Shared Digital Pre-Distortion for Multi-Band Power Amplifiers
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Solution Overview
Problem
Active repeater systems in wireless communication suffer from intermodulation distortion due to power amplifiers operating at saturation, leading to increased costs from the need for multiple digital pre-distortion circuitries for each power amplifier across different RF transmit bands.
Innovation Solution
Implementing a method with at least two parallel power amplifiers, each operating in a unique transmit band, and using a single digital pre-distortion system to pre-distort signals based on corresponding power amplified signals, thereby diminishing intermodulation distortion products across multiple bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If multiple digital pre-distortion circuitries are used for each power amplifier across different RF transmit bands, then intermodulation distortion is effectively reduced, but system cost increases
Solution Approach 1:
The patent combines multiple digital pre-distortion circuitries into a single shared circuitry that serves multiple power amplifiers across different RF transmit bands. The DPD system is configured to receive feedback signals from multiple power amplifiers and generate pre-distorted output signals for each band, thereby reducing the total number of DPD circuitries while maintaining effective IMD reduction across all bands.
Solution Approach 2:
The single digital pre-distortion system is designed to perform multiple functions by handling signals from different RF transmit bands simultaneously. The DPD system processes feedback signals from multiple power amplifiers and generates appropriate pre-distorted signals for each unique transmit band, making the circuitry universal rather than dedicated to a single band or amplifier.
2Measurement precision
If multiple data converters are used for each power amplifier, then signal processing accuracy is improved, but system cost increases
Solution Approach 1:
The patent merges multiple data converters into a single shared data converter that processes feedback signals from multiple power amplifiers. The data converter is configured to convert analog feedback signals to digital signals for the DPD system, reducing the total number of data converters while maintaining signal processing accuracy through proper signal routing and processing.
3Use of energy by moving object
If power amplifiers operate at saturation for higher power added efficiency, then power efficiency is improved, but intermodulation distortion increases
Solution Approach 1:
The patent applies preliminary action by pre-distorting the input signals to power amplifiers before they are amplified. The DPD system modifies the input signals to compensate for the non-linear behavior of power amplifiers operating at saturation, thereby maintaining high power added efficiency while pre-canceling the intermodulation distortion that would otherwise be generated during amplification.
Solution Approach 2:
The patent implements feedback by routing a portion of the output signal from each power amplifier back to the DPD system. This feedback signal is used to continuously adjust and optimize the pre-distortion parameters, ensuring that the DPD system effectively compensates for the non-linear behavior of power amplifiers operating at saturation and minimizes intermodulation distortion.
Data Source
AI summary
A method is provided. The method, comprises: power amplifying, with at least two parallel power amplifiers, at least two pre-distorted signals each corresponding to a unique transmit band, wherein each power amplifier operates in a unique transmit band; and pre-distorting, with a single pre-distortion system, at least two signals in different transmit bands, where the pre-distortion of each of the at least two signals is based upon a portion of a corresponding power amplified, pre-distorted signal, and where the pre-distortion diminishes certain IMD products in the corresponding power amplified, pre-distorted signal.