Terminal TCI State Indication for Downlink Reception Control

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Solution Overview

Problem

The application of Transmission Configuration Indication (TCI) states in future radio communication systems is not clear, leading to potential degradation in communication quality and throughput reduction.

Innovation Solution

A terminal and base station that include a receiving section and a control section to determine a unified TCI state based on downlink control information (DCI) for appropriate application of TCI states to downlink channels and reference signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a unified TCI state is indicated by DCI for multiple DL channels and reference signals, then communication quality and throughput are improved, but the method of applying TCI states is not clear leading to implementation complexity

Engineering Contradiction:
Improvecommunication qualityVSAvoidTCI state application method
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the TCI state application by introducing a specific field in DCI that explicitly indicates which TCI state should be applied to which DL channel or reference signal. This segmentation resolves the ambiguity by dividing the indication process into discrete, clearly defined components rather than attempting a unified indication method for all channels.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by allowing different TCI states to be indicated for different DL channels and reference signals through the specific DCI field. Each channel or reference signal can have its own TCI state indication, enabling localized optimization of reception parameters rather than applying a single TCI state uniformly across all channels.

Inventive Principle:
Principle #3Local quality

2Reliability

If TCI state indication method is not clear, then communication quality degradation occurs, but defining clear indication methods increases system complexity

Engineering Contradiction:
Improvecommunication qualityVSAvoidTCI state indication system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements preliminary action by pre-defining the structure and format of the TCI state indication field in DCI through higher-layer configuration. The indication method is established in advance with clear rules for how the field maps to specific TCI states, eliminating ambiguity during actual operation without requiring complex runtime decision-making.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces an intermediary mechanism through the specific field in DCI that serves as a mediator between the base station's TCI state selection and the terminal's reception parameter configuration. This intermediary field provides a clear, standardized interface that simplifies the indication process while maintaining flexibility in TCI state application.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4668596A1Terminal, wireless communication method, and base station
Publication Date: 2025.12.24 NTT DOCOMO INC
  • EP4668596A1 patent drawingFigure 1A~1B
  • EP4668596A1 patent drawingFigure 2A~2B
  • EP4668596A1 patent drawingFigure 3

AI summary

A terminal according to one aspect of the present disclosure includes a receiving section that receives at least one of a downlink (DL) channel and a DL reference signal scheduled or triggered by downlink control information (DCI), and a control section that determines, based on a unified Transmission Configuration Indication (TCI state) indicated by a specific field included in the DCI, an indicated TCI state to be applied to reception of the DL channel or the DL reference signal. According to one aspect of the present disclosure, it is possible to appropriately apply a TCI state(s).