Multi-TRP Beam Failure Detection Reference Signal Selection

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Solution Overview

Problem

The need for improved methods and apparatus for Beam Failure Detection (BFD) Reference Signal (RS) determination in multi-TRP scenarios of the 5G NR system, particularly in handling multiple Transmission Configuration Indication (TCI) states for enhanced PDCCH reliability and robustness, is not adequately addressed in existing technologies.

Innovation Solution

Introduction of new MAC CE formats with fixed and variable sizes to indicate multiple TCI states for PDCCH monitoring, along with specific rules for selecting BFD RSs implicitly from activated TCI states, ensuring clear guidelines for beam failure detection and recovery in multi-TRP environments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple TCI states are activated for PDCCH monitoring in multi-TRP scenarios, then PDCCH reliability and robustness are improved, but the complexity of BFD RS determination increases

Engineering Contradiction:
ImprovePDCCH reliabilityVSAvoidBFD RS determination complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the BFD RS determination process by introducing separate MAC CE formats for different scenarios: one format for indicating a single TCI state and another for indicating multiple TCI states. This segmentation allows the UE to handle each case with appropriate processing rules, reducing overall determination complexity while maintaining PDCCH reliability through multi-TRP support

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the parameter structure of MAC CE formats to accommodate different numbers of TCI states. By defining fixed-size and variable-size MAC CE formats with specific field structures (e.g., TCI State ID fields, repetition indicators), the system enables flexible TCI state indication while providing clear rules for BFD RS selection, thus managing complexity alongside reliability improvement

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If MAC CE formats are designed to indicate multiple TCI states, then flexibility in beam management is improved, but the size and structure of MAC CE messages increase

Engineering Contradiction:
Improvebeam management flexibilityVSAvoidMAC CE message size
Core Design Contradiction:
Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The patent introduces both fixed-size and variable-size MAC CE formats, providing dynamic adaptability. The fixed-size format ensures efficient signaling when a specific number of TCI states are needed, while the variable-size format allows flexibility to indicate different numbers of TCI states based on network requirements, optimizing message size while maintaining beam management versatility

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The MAC CE formats are designed with universal structures that can indicate one or multiple TCI states through configurable fields. The same MAC CE mechanism handles both single-TRP and multi-TRP scenarios, as well as different BFD RS determination modes, reducing the need for multiple specialized message formats and optimizing overall signaling efficiency

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

Data Source

PatentEP4098012B1Methods and apparatus for beam failure detection reference signal determination
Publication Date: 2025.09.24 SHARP KK
  • EP4098012B1 patent drawingFigure 1
  • EP4098012B1 patent drawingFigure 2
  • EP4098012B1 patent drawingFigure 3

AI summary

A method and apparatus for Beam Failure Detection (BFD) Reference Signal (RS) determination are provided. The method includes receiving at least one Medium Access Control (MAC) Control Element (CE) for Transmission Configuration Indicator (TCI) state activation, each MAC CE indicating a Control Resource Set (CORESET) and at least one TCI state, at least part of the indicated TCI state (s) belonging to a first group of TCI states associated with a first Transmission/Reception Point (TRP); and performing first operations after determining that a total number of TCI states included in the first group of TCI states is larger than a first threshold number, the first operations including: selecting at least one first TCI state from the first group of TCI states; and determining at least one first BFD RS for detecting a first beam failure condition of the first TRP based on the at least one first TCI state.