Subspace method for blind CFO estimation for OFDM systems with constant modulus constellations

In this paper, we propose a novel subspace based approach for blind carrier frequency offset estimation in OFDM. Correlation in squared spectrum of the channel is exploited. Low rank signal model is thereby obtained without virtual subcarriers. The proposed estimator accomplishes frequency synchronization with a single OFDM block. No extensive time averaging is needed, which makes the approach very attractive for time and frequency selective channels where the offset may be time varying. Superior performance is achieved over existing algorithms exploiting virtual carriers or constant modulus criterion.