# Digital Predistortion in Large-Array Digital Beamforming Transmitters

## TL;DR

This paper introduces a new digital predistortion method for large-array transmitters that simplifies linearization by using only one DPD for multiple power amplifiers, reducing complexity and energy consumption.

## Contribution

The paper presents a novel DPD approach that linearizes multiple PAs with a single DPD, unlike existing methods requiring one per PA, suitable for large-scale antenna arrays.

## Key findings

- Single DPD effectively linearizes multiple PAs in large arrays.
- Significant reduction in complexity and energy consumption.
- Partial suppression of emissions in non-target directions.

## Abstract

In this article, we propose a novel digital predistortion (DPD) solution that allows to considerably reduce the complexity resulting from linearizing a set of power amplifiers (PAs) in single-user large-scale digital beamforming transmitters. In contrast to current state-of-the art solutions that assume a dedicated DPD per power amplifier, which is unfeasible in the context of large antenna arrays, the proposed solution only requires a single DPD in order to linearize an arbitrary number of power amplifiers. To this end, the proposed DPD predistorts the signal at the input of the digital precoder based on minimizing the nonlinear distortion of the combined signal at the intended receiver direction. This is a desirable feature, since the resulting emissions in other directions get partially diluted due to less coherent superposition. With this approach, only a single DPD is required, yielding great complexity and energy savings.