Propagation-Delay Cell Reselection for Non-Terrestrial Networks

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Solution Overview

Problem

In non-terrestrial wireless communication networks, existing cell selection and reselection methods based on reference signal received power are inadequate due to the large distances and varying mobility, leading to unreliable and inefficient cell switching.

Innovation Solution

A method and apparatus for UE to perform cell selection and reselection using propagation delay calculations based on timing information from multiple cells, utilizing absolute or relative time-based delay measurements, and synchronization signal blocks to determine optimal cell connections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If cell selection and reselection are based on reference signal received power, then the method is simple to implement, but the reliability is poor due to large distances and varying mobility in non-terrestrial networks

Engineering Contradiction:
Improvecell switching reliabilityVSAvoidcell selection method complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent changes the selection parameter from reference signal received power to propagation delay. By measuring the time delay of synchronization signal blocks from different cells and selecting the cell with the minimum delay, the system achieves more reliable cell selection in non-terrestrial networks while maintaining implementation feasibility through standardized timing measurement mechanisms.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If traditional cell selection methods are used in non-terrestrial networks, then the implementation is straightforward, but the efficiency is low due to unreliable cell switching

Engineering Contradiction:
Improvecell switching efficiencyVSAvoidcell selection operation simplicity
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The patent substitutes the traditional power-based cell selection mechanism with a time-based propagation delay measurement mechanism. This replacement leverages the precise timing capabilities already present in 5G NR systems to achieve more efficient and reliable cell switching, particularly for mobile UEs in non-terrestrial networks where signal power varies significantly with distance.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If propagation delay-based cell selection is implemented, then the reliability and efficiency of cell switching improve, but the measurement and calculation complexity increases

Engineering Contradiction:
Improvecommunication link stabilityVSAvoidpropagation delay measurement difficulty
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent utilizes the UE's own timing capabilities to perform propagation delay measurements. The UE independently measures the arrival times of synchronization signal blocks from different cells and calculates propagation delays using its local clock, eliminating the need for complex network-side measurement infrastructure and reducing the actual difficulty of implementation despite the increased measurement requirements.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4278697B1Delay-based cell selection or cell reselection for communication networks
Publication Date: 2026.02.18 QUALCOMM INC
  • EP4278697B1 patent drawingFigure 1
  • EP4278697B1 patent drawingFigure 2A
  • EP4278697B1 patent drawingFigure 2B

AI summary

Methods, systems, and devices for wireless communication at a user equipment (UE) are described. A UE may receive a first timing information associated with a first cell and a second timing information associated with a second cell. In some examples, the first cell may be associated with a first non-terrestrial device and the second cell may be associated with a second non-terrestrial device. In some examples, the first cell and the second cell may be associated with a common non-terrestrial device. The UE may calculate a propagation delay in accordance with a type of delay measurement and select a cell based on the propagation delay. The UE may calculate a propagation delay in accordance with a type of delay measurement and reselect a cell based on the propagation delay. In some examples, the propagation delay may be based on the first timing information and the second timing information.