PSFCH Resource Mapping for Reliable Sidelink Feedback Under LBT

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Solution Overview

Problem

In sidelink communication over unlicensed spectrum bands, the uncertainty of channel availability due to Listen Before Talk (LBT) failures leads to frequent PSFCH transmission failures, resulting in reduced spectrum efficiency and increased latency and transmission overhead.

Innovation Solution

A feedback channel mapping method that groups PSFCH resources based on the number of sub-channels and PSSCH slots, allocating divided PSFCH resource groups to each PSSCH slot and sub-channel to reduce the probability of transmission failure and retransmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If LBT is performed before PSFCH transmission, then channel availability is ensured, but transmission failures occur when LBT fails

Engineering Contradiction:
ImprovePSFCH transmission reliabilityVSAvoidspectrum efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent segments the PSFCH resources into multiple groups based on sub-channel and PSSCH slot characteristics. By dividing the feedback channel resources into distinct groups that can be independently allocated and transmitted, the system reduces the impact of LBT failures on overall transmission reliability while maintaining spectrum efficiency through targeted resource utilization.

Inventive Principle:
Principle #1Segmentation

2Reliability

If PSFCH resources are allocated to each PSSCH slot, then feedback transmission is ensured, but transmission overhead increases

Engineering Contradiction:
Improvefeedback transmission reliabilityVSAvoidtransmission overhead
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges multiple PSFCH resources into unified PSFCH resource groups that can be shared across multiple PSSCH slots. Instead of allocating separate resources to each slot, the system combines resources into groups that serve multiple slots through time-sharing, thereby reducing overall transmission overhead while maintaining feedback reliability.

Inventive Principle:
Principle #5Merging (Combining)

3Adaptability or versatility

If multiple RB sets are used, then resource flexibility is improved, but LBT failure probability increases

Engineering Contradiction:
Improveresource allocation flexibilityVSAvoidchannel availability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent dynamically determines which PSFCH resource group to use based on the actual channel availability and LBT outcomes. The system adapts its resource selection in real-time, switching between different RB sets and PSFCH groups depending on whether LBT succeeds or fails, thereby maintaining flexibility while improving reliability through adaptive resource allocation.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4593492A1Feedback channel mapping method, electronic device and storage medium
Publication Date: 2025.07.30 ZTE CORP
  • EP4593492A1 patent drawingFigure 1~2
  • EP4593492A1 patent drawingFigure 3
  • EP4593492A1 patent drawingFigure 4~5

AI summary

Provided are a feedback channel mapping method, an electronic device and a storage medium. The feedback channel mapping method includes the following: For each resource block set in a resource pool, a physical sidelink feedback channel, PSFCH, resource set in the resource block set and a sub-channel corresponding to a PSFCH resource in the resource block set are determined. For each resource block set, PSFCH resources in the PSFCH resource set are grouped based on the number of sub-channels corresponding to the PSFCH resources in the PSFCH resource set and the number or maximum number of physical sidelink shared channel, PSSCH, slots associated with a PSFCH slot, and divided PSFCH resource groups are allocated to each PSSCH slot in the PSSCH slots associated with the PSFCH slot and to each sub-channel in the sub-channels.