5G Context Transfer with Dual IP Assignment for UPF Change

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Solution Overview

Problem

Existing context transfer procedures in 5G mobile communication systems fail to address scenarios where the User Plane Function (UPF) needs to be changed, leading to complex O&M actions and potential disruptions for long-lived IP sessions, especially in IoT environments.

Innovation Solution

A method for context transfer that involves establishing a new session with a second gateway entity while the UE is in an inactive state, assigning both an old and a new IP address to the UE, and delaying the provision of the new IP address until the UE enters an active state, thereby avoiding unnecessary reactivation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the UPF is changed during context transfer, then the gateway entity can be updated to improve network performance and adaptability, but the IP address must be changed which can awaken idle devices and increase operational complexity

Engineering Contradiction:

Improvegateway change capabilityVSAvoidIP address management complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by assigning both the old IP address and the new IP address to the UE during the context transfer process, before the actual gateway switch occurs. This allows the network to prepare the IP address configuration in advance, and the UE can seamlessly switch between IP addresses without being awakened from idle state, thus avoiding the complexity of iterative O&M actions for IP address reconfiguration.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If the IP address is changed during context transfer, then the new gateway can be properly configured, but idle devices like IoT machines may be awakened unnecessarily

Engineering Contradiction:

Improvecontext transfer completenessVSAvoidunintended device activation

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies the copying principle by creating a mapping relationship between the old IP address and the new IP address. The network assigns both IP addresses to the UE and maintains a correspondence between them, allowing packets destined for the old IP address to be forwarded to the new IP address. This copying/mapping approach ensures reliable context transfer while avoiding direct IP address changes that would wake idle devices.

Inventive Principle:

Principle #26Copying

3Adaptability or versatility

If iterative O&M actions are performed for reconfiguring IP addresses and routing, then the gateway change can be completed, but the process becomes complex and time-consuming

Engineering Contradiction:

Improvegateway switching capabilityVSAvoidcontext transfer duration

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-assigning both the old IP address and the new IP address to the UE before the gateway switch is executed. This preliminary IP address configuration eliminates the need for iterative O&M actions during the actual gateway transition, significantly reducing the time required for context transfer while maintaining full gateway switching capability.

Inventive Principle:

Principle #10Preliminary action

4Productivity

If the old IP address is immediately released after gateway change, then resources can be freed, but packet loss may occur during the transition period

Engineering Contradiction:

Improveresource utilization efficiencyVSAvoidpacket delivery reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies the copying principle by maintaining a mapping relationship between the old IP address and the new IP address. The old IP address is not immediately released but is kept in a mapping table that allows incoming packets addressed to the old IP to be forwarded to the new IP address. This ensures packet delivery reliability during the transition while eventually freeing up resources for the old IP address to be reassigned.

Inventive Principle:

Principle #26Copying

Data Source

PatentUS12628050B2Technique for performing a context transfer

Publication Date: 2026.05.12 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

A technique for performing a context transfer from a first session management entity to a second session management entity in a mobile communication system is provided, wherein the context transfer concerns a data session associated with a User Equipment, UE, wherein the data session is handled by the first session management entity via a first gateway entity and wherein, after the context transfer, the data session is to be handled by the second session management entity via a second gateway entity. A method implementation of the technique is performed by the second session management entity and comprises, while the UE is in an inactive state, triggering (S302) sending, to the second gateway entity, a session establishment request to establish a new session handling the data session via the second gateway entity, and triggering (S304) providing, to the second gateway entity, an old Internet Protocol, IP, address assigned to the UE as part of an old session handling the data session via the first gateway entity, requesting the second gateway entity to assign the old IP address to the UE as part of the new session, besides a new IP address assigned to the UE as part of the new session, and, when the UE enters an active state from the inactive state, triggering (S306) providing the new IP address to the UE.