The Design And Implementation Of Baseband System For OFDM Based On FPGA

With the social rapid development and the amount of information's increasing, the information transmission speed and frequency spectrum utilization of wireless communications have become the urgent issues now that need to be solved. Since Orthogonal Frequency Division Multiplexing technology (OFDM) has the absolute superiority in this area, so OFDM technology will to be the core technology of next generation of wireless communications. Meanwhile, the two the next generation mobile communication system (4G) candidate standards (LTE-Advanced standard and 802.16m standard of WiMAX technology) determined by ITU both take OFDM as their core technology.Firstly, the paper introduces the research history of OFDM and its developments and applications, by analyzing the present development situation of the wireless communications to give us a basic understanding of OFDM. Secondly, it introduces the basic principle and mathematical model of OFDM. Through the analysis of the application of FFT, cyclic prefix and other key technology in OFDM, an overall diagram of OFDM communication system will be formed, which can deepen our understanding of the OFDM. And then it introduces the Field Programmable Gate Array (FPGA) design process and the application of IP core, analyzes the FPGA hardware system, and by an in-depth study of IEEE 802.11a, to get the main parameter of the OFDM base band system.The paper describes OFDM base band system based on FPGA in details, including serial-parallel conversion, QPSK mapping, pilot frequency insertion, FFT/IFFT, and the design method and implementation process of adding cyclic prefix and other modules, etc. Each module and sytem have been tested and simulated to verify the correctness of the design of each module. Finally, the paper gives a summary and prospect to us.