Multi-Channel Predistortion With Mutual Coupling Filtering
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Solution Overview
Problem
In 5G millimeter wave communication systems, the coupling interference between digital channels affects the performance of MIMO beamforming systems due to the absence of a circulator between the power amplifier and the antenna element, leading to significant nonlinear distortion.
Innovation Solution
A signal distortion pre-correction method involving mutual coupling filtering and predistortion processing is implemented, where mutual coupling filter parameters and predistortion coefficients are trained using feedback signals from a multi-channel coupling element to reduce interference and improve distortion correction accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If digital pre-distortion technology is used to correct nonlinear distortion of multiple PAs simultaneously, then distortion improvement effect is enhanced, but coupling interference between digital channels affects power amplifier characteristics
Solution Approach 1:
The patent divides the correction process into two independent stages: first performing mutual coupling filtering to eliminate interference between channels, then performing predistortion correction on each channel separately. This segmentation allows each stage to focus on a specific problem without interference from the other, resolving the contradiction between achieving high distortion correction accuracy and avoiding coupling interference effects on power amplifier characteristics
Solution Approach 2:
The patent applies mutual coupling filtering as a preliminary action before predistortion correction. By removing coupling interference first, the subsequent predistortion process operates on clean, isolated channel signals, ensuring that the power amplifier characteristics are not affected by inter-channel interference while maintaining high distortion correction accuracy
2Productivity
If one digital channel is connected with multiple analog radio frequency channels in MIMO beamforming system, then system capacity and spectrum utilization are improved, but designing predistorter to correct multiple PAs simultaneously increases device complexity
Solution Approach 1:
The patent segments the complex predistorter design into two independent modules: a mutual coupling filter module that handles inter-channel interference, and a predistortion module that corrects nonlinear distortion. This segmentation simplifies the overall design complexity while maintaining the ability to handle multiple PAs simultaneously, thus preserving high system capacity
Solution Approach 2:
The patent introduces mutual coupling filtering as an intermediary processing stage between the digital channel signals and the predistortion correction. This intermediary module eliminates coupling interference before signals reach the predistorters, allowing each predistorter to be designed more simply while still achieving the required correction performance for multiple PAs
Data Source
AI summary
The embodiments of the present application relate to the field of communications, and provide a signal distortion pre-correction method, a signal distortion pre-correction device, and a non-volatile storage medium. In the present application, the mutual coupling filtering parameters and the predistortion coefficient candidate set are obtained by training the feedback signal collected by the multi-channel coupling element, so that the mutual coupling filtering processing can be performed on the forward signal of the digital channel according to the obtained mutual coupling filtering parameter, to make the target predistortion coefficient selected in the predistortion coefficient candidate set according to the forward signal after mutual coupling filtering and the forward signal of the digital channel to be processed to be the predistortion coefficient considering the mutual coupling factor of the digital channel.