Active Antenna Array Linearization with Shared Pre-Distortion
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Solution Overview
Problem
As the number of active transceiver branches in active antenna arrays increases, the complexity and hardware cost of linearization grow dramatically, exceeding processing power and capacity, leading to degraded traffic capacity and power efficiency.
Innovation Solution
The use of a single or limited number of pre-distorters to linearize multiple power amplifiers, allowing for simultaneous linearization across multiple beams without the need for separate pre-distortion of each amplifier, reducing the number of linearizers and signal processing requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of active transceiver branches in an active antenna array increases, then the system can handle more traffic and provide better coverage, but the complexity and hardware cost of linearization grow dramatically
Solution Approach 1:
The patent merges the linearization function across multiple transceiver branches by using a single pre-distorter that processes the combined signal from all branches. Instead of having separate pre-distorters for each branch, the invention combines the signals and applies one pre-distortion operation, thereby reducing hardware complexity while maintaining the ability to handle multiple branches.
Solution Approach 2:
The single pre-distorter is designed to serve multiple functions simultaneously - it linearizes the output of multiple power amplifiers across different transceiver branches. This universal pre-distorter can handle signals from all branches through the combining network, making one device perform what would traditionally require multiple separate devices.
2Reliability
If separate pre-distorters are used for each power amplifier, then each amplifier can be linearized independently, but the hardware cost and processing power requirements increase dramatically
Solution Approach 1:
The patent combines multiple separate pre-distortion operations into a single unified pre-distortion operation. By merging the signal paths and using one pre-distorter for all branches, the system maintains linearization effectiveness while reducing the number of linearizers from N (one per branch) to just one.
Solution Approach 2:
The single pre-distorter is designed with universal capability to linearize multiple power amplifiers simultaneously. It processes the combined signal that contains contributions from all branches, making it a multi-functional device that replaces multiple specialized pre-distorters.
3Object-generated harmful factors
If more pre-distorters are deployed to linearize multiple amplifiers, then unwanted emissions can be reduced, but the processing power and capacity are exceeded
Solution Approach 1:
The patent merges the computational burden of linearization into a single pre-distorter operation. Instead of having N separate pre-distorters each performing complex calculations, one pre-distorter processes the combined signal, significantly reducing the total processing power required while still achieving the necessary emission reduction.
Solution Approach 2:
The single pre-distorter is designed to handle the linearization task for all branches universally, concentrating the processing requirements in one location. This approach reduces the overall processing power consumption compared to distributing pre-distortion operations across multiple independent devices.
4Adaptability or versatility
If the number of linearizers is increased to match the number of transmission paths, then each path can be optimized individually, but the hardware cost becomes prohibitive
Solution Approach 1:
The patent merges the individual path optimization capability into a single pre-distorter that processes the combined signal from all paths. While individual path optimization is maintained through the signal combining network, the actual linearization function is performed once for all paths, significantly reducing hardware cost.
Solution Approach 2:
The single pre-distorter serves all transmission paths universally, eliminating the need for separate linearizers for each path. This universal approach maintains the ability to optimize individual paths through the combining network while avoiding the prohibitive hardware cost of having N separate pre-distorters.
Data Source
Figure 1a
Figure 1b~2
Figure 3
AI summary
An transmitter arrangement and a method therein are provided for linearization of an active antenna array. The active antenna array comprises a plurality of antenna elements, which are associated with a plurality of power amplifiers. The active antenna array is further associated with a precoder, W, having a number of input and 5 output ports. The method comprises obtaining a first signal X1 provided to the antenna array via a first input port of the precoder W. The method further comprises adapting a pre-distorting linearizer connected to the first input port based on the first signal X1 and on feedback from the plurality of antenna elements, resulting from the propagation of X1 via the precoder W, and via the plurality of power amplifiers.10 Embodiments are also provided for adapting a pre-distorting linearizer based on a plurality of input signals, X1, X2, etc., and feedback from the plurality of antenna elements.