A new frequency offset tracking approach for OFDM has been addressed. Two-dimensional pilot-symbol assisted modulation (2D-PSAM) is employed in coherent OFDM for channel estimation and it is based on inserting known symbols spread out through the 2D time-frequency grid. We show that these scattered symbols can also be employed to perform frequency synchronization. Maximum likelihood estimation has been derived for both time and frequency domains. Also, if a decision-guided strategy is used jointly with the 2D-PSAM signalling, an improvement in performance can be attained.
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