BER Evaluation of OFDM Systems for Short Cyclic Prefix and Doppler Spread in Multipath Rayleigh Channels

The performance in terms of bit error rate for OFDM systems for short cyclic prefix and Doppler spread is obtained. In order to evaluate the effects of the short cyclic prefix and Doppler spread on system performance, expressions for the bit error rate are obtained through mathematical fitting to the results obtained by simulation. We have considered several scenarios with different parameters as bandwidth, number of sub-carriers, channel dispersion time, duration of the cyclic prefix, mobile speed for BPSK modulation. In the scenarios examined in this paper, we have observed linear and nonlinear regions that depend on how much the cyclic prefix is shorter than channel dispersion. We have observed that Doppler spread decreases the performance. This paper is an important tool to evaluate the performance of OFDM systems with short cyclic prefix that can occur in big cells and Doppler spread.