5GS–EPC Core Network Interworking for UE Registration Changes
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Solution Overview
Problem
Existing systems face challenges in seamlessly managing interworking between 5G System (5GS) and Evolved Packet Core (EPC) networks, particularly in scenarios where UEs with different capabilities coexist, leading to inefficiencies in service suspension and registration transitions.
Innovation Solution
The introduction of a mechanism to expose CN type change events, allowing Network Function (NF) nodes to monitor and manage transitions between 5GS and EPC through the SCEF+NEF, which transparently notifies AF of UE reachability and location updates, enabling smooth mobility and registration state changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If UEs with different capabilities (EPC NAS and 5GC NAS) coexist within one PLMN, then the network supports diverse UE capabilities, but the complexity of managing interworking between different core networks increases
Solution Approach 1:
The patent introduces a service exposure function (SCEF/NEF) as an intermediary layer between the core networks and application functions. This mediator handles the complexity of interworking between EPC and 5GC by providing a unified interface for service exposure, thereby reducing the management complexity while maintaining support for diverse UE capabilities
2Reliability
If the network hides the underlying 3GPP network topology from AF, then the network security and simplification is improved, but the ability to perform functions affected by CN type change is reduced
Solution Approach 1:
The patent implements a feedback mechanism where the service exposure function monitors CN type changes and notifies subscribed application functions. This allows the network to maintain security by hiding topology while still providing necessary information about CN type changes through event exposure, enabling functions to adapt their behavior based on the current network type
3Adaptability or versatility
If event exposure is implemented for CN type change, then the adaptability of NF nodes to CN changes is improved, but the complexity of the service exposure function increases
Solution Approach 1:
The patent implements preliminary action by having the service exposure function proactively subscribe to CN type change events and pre-establish notification mechanisms to NF nodes. This allows NF nodes to be prepared and adapt their behavior in advance when CN type changes occur, improving adaptability while managing complexity through automated event-driven architecture
Data Source
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AI summary
The present invention generally relates to interworking between core networks (CNs). More particularly, the present invention relates to a method for supporting interworking between CNs. The present invention also relates to apparatus and computer program product adapted for the same purpose. According to one aspect of the present invention, an apparatus for supporting interworking between core networks (CNs) comprises: a storage device configured to store a computer program comprising computer instructions; and a processor coupled to the storage device and configured to execute the computer instructions to: -a) in response to a CN registration state change for a user equipment (UE), determine whether the UE subscribes to a notification service for the CN registration state change; and -b) if subscribing to the notification service, notify the CN registration state change of a network function (NF) node performing a function associated with the CN registration state change.