Multi-Band RF Amplifier Feedback Sharing for Signal Linearization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In wireless RF networks, existing solutions for managing multiple frequency bands with power amplifiers face challenges in linearization and gain control, particularly due to significant group delay and inter-modulation issues, which affect the efficiency and accuracy of signal transmission.
Innovation Solution
The implementation of a radio apparatus with multiple amplifiers for different frequency bands, utilizing digital predistorters and a common feedback path for linearization, along with gain controllers and post-scaling controllers to minimize group delay effects and optimize signal gain, while routing signals at non-overlapping times to prevent interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If multiple power amplifiers are used to cover different frequency bands, then power efficiency is improved, but device complexity increases due to multiple amplifiers and routing requirements
Solution Approach 1:
The patent combines multiple frequency band processing paths into a single shared feedback path and uses a common digital predistorter for linearization. The output signals from multiple power amplifiers are multiplexed onto one feedback path, reducing the number of separate feedback paths and predistorters needed, thus lowering device complexity while maintaining power efficiency
Solution Approach 2:
The common feedback path and shared digital predistorter serve multiple frequency bands simultaneously. The routing mechanism allows a single feedback path to handle feedback from multiple power amplifiers covering different bands, making the system more universal and reducing redundant components
2Device complexity
If a common feedback path is used for multiple amplifiers, then device complexity is reduced, but signal interference occurs due to overlapping signal routing
Solution Approach 1:
The patent employs time-division multiplexing where the routing mechanism alternates between connecting different amplifier output signals to the common feedback path at non-overlapping time intervals. This periodic switching ensures that only one amplifier's output is present on the feedback path at any given time, eliminating signal interference while maintaining a common feedback path structure
Solution Approach 2:
The routing mechanism is configured to switch amplifier connections to the feedback path in advance of potential interference issues. By controlling the timing of signal routing before overlap occurs, the system prevents interference proactively rather than reactively
3Measurement precision
If digital predistorters are applied to minimize group delay effects, then signal accuracy is improved, but processing time increases due to additional processing steps
Solution Approach 1:
The patent merges the linearization processing for multiple frequency bands into a single shared digital predistorter. Instead of implementing separate predistorters for each band that would process signals in parallel, the system uses one predistorter with time-division multiplexing, reducing total processing time while maintaining accuracy through the application of predistortion to each band sequentially
Data Source
AI summary
An apparatus is disclosed, comprising means for providing two or more amplifiers for amplifying signals in two or more respective frequency bands, receiving a composite signal comprising first and second predistorted input signals in first and second frequency bands and filtering the composite signal to provide (i) the first predistorted signal for input to a first amplifier of the two or more amplifiers for producing an amplified first output signal and (ii) the second predistorted signal for input to a second amplifier of the two or more amplifiers for producing an amplified second output signal. The apparatus may also comprise means for routing, at non-overlapping times, the first and second output signals to a common feedback path and for linearizing received first and second input signals based on the respective first and second output signals received on the common feedback path.