NTN Cell Validity Timing for Lower UE Mobility Signaling

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Solution Overview

Problem

In non-terrestrial networks, such as those utilizing satellites or airborne vehicles, unnecessary UE mobility events and signaling occur due to rapidly changing cell coverage areas, leading to inefficient resource management and increased network load.

Innovation Solution

Implementing a method for base stations to exchange and utilize validity time information for cells, allowing them to manage UE actions more efficiently by determining appropriate handover, measurement, and cell selection/reselection based on the predicted availability of neighboring cells.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If base stations continuously update cell availability information without validity time, then UE can access current cell information, but unnecessary mobility events and signaling occur due to rapidly changing cell coverage areas

Engineering Contradiction:

Improvecell availability information accuracyVSAvoidnetwork signaling efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent applies preliminary action by including validity time information in advance with cell availability data. This allows UE to predict when cell information becomes outdated and avoid unnecessary mobility events before they occur, thereby maintaining reliable cell information while reducing signaling overhead.

Inventive Principle:

Principle #10Preliminary action

2Ease of operation

If base stations exchange detailed cell information frequently, then UE mobility management is improved, but network load and resource management complexity increase

Engineering Contradiction:

ImproveUE mobility managementVSAvoidnetwork resource management

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The patent extracts the critical validity time parameter from detailed cell information exchanges. By transmitting only the essential validity time along with cell availability data, the system simplifies information exchange while maintaining effective UE mobility management, thereby reducing network load and management complexity.

Inventive Principle:

Principle #2Taking out (Extraction)

3Measurement precision

If UE performs measurements on all neighboring cells, then cell selection accuracy is improved, but unnecessary measurements occur when cells are not available

Engineering Contradiction:

Improvecell selection accuracyVSAvoidmeasurement time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies preliminary action by providing UE with validity time information in advance about neighboring cell availability. UE uses this information to pre-determine which cells are worth measuring, avoiding wasted measurement time on unavailable cells while maintaining accurate cell selection for valid cells.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS12556987B2Signaling efficiency improvements in non-terrestrial networks

Publication Date: 2026.02.17 NOKIA TECHNOLOGIES OY

AI summary

A base station serving UE(s) receives validity time information for cell(s) formed by other base station(s). The validity time information indicates at least a time period when corresponding cells are available for use by the UE(s). The base station determines action(s) to perform for the UE(s) based on the validity time information. A UE receives, from a base station, validity time for cell(s) formed by other base station(s). The UE performs action(s) based on the validity time of the cell(s).