AMF-NSSF Slice Replacement Signaling for NSI Status Changes

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Solution Overview

Problem

There is a problem with unnecessary signaling occurring during Network Slice Instance (NSI) and Network Slice Replacement in 3GPP LTE and NR systems, which affects the effectiveness of these replacements.

Innovation Solution

The method involves communication between the AMF, UE, and NSSF through transmission and reception of specific messages such as subscription requests and notifications, as well as PDU session establishment and release commands, to manage network slice replacements efficiently.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If Network Slice Instance Replacement and Network Slice Replacement are implemented in 3GPP LTE and NR systems, then service availability and flexibility are improved, but unnecessary signaling occurs which reduces replacement effectiveness

Engineering Contradiction:

Improvenetwork slice replacement capabilityVSAvoidsignaling overhead

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The AMF subscribes to NSI status change events before replacement is needed, receiving advance notification when NSI becomes unavailable. This preliminary subscription allows the system to prepare for replacement proactively rather than reactively, reducing emergency signaling during actual replacement operations

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The NSSF provides feedback notifications to the AMF about NSI availability status changes. This feedback mechanism enables the AMF to monitor NSI health status continuously and trigger replacements only when necessary, avoiding unnecessary signaling while maintaining service availability

Inventive Principle:

Principle #23Feedback

2Reliability

If continuous monitoring of NSI status is performed to ensure service availability, then reliability is improved, but signaling overhead and resource consumption increase

Engineering Contradiction:

Improveservice availabilityVSAvoidsignaling resource consumption

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The NSSF autonomously monitors NSI status and generates event notifications when changes occur. Instead of the AMF continuously polling for status changes, the NSSF self-manages the monitoring function and pushes notifications only when relevant events occur, eliminating wasteful continuous signaling while maintaining reliable service availability

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system uses event-triggered periodic notifications rather than continuous monitoring. The NSSF subscribes to NSI status events and notifies the AMF periodically only when status changes occur, transforming continuous resource-intensive monitoring into efficient event-driven periodic updates

Inventive Principle:

Principle #19Periodic action

Data Source

PatentEP4679899A1Network slice

Publication Date: 2026.01.14 LG ELECTRONICS INC

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AI summary

One disclosure of the present specification provides a method by which an AMF performs communication. The method may comprise the steps of: transmitting a subscription request message to an NSSF; and receiving a notification message from the NSSF.