FFT Based Superimposed Pilot Aided Carrier Frequency Offset Estimation in OFDM Systems

In this paper, a novel superimposed pilot based carrier frequency offset (CFO) estimator for Orthogonal frequency division multiplexing (OFDM) systems over frequency selective fading channel is proposed. Through utilizing the properly designed superimposed pilots, the CFO estimation can be resolved by implementing the fast Fourier transform (FFT) operation on the average values of the received signals on all subcarriers within several consecutive OFDM blocks. Compared with the existing superimposed training aided algorithm, the proposed scheme can obtain more accurate CFO estimation without increasing computation complexity. The simulation results verify the robustness and effectiveness of the proposed estimator.