RF Power Amplifier Predistortion for In-Band and Out-of-Band Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current wireless transmission devices face challenges with in-band distortion and out-of-band component growth due to the non-linear nature of RF power amplifiers, leading to adjacent channel interference and requiring complex predistortion processes that consume significant computation resources and suffer from unstable numerical convergence.
Innovation Solution
A signal predistortion method involving separate in-band and out-of-band predistortion circuits and filters, along with computation circuits, to generate a full-band predistortion signal that compensates for both in-band and out-of-band distortions effectively, reducing computational complexity and improving numerical stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If digital predistortion technology is used to compensate signals before power amplifier input, then in-band distortion and out-of-band components are reduced, but computation resources are significantly consumed and numerical convergence becomes unstable
Solution Approach 1:
The patent divides the predistortion process into two independent segments: in-band predistortion and out-of-band predistortion. Each segment has its own dedicated circuit and parameter set, allowing separate optimization and calculation. This segmentation reduces the overall computational complexity while maintaining comprehensive distortion compensation across both in-band and out-of-band frequencies.
2Reliability
If complicated predistortion process is implemented to address memory effect, then signal quality is improved, but computation resources are exhausted and numerical convergence is unstable
Solution Approach 1:
The patent separates memory effect compensation into distinct in-band and out-of-band components, each with dedicated parameter sets. This allows the system to address memory effects across different frequency ranges independently, improving signal reliability without requiring a single overly complex computation process that would exhaust resources.
3Device complexity
If single predistortion parameter set is used for both in-band and out-of-band frequencies, then device complexity is reduced, but cancellation of out-of-band components becomes ineffective
Solution Approach 1:
The patent implements separate parameter sets specifically for in-band and out-of-band predistortion. The first parameter set handles in-band frequencies while the second parameter set handles out-of-band frequencies, ensuring that each frequency range receives optimized compensation parameters tailored to its specific characteristics, thereby improving out-of-band component cancellation effectiveness.
Solution Approach 2:
The patent applies different predistortion parameters locally optimized for specific frequency ranges. Instead of using a uniform parameter set across all frequencies, the system provides localized parameter optimization where in-band frequencies receive one set of parameters and out-of-band frequencies receive another, ensuring precise compensation for each band's unique distortion characteristics.
Data Source
AI summary
A signal predistortion method applied to a transmission device. The transmission device includes a signal processing circuit, a transmission chain and a power amplifier, the power amplifier is configured to amplify a radio-frequency (RF) input signal outputted by the transmission chain to generate a RF output signal. The signal predistortion method includes: performing a first signal processing operation on a baseband signal by the signal processing circuit, to generate an in-band predistortion output; performing a second signal processing operation on the in-band predistortion output by the signal processing circuit, to generate an out-of-band predistortion output; and generating a full-band predistortion signal to the transmission chain according to the in-band predistortion output and the out-of-band predistortion output by the signal processing circuit, so that the transmission chain generates the RF input signal according to the full-band predistortion signal.