Over-the-Air Digital Predistortion of 5G FR2 Beamformer Array by Exploiting Linear Response Compensation

A method for the complexity assessment in the context of digital predistortion (DPD) of beamformer arrays is proposed. The technique, demonstrated by over-the-air measurements at 28 GHz, is based on a position-dependent equalization of the linear response of the transmitter by the best linear approximation (BLA) approach. Such a compensation, demonstrated by using different levels of complexity for the equalization as well as for the predistorter model enhances the linearization performance and allows for the analysis of the residual distortion when a unique set of DPD coefficients is used across different beam angles and receiver positions.