A widely nonlinear approach to compensate impairments in I/Q modulators

A novel approach to model impairments in I/Q modulators is presented. The proposal is based on the use of double Volterra series for the I and Q branches. The new model has been shaped as a digital predistorter that can be applied to the compensation of I/Q imbalance, and it has been experimentally validated on a commercial I/Q modulator with superimposed artificial impairments. Measurement results with LTE test signals are compared with other approaches and confirm that the proposed method effectively accomplishes the reduction of carrier leakage, spectral regrowth, and in-band distortion. Performance metrics are within the state-of-the-art, but nearly halving the coefficients of the reference method.