说明：  In a rapidly fading environment in high data rate wireless communication systems the orthogonality of OFDM sub carrier signals destroyed and this phenomenon potentially results in Inter carrier interference (ICI).The novel contribution of the paper is that, the effects of ICI have been analyzed and solutions to ICI diminution have been presented in different frequency offset values such as 0.5,0.15 and 0.30 . The first method is a self-cancellation scheme, in which redundant data is transmitted onto adjacent subcarriers such that the ICI between adjacent sub carriers cancels out at the receiver. The other technique the Extended Kalman Filter (EKF) method statistically estimate the frequency offset and correct the offset using the estimated value at the receiver