Amplifier Linearization Using One Observation Receiver
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Large multi-antenna systems face complexity and cost issues in radio signal processing due to the increasing number of transmit observation receivers (TORs) and switchable networks required for digital pre-distortion, leading to cumbersome and costly implementations.
Innovation Solution
A linearization device that determines pre-distortion parameters for multiple non-linear amplifiers using a single transmit observation receiver and channel coefficients, eliminating the need for directional couplers and complex switching networks by observing a sum of transmission signals and employing a non-linear polynomial model with Kronecker products and least squares estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If each individual transmitter branch is monitored by a dedicated TOR, then measurement precision is improved, but device complexity increases
Solution Approach 1:
Multiple transmitter branches share a single TOR through a combining network, merging the monitoring function into one common receiver instead of having separate TORs for each branch. This reduces the number of TORs from N to 1 while still enabling accurate measurement of individual branch signals through the combining network.
Solution Approach 2:
A single TOR is designed to perform the monitoring function for multiple transmitter branches simultaneously. The TOR becomes a universal monitoring device that can measure signals from any or all branches by receiving combined signals through the circulator and combining network.
2Device complexity
If a shared TOR is used for multiple transmitter branches, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
A combining network acts as an intermediary between the multiple transmitter branches and the single TOR. This intermediary structure allows the TOR to receive individual branch signals in a combined form, enabling the single receiver to accurately measure parameters for multiple branches without direct one-to-one connections.
3Productivity
If the number of transmitter branches increases, then productivity is improved, but device complexity increases
Solution Approach 1:
Instead of increasing the number of TORs proportionally with the number of transmitter branches, the invention merges multiple branch monitoring into a single TOR through a combining network. This allows the system to scale to more transmitter branches without proportionally increasing the number of receivers or switching complexity.
Data Source
AI summary
A linearization device (380) is disclosed, which is configured to determine pre-distortion parameters associated with a plurality of non-linear amplifiers (331, 332, 333, 334), each associated with a non-linear amplifier characteristic. The linearization device comprises determination circuitry (383), a first port (381) and a second port (382). The first port is configured to receive a plurality of channel coefficients indicative of channel characteristics of a plurality of communication paths (391, 392, 393, 394) between the plurality of non-linear amplifiers and a transmit observation receiver (370). The second port is configured to receive, from the transmit observation receiver, a sum of transmission signals generated by the plurality of non-linear amplifiers and transferred over the plurality of communication paths. The determination circuitry is configured to determine the pre-distortion parameters based on the received plurality of channel coefficients, the received sum of transmission signals, and a model of the non-linear amplifier characteristics of the non-linear amplifiers. Corresponding arrangement, wireless transmitter node, cloud based server node, method and computer program product are also disclosed.