Dynamic LUT Digital Correction for Varying Nonlinear Amplifiers
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Solution Overview
Problem
Existing digital pre-distortion (DPD) techniques struggle to adapt quickly to dynamically varying non-linear systems, such as power amplifiers in 5G and beyond wireless communication standards, due to the complexity and impracticality of fast adaptation algorithms.
Innovation Solution
A digital correction system that uses look-up tables (LUTs) addressed by dynamically varying parameters like average power and beam index, allowing for slow adaptation and interpolation/extrapolation to capture dynamic changes without requiring fast adaptation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If fast adaptation algorithms are used to track dynamic changes in non-linear systems, then the system can adapt quickly to varying conditions, but the complexity and practical implementation become prohibitively difficult
Solution Approach 1:
The patent segments the adaptation problem by dividing the dynamically varying parameters into discrete, pre-defined states (e.g., different average power levels, different beam indices). Instead of continuous fast adaptation, the system uses multiple pre-characterized models corresponding to different parameter states, selecting the appropriate model based on current conditions. This segmentation transforms a complex continuous adaptation problem into a manageable discrete selection problem.
Solution Approach 2:
The patent applies preliminary action by pre-characterizing the non-linear system for multiple static conditions (different power levels, beam configurations) before actual operation. Look-up tables are pre-computed and stored for various parameter combinations. During runtime, the system simply selects the pre-computed model matching current conditions, eliminating the need for complex real-time adaptation algorithms while maintaining accuracy.
2Reliability
If traditional DPD techniques are used for dynamically varying systems, then linearization can be achieved for static conditions, but the system fails to track fast changes in power and beam configurations
Solution Approach 1:
The patent introduces dynamics by making the correction model selectable and adaptable to changing conditions. Instead of a fixed static DPD model, the system dynamically selects among multiple pre-characterized models based on current operating parameters (average power, beam index). This dynamic model selection enables the system to track changes in power and beam configurations while maintaining linearization accuracy for each specific condition.
Solution Approach 2:
The patent introduces an intermediary mechanism - a controller that monitors dynamic parameters (average power, beam index) and selects the appropriate pre-characterized model from look-up tables. This intermediary layer bridges the gap between static model characterization and dynamic operating conditions, enabling accurate linearization across varying conditions without requiring the model itself to change rapidly.
3Reliability
If multiple pre-characterized models are used to cover different operating conditions, then accuracy across dynamic ranges improves, but memory requirements and model selection complexity increase
Solution Approach 1:
The patent applies universality by designing a multi-functional correction system where a single selectable model structure serves multiple operating conditions. Instead of requiring completely separate correction circuits for each condition, the same model framework is reused across different power levels and beam configurations by simply changing the selected parameters and coefficients from pre-stored look-up tables, reducing overall system complexity and memory requirements.
Data Source
AI summary
A system and method for digital correction for a dynamically varying non-linear system. The system includes a correction circuitry including at least one look-up table (LUT). The correction circuitry is configured to receive an input signal and modify the input signal to be processed by the non-linear system using at least one LUT to correct non-linearity incurred by the non-linear system. The at least one LUT is addressed by a magnitude or power of the input signal and a dynamically varying parameter associated with the input signal. The dynamically varying parameter may be one of average signal power of the input signal, a differential of the average power of the input signal, a directional beam index, or temperature.