Non-Terrestrial Network UE Test System for Doppler and Timing

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Solution Overview

Problem

User equipment for non-terrestrial networks faces challenges in ensuring correct communication with satellite nodes due to rapid position changes and high velocities, requiring effective testing methods to account for Doppler effects and timing advances.

Innovation Solution

A test system provides GNSS and ephemeris data to user equipment, allowing it to determine and apply timing advances and Doppler pre-compensation shifts, with the system analyzing uplink signals to assess performance, including emulating positions and velocities to simulate real-world conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If user equipment communicates with non-geosynchronous satellite nodes, then network coverage and capacity are improved, but position changes and velocity variations cause Doppler effects and timing advances that deteriorate communication reliability

Engineering Contradiction:

Improvenetwork coverageVSAvoidcommunication reliability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The test system performs preliminary configuration by providing GNSS data and ephemeris data to the user equipment before actual communication testing. This allows the UE to pre-calculate timing advances and Doppler pre-compensation shifts based on satellite orbital information, ensuring communication reliability is maintained despite position changes and velocity variations in non-geosynchronous orbits

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The test system dynamically changes testing parameters including satellite position, velocity, orbital elements, and propagation delay to simulate various non-terrestrial network scenarios. This enables comprehensive testing of timing advance and Doppler compensation mechanisms under different operational conditions, resolving the contradiction between network versatility and communication reliability

Inventive Principle:

Principle #35Parameter changes

2Ease of operation

If conventional terrestrial testing methods are used, then testing simplicity is maintained, but they fail to account for Doppler effects and timing advances specific to non-terrestrial networks

Engineering Contradiction:

Improvetesting simplicityVSAvoidperformance assessment accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The test system creates a virtual copy of the non-terrestrial network environment by emulating satellite nodes with configurable orbital parameters, positions, and velocities. This virtual satellite model replicates the Doppler effects and timing characteristics of actual NTN scenarios, enabling accurate performance assessment without requiring physical satellite testing while maintaining operational simplicity through software-based simulation

Inventive Principle:

Principle #26Copying

3Reliability

If actual satellite nodes are used for testing, then real-world conditions are captured, but testing flexibility and controllability are reduced

Engineering Contradiction:

Improvereal-world condition accuracyVSAvoidtesting flexibility

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The test system acts as an intermediary between the physical user equipment and actual satellite nodes. It provides GNSS data and ephemeris data that represent real satellite orbital information while allowing flexible configuration of testing scenarios. This intermediary approach captures real-world Doppler and timing characteristics through accurate orbital data while maintaining full testing flexibility through software-controlled parameter adjustment

Inventive Principle:

Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution enables accurate testing of user equipment performance in non-terrestrial networks by simulating dynamic conditions, ensuring correct timing and frequency adjustments, thereby identifying malfunctions and improving communication reliability.

Implementation Method 1

velocities of the satellite nodes relative to the user-side communication device may be relatively high, such that the Doppler effect has to be taken into account for a correct communication between the user-side mobile communication device and the satellite nodes

Methodology Applied

Scientific EffectDoppler effect: Doppler Effect

Data Source

PatentUS12255730B2Method of testing user equipment for non-terrestrial networks and test system

Publication Date: 2025.03.18 ROHDE & SCHWARZ GMBH & CO KG

AI summary

A method of testing user equipment for non-terrestrial networks is described. The method includes, for example, the steps of:providing GNSS data and ephemeris data by a test system, wherein the GNSS data is associated with a position of a user equipment (UE) device of a non-terrestrial network, and wherein the ephemeris data is associated with a position of a satellite node of the non-terrestrial network;transmitting the GNSS data and the ephemeris data to the UE device;determining a timing advance and/or a Doppler pre-compensation shift by the UE device based on the GNSS data and the ephemeris data;generating an uplink signal by the UE device based on the determined timing advance and/or the determined Doppler pre-compensation shift; andanalyzing the uplink signal by the test system in order to assess a performance of the UE device.Further, a test system for testing user equipment for non-terrestrial networks is described.