Terminal Beam Failure Detection Using TCI State Reference Signals

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Solution Overview

Problem

In future radio communication systems like NR, the lack of clear parameters for radio link monitoring (RLM) and beam failure detection (BFD) leads to inconsistencies between base stations and user terminals, deteriorating RLM performance and communication throughput.

Innovation Solution

A terminal is designed to determine a reference signal for beam failure detection (BFD-RS) when it is not configured, by using the reference signal of a transmission configuration indication (TCI) state associated with at least one transmission/reception point (TRP).

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the UE uses TCI state reference signals as BFD-RS when BFD-RS is not configured, then beam failure detection can be performed without additional configuration, but inconsistency between base station and UE may occur leading to deteriorated RLM performance

Engineering Contradiction:

Improveability to perform beam failure detection without additional configurationVSAvoidRLM performance

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The TCI state reference signal is configured to serve multiple functions: it is used for both PDCCH reception and beam failure detection. This multi-functionality allows the UE to perform BFD without requiring separate BFD-RS configuration, thereby improving adaptability while maintaining reliability through standardized selection rules.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system utilizes existing TCI state reference signal configurations to automatically enable beam failure detection capability. The UE self-determines the BFD-RS from the configured TCI states without requiring additional network configuration or intervention, making the system self-sufficient for BFD operations.

Inventive Principle:

Principle #25Self-service

2Device complexity

If parameters for RLM-RS and BFD-RS are not clearly defined, then the system can operate with existing configurations, but inconsistency between base station and UE occurs deteriorating communication throughput

Engineering Contradiction:

Improveconfiguration complexityVSAvoidcommunication throughput

Core Design Contradiction:

Device complexityVSProductivity

Solution Approach 1:

The base station pre-configures TCI states with reference signal information before beam failure detection is needed. This preliminary configuration establishes clear parameter definitions that both base station and UE can consistently use, avoiding throughput deterioration while maintaining operational simplicity.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent establishes clear feedback mechanisms where the UE reports beam failure detection results based on the predefined TCI state parameters. This structured feedback ensures consistent interpretation of parameters between base station and UE, maintaining communication throughput without increasing complexity.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS12328274B2Terminal and radio communication method

Publication Date: 2025.06.10 NTT DOCOMO INC

AI summary

A terminal according to one aspect of the present disclosure includes: a control section that, when a reference signal for beam failure detection (BFD-RS) is not configured for the terminal, determines a reference signal of a transmission configuration indication (TCI) state associated with at least one transmission/reception point (TRP) as the BFD-RS; and a receiving section that receives the BFD-RS. According to one aspect of the present disclosure, link failure can be appropriately detected.