Performance Estimation of OFDM in Multipath Rayleigh Fading Channel

In recent years high speed wireless data communications have increasingly been used in many application areas like Orthogonal Frequency Division Multiplexing (OFDM) .The principles of OFDM modulation have been in theory for a long time. But in recent years, this technology has crossed the limitations into the real world of modern communication systems to combat Inter-Symbol Interference (ISI) through multicarrier modulation. OFDM has proved to be very effective in mitigating adverse multipath effects of a broadband wireless channel. Counteracting the frequency selectivity of multipath channels by multiplexing information on different orthogonal carriers is the key to the OFDM success. In this research work, the aim is to figure out the way, for improving the performance of transmitting information. Various kinds of modulation techniques will be studied in terms of their performance in a virtual Rayleigh Channel environment. The average BER performance for different MPSK and M-QAM will be evaluated and use of gray coded bit mapping for different modulation schemes to get BER performance with OFDM technique The numerical results are computed and plotted for M=16 and 64.