Design Of The Transmitter Of OFDM Communications System Base On 802.11a And Hardware Implementation

Recently with the 4G networks large-scale commercial,and the rapid development of mobile Internet. More and more people use mobile phones, tablets and other mobile terminal access to the Internet via WLAN.The technology of OFDM has gotten more and more attention.The IEEE802.11 a is one of important standards of WLAN.In the physical layer of IEEE802.11 a,OFDM is adopted as key technology to transmit data. It’s the highest transmission rate can reach 54 Mbps.OFDM technology has strong ability to resist the multi-path effect.It can eliminate the ISI and reduce the ICI.OFDM technology also has high spectrum efficiency,and can easily realize the asymmetry transmission.The advantage of OFDM,enable it to have to be applied to more in the wireless communication system.So the hardware implement of OFDM is very important.In this thesis,the OFDM system is designed based on IEEE802.11 a,according to the regulations of the IEEE802.11 astandard of OFDM signal’s data frame structure to design the transmitter module.The hardware platform adopts FPGA+DSP architecture.The FPGA choose the XC5VSX50 T chip produced by Xilinx,the main sigal processing part is completed in FPGA.The DSP choose the TMS320DM6437 chip produced by TI.In addition to FPGA and DSP module,the hardware platform also has A/D,D/A and MAC interface module.The main process of this system design:1.According to the regulation of IEEE802.11 a to simulation on Simulink, to verify that the system is feasible;2.Using Verilog language implement each module in the integration circumstance of ISE,and do behavioral level simulation;3.Implement each module on the FPGA;4 According to the needs of system to slect chips and design the hardware platform. In this thesis,the first chapter introduces the research background and significance.The development history of OFDM system and the advantages and disadvantages of OFDM system. The second chapter presents the basic principle of OFDM system and hotspot problem of OFDM systems. The third chapter firstly introduces the IEEE802.11 a standard, Then introduces the method to realize the system transmitter module include: training sequence generation module, the scrambler module, convolution encoder module, QAM modulation module, pilot insertion module,IFFT modele and CP insertion module. The fourth chapter mainly introduces the chip selection of the hardware platform,and each module design of the hardware platform.This thesis mainly completed the OFDM transmitter system design based on IEEE802.11 a standard, and complete the design and debug of the system hardware platform.