Shared Digital Predistortion for Multiband IMD Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Active repeater systems in wireless communication suffer from intermodulation distortion (IMD) due to power amplifiers operating in a non-linear region, leading to increased system costs from the need for digital pre-distortion (DPD) circuitry and data converters.
Innovation Solution
The implementation of a multiband front-end system that reduces the number of digital pre-distortion circuitry and data converters by using a single DPD system to diminish IMD products across multiple transmit bands, and adjusting the center frequency of the DPD correction bandwidth to encompass both downlink and uplink bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If digital pre-distortion circuitry is added to each power amplifier to diminish intermodulation distortion, then intermodulation distortion is reduced, but system cost increases
Solution Approach 1:
The patent combines multiple DPD circuitries into a single shared DPD system that serves multiple power amplifiers across different frequency bands. The DPD system processes signals for multiple bands through a unified architecture, eliminating the need for separate DPD circuitry for each power amplifier, thereby reducing system cost while maintaining intermodulation distortion reduction.
Solution Approach 2:
The DPD system is designed to perform multiple functions by handling signals from different frequency bands simultaneously. A single DPD system is configured to process and correct intermodulation distortion for multiple transmit bands, making the system universal and reducing the overall number of DPD components required in the multi-band repeater system.
2Measurement precision
If multiple data converters are used for each power amplifier band, then signal processing accuracy is maintained, but system cost increases
Solution Approach 1:
The patent merges multiple data converters into a single shared data converter that processes signals for multiple frequency bands. The data converter is configured to convert digital signals for different bands sequentially or through time-division multiplexing, maintaining signal processing accuracy while reducing the total number of data converters and associated costs in the system.
3Device complexity
If a single DPD system is used for multiple bands, then system cost is reduced, but the DPD correction bandwidth must cover multiple frequency bands
Solution Approach 1:
The DPD system employs dynamic bandwidth adjustment capability where the correction bandwidth is adaptively configured based on the active transmit bands. The system can dynamically expand or adjust its correction bandwidth to cover the required frequency ranges, allowing a single DPD system to handle multiple bands effectively while maintaining optimal performance for each band.
Data Source
Figure 1
Figure 2A~2B
Figure 3
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.