An Eigenvalue Based Carrier Frequency Offset Estimator for OFDM Systems

Orthogonal frequency division multiplexing (OFDM) is sensitive to frequency synchronization errors. This letter proposes a novel data-aided carrier frequency offset (CFO) estimator. We show that the eigenvalues of the inter-carrier interference (ICI) coefficient matrix are the elements of a geometric series distributed on the unit circle of the complex plane. Then, we prove that estimating the CFO is equivalent to finding the eigenvalues of a two-dimensional ICI coefficient matrix. As a result, by transmitting the corresponding eigenvectors, an estimate of the CFO value can be found. In addition to its simplicity, the proposed estimator is proven to be a maximum likelihood estimator. Simulation results are presented to demonstrate the high accuracy of the proposed estimator in presence of channel noise and fading.