OFDM PHY Layer Simulation

Wireless communication is facing one of the fastest developments of the last years in the fields of technology and computer science in the world. Orthogonal Frequency Division Multiplexing (OFDM) is a kind of digital modulation technology of mufti-carriers, which has many characteristics, such as higher spectrum efficiency, stronger ability of anti-mufti-path interference and lower cost. It is suitable for the demand of the wireless communications in high speed, broad band and mobility. And, in this area, it's a common sense that OFDM will be applied to next generation mobile communication system-Beyond 3G and broad band wireless access as a kernel technique. According to the experiments in practice, by analyzing the key techniques of OFDM, the basic frame of OFDM system simulation design is presented. Finally, the process of design and results of simulation are given according to an example. The main researches and results art the following:At first the technique various communication background of OFDM is introduced and the developments of systems are generalized shortly.Chapter 2 An introduction to the concepts of wireless communications, channel characteristics, wireless local area network (WLAN) are introduced. And the IEEE standard 802.1 la WLAN is discussed.Chapter 3 as a key part of theory research of the dissertation mainly focuses on the OFDM basic theory and mathematics express. Then, the key technology of OFDM including the modulation and demodulation of sub-carries, the circular prefix, the channel estimation and the option of the system parameters are discussed. As the same time, study the influence of these key technologies to the whole OFDM system.Chapter 4 basis of front chapter is about the research on the dynamic simulation of OFDM. With the Simulink toolbox of MATLAB software, the simulation model of the base band OFDM system is built, the BER performance under different conditions are compared and analyzed, and the simulation results provide a valuable theoreticreference to practical system. At last, spectrums that simulated in MATLAB and measured in FPGA base band design with spectrum analyzer instrument are given.Finally, as the end of the dissertation, firstly describes the hardware platform of OFDM base band system, Problems about the system realization using DSP and FPGA are discussed and one scheme are presented for realizing OFDM in last part.