Low-Complexity Blind I/Q Estimation and Compensation of Wideband Zero-IF Receivers

Frequency-dependent I/Q imbalance has become one of the most important factors affecting wireless communication systems in zero intermediate frequency (zero-IF) receivers, due to the communication bandwidth being wider. In this paper, a robust low-complexity blind estimation calibration scheme for I/Q imbalance is proposed. The imbalance estimation method makes use of the second-order statistics of the received signals, and a closed-form solution with linear complexity is given by reasonable approximation. The simulation results demonstrate the validity of the proposed scheme, which shows that the method can increase the image reject ratio (IRR) of the signals by more than 45dB, and the scheme is quite robust.