Blind CFO Estimation for Constant Modulus Signaling Based OFDM Systems

A low-complexity, blind CFO estimator for OFDM systems with constant modulus (CM) signaling is presented. Both single-input single-output (SISO) systems and multiple-input multiple-output (MIMO) systems are considered. Assuming the channel keeps constant during estimation, the CFO can be uniquely and exactly estimated through minimizing the power difference of the received data on the same subcarrier between two consecutive OFDM symbols, thus the identifiability problem is solved. Inspired by the sinusoid-like cost function, curve fitting is applied to simplify our algorithm. This blind scheme can also be applied to a MIMO system.