Wireless Calibration of Multi-Antenna Transceivers

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Solution Overview

Problem

Existing methods for testing and calibrating multi-antenna transceivers, such as conducted tests and two-stage methods, fail to effectively evaluate beamforming algorithms and consider self-interference and in-band interference effects.

Innovation Solution

A method for wirelessly calibrating a multi-antenna transceiver that involves transmitting signaling information to request calibration, estimating channel transfer function matrices using reference signals, and applying precoder matrices to achieve interference-free channels, allowing for the calibration of beamforming networks and transceiver modules.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conducted test is used, then test setup is simple, but beamforming algorithms cannot be evaluated and antenna radiation patterns are not considered

Engineering Contradiction:
Improvetest setup simplicityVSAvoidbeamforming algorithm evaluation capability
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent introduces an intermediary measurement system that includes a signal generator, power amplifier, and measurement equipment connected to the DUT antennas through transmission lines. This intermediary system enables wireless transmission of test signals while maintaining the ability to evaluate beamforming algorithms and antenna radiation patterns, resolving the contradiction between simple test setup and comprehensive measurement capability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If two-stage method is used, then antenna radiation patterns can be measured, but self-interference effects and in-band interferences cannot be evaluated

Engineering Contradiction:
Improveantenna radiation pattern measurementVSAvoidself-interference and in-band interference evaluation
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful self-interference and in-band interference effects into beneficial measurement parameters by intentionally introducing known interference signals and measuring the DUT's response. The measurement system evaluates how the DUT handles these interference effects, transforming them from mere disturbances into useful test data that characterizes the device's performance in real-world conditions.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Measurement precision

If radiated two-stage method is used in anechoic chamber, then self-interference and in-band-interference effects can be evaluated, but test environment is complex and expensive

Engineering Contradiction:
Improveinterference effect evaluationVSAvoidtest environment complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent changes the physical parameters of the test environment by using transmission lines with controlled impedance instead of requiring anechoic chamber materials. The measurement system adjusts signal parameters such as frequency, power level, and phase to evaluate interference effects without needing complex electromagnetic shielding structures, thereby reducing environmental complexity while maintaining measurement precision.

Inventive Principle:
Principle #35Parameter changes

4Ease of manufacture

If wireless calibration method is used, then non-destructive testing of integrated devices is enabled, but channel estimation and precoding complexity increases

Engineering Contradiction:
Improvenon-destructive testing capabilityVSAvoidchannel estimation and precoding complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by performing channel estimation and precoder calculation before the actual calibration measurement. The system first establishes the channel transfer function matrices and computes the precoder matrices in advance, then applies them during the calibration process. This preliminary processing simplifies the overall system complexity by pre-computing necessary parameters rather than requiring complex real-time calculations during testing.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3673275B1Over the air calibration and testing of beamforming-based multi-antenna devices in anechoic and non-anechoic environments
Publication Date: 2025.06.11 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV
  • EP3673275B1 patent drawingFigure 1a~1b
  • EP3673275B1 patent drawingFigure 2~3
  • EP3673275B1 patent drawingFigure 4

AI summary

Embodiments provide a method for wirelessly calibrating/testing RF and digital components of a multi-antenna device under test. The method comprises the step of wirelessly transmitting a first signaling information between the device under test and a device tester, the first signaling information indicating a calibration request, wherein the first signaling information is transmitted by the device under test or the device tester. Further, the method comprises the step of estimating, in response to the first signaling information, channel transfer function matrices between active antenna ports/RF ports of the device under test and antenna ports of the device tester using reference signals wirelessly transmitted between the device tester and the device under test or vice versa. According to a first alternative, the method further comprises a step of wirelessly transmitting precoded reference signals between the device tester and the device under test using precoder matrices selected or determined based on the estimated channel transfer function matrices or the information derived therefrom. According to a second alternative, the method comprises a step of selecting or estimating equalizer matrices using the estimated channel transfer function matrices or the information derived therefrom.