Power-Amplifier Linearization with Multi-Rate Hybrid Predistortion
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Solution Overview
Problem
Existing power amplifier (PA) linearization methods for future wireless communications, such as 6G mobile networks, face significant challenges due to high sampling and processing rates, leading to high implementation costs and complexity, especially with increased signal bandwidth and carrier frequencies.
Innovation Solution
A method for adaptively estimating power amplifier distortion coefficients using a multi-rate hybrid predistortion technique with reduced sampling rates and resolution, employing asynchronous accumulation and averaging, and pseudo-preambles with varying lengths to mitigate low resolution and sampling rate impacts, while using memoryless and memory polynomial predistortion functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high sampling rates and high resolution ADC are used in predistortion systems, then PA linearization accuracy is improved, but device complexity and implementation cost increase significantly
Solution Approach 1:
The patent segments the predistortion system into multiple modules (baseband module, Tx chain, feedback loop) operating at different sampling rates. The baseband module operates at a lower sampling rate while the feedback loop operates at a higher sampling rate, allowing each module to be optimized independently for its specific function rather than requiring all modules to operate at the highest possible rate
Solution Approach 2:
The patent implements adaptive sampling rate adjustment where the feedback loop dynamically adjusts its sampling rate based on the instantaneous signal characteristics and distortion estimation requirements. This allows the system to use high sampling rates only when needed for accurate distortion measurement, while using lower sampling rates during normal operation to reduce complexity
2Measurement precision
If high sampling rates are used in feedback loop, then distortion estimation accuracy is improved, but implementation cost increases
Solution Approach 1:
The patent applies partial action by using high sampling rates only partially - specifically in the feedback loop only when needed for accurate distortion measurement, rather than continuously throughout the entire system. The baseband module and Tx chain operate at lower sampling rates, reducing the overall hardware cost while maintaining sufficient accuracy where required
3Measurement precision
If high resolution ADC is used in feedback loop, then distortion measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The patent applies local quality by assigning different resolution requirements to different parts of the system. The feedback loop uses high resolution ADC only for distortion measurement functions, while the baseband module and Tx chain can use lower resolution converters since they operate at lower sampling rates and have different functional requirements
Data Source
AI summary
A method for adaptively estimating distortion coefficients of a power amplifier for compensating distortion of the power amplifier, the method has the steps of: estimating the power-amplifier distortion coefficients based on a first digital signal for generating a radio-frequency analog signal through the power amplifier, and a second digital signal obtained from the radio-frequency analog signal. The first digital signal has a length adaptively variable based on a predefined distortion-estimation accuracy.