Power Amp Linearization Using Digital Pre-distortion in Analog Beamforming Systems

This paper deals with digital pre-distortion (DPD) problem for compensating non-linearity of power amplifier (PA) in analog beamforming (BF) systems. The beamforming system in this work has one digital chain and multiple PAs. As a consequence, the single DPD has to linearize the multiple PAs simultaneously. To design such DPD, this paper proposes a cost function which is the sum of the square errors for all the PAs. The proposed DPD technique combines all the feedback samples from multiple PAs after phase de-rotation, and then the conventional adaptive algorithm finds the DPD parameters. The experiment results show that the proposed DPD can linearize multiple PAs simultaneously in the analog BF systems.