Research And Realization Of OFDM Based And System Based On FPGA Technology

Orthogonal Frequency Division Multiplexing(OFDM) is a technique which has the highest spectrum efficiency currently, suitable for the multi-path transmission and Doppler frequency shift of the wireless mobile channel to transfer high-speed data. OFDM not only can effectively resist multi-path effects, eliminating inter symbol interference and resisting frequency-selective fading but also has high spectrum efficiency and easy implement with hardware. It has been the first choice in the fourth generation mobile communication technology and is a hot issue for the current mobile communications technology research.This paper focues on the research and realization of the OFDM baseband system based on FPGA. First of all,we do a lot of in-depth analysis and research on the principle of OFDM, the realization of OFDM modulation with DFT and the basic model of the OFDM baseband system. Then we have a detailed presentation about DVB-T standard, and on this basis, a whole OFDM baseband system block diagram is given.Then the use of Altera's IP core, as well as hardware description language VHDL (Very High Speed Integrated Circuit Hardware Description Language),we realize modules of the system, such as FFT transform, frame adaptation, pilot and TPS signals module, constellation mapping and reverse transform, cyclic prefix and remove cyclic prefix module, interleaver module and reverse transform, convolutional coder and viterbi decoder, ping-pang operation and data adjustment module. And then we use Altera's IDE software QuartusⅡand MathWorks's software Matlab to do timing simulation. Compared with traditional simulation with Matlab algorithm, joint simulation adds hardware delay information, thus it is closer to actual hardware operation mode, having a higher reliable simulation result. Finally, we test OFDM baseband system on hardware circuit.