Multi-Antenna Digital Pre-Distortion Without Per-Antenna Feedback
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Solution Overview
Problem
Current digital pre-distortion methods for power amplifiers in wideband multi-carrier wireless communication systems face challenges in achieving high linearity and efficiency, particularly due to the high peak-to-average power ratio and nonlinearity issues, which result in significant out-of-band interference and reduced efficiency, making it difficult to meet the requirements of 3GPP standards.
Innovation Solution
A digital pre-distortion processing method and apparatus that involves transmitting a specifically designed training signal to the radio frequency front-end device, acquiring its output, training, and updating the DPD coefficients as needed, allowing for efficient compensation of nonlinearity without real-time operation and separate configuration for each antenna, thus improving linearity and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If power back-off is applied to ensure linear characteristic of power amplifier, then linearity is improved, but efficiency becomes very low (below 10%)
Solution Approach 1:
The patent applies digital pre-distortion to the input signal before amplification, pre-compensating for the non-linear characteristics of the power amplifier. This allows the amplifier to operate at high power levels without requiring power back-off, thereby maintaining both high efficiency and acceptable linearity through predictive correction rather than reactive compensation
Solution Approach 2:
The patent implements a feedback mechanism where the output signal from the power amplifier is captured, processed, and used to train and update the pre-distortion coefficients. This closed-loop system continuously optimizes the pre-distortion parameters to compensate for amplifier non-linearities, enabling high efficiency operation while maintaining linearity requirements
2Manufacturing precision
If digital pre-distortion with real-time signal tracking is implemented, then linearity is improved, but device complexity and cost increase due to separate configuration for each antenna
Solution Approach 1:
The patent merges the pre-distortion processing functions into a centralized digital baseband unit that serves multiple antennas. Instead of having separate pre-distortion systems for each antenna, a single processing unit generates pre-distorted signals that are distributed to multiple radio frequency front-end devices, significantly reducing device complexity and cost while maintaining linearity performance across all antennas
Solution Approach 2:
The patent creates a universal pre-distortion processing system that can handle multiple antennas and signal types through a single apparatus. The digital baseband unit performs pre-distortion for all antennas using shared resources and algorithms, making the system multi-functional and eliminating the need for separate dedicated systems for each antenna
Data Source
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AI summary
This invention discloses a digital pre-distortion processing method and apparatus, the method including that: training signals are sent to at least one radio frequency front-end device as needed (201); the output training signals of the radio frequency front-end devices are collected through a feedback channel as needed (202); digital pre-distortion (DPD) coefficients of the radio frequency front-end devices are trained as needed (203); after the coefficient training is completed, the DPD coefficients of the corresponding radio frequency front-end devices are updated as needed. There is no need to track the variation of the signals all the time and to compare the signals with a long-time statistical signal template to trigger the training in the invention. The invention can accommodate a multi-antennas application without configuring a corresponding digital pre-distortion feedback channel and coefficient training module separately for each antenna, thereby when the antennas are increased, the volume and cost are not increased and the invention can be of good feasibility from the perspective of commercialization.