臺灣博碩士論文加值系統

正交分頻多工系統在快速時變通道下所造成的子頻帶間干擾是一個很重要的問題，它使得位元錯誤率不會因為高訊雜比而下降，子頻帶間干擾的問題在近幾年來越來越被探討。同樣的，這個問題也發生在使用頻率等化的單載波區塊傳輸系統。子頻帶間干擾由兩大原因造成，載波頻率位移及快速時變通道。在本論文中，我們針對第二種原因去做討論。
眾多在正交分頻多工系統下的子頻帶間干擾消除方法已經被提出來，然而還並不確定是否適用於單載波區塊傳輸系統。在此論文裡，我們選擇了一個發展於正交分頻多工系統上自相消除子頻間干擾的演算法，來研究在它單載波區塊傳輸系統上是不是也能正確改善子頻帶間干擾。此演算法運算簡單，不會增加舊有系統的複雜度，論文最後模擬的結果證明可以套用於單載波區塊傳輸系統。

Inter-subchannel interference (ICI) is an important problem for the orthogonal frequency-division multiplexing (OFDM) system in the fast time-varying channel. It limits the achievable bit-error rate (BER) at high signal-to-noise ratio (SNR). The ICI problem has caused more concerns recently. The ICI problem also occurs in the single-carrier (SC) frequency-domain equalization (FDE) system. There are two main causes of ICI, including the carrier frequency shift and the high-mobility (fast time-varying) channel. In this thesis, we focus on the second one.
Some methods of ICI elimination or reduction have been proposed for the OFDM system. However, not all these algorithms are suitable for the SC-FDE system. In this thesis, we consider an ICI self-cancellation algorithm and apply it in the SC-FDE system. This algorithm is quite simple and almost does not increase the complexity of the system. The simulation results validate its effectiveness.

中文摘要 I
Abstract II
Acknowledgement III
Contents IV
List of Figures VI

Chapter 1 Introduction 1

Chapter 2 Single-Carrier Frequency-Domain Equalization 3
2.1 SC-FDE Systems 3
2.1.1 OFDM Systems 3
2.1.2 Linear Precoded OFDM Systems 6
2.1.3 SC-FDE Systems 10
2.2 Channel Model 11
2.2.1 Modification of Jakes' Rayleigh Fading Model 11
2.2.2 Time-Variant Channel of Jakes’ Model 13
2.3 Channel Estimation 16
2.3.1 Least-Square Fitting Approach (LSF) 17
2.4 Frequency-Domain Equalization 19
2.4.1 Minimum Mean Square Error (MMSE) 19

Chapter 3 ICI Self-Cancellation for OFDM Systems 22
3.1 Introduction of Inter-Subchannel Interference (ICI) 22
3.2 The Algorithm of ICI Self-Cancellation for OFDM Systems 24
3.2.1 The Pre-Processor in The Transmitter 25
3.2.2 The Post-Processor in The Receiver 26
3.3 The Simulation in OFDM Systems 33

Chapter 4 ICI Self-Cancellation in SC-FDE Systems Simulation 36
4.1 The Structure of ICI Self-Cancellation for SC-FDE Systems 36
4.2 Analysis of Simulation Results 38

Chapter 5 Conclusions 43

Bibliography 44

[1]W. G. Jeon, K. H. Chang, and Y. S. Cho, “An equalization technique for orthogonal frequency-division multiplexing systems in time-variant multipath channels, IEEE Trans. Commun., vol. 47, pp. 27-32, Apr. 1999.
[2]A. Seyedi and G. J. Saulnier, “General ICI self-cancellation scheme for OFDM systems, IEEE Trans. Veh. Technol., vol. 54, pp. 198-210 Jan. 2004.
[3]M. X. Chang and Y. T. Su, “Performance analysis of equalized OFDM systems in Rayleigh fading, IEEE Trans. Wireless Commun., vol. 1, no. 4, pp. 721-732, Oct. 2002.
[4]M. X. Chang, “A Novel Algorithm of Inter-Subchannel Interference Self-Cancellation for OFDM Systems, IEEE Trans. Wireless Commun., vol. 6, no. 8,pp. 1881-1893, Aug. 2007
[5]H. G. Myung, J. Lim, and D. J. Goodman, Single-Carrier FDMA for Uplink Wireless Transmission, IEEE Veh. Technol.vol.6, pp. 30-38, Sep. 2006
[6]H. G. Myung, Introduction to Single-Carrier FDMA, 15th EUSIPCO, Poznan, Poland, September 3-7. 2007.
[7]H. G. Myung, Single-Carrier Orthogonal Multiple Access Technique for Broadband Wireless Communications, Ph.D. Dissertation, Polytechnic University, Brooklyn, NY, Jan. 2007.
[8]Y. Li, and X. Huang, “The Simulation of Independent Rayleigh Faders, IEEE Trans. Commun., vol. 50, NO. 9, pp. 1503-1514, Sept. 2002.
[9]M. Russell and G. L. Stüber, “Interchannel interference analysis of OFDM in a mobile environment, in Proc. IEEE VTC’95, Chicago, USA, July 25-28. 1995.