Untrusted 3GPP Access via VPN Gateway Without Roaming

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Solution Overview

Problem

Existing mobile networks face challenges in providing seamless connectivity for mission-critical users like emergency services and unmanned aerial vehicles when there is no roaming agreement between the home and visited networks, especially in areas without WLAN access, leading to disconnected network coverage.

Innovation Solution

A method and system that allows user equipment to access a visited cellular network without a prior authentication or authorization, using an untrusted 3GPP access mechanism to establish a data packet session through a VPN gateway, enabling connection to the home network even when no roaming agreement exists.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional roaming architecture is deployed between home and visited networks, then authentication and authorization are properly established, but network setup complexity and cost increase significantly

Engineering Contradiction:

Improveauthentication reliabilityVSAvoidnetwork setup complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces a roaming partner network as an intermediary entity that mediates between the home network and visited network. The roaming partner network receives authentication requests from the visited network, forwards them to the home network, and relays the authentication results back, thereby eliminating the need for direct roaming agreements between home and visited networks while maintaining secure authentication

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent segments the direct roaming connection into two separate connections: one between the home network and roaming partner network, and another between the roaming partner network and visited network. This segmentation allows each network to have simplified configurations while still achieving end-to-end authentication through the partner network

Inventive Principle:

Principle #1Segmentation

2Adaptability or versatility

If roaming agreements are established between home and visited networks, then seamless connectivity is achieved, but service level agreement configuration and network deployment effort increase

Engineering Contradiction:

Improvenetwork connectivity adaptabilityVSAvoidnetwork deployment ease

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The roaming partner network serves as a mediator that enables connectivity between home and visited networks without requiring direct roaming agreements. The partner network maintains pre-configured relationships with multiple home networks, allowing UEs to seamlessly connect to visited networks through the partner network infrastructure

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The roaming partner network provides universal access functionality by supporting multiple home networks through a single infrastructure. Instead of each visited network needing individual roaming agreements with every home network, the partner network offers multi-functional connectivity to multiple operators, simplifying deployment

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If WLAN access is used to reach the Internet when no roaming agreement exists, then Internet access is possible, but coverage is spotty and not everywhere available

Engineering Contradiction:

Improveaccess method versatilityVSAvoidaccess availability reliability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

Instead of using untrusted WLAN access to reach the Internet and then accessing home network services, the patent inverts the approach by enabling direct 3GPP access to the visited network through the roaming partner network. This allows UEs to access both Internet and home network services through the trusted 3GPP infrastructure rather than through untrusted WLAN

Inventive Principle:

Principle #13The other way round (Inversion)

4Adaptability or versatility

If untrusted non-3GPP access is used to access home network, then access is possible without roaming agreement, but authentication is required in the visited network which complicates the process

Engineering Contradiction:

Improveaccess flexibilityVSAvoidauthentication process complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The roaming partner network acts as an intermediary that handles authentication on behalf of the home network. When a UE accesses the visited network through the partner network, the partner network receives and processes authentication requests, forwarding them to the home network's authentication mechanisms, thereby simplifying the UE's access process while maintaining secure authentication

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS20250311018A1Untrusted 3GPP access

Publication Date: 2025.10.02 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

A method for operating a user equipment operating in a visited cellular network for which no roaming agreement exists between a home cellular network of the user equipment and the visited cellular network. The user equipment transmits an access request to the visited cellular network requesting access to the visited cellular network. The access request includes an identifier indicating to originate from a user equipment for which no roaming agreement exists with the home cellular network of the user equipment. The user equipment transmits a session establishment request to the visited network to establish a data packet session in the visited cellular network. The UE determines an address of a gateway providing access to the home cellular network, and establishes a connection to the gateway based on the determined address via the visited cellular network.