Multi-Access PDU Session Release Handling in 5G Networks
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Solution Overview
Problem
In 5G wireless communication networks, the undefined behavior of user equipment (UE) when handling multi-access (MA) PDU session releases, particularly when the access type indicated in the PDU session release command is not included in the MA PDU session or is the only access type included, leads to synchronization issues between the UE and the 5G system.
Innovation Solution
The proposed method involves the UE determining whether to release or maintain an MA PDU session based on the access type indicated in a PDU session release command, considering the presence of user plane resources on different radio access technologies (RATs), and transmitting a PDU session release complete message or a 5G session management status message to the 5G system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE releases the entire MA PDU session when receiving a release command for a specific access type, then the synchronization issue is resolved, but unnecessary user plane resources on other access types are released
Solution Approach 1:
The patent segments the MA PDU session into separate access-specific sessions. When a release command is received for a specific access type (3GPP or non-3GPP), only the corresponding access session is released while the other access session remains intact. This segmentation allows independent management of each access type, resolving the synchronization issue without unnecessarily releasing resources on other accesses.
2Loss of substance
If the UE maintains the MA PDU session when the indicated access type is not included, then user plane resources are preserved, but synchronization issues arise between UE and 5GS
Solution Approach 1:
The patent implements feedback mechanisms where the UE sends a PDU Session Release Complete message or 5GSM Status message to the 5GS after processing the release command. This feedback confirms to the network whether the session was released or maintained, ensuring both the UE and 5GS have consistent understanding of the session state, thereby resolving synchronization issues.
3Reliability
If the UE releases the PDU session when it is a single-access PDU session and a release command is received, then synchronization is maintained, but the session is released even when not needed
Solution Approach 1:
The patent applies dynamic behavior where the UE determines whether to release or maintain the PDU session based on the current state and configuration. For single-access PDU sessions, the UE releases the session when a release command is received, maintaining synchronization. The system dynamically adapts its behavior based on whether the session is single-access or multi-access, optimizing both synchronization and session availability.
Data Source
AI summary
A method for handling multi-access (MA) Protocol data unit (PDU) session release is proposed. An MA PDU session uses one 3GPP access network or one non-3GPP access network at a time, or simultaneously one 3GPP access network and one non-3GPP access network. Upon receiving a PDU session release command message including an access type, the user equipment (UE) transmits a PDU session release complete message or a 5G session management (5GSM) status message to the 5G system (5GS). In addition, the UE determines the user plane resources of the MA PDU session on the access indicated in the access type as released, or determines the MA PDU session as released, depending on the access indicated in the access type and the access(es) over which the user plane resources of the MA PDU session are established.