Per-TRP Beam Failure Detection in Multi-TRP NR Systems

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Solution Overview

Problem

Existing Beam Failure Detection (BFD) procedures in New Radio (NR) are inadequate for multi-Transmission and Reception Point (TRP) deployments, as they are defined per serving cell and cannot detect beam failures on individual TRPs or subsets of TRPs, which can experience channel blockages while others remain functional.

Innovation Solution

A method where a User Equipment (UE) receives messages to activate multiple TCI states associated with different Physical Cell Identifiers (PCIs), allowing it to perform beam failure detection independently for each TRP by monitoring specific reference signals, thereby detecting beam failures on individual TRPs or subsets without modifying higher-layer operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If beam failure detection is performed per serving cell using existing NR procedures, then the detection mechanism is simple and standardized, but it cannot detect beam failures on individual TRPs in multi-TRP deployments

Engineering Contradiction:

Improvecapability to detect beam failures in multi-TRP scenariosVSAvoidcomplexity of beam failure detection mechanism

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the beam failure detection mechanism by introducing per-TRP detection counters and state tracking. Instead of a single cell-level detection mechanism, each TRP now has its own counter (e.g., firstCounter for first TRP, secondCounter for second TRP) that independently tracks beam failure instances. This segmentation enables fine-grained detection while maintaining the overall standardized framework.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by making the detection threshold and counter behavior TRP-specific. Each TRP has its own failure counter and can be configured with specific thresholds (e.g., firstThreshold for first TRP, secondThreshold for second TRP). This allows different TRPs to have differentiated detection parameters based on their individual channel conditions and failure characteristics.

Inventive Principle:

Principle #3Local quality

2Reliability

If beam failure detection is extended to per-TRP level, then individual TRP failures can be detected, but higher-layer operations require modifications

Engineering Contradiction:

Improveaccuracy of beam failure detectionVSAvoidease of implementation

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent extracts the beam failure detection functionality to the physical layer, separating it from higher-layer operations. By implementing detection counters and threshold comparison at the physical layer (e.g., counting out-of-sync indications per TRP), the mechanism achieves per-TRP detection accuracy without requiring modifications to upper-layer protocols. The physical layer independently manages TRP-specific detection states.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces physical layer counters and indicators as intermediaries between the TRP physical layer and higher layers. These counters (firstCounter, secondCounter) act as mediators that track beam failure instances without directly modifying higher-layer operations. The indicators provide TRP-specific failure information to higher layers while maintaining the integrity of existing higher-layer protocols.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If per-TRP beam failure detection is implemented, then beam management in multi-TRP scenarios is improved, but the detection mechanism becomes more complex at the physical layer

Engineering Contradiction:

Improveefficiency of beam managementVSAvoidcomplexity of physical layer detection mechanism

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent introduces dynamic counter reset mechanisms based on TRP operational status. When a TRP is deactivated or becomes unavailable, the corresponding counter (e.g., firstCounter) is reset to zero. This dynamic behavior allows the system to adapt to changing TRP configurations without requiring complex reconfiguration procedures, maintaining efficiency while managing physical layer complexity.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent implements periodic monitoring of TRP conditions and counter states. The system periodically checks whether TRPs are available, updates counters accordingly, and compares counter values against thresholds at regular intervals. This periodic action simplifies the physical layer mechanism by using regular cycles of measurement and comparison rather than continuous complex processing.

Inventive Principle:

Principle #19Periodic action

Data Source

PatentUS20230413077A1Beam failure detection

Publication Date: 2023.12.21 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

A method (200) performed by a UE (102). The method includes receiving (s202) one or more messages for activating at least i) a first set of configured TCI states and ii) a second set of configured TCI states, wherein the first set of activated TCI states is associated with a first PCI and indicates a first set of reference signals, and the second set of activated TCI states is associated with a second PCI and indicates a second set of reference signals. The method also includes performing (s204) beam failure detection, BFD, monitoring. Performing the BFD monitoring comprises: determining (s206) whether a beam failure with respect to the first PCI has occurred based on the first set of reference signals; and determining (s208) whether a beam failure with respect to the second PCI has occurred based on the second set of reference signals.