The Design And Implementation Of OFDM Modulation Technology Based On FPCA

Orthogonal frequency division multiplexing (OFDM) as when the firsttechnology the core of4G modulation technology, has high spectrum efficiency andrealize the advantages of simple, can effectively offset frequency selective fading andthe negative influence of intercarrier interference, and it also can choose differentaccording to the stand or fall of channel adaptive modulation mode, improve thecapacity of the system.In general, in the hardware implementation scheme of OFDM technology, thereare mainly two different directions.One is based on DSP+FPGA hardware platformfor development, in the scenario, the DSP code and FPGA need programmingrespectively, different types of hardware interface chip baseband board also need toseparate debugging, so the way to accomplish this difficult task to pay larger, and thehardware and software costs are high.Another is based on the FPGA implementationscheme, and mainly adopted a plan now.The FPGA chip internal clock, logicresources and function module, can satisfy the function and task of most of thedesign.As its application and diversified, there are more and more dedicated IPcore.This makes us when designing the system, need to set up a proper kernelparameters, and compared with the logic of special bonding together can solve theproblem.Low-cost and FPGA designer uses one of its main reasons, when need to beimproved, by EDA tools only modify the software without modifying the hardwareplatform can achieve.This thesis first introduces the development status and trend of mobilecommunication, and the characteristic of FPGA and the future development direction,based on this background, introduces the mathematical model and the basic principleof OFDM, and lead to its key technologies and implementation diagram, thenintroduced the design of the hardware platform based on FPGA, FPGA chips, FIFOchips and DA chip selection, after developed with Xilinx company XC3S500E FPGAchip as the core, the devices such as analog-to-digital conversion chip ISL5827 combining with OFDM baseband system hardware platform.Finally using VerilogHDL language programming for OFDM systems of various modules, realizes thescrambler, convolutional coding, interleaving,16QAM modulation, pilot insertion,IFFT/FFT and cyclic prefix, and other functions, and analyses the convolutionalcoding module.Whole design by using the top-down and pipeline technology, greatlyimprove the validity and reliability of the system.The use of software Modelsim foreach module function and timing simulation results quite right; Also use onlinedebugging tools ChipScope Pro for some key module hardware platform of on-linedebugging analysis, simulation and on-line debugging results has the very highalignment.