Blind CFO estimation in OFDM systems using diagonality criterion

In this paper, we address the problem of blind carrier frequency offset (CFO) estimation in OFDM systems, in the case of frequency selective channels. By assuming real constellations, the proposed blind method enforces a diagonal structure for signal pseudo covariance matrices in the frequency domain. The power of non-diagonal elements is minimized. A closed-form solution is derived which leads to accurate and computationally efficient CFO estimation in multipath fading channels. Moreover, in the case of complex circularly symmetric noise, the theoretical performance does not depend on the SNR. Simulation results are presented using realistic channel models in typical urban scenarios.