The Investigation of System Performance for OFDM Systems Operating in Frequency Non-Selective Fading Channels
鄭奇泓、陳雍宗
E-mail: 9511514@mail.dyu.edu.tw
ABSTRACT
The OFDM (orthogonal frequency division multiplexing) signaling is one kind of "Multi-Carrier" technology, which can slow down delayed transmission especially for operating at frequency non-selective fading channels. Therefore, it gains quite large profit making a study of executing efficiency at different frequency non-selective fading channels. The OFDM system has become the most popular choice of transmission modulation in the new wireless communication field. Hence, in this article utilize a method of OFDM modulation to explore the statistical characteristic of distributions of Rayleigh、Ricean、Weibull while working in fading channel.
And then use SC(selective combining) at the output of receiver to research efficiency analysis of OFDM system under different fading factor.
Keywords : OFDM(orthogonal frequency division multiplexing),Multipath , non-selective fading, fading channel, BER(bit error ratio)
Table of Contents
封面內頁 簽名頁 授權書...iii 中文摘要...iv 英文摘要...v 誌
謝...vi 目錄...vii 圖目錄...x 表目錄...xii 第一章 緒論 1.1研究動機與目的...1 1.2論文架構...2 第二章 正交分頻多工系統 2.1正交分頻多工系統 簡介...4 2.2正交特性...5 2.3多重路徑衰減...6 2.4 保護區間特性...8 2.5正交分頻多工調變原理...10 2.6發射器/接收器模型...15 2.6.1 編碼器...16 2.6.2 對 應...16 2.6.3 插序...16 2.6.4串列轉並列...17 2.6.5並列轉串
列...18 2.6.6數位/類比轉換器...19 第三章 無線通訊衰落通道 3.1無線通道特性之描
述...20 3.1.1無線衰落通道種類之型態...20 3.1.2多路徑衰減通道之模型...24 3.2衰落通道的 數學模型...24 3.3 Normal(Gaussian)衰落分佈...27 3.3.1單變數常態分佈...27 3.3.2雙變數 常態分佈...29 3.4 Rayleigh 衰落分佈...30 3.5 Ricean 衰落分佈...32 3.6 Nakagami-m 衰落分佈...34 3.7 Weibull 模型...36 第四章 正交分頻多工系統工作於非頻率選擇性衰落通道的 效能 分析無線通訊衰落通道 4.1分集合成技術...41 4.2選擇性合成(selective combining, SC)...42 4.3正交 分頻多工系統工作於非頻率選擇性衰落通道 呈現Ricean分佈之系統效能分析...43 4.4正交分頻多工系統工作於非 頻率選擇性衰落通道 呈現Rayleigh分佈之系統效能分析...45 4.5.正交分頻多工系統工作於非頻率選擇性衰落通道 呈現Weibull分佈之系統效能分析...47 第五章 結論...54 參考文獻...55 圖 目錄 圖2.1基本OFDM系統...5 圖2.2正交副載波...6 圖2.3多重路徑示意
圖...7 圖2.4分頻多工與正交分頻多工的差異...7 圖2.5保護區間GI示意圖...8 圖2.6.a未加入保護區間(GI)...8 圖2.6.b加入保護區間(GI)...9 圖2.7在接收端不同取樣時序位置之 符碼產生的影響...9 圖2.8正交分頻多工系統架構圖...14 圖2.9正交分頻多工系統發射機架構
圖...15 圖2.10正交分頻多工系統接收器架構...16 圖2.11傳統多重載波調變系統架構圖...18 圖3.1小尺度衰減訊號...21 圖3.2多路徑傳輸衰落效應...25 圖3.3時變通道脈衝響
應...27 圖3.4單變數Gaussian衰落信號包封機率密度函數...28 圖3.5 Rayleigh 衰減信號包封機率密度函 數...31 圖3.6 Ricean分佈在不同K值時的機率密度函數...34 圖3.7 Nakagami-m分佈在不同 值時的機率密度函 數...35 圖3.8依賴因子 和相關係數 與Weibull衰落參數 之關係...39 圖4.1選擇性分集合成系統方塊
圖...42 圖4.2正交分頻多工系統工作於非頻選擇性衰落通道呈現 Ricean分佈之效能...45 圖4.3正交分頻多工系統工作於非頻選擇性衰落通道呈現 Rayleigh分佈之效能...47 圖4.4正交分頻多工系 統工作於非頻選擇性衰落通道呈現 Weibull分佈之效能( 變動, )...51 圖4.5正交分頻多工系統工作於非頻選擇 性衰落通道呈現 Weibull分佈之效能( 變動, )...52 圖4.6正交分頻多工系統工作於非頻選擇性衰落通道呈現 Weibull分佈之效能( 變動, )...52 圖4.7正交分頻多工系統工作於非頻選擇性衰落通道呈現 Weibull分佈之效能(
變動, )...53 表目錄 表2.1 資料傳輸率與Shift Keying 調變技術...10
REFERENCES
[1] R. W. Chang “Synthesis if Band-limited Orthogonal Signals Formultichannel Data Transmission,” BSTJ, vol. 46, pp. 1775-1796, Dec. 1966.
[2] Y. W. Cheong﹐R. S. Cheng﹐K. B. Lataief﹐and R. D. Murch﹐ “Multiuser OFDM with Adaptive Subcarrier Bit and Power Allocation,”
IEEE J. Selected Areas Comm.﹐vol.17﹐pp.1747-1758, Oct. 1999.
[3] S. Ben Slimane, Notes for Advanced Communication Theory, RoyaInstitute of Technology, Mar. 2002.
[4] Alan Triggs, Notes for Wireless, Cellular & Personal Telecommunications, Lecture 7, Southern Methodist University, Fal. 2001.
[5] Van Nee, R. & Prasad R., OFDM for Wireless Multimedia Communications, Artech House, Norwood, MA, 2000.
[6] Institute of Electrical and Electronics Engineers, 802.11a, Wire-less LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications: High-Speed Physical Layer Extension in the 5 GHz Band, Sep. 1999.
[7] 林千惠，張國安，”BFSK-OFDM訊號簡介及性能分析”， 無線 電界， 43-65頁，July. 2000.
[8] Weinstein, S. B. , and P. M. Ebert, “Data Transmission by Frequency Division Multiplexing using the Discrete Fourier Transform,” IEEE Transactions on Communications, vol.19, Issue :5, pp.628-634, Oct. 1971.
[9] G. L. Turin, “Signal Design for Sequential Detection Systems with Feedback, “ IEEE Trans. Inform. Theory, vol. IT-11, pp. 401-408, Jul.
1965.
[10] B. Sklar, “Rayleigh Fading Channels in Mobile Digital Communication Systems Part 1: Characterization,” IEEE Trans. Commun., pp.
90-100, Jul. 1997.
[11] Matthias Patzold, “Mobile Fading channel,” Wiley, pp.3-7, 2002.
[12] T. S. Rappaport, “Wireless Communications Principles and Practice.” Prentice Hall PTR, New Jersey, 1996.
[13] K. Bury, “Statistical Distribution in Engineering”, Cambridge, U.K:Cambridge Univ. Press, 1999.
[14] P. J. Crepeau, “Uncoded and Coded Performance of FSK and DPSK in Nakagami Fading Channels, ” IEEE Trans. On Commun., vol.
40, No. 3, pp. 487-493, Mar. 1992.
[15] J. C. Lu and G.. K. Bhattaacharyya, “Some New Constructions of Bivariate Weibull Models,” Ann. Inst. Stat. Math, vol. 42, No.3, pp.
543-559, 1990.
[16] S. Kotz, N. Balakrishnan and N. L. Johnson, “Continuous Multivariate Distributions.” Vol. 1:Model and Applications, John Wiley and Sons, Inc, second ed., 2000.
[17] New York:Wiley, 2000.N. C. Sagias and G.. K. Karagiannidis, “Performance of Dual Selection Diversity in Correlated Weibull Fading Channels” M IEEE Tran. on Commun., vol. 52, No.7, pp. 1063-1067, Jul. 2004.
[18] L. Wan and V. K. Dubey, “BER Performance of OFDM System Over Frequency Nonselective Fast Ricean Fading Channels,” IEEE Commun.Lett., vol. 5, no. 1, pp. 19–21, Jan. 2001.
[19] J. G. Proakis, “Digital Communications.” 3rd ed., McGraw-Hill, New York, 1995.
[20] K. Dietze, C. B. Dietrich, and W. L. Stutzman, “Analysis of a Two-branch Maximal and Selection Diversity System with Unequal SNRs and Correlated Inputs for a Rayleigh Fading Channel,” IEEE Trans. Wireless Commun., vol. 1, pp. 274–281, Apr. 2002.
[21] Sklar, B., Digital Communications: Fundamental and Applications, 2nd ed. Prentice Hall, Upper Saddle River, NJ, 2001.
[22] Simon, M. K., and Alouini, M.-S., Digital Communication Over Fading channel 1st ed. John Wiley, New York, 2000.
[23] Y.-K. Ko, M.-S. Alouini, and M. K. Simon, “Average SNR of Dual Selection Combining over Correlated Nakagami-m Fading Channels,”
IEEE Commun. Lett., vol. 4, pp. 12–14, Jan. 2000.
[24] Abu-Dayya, A.A., and Beaulieu, N.C.: “Analysis of switched diversity systems on generalized -fading channels,” IEEE Trans. Commun., vol. 42, pp. 1813–1831, Nov. 1994.
[25] Tellambura, C., Annamalai, A., and Bhargava, V.K.: “Unified Analysis of Switched Dversity Systems in Independent and Correlated Fading Channels,” IEEE Trans. Commun., vol. 49, pp. 1955–1965, Nov. 2001.
[26] H. Hashemi, “The Indoor Radio Propagation Channel,” Proc. IEEE, vol. 81, pp. 943-968, Jul. 1993.
[27] N. S. Adawi, H. L. Bertoni, J. R. Child, W. A. Daniel, J. E.Dettra, R. P. Eckert, E. H. Flath Jr., R. T. Forrest, W. C. Y. Lee,S. R. Mc Conoughey, J. P. Murray, H. Sachs, G. L. Schrenk, N.H. Shepherd and F. D. Shipley, “Coverage Prediction for Mobile Radio Systems Operating in the 800/900 MHz Frequency Range,” IEEE Transactions on Vehicular Technology, vol. 37, no. 1, pp. 3–72, Feb. 1988.
[28] A. Taneda, J. Takada, and K. Araki, “The Problem of the Fading model Selection,” IEEE Trans. Commun., vol. E84-B, no. 3, pp.355 –358, Mar. 2001.
[29] Papoulis, “Probability, Random Variables, and Stochastic Processes, 3rd ed.” New York:Mcgraw-Hill, 1991.
