SMF Selection Based on Supported DNN in 5G Core

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Solution Overview

Problem

In 5G core network systems, the selection of Session Management Functions (SMFs) does not consider future Data Network Names (DNNs) or network slices subscribed by a User Entity (UE), leading to inefficient SMF selection and increased signaling overhead due to the use of multiple SMFs for different DNNs/APNs.

Innovation Solution

The Access and Mobility Function (AMF) utilizes the Network Repository Function (NRF) to retrieve a list of SMFs that support the requested DNN and network slices, allowing for the selection of an SMF that can handle multiple subscribed DNNs and slices, thereby optimizing SMF selection and reducing signaling complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the AMF selects SMF based only on current DNN without considering future subscribed DNNs, then the SMF selection process is simple, but multiple SMFs must be used for different DNNs leading to increased signaling overhead

Engineering Contradiction:
ImproveSMF selection process complexityVSAvoidnumber of SMF instances and signaling messages
Core Design Contradiction:
Device complexityVSQuantity of substance

Solution Approach 1:

The AMF performs preliminary action by retrieving the list of subscribed DNNs for the UE before selecting an SMF. This allows the AMF to anticipate future DNN access needs and select an SMF that can handle both current and future DNNs, avoiding the need to switch SMFs later and reducing signaling overhead.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention applies universality by selecting an SMF that can serve multiple DNNs (both current and future subscribed DNNs) through a single instance. This multi-functional SMF approach consolidates what would otherwise require multiple specialized SMF instances, reducing the overall number of SMF instances needed and the associated signaling overhead.

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

2Adaptability or versatility

If the AMF retrieves extended information about further supported DNNs and slices from NRF, then the adaptation to UE needs is enhanced, but the information retrieval and processing complexity increases

Engineering Contradiction:
Improveadaptation to UE needsVSAvoidinformation retrieval and processing complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The AMF performs preliminary retrieval of extended SMF information including supported DNNs and network slices from the NRF before making the selection decision. This advance information gathering enables better matching of SMF capabilities with UE subscription data, enhancing adaptability while allowing the processing to be done in a structured, efficient manner.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention uses feedback by comparing the UE's subscribed DNNs and slices with the SMF's supported DNNs and slices. This feedback mechanism allows the AMF to make an informed selection that maximizes compatibility, ensuring the selected SMF can handle the UE's current and future service requirements.

Inventive Principle:
Principle #23Feedback

3Adaptability or versatility

If multiple SMFs are used for different DNNs, then each DNN can be handled by a specialized SMF, but signaling overhead increases due to separate messages for each SMF

Engineering Contradiction:
Improvespecialized DNN handling capabilityVSAvoidnumber of signaling messages
Core Design Contradiction:
Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The invention merges the handling of multiple DNNs into a single SMF instance. By selecting one SMF that supports multiple subscribed DNNs, the system consolidates what would otherwise be separate SMF instances and their associated signaling messages, reducing the total number of messages while maintaining specialized handling capabilities through the SMF's multi-DNN support.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3603208B1SMF selection based on supported dnn
Publication Date: 2022.08.17 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3603208B1 patent drawingFigure 1
  • EP3603208B1 patent drawingFigure 2
  • EP3603208B1 patent drawingFigure 3

AI summary

There are provided methods, arrangements and entities for an Access and mobility Function, AMF, and for a NF Repository Function, NRF in a 5G supporting Communication Network, CN, providing services to a User Entity. Also, a NF Repository Function, NRF, is described. A request (2A) for SMF information to the NRF to retrieve at least a list of SMFs that supports the DNN and optionally which network slices each SMF supports is transmitted.