UE Dual-Access Registration After 5G Out-of-Service Timer Expiry

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Solution Overview

Problem

Existing methods and systems lack mechanisms for handling non-3GPP access registration and session management when a user equipment's periodic timer expires in an Out Of Service state in a 5G network, leading to incomplete context handling and inconsistent behavior.

Innovation Solution

A method and system for user equipment to register with both a 3GPP and non-3GPP access networks, triggering a registration procedure over 3GPP when the periodic timer expires, and reinitiating non-3GPP registration upon context transfer failures, with mechanisms for context management and PDU session handling across different access types.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the UE triggers a registration procedure over 3GPP when the periodic timer expires in OOS state, then the registration process can be initiated, but the context transfer from non-3GPP access may fail, leading to incomplete registration

Engineering Contradiction:

Improveregistration completenessVSAvoidcontext management complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The UE performs preliminary actions by reinitiating the registration procedure over non-3GPP access before completing the 3GPP registration process. This ensures that the UE context is established in the non-3GPP access network prior to relying solely on 3GPP registration, preventing context transfer failures and ensuring complete registration.

Inventive Principle:

Principle #10Preliminary action

2Productivity

If the network deletes the UE context for 3GPP access when the UE is in OOS state, then network resources are freed, but the UE cannot maintain proper registration state, leading to registration failures

Engineering Contradiction:

Improvenetwork resource efficiencyVSAvoidregistration reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent segments the UE context management into separate 3GPP and non-3GPP access contexts. The network can delete the 3GPP access context when the UE is in OOS state to free up network resources, while the UE maintains its non-3GPP access context through the AMF. This segmentation allows independent management of different access types, ensuring both network resource efficiency and registration reliability.

Inventive Principle:

Principle #1Segmentation

3Reliability

If the UE reinitiates registration procedure over non-3GPP access, then context integrity is maintained, but additional signaling and processing time are required

Engineering Contradiction:

Improvecontext integrityVSAvoidregistration processing time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The AMF provides feedback information to the UE about the registration status and context management state. Based on this feedback, the UE can determine whether to reinitiate the registration procedure over non-3GPP access, avoiding unnecessary signaling when the context is already properly established and reducing processing time when reinitiation is required.

Inventive Principle:

Principle #23Feedback

4Adaptability or versatility

If the UE is registered to both 3GPP and non-3GPP access networks, then service continuity is improved, but the management complexity increases

Engineering Contradiction:

Improveaccess network flexibilityVSAvoiddual registration management

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The AMF acts as an intermediary that manages the UE context for both 3GPP and non-3GPP access networks. The AMF receives the UE context from the non-3GPP access network and stores it, enabling the UE to be registered to both access types without the UE having to directly manage the complexity of dual registration. This intermediary approach simplifies the UE's management burden while maintaining access network flexibility.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS12477446B2Method and system for handling paging in wireless communication system

Publication Date: 2025.11.18 SAMSUNG ELECTRONICS CO LTD

AI summary

Embodiments herein achieve a method for handling registration and session management in a wireless communication system. The method includes registering, by a User Equipment (UE), with a first core network entity over a 3GPP access network and a non-3GPP access network. Further, the method includes triggering, by the UE, a registration procedure to a second core network over the 3GPP access network when a periodic timer of the UE expires in an OOS state. Further, the method includes receiving, by the UE, a non-access stratum (NAS) message, over the 3GPP access network, with an indication to register for the non-3GPP access network with the second core network entity. Further, the method includes reinitiating the registration procedure to register again for the non-3GPP access with the second core network entity through the non-3GPP access network.