Orthogonal frequency division multiplexing (OFDM) system has been received considerable attention for application in broadband wireless communication systems[1]. OFDM is attractive due to the ease with which it can combat channel dispersion, provided the channel delay spread is not greater than the length of the cyclic prefix (CP). However, if the cyclic prefix is not long enough, the orthogonality of the subcarriers will lose, causing intercarrier interference (ICI) and intersymbol interference (ISI). Long CP reduces transmission efficiency especially at high data rate. This thesis addresses the issues behind using a time domain equalizer (TEQ) to improve the performance of high data rate OFDM system. The TEQ is placed in the receiver to shorten the effective channel impulse response and to enhance the transmission efficiency. Minimum mean square error (MMSE) for TEQ is adopted in this work and implemented 7th order finite impulse response (FIR). Mathematical analysis and simulation results are provided to show the validity and the advantages of the algorithm. Simulink model for OFDM system incorporating TEQ is developed by using MATLAB version 7. The simulation results are presented for 16-QAM OFDM system operating at 54 Mbps data rate over multipath Rayliegh fading channel. The results showed clearly the effectiveness of TEQ in improving system performance. A signa – to-noise ratio gain is approximately 14dB is achieved at BER=10-4 when TEQ is employed.