Power Amplifier Linearization Using Multi-Route Digital Predistortion
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Solution Overview
Problem
Power amplifiers in mobile communication systems face inefficiency and distortion due to multiple distortion generating sources, limiting their ability to provide linear amplification and maintaining signal quality, especially with increasing peak-to-average power ratio (PAPR) and memory effects.
Innovation Solution
A method and apparatus utilizing multiple digital predistortion compensators to address the non-linear characteristics and memory effects of different distortion sources, with a signal division unit selecting the appropriate predistortion route based on the input signal amplitude and combining predistorted signals to compensate for these distortions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a power amplifier operates at a back off point equal to or greater than the peak-to-average power ratio of a signal to provide linear amplification, then the linear characteristics are improved, but the efficiency characteristic deteriorates to a considerably low level
Solution Approach 1:
The power amplifier is divided into multiple distortion generating sources, each compensated by a separate digital predistortion compensator. This segmentation allows each compensator to target specific distortion characteristics, achieving better overall linearization efficiency
Solution Approach 2:
Digital predistortion is applied to the input signal before amplification to pre-compensate for expected nonlinear distortions. This preliminary action counteracts the distortion that will occur during amplification, enabling the amplifier to operate more efficiently while maintaining linear output characteristics
2Manufacturing precision
If multiple digital predistortion compensators are used to compensate for distortion characteristics of respective distortion generating sources, then the linearization effectiveness is improved, but the device complexity increases
Solution Approach 1:
The distortion compensation function is segmented into multiple specialized compensators, each handling specific distortion generating sources. This segmentation improves compensation precision while allowing independent optimization of each compensator
Solution Approach 2:
The signal division unit and signal combination unit serve as universal components that route signals through appropriate compensators and recombine outputs. These multi-functional units manage the complexity of multiple compensators through centralized control logic
3Measurement precision
If a signal division unit selects one route of multiple digital predistorters based on input signal amplitude, then the compensation accuracy is improved, but the control complexity increases
Solution Approach 1:
Different predistortion routes are selected based on local signal conditions (amplitude levels). Each route is optimized for specific operating conditions, providing locally optimal compensation accuracy without requiring a single complex solution for all conditions
Data Source
AI summary
Disclosed is a method and apparatus for linearizing a power amplifier using a digital signal process (DSP), and particularly, is a method and apparatus for effectively linearizing an amplifier which has a plurality of distortion generating sources. To this end, there is a plurality of compensation methods and compensation units which can generate inverse distortion signals corresponding to the distortion components outputted by the plurality of distortion generating sources, thereby making it possible to provide superior linearity.