Dynamic Multi IMSI Roaming via Identification Code Segmentation

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Solution Overview

Problem

Current roaming technologies face challenges when a User Equipment (UE) transitions to a new cellular carrier, as the UE's International Mobile Subscriber Identity (IMSI) may be unknown to the home network, leading to rejection of Packet Data Protocol (PDP) context create messages and requiring manual intervention or changes to Access Point Name (APN) settings.

Innovation Solution

A method and system that generate an identification code and send it to the home network, allowing the UE to be configured with instructions to insert this code into a PDP context request or registration request, enabling the home network to mark the UE's identification element and direct incoming roaming data to a mediating roaming service server, which can handle data routing and charging independently, without the need for human intervention or APN changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the UE uses its original IMSI when roaming to a new carrier, then the home network can maintain control over user data, but the home network may reject the PDP context create message because the IMSI is unknown to the new carrier

Engineering Contradiction:
Improvedata transmission reliabilityVSAvoidroaming compatibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The solution segments the identification function by introducing a separate identification code that is distinct from the IMSI. This code is embedded in the PDP context create message to uniquely identify the UE to the home network, while the IMSI is used for carrier-specific authentication. This segmentation allows the home network to recognize and control user data without requiring the new carrier to recognize the original IMSI.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The identification code acts as an intermediary element between the UE and the home network during roaming. Instead of relying solely on the IMSI which is unknown to the new carrier, the identification code serves as a mediator that enables the home network to recognize and control the user's data session without requiring the new carrier to recognize the original IMSI.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the home network rejects the PDP context create message due to unknown IMSI, then security is maintained, but manual intervention or APN changes are required which increases complexity

Engineering Contradiction:
Improvenetwork securityVSAvoidroaming configuration complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The identification code is prepared and embedded in the PDP context create message before the roaming connection is established. This preliminary action ensures that when the message is sent to the home network, the UE is already properly identified, eliminating the need for manual intervention or subsequent APN changes that would increase complexity.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system enables automatic identification and routing of roaming users through the embedded identification code. The home network can automatically recognize the UE and apply appropriate control policies without requiring manual configuration or APN changes, thereby reducing operational complexity while maintaining security.

Inventive Principle:
Principle #25Self-service

3Ease of operation

If the UE vendor implements automatic APN setting based on MCC/MNC, then roaming data transmission is facilitated, but the system cannot handle cases where the UE IMSI is unknown to the home network

Engineering Contradiction:
Improveautomatic roaming setupVSAvoidPDP context creation success
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The solution separates the automatic APN setting function from the UE identification function. While the APN is automatically configured based on MCC/MNC for ease of operation, the identification code is separately embedded in the PDP context create message to ensure reliable UE identification by the home network, even when the original IMSI is unknown to the new carrier.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The identification code serves as an intermediary that bridges the gap between automatic APN configuration and reliable home network recognition. It allows the system to benefit from automatic roaming setup while simultaneously ensuring that the home network can reliably identify and control the user's data session.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3682655B1Dynamic multi IMSI with native apn
Publication Date: 2021.07.07 ROAMABILITY LTD
  • EP3682655B1 patent drawingFigure 1
  • EP3682655B1 patent drawingFigure 2
  • EP3682655B1 patent drawingFigure 3

AI summary

A method for roaming between cellular carriers, the method comprising: obtaining from a Home Public Land Mobile Network (home network) at least one International Mobile Subscriber Identity (IMSI) number; generating an identification code and sending it to the home network with an indication of a location of the identification code in a Packet Data Protocol (PDP) of a context request response; configuring a User Equipment (UE) with instructions to insert the identification code into a specific mandatory characteristic of the PDP, in a response to a context request received from the home network; requesting the home network to mark an UE's identification element, presenting the identification code located in the specific mandatory characteristic of the PDP, to distinguish it from other UEs; and requesting the home network carrier operator to direct incoming roaming data from the UE using a marked UE identification element to a mediating roaming service server.