NTN Timing Advance Updates for Variable Satellite Delay
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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 experience and interference issues with existing terrestrial network scheduling parameters.
Innovation Solution
User equipment (UE) devices in NTNs are equipped to detect trigger events for updating timing advance values, perform blind transmissions, and dynamically update timing offsets based on location and satellite scenarios to maintain synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional terrestrial network timing mechanisms are used in non-terrestrial networks, then existing infrastructure can be maintained, but timing synchronization deteriorates due to increased and variable propagation delays
Solution Approach 1:
The patent implements dynamic timing advance adjustments where the UE continuously monitors propagation delay changes and updates timing advance values in real-time. The network configures multiple timing advance values corresponding to different propagation delay scenarios, allowing the system to adapt dynamically to changing satellite positions and distances, thereby maintaining reliable timing synchronization despite variable propagation delays.
Solution Approach 2:
The system changes the timing advance parameter based on detected propagation delay variations. When the UE detects that the current timing advance value is no longer appropriate due to changed propagation conditions, it triggers an update by transmitting a timing advance report to the network, which then provides an updated timing advance value to compensate for the propagation delay changes.
2Measurement precision
If timing advance values are updated frequently to maintain synchronization, then timing accuracy improves, but signaling overhead and network traffic increase
Solution Approach 1:
The patent implements a feedback mechanism where the UE monitors timing synchronization status and only triggers timing advance updates when necessary. The UE compares current timing measurements against thresholds and only transmits timing advance reports when significant deviations are detected, allowing the system to maintain timing accuracy while minimizing unnecessary signaling overhead.
Solution Approach 2:
Instead of continuously updating timing advance values, the system uses partial action by updating only when propagation delay changes exceed a certain threshold. This approach maintains sufficient timing accuracy for normal operation while avoiding the excessive signaling that would result from continuous updates, striking an optimal balance between synchronization quality and network overhead.
3Reliability
If blind transmissions are used to ensure timing information delivery, then reliability of timing updates improves, but network resource consumption increases
Solution Approach 1:
The patent configures the UE with multiple candidate timing advance values in advance, corresponding to different propagation delay scenarios. When the UE needs to update timing information, it can immediately use one of the pre-configured values without waiting for network confirmation, ensuring reliable timing updates while reducing the need for repeated transmission attempts and associated resource consumption.
Data Source
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.