Multi-Cell Beam Failure Recovery With Cell-Specific Reporting

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Solution Overview

Problem

Existing wireless communication technologies face challenges in managing beam failures, particularly in secondary cells (SCells), leading to ambiguity in UE behavior and interruptions in services due to varying SCell configurations and capabilities in beam management.

Innovation Solution

Implement methods for detecting beam failures in wireless networks, determining availability of alternative beams, and transmitting messages indicating availability or non-availability, with specific durations based on UE capabilities and carrier frequencies, to facilitate efficient beam recovery and reduce energy consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If beam failure detection and recovery procedures are implemented in multi-cell configuration, then communication reliability is improved, but device complexity and procedure ambiguity increase

Engineering Contradiction:
Improvecommunication reliabilityVSAvoidprocedure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by differentiating beam failure recovery procedures based on cell type (PCell, PSCell, SCell). Each cell type has specific recovery mechanisms defined - PCell/PSCell use random access procedure while SCell uses MAC CE reporting. This localized approach resolves the contradiction by providing clear, cell-specific procedures that improve reliability without creating universal complexity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent segments the beam failure recovery process into distinct phases: detection phase (monitoring beam quality), determination phase (evaluating alternative beams), and reporting phase (transmitting failure indication). This segmentation reduces procedural ambiguity by defining clear boundaries and actions for each phase, thereby improving reliability while managing complexity.

Inventive Principle:
Principle #1Segmentation

2Reliability

If comprehensive beam failure detection and recovery procedures are implemented across all cell types, then service continuity is improved, but energy consumption increases

Engineering Contradiction:
Improveservice continuityVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent implements energy-efficient beam failure recovery by applying different procedures to different cell types. SCell beam failure uses lightweight MAC CE reporting while PCell uses more robust random access procedure. This local differentiation maintains service continuity for critical cells while reducing energy consumption for less critical SCells.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent applies partial action by implementing beam failure detection and recovery only where necessary - primarily for PCell and PSCell which are critical for service continuity. For SCell, a simplified MAC CE-based approach is used instead of full random access procedure, reducing energy consumption while maintaining adequate service continuity.

Inventive Principle:
Principle #16Partial or excessive action

3Ease of operation

If beam failure recovery procedures are standardized for all cells, then ease of operation is improved, but adaptability to different cell configurations decreases

Engineering Contradiction:
Improveprocedure simplicityVSAvoidcell configuration adaptability
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent resolves this contradiction by defining local quality rules for different cell types. PCell and PSCell follow one standardized procedure (random access), while SCell follows another (MAC CE reporting). This approach maintains ease of operation through standardization within cell types while providing adaptability across different cell configurations.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent applies universality by creating a multi-functional beam failure recovery framework that works across different cell types (PCell, PSCell, SCell) and configurations (carrier aggregation, dual connectivity). The framework provides universal principles adapted to specific cell roles, achieving both simplicity and configurability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP4133897B1Beam failure recovery in multi-cell configuration
Publication Date: 2026.01.21 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP4133897B1 patent drawingFigure 1~2
  • EP4133897B1 patent drawingFigure 3~4
  • EP4133897B1 patent drawingFigure 5

AI summary

Method for a user equipment, UE), to communicate with a wireless network via multiple cells. The method includes detecting(1210) failure of a first beam associated with a first cell of the plurality of cells and determining (1230) availability or unavailability of other beams, than the first beam, that are associated with the first cell. The method further includes transmitting (1280), to one of the multiple cells, a message indicating availability or unavailability of the other beams associated with the first cell. The message is transmitted within a first duration (1220) after detecting the failure of the first beam, the first duration based on a maximum time for determining availability of the other beams and on a periodicity of resources allocated for beam failure reporting in the cell where the message is transmitted. Other embodiments include complementary method for a network node, UE and network node configured to perform such method.