臺灣博碩士論文加值系統

近年來無線區域網路蓬勃發展,其中以正交分頻多工(Orthogonal Frequency
Division Multiplexing, OFDM)系統最受歡迎,後來又有人把多輸入多輸出(Multiple
Input Multiple Output, MIMO) 跟OFDM 結合變成MIMO-OFDM 系統, 使OFDM 透過多天線傳輸, 將傳輸速率提升數倍。而在基頻接收機中同步(Synchronization)演算法的好壞會對系統效能造成影響, 而同步又分為能量偵測、頻率同步、時序同步。本論文參考EWC HT PHY Spec v1.27規格, 使用20MHz模式,天線為傳送端與接收端各兩根,將基頻接收機的同步演算法使用Verilog硬體描述語言實現, 再進一步使演算法貼近硬體架構並使用切換訊號的方法簡化硬體複雜度,使其合乎成本而又保持效能。本論文使用Xilinx ISE進行合(Synthesis),並且用FPGA板進行驗證, 結果節省了16.6%的gate count。

The orthogonal frequency division multiplexing (OFDM) based wireless local area
network (WLAN) prevails recently. The use of multiple antennas at both the transmitter and receiver sides, which is called the multiple input multiple output (MIMO) system, together with the OFDM technique is now called the MIMO-OFDM system. The MIMO-OFDM system is expected to enhance data rate that grows linearly with the number of transmit antennas. The synchronization algorithms, including energy detection, frequency synchronization, and timing synchronization, play critical roles to the performance of the MIMO-OFDM baseband receiver. This thesis considers the 2-by-2 MIMO system for the 20 MHz mode of the EWC HT PHY Specification version 1.27 proposed for future highthroughput WLAN. The synchronization algorithms are implemented by codes written in Verilog hardware Description Language (VHDL). The designed hardware structure that processes alternately signals from two antennas effectively reduces gate count by about 16.6%. The designed circuits are downloaded to and successfully verified by FPGA.

1 緒論
2 多輸入多輸出正交分頻多工系統與IEEE 802.11n規格介紹4
2.1 正交分頻多工系統
2.2 多輸入多輸出系統
2.3 IEEE 802.11n
2.3.1 前言
2.3.2 IEEE 802.11n前置訊號(Preamble)形式
2.3.3 前置訊號的詳細介紹與弁?
2.3.4 其他規格介紹
3 IEEE 802.11n同步演算法
3.1 IEEE 802.11n能量偵測(Energy detection)
3.2 IEEE 802.11n頻率同步(Frequency synchronization)
3.3 IEEE 802.11n時序同步(Timing synchronization)
4 IEEE 802.11n同步電路設計
4.1 電路設計流程
4.2 IEEE 802.11n能量偵測電路設計
4.2.1 演算法與硬體考量
4.2.2 模擬結果
4.3 IEEE 802.11n頻率同步電路設計
4.3.1 演算法與硬體考量
4.3.2 模擬結果
4.4 IEEE 802.11n時序同步電路設計
4.4.1 演算法與硬體考量
4.4.2 模擬結果
4.5 IEEE 802.11n同步電路實現
4.6 實作心得
5 第五章結論與未來工作
Reference
中英名詞對照表

[1] IEEE 802.11, Wireless LAN Medium Access Control (MAC) and Physical Layer
(PHY) specifications. IEEE Std 802.11, 1999.
[2] IEEE 802.11b, Wireless LAN Medium Access Control (MAC) and Physical Layer
(PHY) specifications: High-speed Physical Layer in the 2.4 GHz Band. IEEE Std
802.11b, 1999.
[3] IEEE 802.11a, Wireless LAN Medium Access Control (MAC) and Physical Layer
(PHY) specifications: High-speed Physical Layer in the 5 GHz Band. IEEE Std
802.11a, 1999.
[4] S. B. Weinstein and P. M. Ebert, ”Data transmission by frequency division multiplexing using Fourier transform,” IEEE Trans. Commun. Technol., vol. COM-19, pp. 628-634, Oct. 1971.
[5] A. Peled and A. Ruiz, ”Frequency domain data transmission using reduced computational complexity algorithms,”IEEE int. Conf. Acoust., Speech, Signal Processing, 1980, pp. 964-967
[6] O.M. Bucci, G. Pelosi, S. Selleri, ”The work of Marconi in microwave communications,”in Proc. IEEE Antennas and Propagation Magazine, vol. 45, Issue 5, pp. 46-53, Oct. 2003.
[7] P.W. Wolniansky, G.J. Foschini, G.D. Golden, and R.A. Valenzuela, ”V-BLAST:An architecture for realizing very high data rates over rich scattering wireless channels,”in Proc. ISSSE-98, Sept. 1998, pp. 295-300
[8] M. R. McKay and I. B. Collings, ”Capacity and performance of MIMO-BICM with
zero forcing receivers,” IEEE Trans. Commun., vol. 53, no. 1, pp. 74-83, Jan. 2005.
[9] M. Honqlei, M. J. Juntti, ”Space-time channel estimation and performance analysis for wireless MIMO-OFDM systems with spatial correlation,” IEEE Trans. Vehic. Tech., vol. 54, pp. 2003-2016, Nov. 2005.
[10] J. Terry and J. Heiskala, OFDM Wireless LANs: A Theoretical and Practical Guide. SAMS Publishing, 2001.
[11] L. Schwoerer, ”VLSI suitable synchronization algorithms and architecture for IEEE 802.11a Physical Layer,” in Proc. Int. Symp. Circuits and Systems, vol. 5, May 2002, pp. 721-724.
[12] P. H. Moose, ”A technique for orthogonal frequency division multiplexing frequency offset correction,” IEEE Trans. Commun., vol. 42, no. 10, pp. 2908-2914, Oct. 1944.
[13] A. G. Armada, ”Understanding the effect of phase noise in orthogonal frequency division multiplexing(OFDM),” IEEE Trans. Commu., vol. 45, pp. 153-159, Jun. 2001.
[14] J.-J. van de Beek, M. Sandell, and P. O. Borjesson, ”ML estimation of time and frequency offset in OFDM systems,” IEEE Trans. Signal Processing, vol. 45, pp. 180-1805, July 1997.
[15] T. M. Schmidl, D. C. Cox, ”Low-Overhead, low-complexity [burst] synchronization for OFDM,” in Proc. IEEE Int. Conf. Commun., vol. 3, 1996, pp. 1301-1306.
[16] T. M. Schmidl, D. C. Cox, ”Robust frequency and timing synchronization for
OFDM,” IEEE Trans. Commun., vol. 45, pp. 1613-1621, Dec. 1997.
[17] A. V. Zelst and T. C. W. Schenk, ”Implementation of a MIMO OFDM-based wireless LAN system,” IEEE Trans. Signal Process., vol. 52, no. 2, pp. 483-494, Feb. 2004.
[18] EWC HT PHY Specification, available:
http://www.enhancedwirelessconsortium.org/home/EWC PHY spec V127.pdf
[19] A. van Zelst, R. van Nee, and G. A. Awater, ”Space division multiplexing (SDM) for OFDM systems,” in Proc. IEEE Veh. Technol. Conf., May 2000, pp. 1070-1074.
[20] Xilinx Inc. online technical documentation for ”Complete Data Sheet for Virtex-II Platform FPGAs”, http://direct.xilinx.com/bvdocs/publications/ds031.pdf
[21] 黃志清, IEEE 802.11a 基頻接收機頻率與時序同步電路設計, 中正大學通
訊工程研究所碩士論文. 中華民國93年7月.
[22] J. G. Proakis, Digital Communications. 4th Ed., New York: McGraw-Hill, 2001.