Non-data-aided I/Q mismatch estimation in low-IF receivers

A digital signal processing (DSP) technique is presented that can compensate for the I/Q mismatch in low-IF receivers. In particular, a non-data-aided (NDA) I/Q mismatch estimator is derived by exploiting the statistical independence between the desired and image signals. The mean square error (MSE) of the estimate is analyzed. Computer simulation results indicate that the proposed technique can outperform existing adaptive DSP techniques that are based on the use of blind signal separation algorithms. It is observed that the image rejection ratio (IRR) of the proposed technique decreases monotonically with the number of observed samples for estimation, while that of conventional methods exhibits some floor.