Amplifier Control for Active Antenna Systems
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Solution Overview
Problem
Active antenna systems face challenges with non-linear power amplifiers causing spectral regrowth and mutual coupling, leading to increased computational resources and power consumption in digital pre-distortion techniques, which can result in coverage loss when power amplifier back-off is applied.
Innovation Solution
A method and apparatus that selectively control amplifiers to operate in a reduced power mode or predistortion mode based on signal quality parameters such as SINR, path loss, or positional information, allowing for efficient use of predistortion techniques and minimizing coverage loss by determining the appropriate mode of operation for each user equipment device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If digital pre-distortion techniques are used to compensate for power amplifier non-linearity, then spectral regrowth is reduced and ACLR is improved, but computational resources and power consumption increase
Solution Approach 1:
The patent applies dynamics by making the pre-distortion processing dynamic and adaptive. The system adjusts the level of pre-distortion processing based on operating conditions such as power amplifier back-off levels, signal characteristics, and channel conditions. This allows the system to apply computational resources only when necessary, reducing overall power consumption while maintaining spectral regrowth suppression when needed.
Solution Approach 2:
The patent changes parameters by adjusting pre-distortion coefficients, processing depth, and activation thresholds based on system state. The system monitors parameters such as ACLR requirements, power amplifier efficiency points, and signal characteristics to dynamically adjust the pre-distortion processing parameters, optimizing the trade-off between spectral performance and computational power consumption.
2Object-affected harmful factors
If power amplifier back-off is applied to reduce non-linearity effects, then spectral regrowth is reduced, but coverage is degraded due to reduced transmit power
Solution Approach 1:
The patent applies preliminary action by applying pre-distortion to the input signal before amplification. This pre-processing transforms the signal in advance to compensate for the anticipated non-linear effects of the power amplifier, allowing the amplifier to operate at higher power levels (reducing back-off) while still achieving the desired spectral performance and maintaining coverage.
Solution Approach 2:
The patent converts the harmful effect of power amplifier non-linearity into a beneficial outcome through pre-distortion. By intentionally distorting the input signal in a controlled manner, the system causes the amplifier's non-linear operation to produce the desired linear output, thereby maintaining both high power operation and spectral purity.
3Loss of energy
If amplifiers operate in non-linear region for good efficiency, then power efficiency is improved, but signal leakage to other frequency bands increases
Solution Approach 1:
The patent applies preliminary action by pre-distorting the signal before it enters the non-linear amplifier. This advance processing prepares the signal to compensate for the upcoming non-linear effects, allowing the amplifier to operate efficiently in its non-linear region while the pre-distortion ensures that the output signal maintains spectral purity and minimizes leakage to adjacent bands.
Solution Approach 2:
The patent applies preliminary anti-action by applying a pre-distortion that is essentially the opposite of the expected amplifier non-linearity. This counter-distortion applied in advance cancels out the harmful spectral regrowth that would otherwise occur, allowing the amplifier to operate in the efficient non-linear region without causing signal leakage.
4Area of stationary object
If mutual coupling between antenna elements is strong due to limited integration volume, then system integration is improved, but signal corruption from adjacent elements increases
Solution Approach 1:
The patent applies preliminary action by incorporating mutual coupling compensation into the pre-distortion process. The system characterizes the mutual coupling effects between antenna elements in advance and integrates this compensation into the pre-distortion coefficients, thereby correcting for signal corruption from adjacent elements before transmission occurs.
Solution Approach 2:
The patent uses pre-distortion coefficients as an intermediary to manage mutual coupling effects. These coefficients act as a mediator that transforms the transmitted signals to account for the expected interference from adjacent antenna elements, thereby reducing signal corruption while maintaining the compact integrated antenna array structure.
Data Source
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AI summary
A method of controlling one or more amplifiers of a network node, wherein the network node is adapted to communicate with a plurality of user equipment devices within a cell of a wireless communication network. The method comprises evaluating back-off criteria relating to the plurality of user equipment devices, and selectively controlling one or more amplifiers to operate in a reduced power mode or a predistortion mode, based on the result of the evaluation.