Doppler Frequency Effect and BER Performance of FFT Based OFDM System

In the present scenario, there is a rising demand of high capacity, high performance and low Bit Error Rate (BER) in Wireless Communication systems. TheOrthogonalFrequency Division Multiplexing (OFDM) is an attractivemulti carrier modulation technique for wireless transmission systems. In this paper, we discuss the effect of Doppler frequency in Fast Fourier Transform (FFT) based OFDM system over Rayleigh fading channel. Multipath fading channel effect and BER on the performance of OFDMis shown in this paper. In this paper two type of modulation schemes are used. Phase Shift Key (PSK) modulation scheme is used for understanding the Doppler frequency effect on the OFDM system with RAYLEIGHFading channel while QAM modulation schemeis used for studying the performance of BER in the OFDM system with RAYLEIGH and AWGN channel. The OFDM SYSTEM was implemented by using MATLAB.