Modeling And Simulating The Characteristics Of OFDM Wireless Channel

The broadband communication has become an inevitable trend of the wireless communication while OFDM(Orthogonal Frequency Division Multiplexing) is the core technology of next-generation wireless mobile communication system. Therefore, the study of OFDM broadband wireless channel such as modeling the channel, simulating with simulator, analyzing the performances of communication and the changes of electromagnetic waves in the wireless channel can provide the basis for enhancing the validity and the reliability of data transmission on determining the ways of the best modulation, error correction and channel equilibrium of the OFDM communication system.In this dissertation, the characteristics of the OFDM wireless channel are modeled and simulated, the work as follow has been completed.(1) Based on studying the theory of the spread of wireless channel, the characteristics of wireless channel are analyzed, the models of a variety of fading channel are established, and the model of the wireless channel with tap delay line and Jakes channel model are designed.(2) The large-scale path loss channel models are analyzed, the characteristics are compared, the model errors are simulated, a variety of application environment for the models are show.(3) By the simulation of the small-scale fading channel with Jakes simulation, the fading characteristics of the flat fading and frequency selective fading channel are verified, and the various performance parameters of small-scale fading are analyzed.(4) By simulating the OFDM system, comparison the bit error rate of the system with the protection spacing and without it, the unique anti-fading characteristics of OFDM are proposed.(5) The speed of mobile and the surrounding environment effect on the BER, envelope, Doppler-Power-Spectral-Density and the transfer functions are analyzed, the relationship between the decline of small-scale and the speed or the surrounding environment are proposed.