DCI Reference Carrier Indication for Multi-Carrier Scheduling

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing DCI mechanisms for scheduling PDSCHs or PUSCHs on multiple carriers face challenges in determining an appropriate reference cell, leading to unclear restrictions on blind detections, CCEs, DCI sizes, and search space configurations.

Innovation Solution

A method is introduced to specify a reference carrier for determining specification restrictions on specific downlink control information (DCI) using various options, including cell index, existing DCI usage, and higher layer parameters, allowing appropriate execution of restrictions on blind detections, CCEs, and search space configurations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If single DCI multi-carrier scheduling is implemented, then channel management efficiency is improved, but reference cell determination becomes ambiguous

Engineering Contradiction:
Improvechannel management efficiencyVSAvoidreference cell determination complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by introducing a reference cell indication field in the DCI that can take different values (first carrier index or second carrier index) to explicitly specify which carrier should be treated as the reference cell. This resolves the ambiguity by changing the parameter space of carrier identification from implicit to explicit, allowing the terminal to correctly determine restrictions on blind detections, CCEs, and search spaces based on the indicated reference cell.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If multiple carriers are scheduled using a single DCI, then resource allocation efficiency is improved, but DCI restriction execution becomes unclear

Engineering Contradiction:
Improveresource allocation efficiencyVSAvoidDCI restriction execution accuracy
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent introduces a reference cell as an intermediary concept that mediates between the single DCI and multiple carriers. By identifying which carrier serves as the reference cell through the reference cell indication field, the terminal can accurately execute DCI restrictions (such as maximum number of blind detections, CCEs, and search space configurations) that were originally designed for single-carrier scenarios, thus maintaining reliability while enabling multi-carrier scheduling.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Adaptability or versatility

If existing DCI mechanisms are used for multi-carrier scheduling, then backward compatibility is maintained, but specification restrictions cannot be appropriately applied

Engineering Contradiction:
Improvebackward compatibilityVSAvoidspecification restriction application accuracy
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent achieves universality by making the DCI structure multi-functional: it can indicate either the first carrier index or the second carrier index as the reference cell, allowing the same DCI mechanism to work for both single-carrier and multi-carrier scheduling scenarios. This maintains backward compatibility while enabling accurate application of specification restrictions through the flexible reference cell indication capability.

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

Data Source

PatentEP4618669A1Terminal, base station, wireless communication system, and wireless communication method
Publication Date: 2025.09.17 NTT DOCOMO INC
  • EP4618669A1 patent drawingFigure 1
  • EP4618669A1 patent drawingFigure 2
  • EP4618669A1 patent drawingFigure 3

AI summary

A terminal includes: a receiving unit that receives single specific downlink control information for scheduling channels to be transmitted on two or more carriers; and a control unit that assumes, using a specification method, a reference carrier for determining a specification restriction on the specific downlink control information.