This thesis is concerned with data-aided (DA) scheme and CFO tracking for OFDM system. OFDM system model is developed first without CFO and then with CFO. The system performance is evaluated via simulation. The bit error rate (BER), constellation diagram, the phase output and phase error were taken as performance measures. The performance is evaluated for different types of modulation over different channel conditions. In this thesis, a dual bandwidth for CFO tracking based on type-2 control loop to reduce the acquisition time of PLL is proposed. It is proved that the proposed scheme is significantly faster than, and improves the system BER. Also, further refinement to the dual bandwidth scheme is improved by using clustered pilot tones. The improved dual bandwidth scheme is better than the dual bandwidth scheme.