做為未來世代行動通訊的重要候選方案之一，偏移正交振幅調變濾波器組多載波系統(filter bank multicarrier, FBMC)受到了廣泛的關注，但現有的文獻中在接收端做等化時大多假設通道完美已知，而在實際系統中通道則是未知的，為了更符合現實環境，本論文根據符合IEEE 1900.7規格之前置符號設計通道估計演算法，並以估計之通道在接收端做等化。本論文從頻域以及時域兩方面做通道估計，並且針對規格中不同的前置符號而使用相對應的估計方法。在頻域通道估計上通常假設訊號經過平坦衰弱(flat fading)通道，常使用干擾消除法(interference cancellation method, ICM)以及干擾近似法(interference approximation method, IAM)，而規格中的前置符號因不滿足干擾近似法的準則，因此在頻域通道估計上本論文使用了干擾消除法，並用規格中的前置符號與其他的前置符號做比較。而時域通道估計則沒有通道上的限制，因此可應用在頻率選擇性通道(frequency-selective fading)，本論文研究了最小平方法(least squares, LS)以及線性最小均方誤差(linear minimum mean square error, LMMSE)，模擬結果發現，最小均方誤差因多考慮了通道之統計特性，在均方誤差及位元錯誤率上都優於最小平方法。

As one of the promising candidates of future-generation mobile communication technology, filter bank multicarrier (FBMC) has received much attention. Most of the studies on equalization in the literature assume that the channel is perfectly known at the receiver. In reality, however, the channel is unknown and needs to be estimated. In the thesis, we design channel estimation algorithms based on the preambles defined in the IEEE 1900.7 specification and study the impact of channel estimation errors on equalization performance. In the thesis, we study both frequency-domain and time-domain channel estimation techniques. Well-known frequency-domain techniques include the interference cancellation method (ICM) and interference approximation method (IAM); they are designed based on assumption that the channel is flat fading. Since the preamble of the
IEEE 1900.7 specification does not match IAM’s principle, we study the performance of ICM in the flat fading channel. For the time-domain channel estimation techniques, we consider primarily the linear minimum mean square error (LMMSE) and least squares (LS) channel estimators. The simulation results demonstrate that the LMMSE estimator achieves a better performance than the LS estimator because the channel statistics is exploited

[1] B. Farhang-Boroujeny, "OFDM versus filter bank multicarrier," IEEE Signal Processing Mag., April 2011, pp. 92-112.
[2] B.R. Saltzberg,“Performance of an Efficient Parallel Data Transmission System,” IEEE Trans. Commum. Tech., vol. 15, no.6, PP. 805-811, Dec. 1967.
[3] L. G. Baltar, D. S. Waldhauser and J.A. Nossek,, “MMSE subchannel decision feedback equalization for filter bank based multicarrier systems,” IEEE ISCAS 2009, pp. 2802-2805, Taipei, 24-27 May 2009.
[4] Kuei-Chiang Lai, Yung-Jie Huang, Chun-Ting Chen, Cheng-Feng Lin "A Family of MMSE-Based Decision Feedback Equalizers and Their Properties for FBMC/OQAM Systems," in IEEE Transactions on Vehicular Technology, vol. 68, no. 3, pp. 2346-2360, March 2019 .
[5] Wei Li , Daiming Qu, Tao Jiang “An Efficient Preamble Design Based on CombType Pilots for Channel Estimation in FBMC/OQAM Systems,” IEEE Access(Volume:6) , October 2018
[6] Dejin Kong, Daiming Qu, and Tao Jiang, “Time Domain Channel Estimation for OQAM-OFDM Systems: Algorithms and Performance Bounds,” IEEE Trans. Signal Process., vol. 62, no. 2, pp. 322–330, January 2014.
[7] C. Lele, P. Siohan, R. Legouable and J.-P. Javaudin, “Preamble-based channel estimation techniques for OFDM/OQAM over the powerline,” IEEE International Symposium on Power Line Communications and Its Applications, March 2007.
[8] C. Lele, P. Siohan, R. Legouable and J.-P. Javaudin, A. Skrzypczak, “Channel estimation methods for preamble‐based OFDM/OQAM modulations,” European Transactions on Telecommunications , pp. 741-750, September 2008.
[9] Eleftherios Kofidis, “Preamble-Based Estimation of Highly Frequency Selective Channels in FBMC/OQAM Systems,” IEEE Trans. Signal Process., vol. 65 no. 7, pp. 1855-1868 April 2017.
[10] A. Viholainen, T. Ihalainen, T. H. Stitz, M. Renfors and B. G. Bellanger, “Prototype filter design for filter bank based multicarrier transmission,” IEEE, Signal Processing Conference, pp. 1359-1363, Glasgow, 24-28 Aug. 2009.
[11] P. W. Wolniansky, G. J. Foschini, G. D. Golden, and R. A. Valenzuela, “V-BLAST: An architecture for realizing very high data rates over the rich-scattering wireless channel,” in Proc. URSI Int. Symp. Signals, Syst., Electron, Pisa, Italy, Oct. 1998, pp. 295–300.
[12] X. Mestre, M. Majoral, and S. Pfletschinger, “An asymptotic approach to parallel equalization of filter bank multicarrier signals,” IEEE Trans. Signal Process., vol. 61, no. 14, pp. 3592–3606, Jul. 2013.
[13] V. Erceg et al., “Channel Models for Fixed Wireless Applications” IEEE 802.16.3c-01/29r1, Feb. 23, 2001.
[14] T. Ihalainen, A. Ikhlef, J. Louveaux, and M. Renfors, “Channel equalization for multi-antenna FBMC/OQAM receivers,” IEEE Transactions on Vehicular Technology, vol. 60, no. 5, pp. 2070–2085, Jun 2011.
[15] T. Ihalainen, T. Hidalgo Stitz, M. Rinne, and M. Renfors, “Channel equalization in filter-bank-based multicarrier modulation for wireless communications,” EURASIP J. Adv. Signal Process., vol. 2007, pp. 1–18, 2007, Article ID 49389.
[16] IEEE, “1900.7-2015-IEEE Standard for Radio Interface for White Space Dynamic Spectrum Access Radio Systems SupportingFixed and Mobile Operation,” Feb. 2016.
[17] M.G. Bellanger,“Specification and design of a prototype filter for filter bank based multicarrier transmission,” IEEE Int. Conf. Acoustics, Speech, and Signal Processing, vol.4, pp. 2417-2420, Salt Lake City, 07-11 May 2001.
[18] Chun-Ting Chen, “Linear and Non-linear Equalization for FBMC/OQAM Systems Based on the Criterion of Minimum Mean Square Error,” Institute of Computer and Communication Engineering National Cheng Kung University Thesis for Master of Science .Jul 2016.