SMF Session Suspension for LADN Signaling Reduction
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Solution Overview
Problem
Current 5G systems lack a detailed implementation solution for session management by the Session Management Function (SMF) network element in Local Area Data Networks (LADNs), leading to high signaling overheads due to frequent UE movements in and out of the service area, and inefficient data transmission.
Innovation Solution
The SMF network element implements a method to learn the UE's location relative to the LADN service area, pausing data transmission of the LADN PDU session when outside the area while maintaining resources, and restoring it when re-entering, based on predefined policies to minimize signaling overheads and optimize data transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the SMF deactivates the PDU session when the UE moves out of the LADN service area, then data transmission is stopped to avoid wasting resources, but the signaling overhead increases when the UE re-enters the service area requiring session re-establishment
Solution Approach 1:
The SMF performs preliminary actions by suspending the PDU session rather than fully deactivating it when the UE moves out of the LADN service area. The session context, including QoS parameters and network resource allocations, are preserved in a suspended state. When the UE re-enters the service area, the session can be quickly restored without full re-establishment procedures, thus reducing both time loss and signaling overhead.
2Loss of time
If the SMF maintains the PDU session resources when the UE moves out of the LADN service area, then session re-establishment is faster when re-entering, but network resources are continuously occupied without data transmission
Solution Approach 1:
The patent implements a dynamic session state management mechanism where the PDU session transitions between active, suspended, and deactivated states based on UE location relative to the LADN service area. When the UE moves out, the session is suspended with resources held temporarily. If the UE returns within a predetermined time window, resources are restored; otherwise, they are released. This dynamic approach balances resource efficiency with quick re-establishment capability.
3Loss of energy
If the SMF frequently activates and deactivates the PDU session based on UE movement in and out of the LADN service area, then data transmission efficiency is maintained, but signaling overhead increases due to frequent session management operations
Solution Approach 1:
The patent applies preliminary anti-action by implementing a suspension mechanism that prevents the harmful effect of frequent session activation/deactivation. Instead of fully deactivating the session each time the UE leaves the LADN service area, the session is suspended with its context preserved. This preliminary protective measure prevents the need for frequent re-establishment signaling, thus reducing signaling overhead while maintaining data transmission efficiency when the UE returns.
Data Source
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AI summary
A session management method and a session management function network element are provided. The session management method includes: learning, by a session management function SMF network element, of whether a first condition is met, where the first condition includes: a first location of user equipment UE is outside a service area SA of a local area data network LADN; and when the first condition is met, stopping, by the SMF network element, data transmission of an LADN packet data unit PDU session of the LADN, and maintaining, by the SMF network element, a resource of the LADN PDU session.