S-NSSAI Association for 5G Session Continuity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The maintenance and handling of Single-Network Slice Selection Assistance Information (S-NSSAI) for ensuring session continuity are unclear during handovers between different modes in 5G wireless communication networks, specifically when transitioning between 3GPP and non-3GPP access networks.
Innovation Solution
A method where a 5G capable User Equipment (UE) maintains and updates the S-NSSAI association with new PDN connections/PDU sessions during interworking among S1 mode, N1 mode, and ePDG, ensuring session continuity by applying the existing S-NSSAI regardless of network provision, and updating it upon receiving new values from the network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If S-NSSAI is provided by network during PDN connection establishment, then session continuity is ensured, but device complexity increases due to multiple handover scenarios
Solution Approach 1:
The UE autonomously maintains S-NSSAI association with PDN connections without requiring network provision in every handover scenario. The device self-manages the S-NSSAI information, determining when to retain existing associations and when to update them based on interworking conditions between S1 mode, N1 mode, and ePDG.
Solution Approach 2:
The UE pre-establishes S-NSSAI associations during initial PDN connection setup or previous network modes, preparing the information in advance so that during subsequent handovers between 3GPP and non-3GPP access, the session continuity is maintained without requiring real-time network provisioning for every transition.
2Reliability
If S-NSSAI is maintained during interworking, then session continuity is achieved, but loss of information occurs when handover between modes without clear maintenance rules
Solution Approach 1:
The UE continuously monitors interworking conditions between different network modes (S1, N1, ePDG) and adjusts S-NSSAI maintenance accordingly. When operating in modes where S-NSSAI is supported, the UE retains associations; when transitioning to modes without clear support, the UE updates or releases associations based on received network information, creating a feedback-driven information maintenance mechanism.
3Adaptability or versatility
If UE updates S-NSSAI upon receipt from network, then adaptability improves, but loss of time occurs during S-NSSAI maintenance and handling
Solution Approach 1:
The UE updates S-NSSAI information selectively rather than continuously. Updates are performed only when necessary - specifically when new S-NSSAI values are received from the network during PDN connection establishment or when interworking conditions change. This partial action approach avoids unnecessary update operations and associated time losses while maintaining adaptability to network requirements.
Data Source
AI summary
A method for S-NSSAI handling of a 5GS capable UE supporting session continuity between 3GPP and non-3GPP interworking is proposed. The UE maintains a PDN connection/PDU session. The UE performs interworking among S1 mode, N1 mode (including 3GPP and non-3GPP access), and ePDG. The UE associates the existing S-NSSAI with the new PDN connection/PDU session after interworking, no matter whether the S-NSSAI is provided by the network or not. The UE can update the S-NSSAI upon receipt of new value from the network. When interwork to N1 mode, the UE applies the S-NSSAI.