Sidelink LBT Failure Recovery via Virtual Channel Assessment

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Solution Overview

Problem

In wireless communications, particularly in sidelink (SL) operations with shared spectrum channel access, consistent listen before talk (LBT) failures are not efficiently recovered, leading to potential interruptions in SL transmissions due to unclear mechanisms for reusing resource blocks (RBs) and impeded hybrid automatic repeat request (HARQ) feedback.

Innovation Solution

A method is introduced to detect and recover from consistent LBT failures by performing virtual LBT procedures based on a reference SL format, incrementing a counter for successful LBTs, and cancelling the failure when a predefined threshold is met, ensuring reliable reuse of RBs for SL transmissions and maintaining uninterrupted HARQ feedback.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If consistent LBT failure detection is implemented for SL transmissions on shared spectrum, then channel access reliability is improved, but transmission interruptions occur due to unclear RB reuse mechanisms

Engineering Contradiction:

Improvechannel access reliabilityVSAvoidtransmission interruption time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent performs virtual LBT procedures as a preliminary action to assess channel availability before actual SL transmissions. By conducting these virtual LBT attempts based on a reference SL format and counting successes against a threshold, the system proactively determines whether RBs can be safely reused, preventing transmission interruptions while maintaining reliable channel access

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces a counter mechanism as an intermediary between LBT failure detection and RB reuse decisions. This counter tracks successful virtual LBT attempts and, when reaching a predefined threshold, mediates the cancellation of consistent LBT failure status, enabling RB reuse without direct transmission interruptions

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If virtual LBT procedures are performed to recover from consistent LBT failures, then RB reuse efficiency is improved, but HARQ feedback may be impeded during the recovery process

Engineering Contradiction:

ImproveRB reuse efficiencyVSAvoidHARQ feedback reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent segments the LBT recovery process into distinct phases: virtual LBT procedure execution, counter incrementing, threshold evaluation, and failure cancellation. This segmentation allows the system to perform RB reuse assessments through virtual procedures while maintaining separate HARQ feedback pathways, ensuring that productivity improvement in RB reuse does not compromise HARQ feedback reliability

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS20250024500A1Techniques for listen before talk failure recovery for sidelink

Publication Date: 2025.01.16 LENOVO (SINGAPORE) PTE LTD

AI summary

Various aspects of the present disclosure relate to techniques for listen before talk failure recovery for sidelink. An apparatus includes at least one memory and at least one processor coupled with the at least one memory. The at least one processor is configured to cause the apparatus to detect a consistent LBT failure on a set of resource blocks RBs, perform at least one LBT on the set of RBs, wherein the LBT is performed based on a reference sidelink SL format, increment a counter in response to determining a success for one of the at least one LBT, wherein the counter is associated with the set of RBs, and, in response to determining that the counter satisfies a predefined threshold, cancel the consistent LBT failure.