CAG Cell Suitability Checks for Limited NPN Service Access
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Solution Overview
Problem
Existing systems fail to enable user equipment (UE) to efficiently discover, select, and access non-public networks (NPNs) that provide localized services, particularly when the UE is not authorized to access certain cells due to time and location validity criteria associated with Closed Access Groups (CAGs).
Innovation Solution
The UE determines whether a camped CAG cell is suitable by checking if the current CAG cell meets time and location validity criteria, entering a limited service state if these criteria are not met, and triggering cell reselection or PLMN selection procedures to ensure authorized access to NPNs providing localized services.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the UE automatically selects and accesses CAG cells without validity criteria checking, then access speed is improved, but unauthorized access control is compromised
Solution Approach 1:
The patent applies preliminary action by pre-configuring validity criteria (time and location) in the UE before cell selection. The UE checks these criteria before accessing CAG cells, preventing unauthorized access in advance while maintaining fast access when criteria are met. This resolves the contradiction by performing authorization checks beforehand rather than during access.
Solution Approach 2:
The patent introduces validity criteria (time and location conditions) as an intermediary between the UE and CAG cell access. This intermediary layer filters access requests based on pre-configured conditions, enabling fast access when valid while blocking unauthorized access, thus resolving the speed-reliability contradiction.
2Reliability
If the UE checks time and location validity criteria before accessing CAG cells, then access control reliability is improved, but access time is increased
Solution Approach 1:
By performing validity criteria configuration in advance (pre-loading time and location conditions into the UE), the patent minimizes access time during actual cell selection. The UE only needs to compare current position/time against pre-stored criteria rather than performing complex validation during access, thus reducing time loss while maintaining reliability.
3Reliability
If the UE enters limited service state when validity criteria are not met, then network security is improved, but service availability is reduced
Solution Approach 1:
The patent applies dynamics by making the UE's service state adaptive rather than static. When validity criteria are not met, the UE dynamically transitions to limited service state for CAG cells while maintaining normal service for non-CAG cells. This dynamic adaptation ensures security for restricted services while preserving availability of general services, resolving the security-availability contradiction.
Data Source
AI summary
A method of a UE determining whether a current camped CAG cell is suitable and thereby entering limited service state for PNI-NPN as a hosting network is provided. When the PNI-NPN is a hosting network providing localized services, one or more allowed CAG IDs are associated with validity information per UE stored configuration, e.g., time and/or location validity criteria. Once a CAG cell is selected and camped by the UE in a PLMN, the UE needs to consider whether the current CAG cell is suitable for obtaining normal service from the PLMN. If the hosting network functionality is not enabled (by user), or if the time and/or location validity criteria associated with CAG-IDs broadcasted by the current CAG cell are not met, then the current CAG cell is not suitable. As a result, the UE enters limited service state, and triggers cell reselection or PLMN selection procedure.