Multi-Access PDU Session Handover Between ATSSS Networks
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The handling of Multi-Access (MA) PDU sessions during inter-system changes from 5G to EPS is undefined, particularly when ATSSS-supported and ATSSS-not-supported networks are involved, leading to unclear procedures for handover and traffic management between 3GPP and non-3GPP access networks.
Innovation Solution
A method is proposed to handle MA PDU sessions by transferring the 3GPP part to a PDN connection if interworking with EPS is supported, and maintaining the session over non-3GPP access if not supported, with data traffic being rerouted accordingly to ensure seamless handover and traffic distribution across different radio access technologies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If MA PDU session handover procedures are defined for inter-system changes, then handover reliability is improved, but device and network complexity increases due to additional protocol handling requirements
Solution Approach 1:
The patent segments the MA PDU session into separate 3GPP access part and non-3GPP access part, allowing independent handling of each access type during inter-system change. This segmentation enables the 3GPP part to be transferred to EPS while the non-3GPP part is released, providing clear procedural guidance without requiring complex integrated handling of both accesses simultaneously.
Solution Approach 2:
Instead of attempting to maintain both 3GPP and non-3GPP accesses during inter-system change (the conventional approach), the patent inverts the approach by releasing the non-3GPP access part while transferring only the 3GPP part to EPS. This inversion simplifies the handover procedure by eliminating the complexity of coordinating multiple access types across system boundaries.
2Productivity
If traffic is distributed across multiple access networks, then network capacity utilization is improved, but traffic management complexity increases
Solution Approach 1:
The patent segments traffic management by access type, with the UE maintaining separate QoS flow mappings for 3GPP and non-3GPP accesses. During inter-system change, traffic management is simplified by transferring only 3GPP-related QoS flows to EPS while releasing non-3GPP flows, avoiding the complexity of managing heterogeneous traffic policies across access boundaries.
Solution Approach 2:
The patent applies local quality by implementing access-specific QoS handling, where 3GPP access traffic receives EPS bearer mapping while non-3GPP access traffic is released. This localized treatment of different access types allows optimized traffic management for each access without requiring complex global traffic coordination mechanisms.
3Reliability
If QoS flows are mapped to EPS bearers during inter-system change, then service continuity is improved, but signaling overhead increases
Solution Approach 1:
The patent extracts only the necessary 3GPP-related QoS flow mappings for EPS bearer establishment during inter-system change, while excluding non-3GPP QoS flows from the transfer process. This extraction approach ensures service continuity for 3GPP services by mapping them to EPS bearers, while avoiding unnecessary signaling for non-3GPP flows that will be released anyway.
Solution Approach 2:
The patent applies partial action by performing QoS flow mapping only for the 3GPP access part that requires service continuity in EPS, rather than attempting to map all QoS flows including those from non-3GPP access. This partial mapping reduces signaling overhead by focusing only on the essential service continuity requirements.
Data Source
AI summary
A method of handling multi-access (MA) Protocol data unit (PDU) session handover is proposed. A UE and network can support Access Traffic Steering Switching and Splitting (ATSSS) functionalities to distribute traffic over 3GPP access and non-3GPP access for the established MA PDU session. An ATSSS-Supported UE first establishes a MA PDU Session on both 3GPP and non-3GPP access in a currently registered PLMN which is an ATSSS-Supported network. The UE then moves from the ATSSS-Supported network to an ATSSS-not-Supported network and finally reaches another ATSSS-Supported network. In one novel aspect, a solution is provided on how to handle the ongoing MA PDU Session with two accesses under handover scenarios between ATSSS-Supported and ATSSS-not-Supported networks. Furthermore, if the ongoing MA PDU Session cannot handover, a solution is provided on how to handle the MA PDU Session.