Non-Terrestrial Network Timing Relationships with Dynamic Offset Control

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Solution Overview

Problem

Non-terrestrial networks (NTNs) introduce greater and more variable propagation delays due to satellite distances, leading to degraded user experiences and interference issues with existing network scheduling parameters.

Innovation Solution

User Equipment (UE) devices in NTNs are equipped to detect trigger events for updating scheduling offset values by calculating and reporting timing advance values, employing blind transmissions and dynamic timing offset adjustments based on satellite altitude and location information to maintain timing synchronization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If traditional terrestrial network scheduling parameters are used in NTNs, then network infrastructure compatibility is maintained, but timing synchronization deteriorates due to greater and more variable propagation delays

Engineering Contradiction:
Improvenetwork infrastructure compatibilityVSAvoidtiming synchronization
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent implements dynamic scheduling offset adjustments based on satellite propagation delay characteristics. The network configures different scheduling offset values (K_offset) for NTN UEs compared to terrestrial UEs, and these offsets are dynamically adjusted based on satellite altitude, velocity, and position information. This dynamic adaptation resolves the contradiction by maintaining compatibility with terrestrial network infrastructure while achieving reliable timing synchronization specific to NTN conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes key timing parameters including scheduling offset (K_offset), timing advance (TA) values, and slot timing configurations to account for NTN propagation delays. The network provides NTN-specific parameter configurations that modify standard terrestrial parameters, enabling reliable timing synchronization while maintaining infrastructure compatibility through parameter adaptation rather than system redesign.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If scheduling offset values are frequently updated to maintain timing accuracy in NTNs, then timing synchronization is improved, but signaling overhead and processing complexity increase

Engineering Contradiction:
Improvetiming synchronizationVSAvoidprocessing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements periodic updates of scheduling offset values based on satellite orbital characteristics and predetermined thresholds. Rather than continuous updates, the system periodically adjusts K_offset and timing advance values when satellite position changes exceed configured thresholds or at scheduled intervals. This periodic approach maintains timing synchronization while reducing processing complexity compared to continuous updates.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent employs feedback mechanisms where UEs report timing information and the network adjusts scheduling offsets based on observed timing errors and satellite ephemeris data. The network monitors timing synchronization status and only triggers parameter updates when deviations exceed thresholds, creating a feedback-controlled system that maintains synchronization while minimizing unnecessary processing.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If timing advance values are calculated and reported frequently to maintain synchronization in NTNs, then timing accuracy is improved, but uplink signaling overhead increases

Engineering Contradiction:
Improvetiming accuracyVSAvoiduplink signaling overhead
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent extracts and separates timing advance information into dedicated MAC CE (Medium Access Control Control Element) messages and uplink grant configurations, rather than embedding timing information in every uplink transmission. By extracting timing advance reporting into specific dedicated channels and only transmitting when updates are necessary (based on threshold comparisons), the system achieves high timing accuracy while minimizing uplink signaling overhead.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent implements partial timing advance reporting where UEs only report timing advance values when changes exceed predetermined thresholds or when specifically requested by the network. This partial action approach provides sufficient timing accuracy for NTN operations without the excessive signaling overhead of reporting every timing value change, achieving an optimal balance between precision and overhead.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP4176613B1Systems and procedures of non-terrestrial network timing relationship
Publication Date: 2025.09.03 APPLE INC
  • EP4176613B1 patent drawingFigure 1~2
  • EP4176613B1 patent drawingFigure 3
  • EP4176613B1 patent drawingFigure 4

AI summary

Methods, apparatuses, and systems are disclosed for enhancing timing relationships in non-terrestrial networks (NTNs), e.g., by managing timing offset values and intelligently handling reporting failure relating to timing information reporting. To accommodate increased propagation delay in NTNs, a user equipment (UE) may supplement its timing advance (TA) value with component values representing roundtrip times to the satellite. The UE may maintain both open-loop and closed-loop portions of the TA value, and may report the TA value, or components thereof, to the network for timing synchronization. Methods and systems are also disclosed for failure handling in this reporting process.