CAG Cell Access Handling for Emergency PDU Session Conflicts
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Solution Overview
Problem
Existing systems fail to effectively manage UE access to non-public networks (NPNs) when the UE's CAG-related configuration is out of sync with the network's configuration, leading to unauthorized access attempts during emergency PDU sessions.
Innovation Solution
A method is proposed to handle service requests from UEs camped on CAG cells where access is not authorized, involving the network's local release of non-emergency PDU sessions associated with 3GPP access, ensuring compliance with CAG restrictions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the network accepts service requests from UEs with emergency PDU sessions even when CAG configuration is out of sync, then emergency service availability is maintained, but unauthorized access to NPNs occurs
Solution Approach 1:
The patent segments the service request handling by separating emergency service requests from non-emergency requests. When a service request is received, the network determines whether it is an emergency request based on the UE's emergency PDU session status. Emergency requests are accepted even with CAG configuration mismatch, while non-emergency requests are rejected. This segmentation allows the system to maintain emergency service availability while preventing unauthorized access for regular services.
Solution Approach 2:
The patent applies different access control policies locally based on the type of service request. For emergency service requests, the network locally accepts the request and releases the emergency PDU session without strict CAG verification. For non-emergency requests, the network enforces strict CAG configuration matching. This local quality differentiation resolves the contradiction by allowing flexible handling of emergency cases while maintaining security for regular access.
2Object-affected harmful factors
If the network enforces strict CAG configuration synchronization, then network security and access control are improved, but emergency service access may be blocked
Solution Approach 1:
The patent implements dynamic access control where the network adapts its CAG verification behavior based on the service request type and UE's emergency session status. When a UE has an emergency PDU session, the network dynamically relaxes CAG configuration requirements to allow emergency service access. For UEs without emergency sessions, strict CAG verification is enforced. This dynamic approach ensures both security and emergency service accessibility.
Solution Approach 2:
The patent changes the access control parameter (CAG configuration matching requirement) based on the emergency service context. When emergency service is detected, the network modifies the access control parameter to accept service requests even with CAG configuration mismatch. For non-emergency services, the original strict parameter is maintained. This parameter change mechanism resolves the contradiction between security and emergency access.
3Reliability
If the network releases all non-emergency PDU sessions when accepting emergency service requests, then emergency service priority is ensured, but network resource utilization decreases
Solution Approach 1:
The patent applies preliminary anti-action by proactively releasing non-emergency PDU sessions when an emergency service request is detected. The network anticipates the need for emergency service and preemptively clears conflicting non-emergency sessions to ensure emergency service priority and avoid resource contention. This preliminary action ensures emergency services receive necessary network resources without competition from non-critical traffic.
Solution Approach 2:
The patent converts the potentially harmful effect of reduced network resource utilization into a benefit by selectively releasing only non-emergency PDU sessions while preserving emergency sessions. The release of non-emergency sessions creates beneficial conditions for emergency service delivery, ensuring critical services receive adequate resources. The overall system benefit from improved emergency service reliability outweighs the temporary reduction in total resource utilization.
Data Source
AI summary
A method of handling a service request from a UE camped on a CAG cell with emergency PDU session is proposed, where the UE is not authorized to access the current CAG cell. When the UE-maintained CAG related configuration is not synchronized with the NW-maintained CAG related configuration, the UE may try to access a CAG cell and sends a service request, but the NW may determine that the CAG cell is not suitable. Because the UE has an existing emergency PDU session, the network will accept the service request, and locally releases all non-emergency PDU sessions associated with 3GPP access. Specifically, the network will locally release SA non-emergency PDU sessions associated with 3GPP access, or MA PDU sessions with only 3GPP access user-plane resources, or 3GPP user-plane resources of MA PDU sessions with both 3GPP and non-3GPP access user-plane resources.