Digital Predistortion Adaptation for Multiple Power Amplifiers
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Solution Overview
Problem
Existing digital predistortion (DPD) systems for power amplifiers (PAs) are resource-intensive and expensive when trained for individual PAs with different nonlinearities, making it challenging to provide an effective pre-distorted signal for multiple PAs with varying characteristics.
Innovation Solution
A single DPD circuit is adapted to generate a pre-distorted signal suitable for multiple PAs by using an adaption circuit that generates predistortion parameters based on feedback signals from each PA, updating predistortion correlation data and coefficients to account for the unique nonlinearities of each PA, allowing the DPD circuit to provide a pre-distorted signal that can be used across multiple PAs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a separate DPD circuit is trained for each PA with different nonlinearities, then signal quality and distortion reduction are improved, but device complexity and cost increase
Solution Approach 1:
The patent implements a single DPD circuit that can be adapted to work with multiple PAs having different nonlinearities. The adaption circuit enables the DPD to generate different predistortion parameters for each PA, making the system universal rather than requiring dedicated DPD circuits for each PA. This resolves the contradiction by maintaining high signal quality across multiple PAs while avoiding the complexity of multiple separate DPD circuits.
Solution Approach 2:
The patent changes the parameters of the DPD circuit through the adaption circuit, which generates specific predistortion parameters based on feedback from each PA. By dynamically adjusting the predistortion parameters rather than using fixed circuit configurations, the system achieves PA-specific optimization without requiring separate hardware circuits for each PA, thus resolving the contradiction between signal quality and device complexity.
2Object-generated harmful factors
If a separate DPD circuit is trained for each PA with different nonlinearities, then distortion reduction is improved, but manufacturing cost increases
Solution Approach 1:
The patent employs a universal DPD circuit design that can serve multiple PAs through parameter adaption rather than requiring separate dedicated circuits for each PA. This single-circuit-multiple-PAs approach significantly reduces manufacturing cost while maintaining the ability to correct distortion for each individual PA through the adaption circuit's parameter generation capability.
Solution Approach 2:
By implementing dynamic parameter changes through the adaption circuit, the patent enables a single DPD circuit to achieve PA-specific distortion correction. This eliminates the need for expensive custom-trained hardware circuits for each PA, reducing manufacturing costs while maintaining effective distortion reduction through software-controlled parameter adjustment.
3Device complexity
If a single DPD circuit is used for multiple PAs, then device complexity and cost are reduced, but adaptability to different PA nonlinearities deteriorates
Solution Approach 1:
The patent incorporates a feedback mechanism where the output of each PA is fed back to the adaption circuit. This feedback enables the adaption circuit to measure the actual performance of each PA and adjust the predistortion parameters accordingly, ensuring high adaptability to different PA nonlinearities while using a single DPD circuit, thus resolving the contradiction between device complexity and adaptability.
Solution Approach 2:
The adaption circuit dynamically changes the predistortion parameters based on feedback from each PA, enabling a single DPD circuit to adapt to different PA characteristics. This parameter-based adaption approach provides the versatility needed to handle multiple PAs with different nonlinearities without requiring separate hardware circuits for each, resolving the contradiction between device complexity and adaptability.
Data Source
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AI summary
Various examples are directed to systems and methods for operating a plurality of power amplifiers. A predistortion circuit may pre-distort an input signal according to a predistortion configuration to generate a pre-distorted signal for the plurality of power amplifiers. An adaption circuit may receive a first feedback signal from a first power amplifier of the plurality of power amplifiers and generate predistortion correlation data describing a correlation between parameters of a model describing the plurality of power amplifiers. The adaption circuit may receive a first feedback signal from a second power amplifier of the plurality of power amplifiers and update the predistortion correlation data to generate updated predistortion correlation data using the first feedback signal from the second power amplifier. The adaption circuit may also generate the predistortion configuration using the updated predistortion correlation data.