MTC Device Attach Procedure PLMN Selection

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Solution Overview

Problem

In machine-type communication (MTC) systems, the existing attach procedure for MTC devices involves sending the International Mobile Subscriber Identity (IMSI) even when switching to a new Public Land Mobile Network (PLMN), which is not in the equivalent PLMN list, leading to redundant parameter transmission and potential security risks due to the exposure of critical subscriber information.

Innovation Solution

The MTC device performs an attach procedure by identifying itself with IMSI in the attach request message without sending information elements related to temporary identifiers or last location, thereby reducing redundant parameters and enhancing security by avoiding unnecessary IMSI exposure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the MTC device sends IMSI in the attach request message when switching to a new PLMN, then the network can identify the subscriber, but redundant parameter transmission occurs and security risks increase due to exposure of critical subscriber information

Engineering Contradiction:
Improvesubscriber identification reliabilityVSAvoidsecurity risk from IMSI exposure
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent extracts and removes the IMSI transmission from the attach request message when the device is already identified by a temporary identifier. The network can recognize that the temporary identifier (GUTI or S-TMSI) is sufficient for identification, and the IMSI is excluded from the message, thereby eliminating the security risk while maintaining identification reliability

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of always sending IMSI as in traditional procedures, the patent inverts the approach by sending temporary identifiers as the primary identification method and only using IMSI when absolutely necessary (i.e., when no temporary identifier is available). This reversal prioritizes security while maintaining functional reliability

Inventive Principle:
Principle #13The other way round (Inversion)

2Adaptability or versatility

If the MTC device sends all traditional attach request parameters including temporary identifiers and last location, then compatibility with existing networks is maintained, but message size increases and unnecessary information is transmitted

Engineering Contradiction:
Improvenetwork compatibilityVSAvoidmessage parameter quantity
Core Design Contradiction:
Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The patent extracts and removes unnecessary parameters from the attach request message, specifically temporary identifiers and last location information when the device is attaching to a new PLMN. This reduction eliminates redundant data transmission while preserving essential information needed for network compatibility and attach procedure completion

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the parameter set in the attach request message based on the specific scenario (new PLMN selection). Instead of using a fixed parameter set, the message adapts its content to include only necessary parameters for the current context, reducing overall message size while maintaining adaptability to different network scenarios

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2439989B1Method of handling a network attach procedure for a machine-type-communication (MTC) device selecting a new PLMN and related MTC device
Publication Date: 2013.03.27 HTC CORP
  • EP2439989B1 patent drawingFigure 1
  • EP2439989B1 patent drawingFigure 2
  • EP2439989B1 patent drawingFigure 3

AI summary

A method of handling an attach procedure for a MTC device in a wireless communication system is disclosed. The method comprises performing the attach procedure when a new PLMN not being the registered PLMN or an equivalent PLMN to the registered PLMN is selected and identifying the MTC device with the INSI; and not sending an information element relating to a plurality of temporary identifiers of the MTC device or relating to a last location in an attach request message associated with the attach procedure.