Antenna Array Precoding with Distortion-Reducing Matrix
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Solution Overview
Problem
Power amplifiers in wireless communication systems exhibit nonlinear characteristics and drift over time due to temperature changes, voltage variations, and channel changes, leading to distortion that existing technologies struggle to manage effectively.
Innovation Solution
Implement a distortion reducing matrix in the signal processing chain to minimize error signals at power amplifier outputs, combined with digital pre-distortion models to compensate for nonlinear distortions, and update the matrix coefficients in response to changes in PA behavior or coupling effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If power amplifiers operate near saturation region to improve efficiency, then power efficiency is improved, but nonlinear distortion increases
Solution Approach 1:
The patent applies digital predistortion processing before the power amplifier to pre-compensate for nonlinear distortions. The predistorter modifies the input signal in advance to counteract the expected nonlinear behavior of the PA operating near saturation, thereby maintaining both high efficiency and low distortion
Solution Approach 2:
The patent implements feedback mechanisms to monitor and adjust for PA characteristics drift over time. By continuously measuring output distortions and adjusting predistortion parameters, the system maintains optimal performance despite temperature changes, voltage variations, and component aging
2Object-generated harmful factors
If digital predistortion models are used to compensate nonlinear distortion, then distortion compensation is improved, but model complexity and processing requirements increase
Solution Approach 1:
The patent focuses predistortion efforts on the most significant distortion components rather than attempting to compensate all nonlinearities perfectly. By targeting the dominant distortion mechanisms, the system achieves effective compensation with simpler, more computationally efficient models
Solution Approach 2:
The patent adapts predistortion model parameters dynamically based on operating conditions such as temperature, voltage, and input power level. This allows the use of simpler models that can be adjusted through parameter changes rather than requiring complex structural modifications to handle varying operating conditions
3Reliability
If PA characteristics are managed to reduce distortion drift over time, then signal quality is improved, but system complexity and management overhead increase
Solution Approach 1:
The patent implements self-calibration and adaptive algorithms that automatically adjust predistortion parameters based on measured performance. The system monitors its own distortion characteristics and performs self-correction without requiring external intervention or complex manual management, thereby maintaining signal quality with minimal overhead
Data Source
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AI summary
An apparatus may be configured to receive a signal to be transmitted via an array of antennas by a zero-forcing precoder, wherein the signal is processed by the linear precoder based on one or more input power criteria for power amplifiers of the array of antennas; apply a distortion reducing matrix to the processed signal, wherein the distortion reducing matrix is trained to reduce the distortion at each output of the power amplifiers based on minimizing an error signal corresponding to a difference between measured and calculated outputs of the power amplifiers after a coupling effect between the power amplifiers based on the applied matrices; and provide an output of the distortion reducing matrix to be used in digital pre-distortion processing of an input signal for the power amplifiers.