Terminal Attachment to Access Networks Using Pre-provisioned IMSI

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Solution Overview

Problem

The limited availability of International Mobile Subscriber Identity (IMSI) numbers poses a challenge as billions of machine-to-machine (M2M) devices are predicted to exceed human communication devices, leading to IMSI shortages, and existing solutions fail when devices attempt to attach to networks that do not support new or unsupported subscriber identifiers.

Innovation Solution

A user terminal is provisioned with a determining function to identify unsupported subscriber identifiers and uses a pre-stored access IMSI to attach to networks, requesting and dynamically receiving a roaming IMSI from a home network, allowing it to reattach using the roaming IMSI, thereby enabling access to networks that do not support its original identifier.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If new types of subscriber identifiers (such as combination of IMSI and IMEI) are introduced to extend the number of available identifiers, then the quantity of available subscriber identifiers is improved, but the adaptability to legacy networks that do not support these new identifier formats deteriorates

Engineering Contradiction:
Improvenumber of available subscriber identifiersVSAvoidcompatibility with legacy networks
Core Design Contradiction:
Quantity of substanceVSAdaptability or versatility

Solution Approach 1:

The terminal is pre-configured with multiple access IMSIs stored in memory before attempting to attach to a network. When the primary subscriber identifier is not supported by the visited network, the terminal can immediately switch to using a pre-stored access IMSI to establish connection, thus resolving the compatibility issue before it becomes a blocking problem.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements dynamic selection of subscriber identifiers based on network support. The terminal dynamically switches between different identifier types (primary IMSI, access IMSI, roaming IMSI) depending on which format the current network environment supports, making the identifier system flexible and adaptable rather than static.

Inventive Principle:
Principle #15Dynamics

Solution Approach 3:

The access IMSI acts as an intermediary identifier that enables terminals with new identifier formats to connect to legacy networks. This intermediate identifier format serves as a bridge, allowing the terminal to first attach to the network using a supported format, then obtain a roaming IMSI to maintain the connection while preserving the original subscription identity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If a terminal uses a new type of subscriber identifier that is not supported by the visited network, then the terminal can utilize extended identifier capabilities, but the terminal cannot attach to the visited network

Engineering Contradiction:
Improveuse of extended identifier formatsVSAvoidability to attach to visited network
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent changes the parameter of the subscriber identifier format based on network requirements. The terminal can switch between different identifier parameters (standard IMSI, extended IMSI-IMEI combination, access IMSI, roaming IMSI) depending on what the current network environment supports, thus maintaining reliability across different network types.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The terminal performs preliminary configuration by storing multiple access IMSIs in memory before network attachment. This preliminary preparation ensures that when the primary identifier is rejected by the visited network, the terminal already has alternative identifiers ready to use, preventing attachment failure.

Inventive Principle:
Principle #10Preliminary action

3Quantity of substance

If IMSI numbers are extended to accommodate billions of M2M devices, then the quantity of identifiers is improved, but the complexity of managing and distributing these identifiers increases

Engineering Contradiction:
Improvetotal number of subscriber identifiersVSAvoididentifier management complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent segments the identifier management into multiple components: access IMSIs stored locally in the terminal, roaming IMSIs provided by the home network, and the original subscription identifiers. This segmentation distributes the management burden across different entities (terminal, visited network, home network) rather than requiring centralized management of all identifiers.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent creates a universal identifier management system that handles multiple identifier types through a common framework. The same procedural steps (attach with access IMSI, request roaming IMSI, detach and reattach) work regardless of whether the terminal uses traditional IMSI or extended IMSI-IMEI combinations, simplifying the overall management complexity.

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

Data Source

PatentEP2499853B1Attaching to an access network
Publication Date: 2015.09.16 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP2499853B1 patent drawingFigure 1
  • EP2499853B1 patent drawingFigure 2~3
  • EP2499853B1 patent drawingFigure 4~5

AI summary

A method and apparatus for allowing a terminal to attach to an access network. The terminal determines that the access network does not support a subscriber identifier used by the terminal, and so it attaches to the access network using an IMSI, the IMSI having been pre-provisioned at the terminal. The terminal, once attached, sends a request for a roaming IMSI to a remote node in the subscriber's home network. It then receives a roaming IMSI from the remote, the roaming IMSI being associated with the subscription and related subscriber identifier. The terminal detaches from the access network and then re-attaches to the access network using the roaming IMSI.