Prioritizing Synchronized Cells for Lower Layer Triggered Mobility

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Solution Overview

Problem

Existing wireless communication systems face challenges in maintaining effective mobility for user equipment (UE) as it moves between cells, particularly in reducing latency and overhead during handovers between synchronized and non-synchronized cells, where timing advance (TA) information is crucial but signal strength also plays a significant role.

Innovation Solution

A network node that supports distributed unit functionality, determines candidate cells for UE connection by prioritizing synchronized cells over non-synchronized cells using signal strength measurements and applying an offset to ensure preferential selection of synchronized cells, even if non-synchronized cells have slightly better signal strength, thereby reducing latency and interruptions during handovers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If synchronized cells are preferentially selected for handovers, then latency and interruptions are reduced, but signal strength optimization may be compromised when non-synchronized cells have better signal strength

Engineering Contradiction:
Improvehandover latencyVSAvoidsignal strength optimization
Core Design Contradiction:
Loss of timeVSReliability

Solution Approach 1:

The patent applies parameter changes by introducing an offset value that modifies the signal strength measurement criterion for cell selection. This offset parameter allows the system to prioritize synchronized cells by effectively adjusting the threshold for handover decisions, thereby reducing handover latency while maintaining a controlled trade-off with signal strength optimization

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements dynamics by making the cell selection criterion adaptive rather than static. The system dynamically adjusts the handover decision based on the synchronization status of candidate cells and their signal strength measurements, allowing flexible prioritization of synchronized cells when latency is critical while still considering signal strength conditions

Inventive Principle:
Principle #15Dynamics

2Loss of time

If an offset is applied to prioritize synchronized cells, then handover latency is reduced, but the complexity of cell selection algorithms increases

Engineering Contradiction:
Improvehandover latencyVSAvoidcell selection algorithm complexity
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The patent resolves this contradiction by introducing a simple offset parameter that can be configured and applied to the signal strength measurement. This parameter-based approach adds minimal algorithmic complexity compared to more complex cell selection strategies, as it primarily involves adding a fixed value to the measurement criterion for synchronized cells

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality by differentiating the cell selection criterion based on the synchronization status of individual cells. Rather than applying a uniform complex algorithm to all cells, the system applies a simplified offset-based prioritization specifically to synchronized cells, keeping the overall algorithm complexity manageable through localized differentiation

Inventive Principle:
Principle #3Local quality

3Productivity

If synchronized cells are prioritized over non-synchronized cells, then mobility performance is improved, but the flexibility in cell selection is reduced

Engineering Contradiction:
Improvemobility performanceVSAvoidcell selection flexibility
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The patent resolves this contradiction by implementing a dynamic cell selection mechanism that adapts based on synchronization status and signal strength measurements. The system can flexibly prioritize synchronized cells when latency reduction is beneficial while still allowing selection of non-synchronized cells with superior signal strength when appropriate, maintaining adaptability through conditional logic rather than rigid prioritization

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4443964A1Priorisation in lower layer triggered mobility in a wireless communication network
Publication Date: 2024.10.09 NOKIA TECHNOLOGIES OY
  • EP4443964A1 patent drawingFigure 1~2
  • EP4443964A1 patent drawingFigure 3
  • EP4443964A1 patent drawingFigure 4a~4b

AI summary

A wireless communication network that supports lower layer triggered mobility and is configured so that in cell handovers, synchronised cells where a timing advance has already been acquired are prioritised as target cells for the handover over non-synchronised cells. Among the synchronised cells further priorisation is performed based on signal measurements using an offset.