FPGA Design And Implementation Of OFDM Baseband Transmission System

Orthogonal Frequency Division Multiplexing(OFDM) as a multi-cartier modulation technology has high bandwidth-efficiency and the ability in coping with multipath fading,which make it suitable for high speed wireless transmission.It's supposed that OFDM will have an extensive application in wireless communication.Now it has been adopted as the physical-layer technology of several specifications.Also many expects that it will be a key technology in the next generationg mobile communicationg system.Nowadays,many researches focusing on the theoretics and simulation performance of OFDM have been gradually matured.So it would be considered to be a key point to the implement of an OFDM transceiver system based on hardware.This design puts emphasis on building up an OFDM transmission platform based on Field Programmable Gate Array(FPGA),which can be used in the theoretic research and performance analysis of OFDM.In this thesis,it first introduced the development and applications of OFDM.Afler comparing with many other hardware implements scheme and analyzing the principles and features of OFDM,it briefly illustrate the adaptive modulation technology which is as the one of the most pivotal technologys of OFDM.It presents a optimum algorithm in discrete allocation to bits and power and simulate it by Matlab simulation tool.According to 802.11 a protocol and correlative development platform,this paper's emphasis is on the design and the implementation of baseband data processing section on FPGA of OFDM communication system.The algorithm principles,coding style and implement method on FPGA which the functional modules of OFDM system takes including channel coding,interleaving,constellation mapping,data inserting,IFFT/FFT translation,cyclic prefix,exponent scaling etc.The reverse modules have been analyzed and discussed.The paper also presents a new simply interface model which is used in self-designing modules in similar with Atlantic interface of IP core.It can improve the compatibility and the stability of the system combind with some of the IP core.Finally,the whole system is built up and pass through the software simulation and hardware debugging.And final results show effectiveness of the design.The software platform of QuartusⅡ7.2,VHSIC Hardware Description Language(VHDL)are used to design.and finished this FPGA implementation of baseband data processing system of OFDM on the hardware platform of Altera Cyclone EP1C12Q240C8 Development Board.