Frequency-Band Cell Selection for Function-Ready Terminal Connections

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Solution Overview

Problem

Terminal apparatuses face challenges in executing predetermined functions due to parameter restrictions when connecting to base stations operating in specific frequency bands, leading to inefficient cell selection and increased signaling time.

Innovation Solution

The terminal apparatus dynamically adjusts its cell selection priority based on the base station's capability to execute specific functions in different frequency bands, using acquired information to determine the most suitable band for function execution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the terminal apparatus selects a connection destination cell based on frequency band priority, then the cell selection speed is improved, but the predetermined function may not be executable due to parameter restrictions

Engineering Contradiction:
Improvecell selection speedVSAvoidfunction executability
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The terminal apparatus performs preliminary checks of base station capability information before finalizing cell selection. By acquiring and evaluating capability information in advance, the terminal can predict whether the predetermined function will be executable, preventing selection of unsuitable cells while maintaining efficient selection speed.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The terminal apparatus uses feedback from acquired base station capability information to adjust its cell selection decisions. The capability information acts as feedback that informs the terminal whether to proceed with selecting a cell in a particular frequency band, ensuring function executability while maintaining selection efficiency.

Inventive Principle:
Principle #23Feedback

2Reliability

If the terminal apparatus checks base station capability information for all frequency bands, then the function executability is improved, but the signaling time increases

Engineering Contradiction:
Improvefunction executabilityVSAvoidsignaling time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The terminal apparatus applies different checking strategies to different frequency bands based on local conditions. Instead of uniformly checking all bands, it focuses capability information acquisition on bands that are both high-priority and likely to support the predetermined function, reducing unnecessary signaling while ensuring reliable selection.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The terminal apparatus performs partial checking of base station capability information rather than exhaustive checking of all frequency bands. By checking capability information for only the necessary or most promising frequency bands, it achieves sufficient reliability for function executability while minimizing signaling time overhead.

Inventive Principle:
Principle #16Partial or excessive action

3Speed

If the terminal apparatus prioritizes frequency bands for cell selection, then the connection establishment speed is improved, but the adaptability to different function requirements deteriorates

Engineering Contradiction:
Improveconnection establishment speedVSAvoidfunction execution adaptability
Core Design Contradiction:
SpeedVSAdaptability or versatility

Solution Approach 1:

The terminal apparatus dynamically adjusts its cell selection priority based on acquired base station capability information. The priority ordering is not fixed but adapts according to whether the predetermined function can be executed, allowing the system to maintain fast connection establishment while being adaptable to different function requirements.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The terminal apparatus changes the priority parameter of frequency bands based on capability information. When capability information indicates that a lower-priority band better supports the predetermined function, the terminal adjusts the priority parameter to select that band, thereby maintaining both connection speed and function execution adaptability.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4181557B1Terminal device that performs cell selection in accordance with frequency band priority, control method for same, and program
Publication Date: 2025.11.05 KDDI CORP
  • EP4181557B1 patent drawingFigure 1~2
  • EP4181557B1 patent drawingFigure 3
  • EP4181557B1 patent drawingFigure 4

AI summary

A terminal apparatus that executes selection of a connection target cell from among a plurality of cells formed by one or more base station apparatuses acquires first information indicating priority for when selecting a connection destination cell relating to a plurality of frequency bands, acquires, from each of the one or more base station apparatuses, second information indicating whether the base station apparatus can execute a predetermined function in a predetermined frequency band from among the plurality of frequency bands, determines, on a basis of the second information and a frequency band, from among a plurality of frequency bands usable by the terminal apparatus, that the terminal apparatus can execute the predetermined function, whether to select a connection destination cell according to a first priority unchanged from the priority indicated by the first information or according to a second priority changed from a priority indicated by the first information, and executes selection of a connection destination cell according to the determination.