5G PDU Session Collision Handling for Handover and MA Resources

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Solution Overview

Problem

The collision between UE-requested PDU session establishment and network-requested PDU session modification procedures in 5G wireless communication networks is not adequately handled, leading to undefined UE/network behaviors.

Innovation Solution

A method is proposed to detect and handle collisions by determining the intent of the PDU session establishment procedure, either for handover or establishing user-plane resources, and accordingly proceed with either the UE-requested or network-requested procedures, or both, based on the detected collision type.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the network initiates a PDU session modification procedure while the UE initiates a PDU session establishment procedure, then both procedures may collide and cause undefined UE/network behaviors, but if one procedure is always prioritized, then the other procedure may be delayed or aborted unnecessarily

Engineering Contradiction:
Improvedefined behaviorVSAvoidprocedure delay
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent changes the behavior parameter based on the type of PDU session establishment. When the establishment is for handover, the network procedure is aborted. When the establishment is for MA PDU session, both procedures continue. This conditional parameter change resolves the contradiction by adapting the handling strategy to the specific scenario.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If the UE proceeds with both PDU session establishment and modification procedures simultaneously, then network efficiency is improved, but the complexity of UE behavior increases

Engineering Contradiction:
Improvenetwork efficiencyVSAvoidUE behavior complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent introduces a parameter-based decision mechanism where the UE checks the type of PDU session establishment (handover vs. MA PDU session) and adjusts its behavior accordingly. This controlled complexity resolution allows the UE to proceed with both procedures in MA PDU session cases while maintaining simpler behavior in handover cases.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4178309B1Handling of collision between PDU session establishment and modification procedure
Publication Date: 2025.09.10 MEDIATEK INC
  • EP4178309B1 patent drawingFigure 1~2
  • EP4178309B1 patent drawingFigure 3
  • EP4178309B1 patent drawingFigure 4

AI summary

A method for handling a collision of a UE-requested PDU session establishment procedure and a network-requested PDU session modification 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, UE and NW proceed with the UE-requested PDU session establishment procedure and abort the NW-requested PDU session modification procedure. When a PDU SESSION ESTABLISHMENT REQUEST message indicates that the UE-requested PDU session establishment request procedure is to establish user plane resources for an MA PDU session, UE and NW proceed with both the UE-requested PDU session establishment procedure and the NW-requested PDU session modification procedure.