MAC CE TCI State Pool Control for Seamless Cell Switching

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

In future radio communication systems, the configuration and activation of TCI states for multiple transmission/reception points and cell switching are unclear, leading to potential communication quality degradation during cell switching.

Innovation Solution

A terminal and base station that include a receiving section for MAC CEs related to cell switching, controlling the application of TCI states based on information within the MAC CE to manage TCI state pools for serving and candidate cells.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If cell switching is performed using MAC CE for target candidate cell indication, then cell switching capability is improved, but TCI state configuration and activation for multiple candidate cells becomes unclear leading to communication quality degradation

Engineering Contradiction:
Improvecell switching capabilityVSAvoidcommunication quality during cell switching
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent segments the TCI state configuration process by introducing separate MAC CE commands for different functions: one MAC CE for TCI state pool configuration and another MAC CE for TCI state activation. This segmentation resolves the ambiguity by clearly separating configuration from activation, ensuring both candidate cells have properly configured and activated TCI states before switching occurs.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements preliminary action by requiring TCI state pool configuration to be completed before cell switching is initiated. The base station configures TCI state pools for candidate cells in advance using MAC CE, ensuring that when cell switching is needed, the TCI states are already prepared and can be activated immediately without communication quality degradation.

Inventive Principle:
Principle #10Preliminary action

2Adaptability or versatility

If TCI state pool is configured for multiple candidate cells including inactive SCells, then cell switching flexibility is improved, but system complexity increases due to unclear configuration and activation procedures

Engineering Contradiction:
Improvecell switching flexibilityVSAvoidTCI state configuration and activation management
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies universality by designing a unified MAC CE-based framework that handles TCI state pool configuration and activation across multiple candidate cells including inactive SCells. The same MAC CE mechanism is used universally for all cell types, providing a consistent and manageable approach rather than requiring separate procedures for different cell types.

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

Solution Approach 2:

The patent introduces MAC CE as an intermediary layer between higher layer signaling and physical layer cell switching operations. This intermediary provides a clear, standardized interface for configuring and activating TCI states, simplifying the management complexity by abstracting the detailed configuration procedures into a manageable MAC layer protocol.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4675938A1Terminal, wireless communication method, and base station
Publication Date: 2026.01.07 NTT DOCOMO INC
  • EP4675938A1 patent drawingFigure 1A~1D
  • EP4675938A1 patent drawingFigure 2A~2B
  • EP4675938A1 patent drawingFigure 3A~3B

AI summary

Even when cell switching is performed, communication is appropriately performed. A terminal according to one aspect of the present disclosure includes a receiving section that receives a Medium Access Control Control Element (MAC CE) related to cell switching, and a control section that controls, based on information included in the MAC CE, application of a transmission configuration indication (TCI) state for a specific cell. The MAC CE includes information related to a TCI state pool for a serving cell or a candidate cell.