Sidelink Feedback Channel Mapping Across Multiple LBT RB Sets

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

In the newly-operated frequency band with higher frequencies, the unlicensed band requires specific regulations for device-to-device direct communication, particularly in managing the association between physical sidelink control and feedback channels using multiple listen before talk (LBT) channels.

Innovation Solution

A terminal is equipped with a reception unit for performing LBT in a resource pool with multiple RB sets, determining channels for receiving feedback information, and a transmission unit for transmitting signals upon successful LBT, facilitating feedback channel transmission in an unlicensed band.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple LBT channels are used for D2D communication in unlicensed band, then channel access reliability is improved, but channel association complexity increases

Engineering Contradiction:
Improvechannel access reliabilityVSAvoidchannel association complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The resource pool is divided into multiple RB sets, each associated with a specific LBT channel. This segmentation allows the system to manage multiple channels independently while maintaining clear associations between resources and channels, thus improving reliability without excessive complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The association between PSCCH/PSSCH and PSFCH channels is predetermined and configured in advance. This preliminary association setup eliminates the need for dynamic channel pairing during operation, reducing real-time complexity while ensuring reliable channel access

Inventive Principle:
Principle #10Preliminary action

2Adaptability or versatility

If LBT procedure is performed in unlicensed band, then regulatory compliance is improved, but communication latency increases

Engineering Contradiction:
Improveregulatory complianceVSAvoidcommunication latency
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The LBT procedure is performed periodically at scheduled intervals before transmissions. This periodic approach ensures regulatory compliance is maintained systematically while allowing the system to predict and optimize timing, reducing overall latency impact

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

Channel access is checked in advance before actual data transmission begins. This preliminary LBT check ensures compliance with unlicensed band regulations while allowing the system to prepare transmission resources ahead of time, minimizing latency during actual communication

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4701263A1Terminal and communication method
Publication Date: 2026.02.25 NTT DOCOMO INC
  • EP4701263A1 patent drawingFigure 1
  • EP4701263A1 patent drawingFigure 2~4
  • EP4701263A1 patent drawingFigure 5

AI summary

A terminal includes a reception unit configured to perform listen before talk (LBT) corresponding to a transmission signal in a resource pool including a plurality of resource block (RB) sets in an unlicensed band; a control unit configured to determine a channel in each of the plurality of RB sets based on a resource of the transmission signal, the channel being for receiving feedback information corresponding to the transmission signal from another terminal; and a transmission unit configured to transmit the transmission signal to the another terminal in a case where the LBT is successful. The reception unit receives, on the channel, the feedback information corresponding to the transmission signal from the another terminal.