Beam Failure Recovery Reporting for Candidate Beam Selection

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Solution Overview

Problem

The existing beam failure recovery (BFR) procedure in next-generation radio communication systems, such as NR, lacks a comprehensive method for determining and reporting new candidate beams, leading to potential system performance deterioration due to delays and frequent radio link failures.

Innovation Solution

A user terminal and radio communication method that employs multiple determination criteria, including received power and interference power, to identify new candidate beams, and includes reporting mechanisms for when no suitable beam is found, ensuring robust beam recovery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a beam failure recovery procedure is implemented in next-generation radio communication systems, then beam recovery capability is improved, but system complexity increases due to the need for multiple determination criteria and reporting mechanisms

Engineering Contradiction:
Improvebeam recovery capabilityVSAvoidprocedure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The beam failure recovery procedure is segmented into distinct determination criteria (received power-based, interference power-based, and combined criteria), allowing the system to handle different failure scenarios through modular evaluation steps rather than a monolithic complex procedure

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary beam identification and classification before actual beam failure occurs by establishing multiple determination criteria in advance. This preliminary setup allows the system to quickly respond to beam failures without complex real-time analysis, reducing procedural complexity during actual recovery

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If multiple determination criteria are used to identify new candidate beams, then beam selection accuracy is improved, but processing time increases

Engineering Contradiction:
Improvebeam selection accuracyVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent dynamically selects which determination criteria to apply based on the specific beam failure scenario and available measurements. Rather than always applying all three criteria (received power, interference power, and combined), the system adapts the evaluation process to the current situation, maintaining accuracy while reducing unnecessary processing time

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameters being measured and evaluated based on the determination criterion being applied. By switching between different parameter sets (power-based, interference-based, or combined) depending on the situation, the system achieves accurate beam selection without consistently processing all parameters, thus balancing precision and speed

Inventive Principle:
Principle #35Parameter changes

3Reliability

If comprehensive reporting mechanisms are implemented for beam failure conditions, then system reliability is improved, but information overhead increases

Engineering Contradiction:
Improvebeam failure reporting reliabilityVSAvoidinformation overhead
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The patent extracts and reports only the essential information needed for beam failure recovery, such as the identified new candidate beam index and the determination criterion used. By taking out only the critical elements rather than reporting all measurement data, the system maintains reliable reporting while minimizing information overhead in uplink transmissions

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP3955700B1Reporting of information in a beam failure recovery procedure
Publication Date: 2025.08.27 NTT DOCOMO INC
  • EP3955700B1 patent drawingFigure 1
  • EP3955700B1 patent drawingFigure 2
  • EP3955700B1 patent drawingFigure 3

AI summary

One aspect of a user terminal according to the present disclosure includes: a receiving section that receives a reference signal configured for a new candidate beam; and a control section that, when a measurement result based on the reference signal does not satisfy a certain determination criterion, performs control so as to transmit information indicating that a new candidate beam cannot be identified or so as not to transmit information related to the new candidate beam in a beam failure recovery procedure.