Conditional Handover Target Cell Selection Using Priority Information

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Solution Overview

Problem

In 5G and 4G communication systems, during conditional handover, the User Equipment (UE) faces challenges in selecting an optimal target cell from multiple candidate cells that meet the handover condition, leading to inefficiencies and potential communication quality issues.

Innovation Solution

A method and apparatus that enable the UE to select a target cell based on priority information, which includes priority levels determined by signal quality, differences in signal quality, number of beams exceeding a threshold, and remaining durations of timers, ensuring the UE is handed over to the optimal target cell, thereby improving handover efficiency and communication quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the UE selects a target cell from multiple candidate cells that satisfy the handover trigger condition, then the handover operation can be performed, but the UE cannot determine which target cell to select without priority information

Engineering Contradiction:
Improvetarget cell selection capabilityVSAvoidtarget cell selection criterion
Core Design Contradiction:
Ease of operationVSLoss of information

Solution Approach 1:

The source base station pre-configures priority information for multiple candidate target cells before handover execution. This preliminary action provides the UE with selection criteria in advance, enabling the UE to autonomously select the most appropriate target cell when handover conditions are met, without requiring real-time network intervention.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Priority information acts as an intermediary between the network's handover decision and the UE's target cell selection. The source base station uses measurement reports and handover decisions as intermediaries to convey selection criteria to the UE, enabling autonomous selection while maintaining network control.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If multiple target cells meet the handover condition, then the UE has more options for handover, but the UE cannot efficiently select the optimal target cell without priority information

Engineering Contradiction:
Improvehandover option availabilityVSAvoidhandover selection efficiency
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The source base station pre-configures priority information for multiple candidate target cells before handover execution. This preliminary action provides the UE with selection criteria in advance, enabling the UE to autonomously select the most appropriate target cell when handover conditions are met, without requiring real-time network intervention.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces priority levels as a new parameter to differentiate between multiple candidate target cells. By assigning different priority values to candidate cells based on factors like signal quality, load conditions, and beam availability, the system transforms the selection process from an ambiguous choice to a deterministic decision based on priority comparison.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If the UE performs cell handover without priority information, then the handover process is simpler, but the handover may not be to the optimal target cell leading to reduced communication quality

Engineering Contradiction:
Improvehandover process complexityVSAvoidcommunication quality
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The source base station pre-configures priority information for multiple candidate target cells before handover execution. This preliminary action provides the UE with selection criteria in advance, enabling the UE to autonomously select the most appropriate target cell when handover conditions are met, without requiring real-time network intervention.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses measurement reports from the UE as feedback to determine priority information. The source base station receives measurement reports containing signal quality information of candidate cells, and uses this feedback to assign priority levels that reflect the optimal handover targets, thereby ensuring communication quality.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3836623B1Cell handover method and apparatus, RRC reestablishment method and apparatus, storage medium and user equipment
Publication Date: 2024.10.23 SPREADTRUM COMMUNICATION (SHANGHAI) CO LTD
  • EP3836623B1 patent drawingFigure 1~2
  • EP3836623B1 patent drawingFigure 3~4

AI summary

A method and a device for cell handover and RRC re-establishment, a storage medium, and user equipment, the cell handover method comprising: receiving conditional handover command information from a base station, the conditional handover command information comprising a handover trigger condition; on the basis of priority information, selecting an ultimate target cell from among a plurality of target cells satisfying the handover trigger condition, the priority information comprising priority grades of the plurality of target cells; and executing a cell handover operation from a current service cell to the ultimate target cell. The technical solution of the present invention makes possible handover to an optimal target cell during cell handover, raising handover efficiency. The RRC re-establishment method comprises: in a cell selection process for RRC re-establishment, selecting an ultimate target cell on the basis of priority information, the priority information comprising the priority grades of the plurality of target cells. The technical solution of the present invention makes possible the selection of an optimal target cell during RRC re-establishment.