Beam Failure Detection Timing for DRX and Non-DRX User Equipment

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Solution Overview

Problem

Existing wireless communication systems face challenges in performing link quality measurement to assist in beam failure detection while achieving energy savings in discontinuous reception (DRX) mode, and beam failure recovery processes in both active and non-active times of UE operation.

Innovation Solution

The method involves setting different evaluation and indication periodicities for link quality measurement in DRX and non-DRX modes to reduce energy consumption, with longer periods in DRX mode to minimize measurements and notifications, and using different timers and configurations for beam failure detection based on the DRX mode.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the UE continuously monitors PDCCH for link quality measurement, then beam failure detection accuracy is improved, but energy consumption increases

Engineering Contradiction:
Improvebeam failure detection accuracyVSAvoidenergy consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent applies periodic action by implementing Discontinuous Reception (DRX) where the UE alternates between active monitoring periods and sleep periods. During active periods, the UE monitors PDCCH for link quality measurement; during sleep periods, monitoring is suspended to save energy. This periodic monitoring pattern resolves the contradiction by providing sufficient measurement opportunities while reducing overall energy consumption compared to continuous monitoring.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent applies dynamics by making the monitoring behavior adaptive based on operational mode. The UE dynamically adjusts between continuous monitoring in non-DRX mode and periodic monitoring in DRX mode. This dynamic adjustment allows the system to optimize the balance between detection accuracy and energy consumption according to current operational requirements.

Inventive Principle:
Principle #15Dynamics

2Speed

If the UE performs frequent link quality measurements, then beam failure detection speed is improved, but energy consumption increases

Engineering Contradiction:
Improvebeam failure detection speedVSAvoidenergy consumption
Core Design Contradiction:
SpeedVSUse of energy by moving object

Solution Approach 1:

The patent implements periodic action through DRX cycles where link quality measurements are performed at regular intervals during active periods rather than continuously. This approach maintains adequate detection speed by ensuring measurements occur frequently enough to detect beam failures in a timely manner, while the periodic nature of the cycles significantly reduces energy consumption compared to continuous measurement.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent applies parameter changes by adjusting the monitoring periodicity and active period duration based on operational mode. In DRX mode, the monitoring periodicity is increased and active period duration is reduced compared to non-DRX mode, thereby reducing energy consumption while maintaining acceptable detection speed through parameter optimization.

Inventive Principle:
Principle #35Parameter changes

3Use of energy by moving object

If the UE operates in DRX mode with periodic monitoring, then energy consumption is reduced, but beam failure detection reliability deteriorates

Engineering Contradiction:
Improveenergy consumptionVSAvoidbeam failure detection reliability
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent implements periodic action through carefully designed DRX cycles that balance energy saving with detection reliability. The active periods are timed and sized to provide sufficient measurement opportunities for reliable beam failure detection, while the periodic suspension of monitoring during sleep periods achieves energy reduction. The cycle parameters are optimized to maintain detection reliability despite the intermittent monitoring nature.

Inventive Principle:
Principle #19Periodic action

4Use of energy by moving object

If the UE uses longer evaluation periods in DRX mode, then energy consumption is reduced, but measurement precision deteriorates

Engineering Contradiction:
Improveenergy consumptionVSAvoidlink quality measurement precision
Core Design Contradiction:
Use of energy by moving objectVSMeasurement precision

Solution Approach 1:

The patent applies parameter changes by adjusting the evaluation period duration based on operational mode. In DRX mode, longer evaluation periods are used to reduce the frequency of measurements and thus reduce energy consumption. In non-DRX mode, shorter evaluation periods are used to maintain higher measurement precision through more frequent measurements. This parameter adaptation resolves the contradiction by accepting reduced precision in DRX mode where energy saving is prioritized.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3791641B1Notification of a beam failure instance indication to a higher layer in DRX mode and non-DRX mode
Publication Date: 2025.09.24 SHARP KK
  • EP3791641B1 patent drawingFigure 1
  • EP3791641B1 patent drawingFigure 2~3

AI summary

The present invention provides a link evaluation method in user equipment and user equipment. The user equipment has a discontinuous reception (DRX) mode and a non-DRX mode. The link evaluation method comprises: measuring a reference signal in an evaluation period; and in the case that a measurement result is lower than a preset threshold, judging that a beam failure instance (BFI) is generated, and notifying a higher layer of the BFI at an interval of an indication period, wherein when the user equipment is in the non-DRX mode, the duration of the evaluation period is first duration; when the user equipment is in the DRX mode, the duration of the evaluation period is second duration; and the second duration is greater than the first duration.