LADN PDU Session Continuity During Application Context Relocation
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Solution Overview
Problem
In 5G NR core networks, mobile WTRUs face service continuity issues when moving across service areas with restricted access to Local Area Data Networks (LADNs) due to geographical limitations, leading to disruptions during Application Context Relocation (ACR) procedures.
Innovation Solution
The proposed solution involves temporarily maintaining active PDU sessions with the previous LADN while establishing a new PDU session with the new LADN during ACR, allowing service continuity by indicating the temporary access request and utilizing timers or ECS notifications for session release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LADN access is restricted to specific service areas, then service security and policy control are improved, but service continuity is worsened when WTRU moves between service areas
Solution Approach 1:
The patent applies preliminary action by establishing a new PDU session with the target LADN before completely releasing the old PDU session. The network maintains the old PDU session active during the ACR procedure and only releases it after the new session is established, ensuring continuous service availability during mobility events.
Solution Approach 2:
The patent uses the ACR procedure as an intermediary mechanism to bridge the old and new LADN connections. During ACR, the network temporarily maintains both the old PDU session (for continuity) and establishes the new PDU session (for future access), with the intermediary ACR procedure coordinating the transition.
2Reliability
If PDU session is maintained during ACR procedure, then service continuity is improved, but network resource utilization is worsened
Solution Approach 1:
The patent applies dynamics by making the PDU session state changeable during ACR. The network dynamically adjusts the session state based on the ACR progress: initially maintaining both old and new sessions for continuity, then transitioning to releasing the old session once the new one is established, optimizing resource utilization at different stages.
Solution Approach 2:
The patent ensures continuity of useful action by maintaining the old PDU session active during the ACR procedure. The session remains useful for continuing service delivery while the new session is being established, and only becomes obsolete after the transition is complete, maximizing resource utilization efficiency.
3Reliability
If temporary access to previous LADN is allowed during ACR, then service continuity is improved, but access control policy is worsened
Solution Approach 1:
The patent applies preliminary action by pre-establishing the new PDU session with the target LADN before releasing the old session. This preliminary establishment allows the network to maintain strict access control policies while ensuring continuity, as the new session is ready and validated before taking over traffic.
Solution Approach 2:
The ACR procedure acts as an intermediary that temporarily suspends strict LADN access control restrictions during the transition period. The procedure provides a controlled window where the old LADN can be accessed temporarily, coordinated by the ACR mechanism, before the new LADN takes over completely.
Data Source
AI summary
The disclosure pertains to a method implemented in a Wireless Transmit/Receive Unit (WTRU) for service continuity during an application context relocation (ACR) procedure. The method includes determining, by the WTRU, one or more local area data network (LADN) data network names (DNNs) that require service continuity. The method additionally includes indicating, to a network by the WTRU, the LADN DNNs that require service continuity. The network is configured to use the list to maintain a protocol data unit (PDU) session toward a source LADN DNN, after the WTRU leaves a service area of a source LADN, while ACR is being executed and release the PDU session when the ACR is complete.