NAS Request Processing for Satellite Tracking Area Ambiguity
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Solution Overview
Problem
In satellite communication networks, especially in Low-Earth Orbit scenarios, the movement of satellites relative to the ground causes ambiguity in determining the tracking area (TA) for terminal devices, leading to issues in normal communication processes due to simultaneous reception of multiple TA codes, which existing mechanisms cannot effectively handle.
Innovation Solution
A method and network device configuration that processes Non-access stratum (NAS) requests by receiving and transmitting TAIs from a second network device to a first network device, allowing the determination of the correct TA for a terminal device, even when it moves between areas, and provides configuration updates or rejection messages to ensure proper communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If the satellite broadcasts multiple TACs simultaneously when covering at least two TAs, then the terminal device can receive all available TACs, but the terminal device cannot determine which TA it is located in
Solution Approach 1:
The patent introduces a core network device as an intermediary between the satellite and the terminal device. The core network device receives location information from the terminal device, determines the current TA based on this location information, and then provides guidance to the terminal device on which TAC to use. This intermediary resolves the ambiguity by centralizing the TA determination logic in the core network rather than requiring the terminal device to independently determine its TA from multiple broadcast TACs.
2Area of stationary object
If the satellite moves relative to the ground, then the satellite can provide wide area coverage, but the terminal device receives multiple TACs simultaneously making TA determination impossible
Solution Approach 1:
The terminal device performs preliminary action by reporting its location information to the core network device before the TA determination is needed. The core network device uses this pre-provided location information to determine the current TA and provide appropriate TAC guidance. This preliminary location reporting enables accurate TA identification even as the satellite moves and coverage areas change.
3Reliability
If the terminal device reports location information to the core network device, then the correct TA can be determined, but additional signaling overhead is introduced
Solution Approach 1:
The patent makes the location information reporting serve multiple functions: it is used both for normal network operations (such as mobility management and service delivery) and for TA determination. By integrating the TA determination function into existing location reporting mechanisms rather than creating a separate dedicated signaling channel, the patent achieves reliable TA determination while minimizing additional signaling overhead.
Data Source
AI summary
A method for processing a Non-access stratum request and network devices are provided. The method includes: receiving the NAS request of a terminal device and at least two tracking area identities for the terminal device from a second network device and accepting the NAS request.