TCI State Acknowledgment for Clear HARQ-ACK and DTX Feedback

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Solution Overview

Problem

The existing challenges in TCI state signaling, particularly in 3GPP Release 17, include ambiguity in HARQ-ACK feedback and TCI state ambiguity between MAC CE and DCI receipt, leading to difficulties in differentiating between NACK and DTX feedback, and uncertainty about the TCI state application timing.

Innovation Solution

Implement mechanisms to differentiate between NACK and DTX feedback by using specific RNTIs, field restrictions in DCI, and additional information in HARQ codebooks to clarify TCI state updates, ensuring clear acknowledgment of TCI information receipt.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If TCI states are configured by RRC signaling and activated by MAC CE with DCI indication, then the TCI state signaling flexibility is improved, but the ambiguity in HARQ-ACK feedback and TCI state application timing increases

Engineering Contradiction:

ImproveTCI state signaling flexibilityVSAvoidHARQ-ACK feedback ambiguity

Core Design Contradiction:

Adaptability or versatilityVSLoss of information

Solution Approach 1:

The patent segments the HARQ-ACK feedback into separate indications: one for TCI state receipt acknowledgment and another for PDSCH decoding status. This segmentation eliminates the ambiguity where a single NACK could not distinguish between TCI state reception failure and PDSCH decoding failure, thereby resolving the information loss while preserving the flexible multi-layer TCI signaling mechanism.

Inventive Principle:

Principle #1Segmentation

2Speed

If DCI is used to indicate TCI states from activated states, then the TCI state update speed is improved, but the difficulty in differentiating NACK and DTX feedback increases

Engineering Contradiction:

ImproveTCI state update speedVSAvoidNACK and DTX feedback differentiation

Core Design Contradiction:

SpeedVSDifficulty of detecting and measuring

Solution Approach 1:

The patent introduces an intermediary mechanism by using specific bit fields in the HARQ-ACK codebook that serve as dedicated mediators for TCI state acknowledgment. These intermediary bits explicitly indicate whether the UE has successfully received and applied the TCI state, separating this acknowledgment function from the general PDSCH decoding feedback and enabling clear differentiation between NACK and DTX conditions.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If a unified TCI framework is introduced for joint uplink and downlink beam indication, then the beam management efficiency is improved, but the complexity of TCI state application timing increases

Engineering Contradiction:

Improvebeam management efficiencyVSAvoidTCI state application timing complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by having the UE prepare and store multiple TCI state candidates in advance based on RRC configuration and MAC CE activation. When DCI arrives with a TCI indication, the UE can immediately apply the indicated state from the pre-prepared set without complex real-time processing, thus maintaining high beam management efficiency while simplifying the timing application complexity through advance preparation.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS20260039421A1Transmission configuration indicator determination and acknowledgment

Publication Date: 2026.02.05 APPLE INC

AI summary

The present application relates to devices and components including apparatus, systems, and methods for determining and acknowledging transmission configuration indicator states.