Ephemeris Validity Timing for NTN Synchronization Accuracy

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Solution Overview

Problem

In Non-Terrestrial Network (NTN) systems, high-speed satellite movement causes rapid changes in time delay and Doppler frequency shift, affecting synchronization performance due to inaccuracies in ephemeris information estimation.

Innovation Solution

A method and apparatus for determining a validity period of ephemeris information, ensuring synchronization requirements by configuring or receiving a validity period in RRC messages, and updating ephemeris information when the period is exceeded, using schemes that consider satellite scenarios, terminal capabilities, and communication protocols.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If ephemeris information is used for satellite communication, then communication coverage is achieved, but synchronization performance deteriorates due to rapid changes in time delay and Doppler frequency shift

Engineering Contradiction:
Improvecommunication coverageVSAvoidsynchronization performance
Core Design Contradiction:
Area of stationary objectVSReliability

Solution Approach 1:

The patent applies preliminary action by pre-configuring a validity period for ephemeris information in RRC messages before the actual communication begins. This validity period is determined in advance based on satellite scenarios and terminal capabilities, ensuring that the ephemeris information remains accurate throughout the configured duration. When the validity period expires, the system proactively updates the ephemeris information, preventing synchronization degradation before it occurs.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If validity period of ephemeris information is extended, then data transmission efficiency is improved, but synchronization accuracy deteriorates

Engineering Contradiction:
Improvedata transmission efficiencyVSAvoidsynchronization accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent applies dynamics by making the validity period configurable rather than fixed. The network device can dynamically adjust the validity period based on real-time satellite scenarios, terminal capabilities, and synchronization requirements. This dynamic configuration allows the system to optimize between data transmission efficiency and synchronization accuracy for each specific operational context, rather than using a static predetermined value.

Inventive Principle:
Principle #15Dynamics

3Reliability

If ephemeris information is updated frequently, then synchronization performance is maintained, but network overhead increases

Engineering Contradiction:
Improvesynchronization performanceVSAvoidnetwork overhead
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies preliminary action by pre-determining an appropriate validity period that balances synchronization requirements with update frequency. By configuring this validity period in advance based on satellite scenarios and terminal capabilities, the system avoids unnecessary frequent updates while ensuring synchronization performance is maintained throughout the valid period. This prevents excessive network overhead from constant ephemeris information transmission.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4345505B1Validity period determining method and apparatus, device, and storage medium
Publication Date: 2025.12.31 GUANGDONG OPPO MOBILE TELECOMMUNICATIONS CORP LTD
  • EP4345505B1 patent drawingFigure 1~4
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  • EP4345505B1 patent drawingFigure 8~9

AI summary

The present disclosure relates to the technical field of communication, and provides a validity period determining method and apparatus, a device, and a storage medium. The method includes: determining, by a terminal, a validity period of ephemeris information, the validity period meeting a synchronization requirement of the terminal. By determining the validity period of the ephemeris information that meets the synchronization requirement, the terminal can ensure the real-time accuracy of the ephemeris information at the terminal, thereby ensuring that a time delay and a Doppler frequency shift calculated by the terminal based on the ephemeris information have only small errors. Since the errors do not exceed a range tolerated by the synchronization requirement, the synchronization performance of the terminal can be guaranteed.