceedings of the 34th Southeastern Symposium System Theory., pp. 467-471, 2004.
    [17]C.-M. Wu, The OFDM System with a Semi-Blind Channel Tracking Algorithm, Master Thesis, Department of Communication Engineering, National Central University, Taoyuang, Taiwan, July 2008.
    [18]S. Haykin, Communication Systems, ed. New York: John Wiley & Sons, Inc., 2001.
    Advisor
  • Dah-Chung Chang(張大中)
  • Files
  • 965203009.pdf
  • approve in 2 years
    Date of Submission 2009-07-21

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