Power Amplifier Predistortion With Adaptive Parameter Updating
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Solution Overview
Problem
Wireless communication devices face signal distortion due to the nonlinearity of power amplifiers, leading to reduced signal quality, disrupted connections, and interruptions in data transfer.
Innovation Solution
A device and method that utilize a pre-distortion circuit to pre-distort input signals based on a parameter set, including coefficients, and an iterative approximation operation to minimize differences between intermediate and output signals, using an indirect training structure and conjugate gradient method to compensate for power amplifier nonlinearity in real-time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional nonlinearity compensation methods are used, then signal quality can be improved, but the number of operations increases and real-time characteristics changes are not reflected
Solution Approach 1:
The patent applies preliminary action by pre-distorting the input signal before amplification to compensate for anticipated nonlinearity effects. The pre-distortion circuit modifies the signal in advance based on stored characteristic data, so that when the signal passes through the power amplifier, the nonlinearity effects are already compensated. This approach improves signal quality without requiring complex real-time calculations during operation.
Solution Approach 2:
The patent uses copying by storing characteristic data of the power amplifier in a separate storage unit. Instead of performing complex calculations directly on the signal path, the system creates a copy of the amplifier's characteristic behavior and uses this copied information to generate compensation parameters. This separates the computational complexity from the signal processing path, reducing the number of operations needed during real-time operation.
2Device complexity
If fixed parameter compensation is used, then device complexity is reduced, but adaptability to real-time changes in power amplifier characteristics is lost
Solution Approach 1:
The patent implements dynamics by making the compensation parameters adaptive rather than fixed. The system includes a parameter generation unit that creates compensation parameters based on stored characteristic data, allowing the compensation to dynamically adjust to changes in power amplifier characteristics. This dynamic approach maintains relatively simple device structure while improving adaptability to real-time changes.
Solution Approach 2:
The system applies self-service by using the power amplifier's own characteristic data to generate its compensation parameters. The storage unit stores characteristic data obtained from the power amplifier, and the parameter generation unit uses this self-generated data to create appropriate compensation parameters. This eliminates the need for external calibration or fixed parameters, enabling the system to self-adjust to real-time changes.
3Manufacturing precision
If pre-distortion is applied, then signal distortion is reduced, but the accuracy of compensation decreases when power amplifier characteristics change over time
Solution Approach 1:
The patent implements feedback by using the stored characteristic data of the power amplifier to continuously inform the compensation process. The system obtains characteristic data from the power amplifier, stores it, and uses this feedback information to generate accurate compensation parameters. This feedback mechanism ensures that the pre-distortion remains accurate even when power amplifier characteristics change over time, as the compensation parameters are based on actual measured characteristics rather than theoretical models.
Data Source
AI summary
Systems and methods are described to perform wireless communication. The device includes a pre-distortion circuit configured to pre-distort an input signal based on a parameter set including a plurality of coefficients and generate a pre-distorted signal, a power amplifier configured to amplify the pre-distorted signal and generate an output signal, and a parameter obtaining circuit configured to perform an iterative approximation operation based on the output signal and the pre-distorted signal, which change over time, according to an indirect training structure configured to minimize a difference between an intermediate signal obtained based on the output signal and the pre-distorted signal, and obtain the parameter set.