Tracking Area Update in Non-Terrestrial Networks
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Solution Overview
Problem
In non-terrestrial satellite communication networks, especially with non-Geostationary Orbit (NGSO) satellites, the rapid movement of satellite beams creates challenges for user equipment (UEs) in maintaining tracking area updates, leading to excessive signaling and performance issues due to the dynamic nature of satellite footprints and the need for frequent location registrations.
Innovation Solution
Preconfiguring network nodes with predetermined mappings of tracking areas based on satellite ephemeris data to minimize the need for UE-initiated tracking area updates, allowing UEs to utilize pre-broadcasted target tracking area information without frequent signaling changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If tracking area updates are performed frequently to track satellite beam movement, then location accuracy is improved, but signaling overhead increases excessively
Solution Approach 1:
The network node pre-configures tracking area mappings based on satellite ephemeris data before the actual tracking area update is needed. This allows the UE to have advance knowledge of future tracking areas, enabling it to perform updates proactively rather than reactively, thereby reducing unnecessary signaling while maintaining location accuracy.
Solution Approach 2:
The system implements a feedback mechanism where the network node broadcasts system information containing tracking area mapping information to UEs. This feedback allows UEs to adjust their tracking area knowledge based on actual network conditions and satellite position, optimizing the balance between location tracking accuracy and signaling overhead.
2Reliability
If tracking area updates are performed frequently to maintain connectivity, then network performance is improved, but device complexity increases
Solution Approach 1:
The network node acts as an intermediary that handles the complexity of tracking area management. By pre-configuring and broadcasting tracking area mappings, the network node absorbs the computational burden of calculating and managing multiple tracking area transitions, thereby simplifying the UE's task to merely receiving and applying the pre-provided mapping information.
3Measurement precision
If frequent location registrations are performed to track satellite movement, then location accuracy is improved, but time consumption increases
Solution Approach 1:
By pre-calculating and broadcasting tracking area mappings based on satellite ephemeris data, the system eliminates the need for UEs to perform time-consuming location registrations in real-time. The UE can directly use the pre-provided mapping information, significantly reducing the time required to track satellite movement and maintain location accuracy.
Data Source
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AI summary
A method for updating a tracking area in a non-terrestrial network comprises determining, at a network node, that a current tracking area in a non-terrestrial network is expiring; determining, at the network node, at least one target tracking area in the non-terrestrial network; and broadcasting, to at least one user equipment in the at least one target tracking area, system information comprising information of the at least one target tracking area. The target tracking area is determined based on a preconfigured mapping which comprises at least one target tracking area code corresponding to a cell identity of a target network node within a period of time or based on a movement of a satellite.