請用此 Handle URI 來引用此文件:
http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/15722
完整後設資料紀錄
DC 欄位 | 值 | 語言 |
---|---|---|
dc.contributor.advisor | 汪重光(Chorng-Kuang Wang) | |
dc.contributor.author | Chun-Hung Chen | en |
dc.contributor.author | 陳俊宏 | zh_TW |
dc.date.accessioned | 2021-06-07T17:50:45Z | - |
dc.date.copyright | 2013-01-16 | |
dc.date.issued | 2012 | |
dc.date.submitted | 2012-11-26 | |
dc.identifier.citation | [1] S. Bellofiore, J. Foutz, C.A. Balanis, and A.S. Spanias, “Smart-antenna system for mobile communication networks Part 2: beamforming and network throughput,” IEEE Antennas and Propagation Magazine, vol. 44, no. 4, pp. 106–114, 2002.
[2] Yusuke Asai and et al, “Interference management using beamforming technique in OBSS environment,” Doc. IEEE802.11-10/0585r3, 2010. [3] F. Liu, J. Lin, Z. Tao, T. Korakis, E. Erkip, and S. Panwar, “The hidden cost of hidden terminals,” IEEE International Conference on Communications (ICC), 2010. [4] N. Golmie, R.E. Van Dyck, and A. Soltanian, “Interference of bluetooth and IEEE 802.11: simulation modeling and performance evaluation,” Proceedings of the 4th ACM international workshop on Modeling, analysis and simulation of wireless and mobile systems, 2001, pp. 11–18. [5] “20 Myths of Wi-Fi Interference: Dispel Myths to Gain HighPerforming and Reliable Wireless,” Cisco White Paper. [6] John Litva and Titus Kwok-Yeung Lo, Digital Beamforming in Wireless Communications, Artech House Publishers, 1996. [7] A. Singh, P. Ramanathan, and B. Van Veen, “Spatial reuse through adaptive interference cancellation in multi-antenna wireless networks,” IEEE Global Telecommunications Conference (GLOBECOM), 2005. [8] Y. Li and N.R Sollenberger, “Adaptive antenna arrays for OFDM systems with cochannel interference,” IEEE Transactions on Communications, vol. 47, no. 2, pp. 217–229, 1999. [9] J. Li, K. B. Letaief, and Z. Cao, “Co-channel interference cancellation for space-time coded OFDM systems,” IEEE Transactions on Wireless Communications, vol. 2, pp.41–49, 2003. [10] Y.F. Chen and C.P. Li, “Adaptive beamforming schemes for interference cancellation in OFDM communication systems,” IEEE 59th Vehicular Technology Conference (VTC- 2004 Spring), 2004, pp. 103–107. [11] C.K. Kim, S. Choi, and Y.S. Cho, “Adaptive beamforming for an OFDM system,” IEEE 49th Vehicular Technology Conference, 1999. [12] Y. S. Choi, K. S. Kim, and C. K. Kim, “Performance of MIMO-OFDM systems with adaptive beamforming algorithm,” IEEE 66th Vehicular Technology Conference (VTC-2007 Fall), 2007. [13] S. Seydnejad and S. Akhzari, “A combined time-frequency domain beamforming method for OFDM systems,” International ITG Workshop on Smart Antennas (WSA), 2010, pp. 292–299. [14] S. Seydnejad and M.S. Akhzari, “CCI suppression and channel equalization in pilot-assisted OFDM systems by space-time beamforming,” International Conference on Communications and Signal Processing (ICCSP), 2011, pp. 14–18. [15] R.H. Clarke, “A statistical theory of mobile-radio reception,” Bell Syst. Tech. J, vol. 47, no. 6, pp. 957–1000, 1968. [16] W.C. Jakes, Microwave mobile communications, Wiley & Sons, 1975. [17] T. Pollet, M. Van Bladel, and M. Moeneclaey, “BER sensitivity of OFDM systems to carrier frequency offset and wiener phase noise,” IEEE Transactions on Communications, vol. 43, no. 243, pp. 191–193, 1995. [18] T. Pollet, P. Spruyt, and M. Moeneclaey, “The BER performance of OFDM systems using non-synchronized sampling,” IEEE Global Telecommunications Conference (GLOBECOM’94), 1994, pp. 253–257. [19] R. W. Chang, “Synthesis of band-limited orthogonal signals for multichannel data transmission,” Bell Syst. Tech. J., vol. 45, pp. 1775–1796, Dec. 1966. [20] Yuan-Pei Lin, See-May Phoong, and P. P. Vaidyanathan, Filter Bank Transceivers for OFDM and DMT Systems, Cambridge University Press, Nov. 2010. [21] “IEEE standard for information technology– local and metropolitan area networks– specific requirements– part 11: Wireless LAN medium access control (MAC) and physical layer (PHY) specifications amendment 5: Enhancements for higher throughput,” IEEE Std 802.11n-2009, pp. 1–565, 2009. [22] J. Terry and J. Heiskala, OFDM Wireless LANs: A heoretical and practical guide, SAMS publishing, 2002. [23] M. Speth, S.A. Fechtel, G. Fock, and H. Meyr, “Optimum receiver design for wireless broad-band systems using OFDM-Part: I,” IEEE Transactions on Communications, vol.47, no. 11, pp. 1668–1677, 1999. [24] M. Speth, S. Fechtel, G. Fock, and H. Meyr, “Optimum receiver design for OFDM-based broadband transmission-Part II: A case study,” IEEE Transactions on Communications, vol. 49, no. 4, pp. 571–578, 2001. [25] M. Lei, P. Zhang, H. Harada, and H. Wakana, “Adaptive beamforming based on frequency-to-time pilot transform for OFDM,” IEEE 60th Vehicular Technology Conference (VTC-2004 Fall), 2004, pp. 285–289. [26] H. Matsuoka and H. Shoki, “Comparison of pre-FFT and post-FFT processing adaptive arrays for OFDM systems in the presence of co-channel interference,” IEEE Proceedings on Personal, Indoor and Mobile Radio Communications (PIMRC), 2003, vol. 2, pp.1603–1607. [27] Y. Sun and H. Matsuoka, “A novel adaptive antenna architecture-subcarrier clustering for high-speed OFDM systems in presence of rich co-channel interference,” IEEE 55th Vehicular Technology Conference (VTC-Spring 2002), 2002, vol. 3, pp. 1564–1568. [28] H. Simon, Adaptive filter theory, Prentice Hall, 2002. [29] V.H. Nascimento, “Improving the initial convergence of adaptive filters: variable-length LMS algorithms,” International Conference on Digital Signal Processing, 2002, vol. 2, pp. 667–670. [30] V. Erceg, L. Schumacher, P. Kyritsi, and et al., “TGn channel models,” Tech. Rep., IEEE, 2004. [31] L. D. Van and C. C. Yang, “High-speed area-efficient recursive DFT/IDFT architectures,” Proc. of the International Symp. on Circuits and Systems (ISCAS), May 2004, vol. 3, pp. 357–360. [32] S. He and M. Torkelson, “Designing pipeline FFT processor for OFDM (de)modulation,” Proc. URSI International Symposium on Signals, Systems, and Electronics, 1998, vol. 29, pp. 257–262. [33] Y.W. Lin and C.Y. Lee, “Design of an FFT/IFFT processor for MIMO OFDM systems,” IEEE Transactions on Circuits and Systems I: Regular Papers, vol. 54, no. 4, pp. 807–815, 2007. [34] C. H. Chang, C. L. Wang, and Y. T. Chang, “A novel memory-based FFT processor for DMT/OFDM applications,” IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP), 1999, vol. 4, pp. 1921–1924. [35] C.M. Chen, C.C. Hung, and Y.H. Huang, “An energy-efficient partial FFT processor for the OFDMA communication system,” IEEE Transactions on Circuits and Systems II: Express Briefs, vol. 57, no. 2, pp. 136–140, 2010. [36] L. D. Van, Y. C. Yu, C. M. Huang, and C. T. Lin, “Low computation cycle and high speed recursive DFT/IDFT: VLSI algorithm and architecture,” IEEE Workshop on Signal Processing Systems Design and Implementation (SiPS), Nov. 2005, pp. 579–584. [37] S. C. Lai, S. F. Lei, C. L. Chang, C. C. Lin, and C. H. Luo, “Low computational complexity, low power, and low area design for the implementation of recursive DFT and IDFT algorithms,” IEEE Transactions on Circuits and Systems-II, vol. 56, no. 12, pp. 921–925, Dec. 2009. [38] F. Lu and H. Samueli, “A 60 MBd, 480 Mb/s, 256 QAM decision-feedback equalizer in 1.2 μm CMOS,” IEEE Journal of Solid-State Circuits, vol. 28, no. 3, pp. 330–338, 1993. [39] L. Jia, Y. Gao, J. Isoaho, and H. Tenhunen, “A new VLSI-oriented FFT algorithm and implementation,” Proc. IEEE ASIC Conference, 1998, pp. 337–341. [40] T. Y. Chen, Y. H. Lin, C. F. Wu, and C. K. Wang, “Design and analysis of cost-efficient IFFT/FFT processor chip for wireless OFDM systems,” IEEE Asia Pacific Conference onCircuits and Systems (APCCAS), 2010, pp. 760–763. | |
dc.identifier.uri | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/15722 | - |
dc.description.abstract | 隨著無線通訊應用之發展,對於無線區域網路的容量需求也隨之上升。在先進之無線區域網路規格中,為了提供更高的資料傳輸速率,通常會採用較寬的訊號頻寬。然而,由於可使用的ISM頻段是有限的,訊號頻寬或是網路使用者之增加,會造成同通道干擾的問題,並使得無線區域網路的吞吐量下降。因此,為了消除同通道干擾,本論文將研究應用於正交分頻多工系統中之束波成型技術。
針對正交分頻多工系統在追蹤階段之同通道干擾及通道等化誤差,本論文提出一決策反饋束波成型及通道等化之聯合演算法。此演算法是根據最小均方誤差的準則,定義出其單一成本函數。束波成型器權重及通道等化器係數之最佳估計值,可透過最小均方誤差演算法遞迴求得。為了增加束波成型器權重估計之準確性,估測誤差是由通道等化器輸出端的所有子載波取得。系統模擬的結果顯示,此聯合演算法可有效地降低殘餘之同通道干擾及通道等化誤差。 此外,考量到聯合演算法之硬體複雜度,本論文亦提出一低運算週期及高能量效益之遞迴式離散傅立葉(反)轉換之演算法。透過輸入分取之技巧,可減少75%的遞迴週期。由於遞迴週期之減少,此演算法可降低58.7%的實數乘法運算及78.9%的實數加法運算。為了更加簡化硬體的複雜度,此遞迴式離散傅立葉(反)轉換處理器中所需之常數乘法器可由位移器及加法器來實現,並透過有號位數表示式之最佳化以得到最小的加法器數目。 最後,所提出之遞迴式離散傅立葉(反)轉換之處理器,透過FPGA進行雛型驗證。後端實體設計的部分使用0.18微米CMOS製程技術,其核心面積為0.37×0.37毫米平方。根據佈局後之模擬結果,本設計在40 MHz工作頻率及1.8 伏特供應電壓下,消耗5.16 毫瓦。 | zh_TW |
dc.description.abstract | The demand for high-throughput wireless local area network (WLAN) has greatly increased in recent years. Normally, large channel bandwidth is adopted in advanced WLAN standards to provide high data rate transmissions. However, since the available ISM band is limited, the extension of channel bandwidth may cause the co-channel interferences (CCIs), which can significantly degrade the throughput of a WLAN. In order to eliminate the CCIs, the beamforming technology can be used in the orthogonal frequency-division multiplexing (OFDM) systems.
In this thesis, a joint decision-directed beamforming and channel equalization algorithm is presented for OFDM systems in the presence of CCI. The cost function of the joint algorithm is proposed to minimize the mean-square decision error. The optimal estimations of beamformer weights and channel equalization coefficients are iteratively obtained with the gradient-based LMS algorithm. In order to increase the accuracy of weight estimation, the estimation errors for adaptation are extracted from the equalizer output on both pilot and data subcarriers. Simulation results show that the joint algorithm can provide 2.2 dB and 3 dB SNR gains at BER of 10^(−5) for QPSK and 16-QAM modulations, respectively, as compared with the conventional pilot-aided beamforming algorithm. In order to reduce the hardware complexity of this algorithm, a low-computation-cycle and energy-efficient recursive DFT/IDFT (RDFT/RIDFT) algorithm is also presented. The proposed RDFT/RIDFT architecture consists of a pre-processor, a decimation buffer, and a recursive filter. The pre-processor performs the input-decimation technique to combine the input sequence into smaller groups, which can save 75% of recursion cycles of the recursive filter. Due to the reduction in recursion cycles, 58.7% of real multiplications and 79.8% of real additions can be decreased. Besides, the constant multiplier with shift-and-add approach is employed to replace the complex multiplication operation. The optimized signed-digit representation of twiddle factors is derived to minimize the number of adders in the multiplier, and thus lower the area and power consumption. Finally, the functionalities of the RDFT/RIDFT algorithm are verified by FPGA emulation. The physical implementation result shows that the core area of this design is 0.37×0.37 mm^2 with 0.18 μm CMOS process. The power consumption is 5.16 mW with 1.8 V supply voltage and 40 MHz clock rate. | en |
dc.description.provenance | Made available in DSpace on 2021-06-07T17:50:45Z (GMT). No. of bitstreams: 1 ntu-101-R99943008-1.pdf: 4105114 bytes, checksum: f47832116c9719be352d13b99dac2580 (MD5) Previous issue date: 2012 | en |
dc.description.tableofcontents | 1 Introduction . . . . . . . . . . . . . . . . . . . . . . 1
1.1 Background . . . . . . . . . . . . . . . . . . . . . . 1 1.2 Motivation . . . . . . . . . . . . . . . . . . . . . . 4 1.3 Thesis Organization . . . . . . . . . . . . . . . . . 5 2 Wireless Channel Model and OFDM Technology . . . . . . . 7 2.1 Wireless Channel Model . . . . . . . . . . . . . . . . 7 2.1.1 Path Loss and Shadowing . . . . . . . . . . . . . . 8 2.1.2 Multipath Fading . . . . . . . . . . . . . . . . . .9 2.1.3 Co-channel Interference . . . . . . . . . . . . . . 12 2.1.4 Transceiver Impairments in OFDM Systems . . . . . . 13 2.2 Orthogonal Frequency-Division Multiplexing . . . . . 14 2.2.1 Introduction . . . . . . . . . . . . . . . . . . . 14 2.2.2 OFDM Signal Model . . . . . . . . . . . . . . . . . 15 2.3 OFDM Receiver Architecture . . . . . . . . . . . . . 20 2.3.1 Receive Filter . . . . . . . . . . . . . . . . . . 20 2.3.2 Beamformer . . . . . . . . . . . . . . . . . . . . 21 2.3.3 Symbol Boundary Detection . . . . . . . . . . . . . 22 2.3.4 Carrier Frequency Offset Synchronization . . . . . 24 2.3.5 Fast Fourier Transform . . . . . . . . . . . . . . 26 2.3.6 Phase Compensation . . . . . . . . . . . . . . . . 27 2.3.7 Frequency-Domain Equalizer . . . . . . . . . . . . 27 3 Joint Decision-Directed Beamforming and Channel Equalization Algorithm . . . . . . . . . . . . . . . . . 29 3.1 Prior Art of Beamforming Algorithms . . . . . . . . . 29 3.2 Joint Decision-Directed Beamforming and Channel Equalization . . . . . . . . . . . . . . . . . . . . . . 31 3.2.1 Uncoded BER and MMSE Criterion . . . . . . . . . . 32 3.2.2 Initial Acquisition and Tracking . . . . . . . . . 33 3.2.3 Proposed Joint Algorithm . . . . . . . . . . . . . 33 3.3 System Simulation . . . . . . . . . . . . . . . . . . 36 3.3.1 Simulation Environment . . . . . . . . . . . . . . 36 3.3.2 Simulation Result and Discussion . . . . . . . . . 37 4 Input-Decimation Recursive DFT/IDFT Algorithm 43 4.1 Partial Sample Updating . . . . . . . . . . . . . . . 43 4.2 Prior Art of Recursive DFT Algorithms . . . . . . . . 45 4.3 Proposed Recursive DFT/IDFT Algorithm . . . . . . . . 48 4.3.1 Input-Decimation Recursive DFT . . . . . . . . . . 48 4.3.2 Symmetric Identity . . . . . . . . . . . . . . . . 50 4.3.3 Recursive IDFT . . . . . . . . . . . . . . . . . . 51 4.4 Comparison and Discussion . . . . . . . . . . . . . . 52 5 Hardware Implementation 55 5.1 Finite Wordlength Analysis . . . . . . . . . . . . . 55 5.2 Adaptive FEQ Design . . . . . . . . . . . . . . . . . 57 5.3 RIDFT Design . . . . . . . . . . . . . . . . . . . . 62 5.4 FPGA Evaluation . . . . . . . . . . . . . . . . . . . 65 5.5 Physical Implementation . . . . . . . . . . . . . . . 66 6 Conclusions . . . . . . . . . . . . . . . . . . . . . . 71 Bibliography . . . . . . . . . . . . . . . . . . . . . . 73 | |
dc.language.iso | en | |
dc.title | 應用於正交分頻多工系統之決策反饋束波成型及通道等化之聯合演算法及FPGA雛型驗證 | zh_TW |
dc.title | Joint Decision-Directed Beamforming and Channel Equalization Algorithm for OFDM Systems and Its FPGA Evaluation | en |
dc.type | Thesis | |
dc.date.schoolyear | 101-1 | |
dc.description.degree | 碩士 | |
dc.contributor.oralexamcommittee | 吳安宇(An-Yeu Wu),周世傑(Shyh-Jye Jou),闕志達(Tzi-Dar Chiueh),薛木添(Muh-Tian Shiue) | |
dc.subject.keyword | 束波成型,通道等化,聯合演算法,正交分頻多工系統,遞迴式離散傅立葉(反)轉換, | zh_TW |
dc.subject.keyword | beamforming,channel equalization,joint algorithm,OFDM,recursive DFT/IDFT, | en |
dc.relation.page | 77 | |
dc.rights.note | 未授權 | |
dc.date.accepted | 2012-11-26 | |
dc.contributor.author-college | 電機資訊學院 | zh_TW |
dc.contributor.author-dept | 電子工程學研究所 | zh_TW |
顯示於系所單位: | 電子工程學研究所 |
文件中的檔案:
檔案 | 大小 | 格式 | |
---|---|---|---|
ntu-101-1.pdf 目前未授權公開取用 | 4.01 MB | Adobe PDF |
系統中的文件,除了特別指名其著作權條款之外,均受到著作權保護,並且保留所有的權利。