5G Event Monitoring for 4G-to-5G Subscription Resynchronization

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Solution Overview

Problem

In scenarios where a user equipment (UE) switches between 4G and 5G networks, there may be no subscription information at the access and mobility management function (AMF) side, or the information may be inaccurate, leading to the need for re-synchronizing subscription information, which existing solutions fail to address effectively, especially in cases of incomplete or aged records.

Innovation Solution

An event monitoring method that includes determining UE access to a 5G network, triggering a first subscription request with a network switching monitoring event, and upon detecting target network switching from 4G to 5G, sending event information through a second subscription request, utilizing network elements like AMF, UDM, and NEF to ensure accurate event information delivery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the AMF clears local subscription records during network switching, then the network switching process is simplified, but the event information corresponding to subscription requests is lost

Engineering Contradiction:
Improvenetwork switching processVSAvoidevent information
Core Design Contradiction:
Device complexityVSLoss of information

Solution Approach 1:

The system performs preliminary actions by having the UDM store event information corresponding to subscription requests before the AMF clears its local subscription records during network switching. This ensures that the information is preserved in a safe location (UDM) and can be retrieved when needed, resolving the contradiction between simplifying the switching process and preserving event information.

Inventive Principle:
Principle #10Preliminary action

2Loss of time

If subscription information is not re-synchronized after network switching, then the processing time is reduced, but the accuracy of event information delivery deteriorates

Engineering Contradiction:
Improveprocessing timeVSAvoidevent information accuracy
Core Design Contradiction:
Loss of timeVSMeasurement precision

Solution Approach 1:

The system implements a feedback mechanism where the AMF sends a notification message to the UDM when it detects that a UE has switched to the 5G network. The UDM then determines whether to re-synchronize subscription information based on this feedback, allowing the system to balance processing time with information accuracy by only re-synchronizing when necessary.

Inventive Principle:
Principle #23Feedback

3Speed

If event information is sent immediately upon network switching, then the responsiveness is improved, but the reliability of information delivery deteriorates when subscription records are incomplete

Engineering Contradiction:
ImproveresponsivenessVSAvoidinformation delivery reliability
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The system performs preliminary actions by storing event information in the UDM before it is needed. When the AMF needs to deliver event information, it can retrieve the complete and accurate information from the UDM, ensuring both responsiveness and reliability even when the AMF's local records are incomplete or cleared during network switching.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4716302A1Event monitoring method and apparatus, electronic device, and storage medium
Publication Date: 2026.03.25 ZTE CORP
  • EP4716302A1 patent drawingFigure 1
  • EP4716302A1 patent drawingFigure 2
  • EP4716302A1 patent drawingFigure 3A~3B

AI summary

Embodiments of the present application relate to an event monitoring method and apparatus, an electronic device, and a storage medium. The method comprises: determining whether a user equipment accesses a 5G network; when it is determined that the user equipment accesses the 5G network, triggering a first subscription request, wherein the first subscription request carries a network switching monitoring event; determining whether the user equipment has performed target network switching, wherein the target network switching indicates that the user equipment switches from a 4G network to the 5G network; and when the user equipment has performed the target network switching, triggering a second subscription request, and when event information corresponding to the second subscription request is detected, sending the event information corresponding to the second subscription request to the user equipment.