Joint CFO and I/Q Imbalance Estimation for OFDM Systems Exploiting Constant Modulus Subcarriers

In this paper, we propose blind methods to jointly estimate carrier frequency offset and in-phase/quadrature-phase imbalance for orthogonal frequency-division multiplexing (OFDM) systems exploiting constant modulus subcarriers. The proposed algorithms support fully loaded transmissions, which enhance the spectral efficiency. Other advantages of the proposed algorithms include: 1) they work well with only one received OFDM block and thus belong to the category of one-shot estimation methods; 2) they are computationally efficient; and 3) they outperform the existing methods. Simulation results and Cramer-Rao bound are provided to demonstrate the superiority of our methods compared to the existing methods.