Power Amplifier Predistortion Across Segmented Frequency Bands
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Solution Overview
Problem
Power amplifiers in wireless communication devices exhibit nonlinearity, leading to distortion in RF output signals, especially at higher frequencies and in antenna arrays, which complicates pre-distortion compensation and results in degraded communication quality and increased bit errors.
Innovation Solution
A device and method that perform adaptive pre-distortion across various frequency bands using a pre-distortion circuit, power amplifier, and parameter obtaining circuit, which divide the frequency band into sections to obtain memory polynomial modeling information, reducing memory storage requirements and enhancing pre-distortion accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pre-distortion is applied to compensate for power amplifier nonlinearity across the entire frequency band, then communication quality is improved, but memory storage requirements increase significantly
Solution Approach 1:
The frequency band is divided into multiple frequency sections, and pre-distortion is applied selectively to sections where nonlinearity is significant. This segmentation allows the system to maintain communication quality in critical bands while reducing memory storage by not storing pre-distortion coefficients for all frequency bands.
2Measurement precision
If pre-distortion coefficients are stored for all frequency bands, then pre-distortion accuracy is improved, but device complexity increases
Solution Approach 1:
Different frequency sections are treated differently based on their nonlinearity characteristics. The system identifies and applies pre-distortion only to frequency sections where it is most beneficial, rather than uniformly across all bands, thereby optimizing accuracy while reducing complexity.
3Reliability
If digital pre-distortion is used to reduce distortion in gain compression region, then bit errors are reduced, but the method becomes less effective at higher RF frequencies
Solution Approach 1:
The system dynamically adapts the pre-distortion application based on the operating frequency band. At higher RF frequencies where mutual coupling affects power amplifiers, the system adjusts which frequency sections receive pre-distortion, making the solution effective across varying frequency conditions rather than being static.
Data Source
AI summary
A device configured to perform wireless communication includes: a pre-distortion circuit configured to generate a pre-distorted input signal by performing pre-distortion on an input signal based on a parameter set comprising a plurality of coefficients; a power amplifier configured to generate an output signal by amplifying an RF signal based on the pre-distorted input signal; and a parameter obtaining circuit configured to obtain second memory polynomial modeling information corresponding to an operating frequency band based on first memory polynomial modeling information corresponding to each of a plurality of frequency sections and obtain a parameter set according to an indirect learning structure by using the second memory polynomial modeling information.