Secure Element Network Switching Without Roaming Agreements

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Solution Overview

Problem

Existing systems fail to automatically switch between public and private telecommunication networks without user intervention, particularly in scenarios where there are no inter-connections or roaming agreements, and the location of private networks is unknown.

Innovation Solution

A method for a secure element to store a higher-priority private network's PLMN code and IMSI, detect network rejections, and initiate an authentication procedure using the associated key to connect to the private network, leveraging existing roaming mechanisms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If manual SIM card changing is used to switch between public and private networks, then network switching is possible, but user convenience deteriorates and operation complexity increases

Engineering Contradiction:

Improvenetwork switching operationVSAvoidphysical SIM card management

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The system performs automatic network switching without user intervention. The secure element autonomously detects network availability, selects appropriate PLMN codes from stored lists, and executes switching operations based on predefined priorities, eliminating the need for manual SIM card changes.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The secure element pre-stores multiple PLMN codes in priority-ordered lists (OPLMN, EHPLMN, FPLMN files) before switching is needed. This preliminary preparation enables rapid automatic switching when network conditions change, as the system already has candidate networks ready to use.

Inventive Principle:

Principle #10Preliminary action

2Adaptability or versatility

If dual UICC is implemented for simultaneous public and private network access, then network switching capability improves, but device complexity and cost increase

Engineering Contradiction:

Improvenetwork access capabilityVSAvoiddual UICC implementation

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

A single secure element performs multiple functions by storing subscriptions for both public and private networks. The same physical UICC can switch between different network types (public, private, tactical) by activating different stored profiles, eliminating the need for separate dual-UICC hardware.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines multiple network subscriptions (public network SIM and private network SIM) into a single secure element. The UICC stores multiple IMSI/PLMN combinations and can activate the appropriate one based on network availability and priority settings, merging what would traditionally require separate physical cards.

Inventive Principle:

Principle #5Merging (Combining)

3Adaptability or versatility

If automatic network switching is implemented without roaming agreements, then network flexibility improves, but compatibility with existing systems deteriorates

Engineering Contradiction:

Improvenetwork switching flexibilityVSAvoidroaming agreement compatibility

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The secure element acts as an intermediary that manages network selection independently of traditional roaming agreements. It stores pre-configured PLMN codes for private networks and uses these directly without requiring authentication through public network operators, bypassing the need for complex inter-network roaming arrangements.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Area of stationary object

If private network coverage is extended using public network infrastructure, then coverage area increases, but network priority and security deteriorate

Engineering Contradiction:

Improvenetwork coverage areaVSAvoidprivate network priority

Core Design Contradiction:

Area of stationary objectVSReliability

Solution Approach 1:

The system dynamically switches between public and private network attachments based on real-time network availability and predefined priorities. When a device enters private network coverage, it automatically attaches to the private network regardless of public network signal strength, ensuring private network priority is maintained while allowing public network fallback when private coverage is unavailable.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS12507163B2Method to automatically switch a subscription between telecommunication networks

Publication Date: 2025.12.23 THALES DIS FRANCE SA

AI summary

Provided is a method for connecting a terminal cooperating with a secure element to a second network, the secure element having a subscription from a first network whilst the secure element is roaming on a third network, the secure element storing the PLMN code of the second network, called second PLMN code, and the PLMN code of the third network, called third PLMN code, the second PLMN code having a higher priority than the third PLMN code in the OPLMN roaming file, the second PLMN having no roaming agreement with the first network nor the third network, and the third network having a coverage that overlaps at least a part of the coverage of the second network, the method comprising, when it is detected that the second network has rejected the attachment request of the terminal.