Sidelink HARQ Feedback for LBT Failure Recovery

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Solution Overview

Problem

In communication systems utilizing sidelink (SL) transmissions in unlicensed spectrum, the instability due to listen-before-talk (LBT) failures is not effectively addressed, leading to inefficiencies in resource management and retransmissions.

Innovation Solution

A feedback method where a terminal determines LBT failures in SL transmission units and sends Hybrid Automatic Repeat reQuest (HARQ) feedback to a network device, enabling dynamic resource scheduling for retransmissions based on the feedback.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the terminal performs LBT on SL transmission in unlicensed spectrum, then the SL communication can operate in unlicensed band, but transmission instability occurs due to LBT failures

Engineering Contradiction:

ImproveSL communication operation in unlicensed spectrumVSAvoidtransmission stability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where the terminal sends HARQ feedback information to the network device based on LBT failure detection. The network device receives this feedback and dynamically schedules retransmission resources, creating a closed-loop system that adapts to LBT failures and maintains transmission reliability in unlicensed spectrum

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent enables dynamic resource scheduling for SL retransmissions. The network device adjusts resource allocation based on real-time HARQ feedback from the terminal, allowing the system to adapt dynamically to changing channel conditions and LBT failure patterns in unlicensed spectrum

Inventive Principle:

Principle #15Dynamics

2Reliability

If HARQ feedback is implemented based on LBT failure detection, then transmission success rate improves, but signaling overhead increases

Engineering Contradiction:

Improvetransmission success rateVSAvoidsignaling overhead

Core Design Contradiction:

ReliabilityVSLoss of information

Solution Approach 1:

The terminal autonomously detects LBT failures and generates HARQ feedback information without requiring explicit network instructions. This self-service approach allows the terminal to independently manage feedback signaling, reducing the need for additional control messages from the network device and minimizing signaling overhead while maintaining high transmission success rates

Inventive Principle:

Principle #25Self-service

Data Source

PatentEP4641961A1Feedback method and apparatus, and device and storage medium

Publication Date: 2025.10.29 BEIJING XIAOMI MOBILE SOFTWARE CO LTD

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AI summary

Provided in the present disclosure are a feedback method and apparatus, and a device and a storage medium. The method comprises: determining whether a sidelink (SL) transmission unit of a terminal device fails to perform listen before talk (LBT) (201); and sending HARQ feedback information to a network device on the basis of a determination result (202). The method of the present disclosure can improve the stability of SL communication.