Beam Failure Detection During Cell DTX in Wireless Links

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Solution Overview

Problem

Existing wireless communication systems face challenges in accurately detecting beam failures, particularly in environments with network energy saving (NES) configurations such as cell discontinuous transmission (DTX) and discontinuous reception (DRX), which can lead to unnecessary beam failure declarations and increased energy consumption.

Innovation Solution

A method and apparatus for beam failure detection in wireless communication systems that involve receiving configuration information for beam failure detection reference signals (BFD RS) and performing beam failure recovery (BFR) only during active periods of cell DTX, allowing for more accurate beam failure detection and reducing unnecessary operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If beam failure detection is performed continuously without considering NES operation, then detection coverage is improved, but false beam failure declarations increase and energy consumption increases

Engineering Contradiction:
Improvebeam failure detection accuracyVSAvoidfalse beam failure declaration rate
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent applies dynamics by making the beam failure detection process adaptive to changing network conditions. The UE dynamically adjusts its detection behavior based on whether the cell is in DTX or non-RTT state, transitioning between different detection modes rather than using a fixed continuous detection approach. This resolves the contradiction by making detection accuracy high when needed while avoiding false declarations during energy saving periods.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the detection parameter state based on cell operation mode. When cell DTX is active, the patent suspends beam failure detection (changing the detection frequency parameter from continuous to suspended). When in non-RTT state, it resumes detection. This parameter change resolves the contradiction by aligning detection activity with actual network availability, preventing false declarations during energy saving while maintaining detection capability when active.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If beam failure detection is performed during all cell DTX periods, then detection coverage is improved, but energy consumption increases

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

Solution Approach 1:

The patent implements periodic action by suspending beam failure detection during cell DTX periods and resuming during non-RTT periods. This creates a periodic detection pattern that aligns with the cell's active periods rather than attempting continuous detection. The UE periodically checks whether the cell is in DTX or non-RTT state and adjusts detection accordingly, reducing energy consumption while maintaining detection capability during active periods.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent applies self-service by having the UE autonomously determine whether to perform beam failure detection based on monitoring the cell's DTX/non-RTT state. The UE serves itself by making intelligent decisions about when to activate or suspend detection based on network conditions, rather than continuously consuming energy regardless of network state. This self-adjusting mechanism resolves the energy consumption contradiction.

Inventive Principle:
Principle #25Self-service

3Use of energy by moving object

If beam failure detection is suspended during cell DTX, then energy consumption is reduced, but detection responsiveness may deteriorate

Engineering Contradiction:
ImproveUE energy consumptionVSAvoidbeam failure detection responsiveness
Core Design Contradiction:
Use of energy by moving objectVSSpeed

Solution Approach 1:

The patent makes the detection system dynamic by suspending detection during cell DTX (when the cell is in energy saving mode) and immediately resuming when the cell transitions to non-RTT state. This dynamic adjustment ensures that detection responsiveness is optimized for each operational context - suspended when the network is unavailable to save energy, and responsive when the network is active and can actually receive failure reports.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the detection activation parameter based on cell state. During cell DTX, the detection parameter is set to suspended; during non-RTT state, it is set to active. This parameter change ensures that detection responsiveness is maintained during periods when the network can actually respond, while avoiding unnecessary energy consumption during DTX periods when responsiveness would be meaningless anyway.

Inventive Principle:
Principle #35Parameter changes

4Measurement precision

If continuous beam failure detection is performed, then detection accuracy is maintained, but unnecessary beam failure declarations occur during NES operation

Engineering Contradiction:
Improvebeam failure detection accuracyVSAvoidfalse declaration rate
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent introduces an intermediary condition (cell DTX/non-RTT state monitoring) that mediates between the detection desire and actual network availability. Before declaring beam failure, the system checks this intermediary state - if the cell is in DTX, detection is suspended and no failure declaration occurs; if in non-RTT state, detection proceeds normally. This intermediary check prevents false declarations by ensuring the network is actually available to receive and process failure reports.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies preliminary anti-action by preemptively suspending beam failure detection when the cell enters DTX state, before any false failure declaration could occur. By anticipating that detection during DTX would lead to false declarations (since the network cannot receive reports), the system takes preventive action by suspending detection in advance. When the cell transitions to non-RTT state, detection resumes, preventing false declarations while maintaining accuracy.

Inventive Principle:
Principle #9Preliminary anti-action

Data Source

PatentEP4694376A1Method and apparatus for beam failure detection in wireless communication system
Publication Date: 2026.02.11 LG ELECTRONICS INC
  • EP4694376A1 patent drawingFigure 1
  • EP4694376A1 patent drawingFigure 2
  • EP4694376A1 patent drawingFigure 3

AI summary

Disclosed are a method and an apparatus for beam failure detection in a wireless communication system. The method performed by a UE in a wireless communication system, according to an embodiment of the present disclosure, may comprise the steps of: receiving first configuration information and second configuration information from a base station, the first configuration information including information related to cell DTX and the second configuration information including information regarding a BFD RS set; evaluating a wireless link quality for the BFD RS set; and on the basis that a beam failure for the BFD RS set is detected only in an active time duration of the cell DTX, performing an uplink transmission for a BFR to the base station.