SMF Selection via Binding Identifier for 4G to 5G Mobility

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Solution Overview

Problem

In the transition of a communication terminal from a 4G to a 5G communication network, there is a need for a mechanism to associate a Packet Data Network connection with the correct Session Management Function (SMF) without relying on a common identifier for the Packet Data Network Gateway (PGW) and SMF instances, which are typically scaled independently and may use different protocols and physical servers.

Innovation Solution

The method involves the Packet Data Network Gateway (PGW) assigning an SMF instance during PDN connection establishment, with the information stored in a repository like HSS+UDM, and the AMF selecting the appropriate SMF instance based on this association for seamless mobility between 4G and 5G networks, allowing independent scaling of PGW and SMF instances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a common identifier is used for PGW and SMF instances, then association between PDN connection and SMF is simplified, but independent scaling of PGW and SMF instances is prevented

Engineering Contradiction:
Improveease of associationVSAvoidindependent scaling capability
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent introduces a binding identifier as an intermediary element that links the PDN connection to the SMF instance. This binding identifier acts as a mediator that enables association without requiring a common identifier between PGW and SMF, thus allowing independent scaling while maintaining the association capability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent segments the identification and association mechanism into separate components: the PDN connection identifier, the SMF instance identifier, and the binding identifier. This segmentation allows each component to be independently managed and scaled, resolving the contradiction between simplified association and independent scaling capability.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If PGW and SMF instances use different protocols and physical servers, then system flexibility and independent scaling are improved, but the complexity of association mechanism increases

Engineering Contradiction:
Improvesystem flexibilityVSAvoidassociation mechanism complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The binding identifier serves as a simplified intermediary that abstracts the complexity of cross-protocol and cross-server association. Instead of implementing complex direct association mechanisms between PGW and SMF using different protocols, the binding identifier provides a unified and simple association interface.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Adaptability or versatility

If SMF instances are selected dynamically during mobility procedures, then network adaptability is improved, but the time and complexity of session management increases

Engineering Contradiction:
Improvenetwork adaptabilityVSAvoidsession management time
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent performs preliminary action by establishing the binding between the PDN connection and the SMF instance before mobility procedures occur. The binding identifier is assigned and stored in advance, so that during mobility, the SMF can be quickly identified and selected without complex real-time decision-making, thus reducing session management time while maintaining adaptability.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3503623B1Moving a communication terminal from a first communication network to a second communication network
Publication Date: 2020.03.04 NTT DOCOMO INC
  • EP3503623B1 patent drawingFigure 1
  • EP3503623B1 patent drawingFigure 2
  • EP3503623B1 patent drawingFigure 3

AI summary

According to an embodiment, a method for moving a communication terminal from a first communication network to a second communication network is described which comprises establishing a communication session for the communication terminal by means of a first session management function of the first communication network, determining a session management function of the second communication network to handle the communication session when providing the communication session by means of the second communication network, informing a Mobility Management Function of the second communication network about the determined session management function and providing the communication session for the communication terminal by means of the determined session management function upon a request by the communication terminal to register in the second communication network or to move the communication session from the first communication network to the second communication network.