The Research And Implementation Of OFDM Baseband System Based On FPGA

Orthogonal frequency division multiplexing (OFDM) is a special multi-carriermodulation technology, which not only has high spectrum efficiency but also cancombat multi-path fading and impulse noise effectively. OFDM has aroused widespreadattention and has been used in many fields in recent years.Now, the OFDM technologyhas considered as the main trend technology of the fourth Generation mobilecommunication system. Meanwhile, the digital processing technology has beendeveloped greatly, and the FPGA (Field Programmable Gate Array, FPGA) has becomemore and more important in digital system design. It is easy to reduce the circuitcomplexity to complete the OFDM communication system based on FPGA, and benefitto transplantation, integration and large-scale production. For all the reasons above, myresearch direction is the implementation and research of OFDM baseband system basedon FPGA.Firstly, this thesis introduces the basic theory, fundamental operating principles andkey technology of OFDM system, and shows more advantages than other modulationtechnology; a brief introduction to FPGA design of the basic principles, the basicprocess and hardware description language. And then finished transmission andreception key modules of OFDM based on FPGA, including: QPSK/16QAMmodulation/demodulation module realization, serial parallel conversion/parallel serialconversion module realization, the adding cyclic prefix module, IFFT/FFT of themodule, timing synchronization module and fractional frequency offset estimationmodule, etc.Meanwhile, an implementation method of OFDM synchronization withconjugated-symmetrical-structured training sequence and repeated-structured trainingsequence based on FPGA was studied.At last, these circuits are downloaded to virtex-6Field Programmable Gate Array (FPGA) development board ML-605based onxc6Vlx240t-1ff1156chip of Xilinx. And, do post simulations by using Modelsim SE6.5b analysis tool, and Chipscope Pro wave observation tool, then analyzes thesimulation results and compare results with principles. The simulated verified that thecorrectness of the design of each module. Finally, the thesis gives a summary and prospect to us.I believe that this thesis has a good reference value in some designs aboutOFDM wireless communication system transmitter and receiver based on FPGA.