Active Antenna OTA Testing with Time-Frequency Beamforming

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Solution Overview

Problem

Current OTA testing methods for Active Antenna Systems (AAS) are inefficient, time-consuming, and do not adequately test the multi-beam systems due to limitations in beamforming weight application and mechanical movement, leading to incomplete testing of spatial characteristics and transient beam behavior.

Innovation Solution

A method and network node that utilize a time/frequency resource grid to apply beamforming weights for efficient OTA testing, enabling simultaneous measurement of multiple beams and testing spatial characteristics across various base station types and beamforming technologies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional conducted measurements are used for OTA testing, then measurement accuracy is improved, but physical access to the Antenna Reference Point is required which is not available in AAS

Engineering Contradiction:

Improvemeasurement accuracyVSAvoidphysical access availability

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The patent replaces mechanical/conducted measurement access with electromagnetic field-based OTA testing. Instead of requiring physical access to the Antenna Reference Point for conducted measurements, the system uses over-the-air transmission and reception of test signals through the antenna system, substituting mechanical measurement access with wireless electromagnetic field interaction to obtain RF characteristics.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If beamforming weights are applied sequentially for each beam direction, then testing completeness is improved, but test time increases significantly

Engineering Contradiction:

Improvetesting completenessVSAvoidtest time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent merges multiple beamforming weight applications into a single simultaneous transmission. Instead of sequentially testing each beam direction one at a time, the system applies multiple beamforming weights concurrently to generate multiple beams that transmit test signals simultaneously in different spatial directions, thereby maintaining testing completeness while dramatically reducing test time.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces a temporal dimension to the testing process by multiplexing multiple beam directions in time within a single transmission opportunity. The time/frequency resource grid enables different beams to be tested in different time slots or frequency resources, allowing comprehensive spatial testing without sequential time consumption.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Measurement precision

If mechanical movement is used to change beam directions, then spatial characteristic testing is improved, but transient beam behavior cannot be tested

Engineering Contradiction:

Improvespatial characteristic testingVSAvoidtransient beam behavior testing

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent replaces static mechanical movement with dynamic electronic beam steering through beamforming weight adjustment. Instead of physically moving antennas or reflectors to change beam directions, the system dynamically changes beamforming weights in the time/frequency resource grid to steer beams electronically, enabling both spatial characteristic testing and transient beam behavior analysis without mechanical constraints.

Inventive Principle:

Principle #15Dynamics

4Productivity

If multiple beams are tested simultaneously, then productivity is improved, but measurement accuracy may deteriorate due to interference

Engineering Contradiction:

Improvetesting efficiencyVSAvoidmeasurement accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent segments the frequency spectrum and time resources to separate multiple beam measurements. The time/frequency resource grid divides the available resources into distinct slots and frequency blocks, allowing multiple beams to be tested simultaneously without mutual interference. Each beam is assigned specific time-frequency resources, enabling parallel processing while maintaining measurement accuracy through resource isolation.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS12375189B2Over-the-air testing of an active antenna system

Publication Date: 2025.07.29 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

There is provided mechanisms for OTA testing of an AAS of an EUT. A method is performed by a network node. The method includes obtaining definition of a test signal to be transmitted or received by the EUT in accordance with a time/frequency resource grid. The method includes applying first beamforming weights to first selected resource elements of the time/frequency resource grid that give first beam directions according to a first type of configuration for first OTA testing of the AAS. The method includes applying second beamforming weights to second selected resource elements of the time/frequency resource grid that give second beam directions according to a second type of configuration for second OTA testing of the AAS. The method includes initiating transmission or reception of the test signal over the AAS using the time/frequency resource grid.