A semi blind technique　for estimating the carrier frequency offset in　OFDM communication systems is　presented in　this
paper. The fractional　and integer　frequency offsets are esti-mated by employing a few　null subcarriers in the　rst　OFDM
symbol in　a frame.　While the　conventional　null subcarrier based methods estimate the offset by a single global search, the
proposed method employs a two stage estimator, which greatly minimize the　computational　complexity. ,A semi blind technique　for estimating the carrier frequency offset in　OFDM communication systems is　presented in　this
paper. The fractional　and integer　frequency offsets are esti-mated by employing a few　null subcarriers in the　rst　OFDM
symbol in　a frame.　While the　conventional　null subcarrier based methods estimate the offset by a single global search, the
proposed method employs a two stage estimator, which greatly minimize the　computational　complexity.