Blind carrier frequency offset estimation for interleaved OFDMA uplink

In this paper, we develop two novel blind carrier frequency offset (CFO) estimators for interleaved orthogonal frequency division multiple access (OFDMA) uplink transmission in a multiantenna system. The first estimator is the subspace-based one and could blindly estimate multiple CFOs from a rank reduction approach. The second estimator is based on the maximum likelihood (ML) approach and improves the performance as compared to the first one. The higher computational complexity of the ML estimator is alleviated by the alternating projection (AP) method. Both the proposed estimators support fully loaded data transmissions, i.e., all subcarriers being occupied, which provides higher bandwidth efficiency as compared to the existing schemes. The numerical results are then provided to corroborate the proposed studies.