5G PDU Session Collision Handling for Release vs Establishment

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Solution Overview

Problem

Existing wireless communication systems face challenges in handling collisions between UE-requested PDU session establishment procedures and network-requested PDU session release procedures, particularly when the procedures involve different purposes such as initial requests, existing sessions, or handovers between 5G 3GPP and non-3GPP access networks.

Innovation Solution

A method is proposed where the UE detects a collision by comparing PDU session IDs in PDU SESSION ESTABLISHMENT REQUEST and RELEASE COMMAND messages, and based on the request type, decides to either proceed with the network-requested release procedure or ignore the release command, aborting the UE's establishment procedure, or continue with the UE's establishment procedure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the UE always proceeds with the UE-requested PDU session establishment procedure when collision occurs, then the UE's session establishment is ensured, but the network's session release control is violated and resource waste occurs

Engineering Contradiction:

ImproveUE session establishment reliabilityVSAvoidnetwork resource waste

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the handling parameter based on the request type parameter in the PDU SESSION ESTABLISHMENT REQUEST message. When request type indicates handover of existing PDU session, the UE follows network release command; otherwise, the UE proceeds with establishment. This parameter-based differentiation resolves the contradiction by adapting behavior to the specific scenario.

Inventive Principle:

Principle #35Parameter changes

2Object-generated harmful factors

If the UE follows the network's PDU session release procedure when collision occurs, then network control is maintained, but the UE's session establishment may be incorrectly aborted

Engineering Contradiction:

Improvenetwork control maintenanceVSAvoidUE session establishment reliability

Core Design Contradiction:

Object-generated harmful factorsVSReliability

Solution Approach 1:

The patent uses the request type parameter to determine whether to follow network release procedure. Only when request type indicates handover of existing PDU session does the UE abort establishment and follow release; for all other cases (initial request, emergency request, new session), the UE ignores the release command. This selective parameter-based approach prevents incorrect abortion while maintaining network control where appropriate.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If the UE distinguishes between different PDU session establishment scenarios, then appropriate handling is achieved, but the collision detection and handling complexity increases

Engineering Contradiction:

Improvescenario differentiation capabilityVSAvoidcollision handling logic complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent leverages the existing request type parameter in the PDU SESSION ESTABLISHMENT REQUEST message to differentiate scenarios without adding new signaling elements. The UE checks this parameter value to determine handling behavior, reusing existing message structures and reducing the need for additional complex detection mechanisms.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent enables the UE to autonomously determine the appropriate collision handling behavior by examining its own previously sent request type parameter. The UE self-evaluates whether its establishment request was for handover of existing session or other purposes, and self-adjusts its collision response accordingly, reducing the need for complex external coordination.

Inventive Principle:

Principle #25Self-service

4Reliability

If the UE ignores the PDU SESSION RELEASE COMMAND message, then UE session establishment proceeds, but network resource management efficiency decreases

Engineering Contradiction:

ImproveUE session establishment reliabilityVSAvoidnetwork resource management efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent changes the default behavior based on the request type parameter. Instead of always ignoring release commands, the UE now conditionally responds: ignoring when request type indicates new session or emergency request (maintaining establishment reliability), and following when request type indicates handover of existing session (improving resource efficiency).

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12550207B2Enhanced handling of 5GSM procedure collision

Publication Date: 2026.02.10 MEDIATEK INC

AI summary

A method for handling a collision of a UE-requested PDU session establishment procedure and a network-requested PDU session release procedure is proposed. When a PDU SESSION ESTABLISHMENT REQUEST message indicates that the UE-requested PDU session establishment request procedure is to handover an existing PDU session between 5G 3GPP access and 5G non-3GPP access, the UE proceeds with the network-requested PDU session release procedure and aborts the UE-requested PDU session establishment procedure. Otherwise, the UE ignores a received PDU SESSION RELEASE COMMAND message and proceeds with the UE-requested PDU session establishment procedure.