Hybrid Beamforming PA Linearization With Single DPD Feedback
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In multi-antenna systems with hybrid beamforming, the high number of digital predistortion (DPD) units required for power amplifier linearization increases power consumption and complexity, as each DPD unit must handle multiple power amplifiers with different magnitudes, making it challenging to achieve efficient linearization and adapt to changing conditions.
Innovation Solution
A power-efficient architecture that uses a single digital predistortion model to control parallel power amplifiers through beamforming factors, adjusting phase and magnitude shifters, and power amplifier control units to minimize the number of DPD units and optimize operating parameters, allowing for similar non-linear behavior across power amplifiers, thereby reducing errors and increasing bandwidth for higher-order modulation schemes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single digital predistortion model is used to control parallel power amplifiers, then device complexity and power consumption are reduced, but the ability to handle different magnitudes and non-linear behaviors of individual power amplifiers becomes more challenging
Solution Approach 1:
The patent combines multiple power amplifier outputs into a single composite signal that is fed back to a single DPD unit. By merging the parallel PA paths into a unified feedback loop, the system reduces the number of DPD units from multiple to one, thereby reducing device complexity and power consumption while maintaining linearization capability through the combined feedback signal.
Solution Approach 2:
The single DPD unit is designed to handle the composite signal from multiple power amplifiers with different magnitudes. The universal DPD model processes the combined feedback signal to generate predistortion parameters that compensate for the non-linear behaviors of all PAs collectively, making the DPD unit multi-functional rather than requiring dedicated units for each PA.
2Reliability
If multiple DPD units are used for each antenna pipe, then linearization accuracy is improved, but power consumption increases
Solution Approach 1:
The patent merges the feedback paths of multiple power amplifiers into a single composite feedback signal. By combining the outputs of multiple PAs and feeding them to a single DPD unit, the system eliminates the need for multiple separate DPD units, thereby reducing power consumption while maintaining the linearization function through the unified feedback mechanism.
3Reliability
If dedicated signals are provided to each antenna pipe for linearization, then linearization performance is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple dedicated linearization paths into a single unified path. By merging the feedback signals from multiple antenna pipes and using a single DPD unit to process the composite signal, the system reduces structural complexity while preserving linearization performance through the combined feedback approach.
Solution Approach 2:
The single DPD unit serves multiple antenna pipes simultaneously by processing the composite feedback signal. This universal approach allows one DPD unit to perform the linearization function for multiple PAs with different magnitudes, eliminating the need for dedicated DPD units for each antenna pipe and thereby reducing overall system complexity.
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
There is provided power efficient and simple structure for linearizing power amplifiers' outputs in multi-antenna beamforming systems. Beamforming factors are obtained for controlling transmission beams of the antennas in an analogue/hybrid beamforming system. At least one power amplifier model is determined on the basis of the power amplifiers' outputs and the beamforming factors. Predistortion parameters, for feeding a predistorted signal to power amplifiers for linearizing the power amplifiers' outputs, are determined such that after the operating parameters of the power amplifiers have been adjusted, errors in power amplifiers' outputs are reduced.