Deferred Detachment Mechanism for Mobile Terminal Context Release

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Solution Overview

Problem

Current mobile communication networks face challenges in efficiently detaching mobile terminals from the network, particularly for Machine Type Communication (MTC) devices, which leads to increased signaling overhead and resource occupation, as existing methods require explicit signaling and re-establishment of connections for detachment.

Innovation Solution

A deferred detachment mechanism is introduced, where the mobile terminal transitions from a connected state to an idle state, and the detachment procedure is initiated after a predetermined time span, allowing for autonomous deletion of context information without additional signaling, coordinated by a detach timer between the mobile terminal and the mobility management entity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If explicit signaling is used for detachment in existing methods, then the detachment procedure can be reliably executed, but the signaling overhead increases and resource occupation is prolonged

Engineering Contradiction:
Improvedetachment execution reliabilityVSAvoidsignaling overhead
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent extracts the detachment execution from the signaling exchange between network and terminal. Instead of requiring explicit confirmatory signaling, the network side autonomously executes detachment by deleting context information after determining the terminal is in idle state, thereby eliminating the need for additional signaling messages while maintaining reliable detachment execution

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The network side performs self-service by autonomously managing the detachment process. Once the terminal transitions to idle state, the network automatically deletes the terminal's context information without requiring further interaction with the terminal, thus reducing signaling overhead while ensuring detachment is properly executed

Inventive Principle:
Principle #25Self-service

2Reliability

If explicit signaling is used for detachment, then the detachment can be confirmed between network and terminal, but the detachment time is prolonged due to additional signaling exchanges

Engineering Contradiction:
Improvedetachment confirmationVSAvoiddetachment time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by having the network side prepare for detachment in advance. When the terminal transitions to idle state, the network immediately initiates context information deletion without waiting for additional signaling exchanges, thus reducing detachment time while maintaining confirmation through the idle state transition itself

Inventive Principle:
Principle #10Preliminary action

3Reliability

If MTC devices remain attached to the network during idle periods, then network connectivity is maintained, but energy consumption increases and network resources are occupied

Engineering Contradiction:
Improvenetwork connectivityVSAvoidterminal energy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent implements periodic action by having MTC devices transition to idle state after data transmission completes. During this idle period, the device remains detached from the network (context information deleted), saving energy and network resources, while the ability to reattach is preserved when new data transmission is needed, thus creating a periodic attach-idle pattern

Inventive Principle:
Principle #19Periodic action

4Speed

If MTC devices remain attached to the network during idle periods, then quick reconnection is possible, but network resource occupation increases

Engineering Contradiction:
Improvereconnection speedVSAvoidnetwork resource occupation
Core Design Contradiction:
SpeedVSQuantity of substance

Solution Approach 1:

The patent applies discarding and recovering by having the network discard (delete) terminal context information when the terminal transitions to idle state, freeing up network resources. When the terminal needs to reconnect for new data transmission, it recovers by performing a new attach procedure, thus dynamically managing network resource occupation while maintaining reconnection capability

Inventive Principle:
Principle #34Discarding and recovering

Data Source

PatentEP2695458B1Detachment of a mobile terminal from a mobile communication system
Publication Date: 2019.05.15 PANASONIC INTELLECTUAL PROPERTY CORP OF AMERICA
  • EP2695458B1 patent drawingFigure 1
  • EP2695458B1 patent drawingFigure 2
  • EP2695458B1 patent drawingFigure 3

AI summary

The invention relates to methods for detaching a mobile terminal from a mobile communication network. Furthermore, the invention also relates to a mobile terminal and a mobility management entity that perform these methods. The invention is inter alia applicable to a 3GPP LTE-A system following the Evolved Packet System (EPS) architecture. The invention proposes that the detach procedure of a mobile terminal is triggered by the mobile terminal being transferred into idle state. The mobility management entity can trigger the detach procedure in response to this event. The detach procedure may be deferred by a given time span. A detach timer may be configured in the mobile terminal and the mobility entity for this purpose, and upon expiry of the detach timer in the mobile terminal and the mobility management entity, both silently delete the context information related to the mobile terminal's user plane and control plane to detach the mobile terminal.