Targeted AMF Offload via 5G-GUTI Subscriber Selection

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Solution Overview

Problem

Existing 5G networks lack the flexibility to selectively relocate specific subscribers from one Access and Mobility Management Function (AMF) to another for network testing or load balancing, as current 3GPP standards impact all subscribers registered with a particular AMF during maintenance, lacking the ability to apply desired relocation logic.

Innovation Solution

A control system that utilizes the 5G-Globally Unique Temporary Identifier (5G-GUTI) to facilitate network-triggered relocation of a subset of active subscribers, allowing for targeted AMF offload by indicating a specific target AMF, and includes configurations for idle and connected mode transitions, UE context transfer, and RAN updates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the 3GPP defined procedure is used to take an AMF out of service for planned maintenance activities, then all subscribers registered with a particular AMF are relocated to other AMFs, but this results in loss of operational flexibility to selectively move specific active subscribers

Engineering Contradiction:
Improveoperational flexibilityVSAvoidrelocation mechanism complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the subscriber base into two groups: those to be relocated and those to remain with the source AMF. This is achieved through the N11 message (e.g., Namf_Communication_UEContextTransfer) which includes a list of 5G-GUTIs identifying specific subscribers for relocation, allowing selective movement rather than blanket relocation of all subscribers.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary actions by first identifying the subset of subscribers to be relocated using selection criteria (SUPI, GPSI, location, PLMN, etc.), then preparing the relocation by sending the N11 message with the target AMF address and subscriber list before actually executing the handover, ensuring a controlled and selective process.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If all subscribers of an AMF are relocated during maintenance activities, then the AMF can be taken out of service, but this causes service disruption for all subscribers including those that should remain active

Engineering Contradiction:
Improveservice continuityVSAvoidservice disruption time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent segments the subscriber population into relocated and non-relocated groups, allowing only the necessary subscribers to be moved during maintenance. The N11 message carries a specific list of 5G-GUTIs for relocation, ensuring that subscribers who should remain active continue to receive service without disruption.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of relocating all subscribers (excessive action), the patent applies partial action by relocating only the specific subset of subscribers identified by the selection criteria. This minimizes service disruption while still achieving the maintenance objective for the targeted subscribers.

Inventive Principle:
Principle #16Partial or excessive action

3Adaptability or versatility

If a control system enables selective relocation of specific subscribers, then operational flexibility is improved, but the complexity of the control system increases

Engineering Contradiction:
Improveselective relocation capabilityVSAvoidcontrol system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent introduces the N11 message (Namf_Communication_UEContextTransfer) as an intermediary mechanism between the source AMF and target AMF. This message carries the selection criteria, target AMF address, and list of subscribers to be relocated, providing a standardized interface that manages the complexity of selective relocation without requiring complex point-to-point control logic.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent makes the existing N11 message universal by extending its functionality to support both traditional AMF handover and the new selective subscriber relocation scenario. The same message structure is used to carry subscriber lists, selection criteria, and target AMF information, reducing the need for separate complex control mechanisms.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP4576851A1Method for targeted AMF offload
Publication Date: 2025.06.25 MAVENIR SYST INC
  • EP4576851A1 patent drawingFigure 1
  • EP4576851A1 patent drawingFigure 2
  • EP4576851A1 patent drawingFigure 3

AI summary

A control system that provides for network-triggered relocation of a subset of active subscribers from one AMF to another AMF allowing for triggering a targeted AMF offload for a subset of active subscribers. The control system provides for indication of a target AMF to which a selected subscriber(s) shall be offloaded to by the source AMF utilizing a 5G-GUTI assigned to UE.