Blind CFO Estimation Based on Computationally Efficient Subspace-based Estimators with Real-Valued Implementation for Interleaved OFDMA Uplink

In this paper, computationally efficient subspace-based estimators with real-valued implementation are presented by introducing a preprocessing transformation to estimate carrier frequency offset (CFO) for interleaved orthogonal frequency division multiple access (OFDMA) uplink systems. Conventional subspace-based estimators inevitably lead to intensive computational complexity due to calculating sample correlation matrix and its complex-valued eigenvalue decomposition. To lessen these problems, in conjugation with preprocessing unitary transformation and Nystrm method, the required signal subspace or orthogonal projection matrix only needs to calculate two submatrices of correlation matrix. Computer simulation is also provided for illustrating the effectiveness of the proposed blind CFO estimators under single OFDMA data block.