mTRP UE Handover Using a Persistent Assisting Cell

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Solution Overview

Problem

Existing handover procedures in multiple transmission and reception point (mTRP) operations in communication networks face issues such as increased communication overhead, service interruptions, and reduced mobility robustness due to break-before-make radio link failures during handovers, especially when cells are not from the same distributed unit (DU).

Innovation Solution

The proposed solution involves maintaining the connection to the assisting cell during the handover process by utilizing the same assisting cell before and after the handover, either through direct coordination between network nodes or central unit management, thereby reducing the need for additional signaling and enabling continuous data transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the target network node selects a new assisting cell after handover finalization, then the mTRP operation can be established at the target node, but communication overhead increases due to additional RRC messages

Engineering Contradiction:
ImprovemTRP operation establishmentVSAvoidcommunication overhead
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The source network node performs preliminary actions by selecting and configuring an assisting cell for the target node before handover finalization. The source node includes assisting cell information in the handover request message to the target node, enabling the target node to have the assisting cell ready before the UE completes handover, thus avoiding additional RRC messaging overhead.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If the target network node selects and configures a new assisting cell after handover, then mTRP operation is established, but service interruption occurs during the setup time

Engineering Contradiction:
ImprovemTRP operation establishmentVSAvoidservice continuity
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The assisting cell is selected and configured in advance by the source network node before handover execution. The target node receives the assisting cell information through the handover request message, allowing the mTRP operation to be immediately established upon handover completion without service interruption.

Inventive Principle:
Principle #10Preliminary action

3Ease of operation

If the assisting cell is released at the source network node before handover completion, then the handover procedure can proceed, but mobility robustness is reduced due to break-before-make operation

Engineering Contradiction:
Improvehandover procedure executionVSAvoidmobility robustness
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The assisting cell maintains continuous operation throughout the handover process. The source network node keeps the assisting cell active and transfers its configuration to the target node, ensuring that the UE can continuously utilize the assisting cell for diversity reception and transmission during the entire handover procedure, thereby maintaining mobility robustness.

Inventive Principle:
Principle #20Continuity of useful action

Data Source

PatentEP4192108B1Handover of a user equipment (UE) involving mtrp (multiple transmission and reception point) operation
Publication Date: 2026.01.21 NOKIA TECHNOLOGIES OY
  • EP4192108B1 patent drawingFigure 1
  • EP4192108B1 patent drawingFigure 2a
  • EP4192108B1 patent drawingFigure 2b

AI summary

Inter-alia, methods are disclosed for handover in the multiple transmission and reception point connection of a user equipment in a communication network.