摘要 IEEE802.11a 系統是一無線傳輸的通訊系統，使用正交分頻多工調變(Orthogonal Frequency Division Multiplexing，OFDM)來增加傳輸的頻寬效益， 也具有一般OFDM 系統所包含的多重路徑干擾(Multipath Channel)、載波頻率偏移(Carrier Frequency Offset) 等問題。 本篇論文利用FPGA 實現IEEE 802.11a 實體層，並在演算法方面探討載波頻率偏移、時序偏移、以及多重路徑干擾對於接收端的影響，也加入通道追蹤(Channel Tracking)模組來增進系統的效能。我們先以VHDL 驗證完成後，再以Xilinx FPGA 及邏輯分析儀作整體硬體上的驗證與分析，最後得到理論與實現上之印證。 Abstract IEEE802.11a is a wireless communication system based on Orthogonal Frequency Division Multiplexing (OFDM) modulation to increase the bandwidth efficiently. As a general OFDM system, it also suffers from inter-carrier interference (ICI) and the inter-symbol interference (ISI) caused by the multipath channel, carrier frequency offset…, etc. This thesis implements the IEEE 802.11a physical layer on FPGA and explores the carrier frequency offset, timing offset, and the effect caused by multipath channels in the algorithm-level. The channel tracking module is also included to improve the system performance. The VHDL design is verified by the FPGA board. The LA (Logic Analyzer) is used to grab the output data for analysis to achieve a comprehensive study.
