ISR Deactivation in Core Network Nodes

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Solution Overview

Problem

Current methods for deactivating idle mode signaling reduction (ISR) in the EPS system are not applicable to detach scenarios other than UE switch-off, leading to incorrect execution and resource wastage due to asynchronous ISR states.

Innovation Solution

A method and device for deactivating ISR that send specific messages to associated core network nodes to perform ISR deactivation, bearer deletion, or local detachment based on the detachment cause, ensuring correct procedure execution and resource management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the current detach procedure is used for all detach scenarios, then the procedure is simple and uniform, but incorrect execution and resource wastage occur in non-UE switch-off detach scenarios due to asynchronous ISR states

Engineering Contradiction:
Improvecorrect execution of detach procedureVSAvoidcomplexity of detach procedure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent changes the parameter of message content by introducing different cause values (e.g., cause value 1 for UE switch-off, cause value 2 for other detach scenarios) in the detach request message. This allows the MME to distinguish between different detach scenarios and execute appropriate ISR deactivation procedures, ensuring reliability without excessive complexity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent segments the detach procedure into different handling paths based on the detach cause. When cause value indicates UE switch-off, the MME sends detach notification to SGSN; when cause value indicates other scenarios, the MME sends ISR deactivation message directly. This segmentation resolves the contradiction by providing scenario-specific handling while maintaining a unified message structure

Inventive Principle:
Principle #1Segmentation

2Reliability

If ISR deactivation message is sent in all detach scenarios, then correct execution is achieved, but resource wastage occurs due to unnecessary bearer deletion in scenarios where it is not needed

Engineering Contradiction:
Improvesynchronization of ISR stateVSAvoidresource wastage
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent uses different cause values in the detach request message to control the deactivation behavior. When cause value indicates UE switch-off, full ISR deactivation with bearer deletion is performed; when cause value indicates other scenarios, only necessary ISR state synchronization is done without unnecessary bearer deletion, thus avoiding resource wastage while maintaining reliability

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the MME sends detach notification to SGSN in all cases, then the SGSN can be notified of UE detachment, but incorrect execution occurs in non-UE switch-off scenarios where ISR should be deactivated differently

Engineering Contradiction:
Improvenotification accuracyVSAvoidmessage handling complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent changes the type of message sent by MME to SGSN based on detach cause. For UE switch-off, detach notification is sent; for other scenarios, ISR deactivation message is sent. This parameter change in message type ensures notification accuracy while the unified cause value mechanism keeps handling complexity manageable

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2293630B1Method for detaching network, method for deactivating ISR and indication device thereof
Publication Date: 2017.08.16 ZTE CORP
  • EP2293630B1 patent drawingFigure 1~2
  • EP2293630B1 patent drawingFigure 3
  • EP2293630B1 patent drawingFigure 4

AI summary

A method for detaching network, a method for deactivating ISR and an indicating device thereof are provided in the present invention, wherein the method for deactivating ISR includes: when a registration state of a user equipment of a current core network node in a pair of core network nodes with ISR activated is changed, sending an ISR deactivating message to an associated core network node and indicating the associated core network node to perform related operation, wherein the related operation comprises one of the following: ISR deactivation, ISR deactivation and bearer deletion. Through the present invention, the ISR deactivation flow could be implemented correctly and the flow error due to the asynchronous ISR state and the resource waste due to the invalid information could be prevented.