Untrusted Network Interworking for Dual UE Registration Control

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Solution Overview

Problem

Existing 3GPP systems lack a method for a user equipment (UE) to register over non-3GPP access while maintaining a single registration in the visited network, especially in roaming scenarios, necessitating a solution for secure connection setup and coordination between visited and home networks.

Innovation Solution

A virtual home AMF (H-AMF) is introduced to manage the registration process, establishing a security association with the UE through the home network, allowing additional N3GPP access while maintaining control in the visited network, and coordinating with the visited AMF (V-AMF) to add the new access to the UE context.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a UE registers over non-3GPP access in a roaming situation, then the UE can access the home network, but the visited network loses control over the UE registration

Engineering Contradiction:
Improveaccess capabilityVSAvoidregistration control
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent introduces a virtual home AMF (H-AMF) as an intermediary entity that mediates between the UE and the visited network AMF (V-AMF). The H-AMF is virtualized and deployed in the home network, allowing the UE to register over non-3GPP access while maintaining control with the visited network. The H-AMF forwards registration requests to the V-AMF and receives updated UE contexts, enabling dual registration without losing control.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the home network establishes a security association with the UE through the home network, then secure connection is established, but the network complexity increases

Engineering Contradiction:
Improvesecurity associationVSAvoidnetwork architecture
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The virtual home AMF (H-AMF) is designed as a multi-functional entity that combines several functions: it establishes security associations with UEs over non-3GPP access, forwards registration requests to the visited network AMF, receives and stores updated UE contexts, and manages the dual registration process. By consolidating these functions into a single virtualized entity, the patent reduces the overall network complexity compared to having separate dedicated components for each function.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If the visited network maintains control over the UE, then registration control is preserved, but the UE cannot access additional networks

Engineering Contradiction:
Improveregistration controlVSAvoidnetwork access
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent segments the AMF function into two distinct entities: a visited network AMF (V-AMF) that maintains control over the UE's primary registration, and a virtual home AMF (H-AMF) that handles additional network access. This segmentation allows the V-AMF to preserve registration control while the H-AMF enables access to additional networks through non-3GPP access, resolving the contradiction between control and versatility.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3580947B1Interworking function using untrusted network
Publication Date: 2026.02.11 WOLLOCHET SOLUTIONS LLC
  • EP3580947B1 patent drawingFigure 1
  • EP3580947B1 patent drawingFigure 2
  • EP3580947B1 patent drawingFigure 3

AI summary

The invention provides a method of registering an access in a network, the method comprising receiving in a second network a request to register a user equipment, UE, device over a second access network, the request including first information that the UE device is registered in a first network over a first access network; receiving in the second network second information regarding the UE device from the first network; establishing in the second network a security association with the UE device over the second access network; forwarding third information regarding the UE device to the first network by the second network; and registering in the first network the UE over the second access network while maintaining the registration of the UE in the first network over the first access network.