  In this paper, we investigate the impact of Forward Error Correction (FEC)
codes namely Cyclic Redundancy Code and Convolution Code on the performance of
OFDM wireless communication system for speech signal transmission over both
AWGN and fading (Rayleigh and Rician) channels in term of Bit Error
Probability. The simulation has been done in conjunction with QPSK digital
modulation and compared with uncoded resultstal modulation. In the fading
channels, it is found via computer simulation that the performance of the
Convolution interleaved based OFDM systems outperform than that of CRC
interleaved OFDM system as well as uncoded OFDM channels.
