Radio Terminal Grant-Free Uplink Control with Dynamic Signaling

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Solution Overview

Problem

In future radio communication systems, UL grant-free transmission lacks flexible control, leading to potential declines in communication throughput and spectral efficiency.

Innovation Solution

Implementing a method where UL grant-free transmission parameters are semi-statically configured via higher layer signaling and dynamically adjusted through physical layer signaling, allowing for flexible control of UL grant-free transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If UL grant-free transmission is performed based on semi-static configurations, then latency is reduced and communication speed is improved, but flexible control is lost leading to decline in communication throughput and spectral efficiency

Engineering Contradiction:
Improvecommunication speedVSAvoidcommunication throughput
Core Design Contradiction:
SpeedVSProductivity

Solution Approach 1:

The patent applies dynamics by transitioning from static semi-static configurations to dynamic parameter adjustment. The base station dynamically controls UL grant-free transmission parameters (such as time-frequency resources, power levels, and modulation schemes) based on real-time channel conditions and traffic demands, allowing the system to adapt flexibly while maintaining low latency characteristics

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements parameter changes by modifying transmission parameters dynamically through physical layer signaling. The base station adjusts key parameters including resource allocation, transmission power, and modulation and coding schemes based on current system state, enabling optimization of both throughput and spectral efficiency without sacrificing the low-latency benefit of grant-free transmission

Inventive Principle:
Principle #35Parameter changes

2Loss of time

If UL grant-free transmission is performed based on semi-static configurations, then communication latency is reduced, but spectral efficiency declines due to lack of flexible control

Engineering Contradiction:
Improvecommunication latencyVSAvoidspectral efficiency
Core Design Contradiction:
Loss of timeVSLoss of energy

Solution Approach 1:

The patent implements feedback mechanisms where the base station receives channel state information and traffic status from user equipment, then uses this feedback to dynamically adjust UL grant-free transmission parameters. This closed-loop control enables the system to maintain low latency while optimizing spectral efficiency through real-time parameter adaptation based on actual channel conditions

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3621402B1Terminal, radio communication method, and system
Publication Date: 2025.08.06 NTT DOCOMO INC
  • EP3621402B1 patent drawingFigure 1A~1B
  • EP3621402B1 patent drawingFigure 2
  • EP3621402B1 patent drawingFigure 3

AI summary

According to one aspect of the present invention, a user terminal has a transmission section that performs UL grant-free transmission, in which UL data is transmitted without a UL transmission indication from the radio base station; and a control section that controls the UL grant-free transmission based on a configuration of the UL grant-free transmission, which is determined based on physical layer signaling. According to one aspect of the present invention, even when UL grant-free transmission is performed, the decline in communication throughput and the like can be reduced.