PSSCH Resource Timing for HARQ Feedback in Unlicensed Sidelink

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Solution Overview

Problem

In wireless communication systems, there is a lack of a solution for determining the appropriate physical sidelink shared channel (PSSCH) resources in an unlicensed frequency band that ensure a minimum time gap for HARQ feedback, particularly in scenarios where multiple PSFCH occasions are mapped to a PSSCH, which is crucial for reliable TB transmission.

Innovation Solution

A method and apparatus for determining a PSSCH resource by identifying a target PSFCH occasion from multiple mapped PSFCH occasions and ensuring a minimum time gap between any two selected PSSCH resources, using unlicensed frequency band resources to support HARQ feedback, where M is an integer greater than 1.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple PSFCH occasions are mapped to a PSSCH, then the HARQ feedback capability is improved, but the resource selection complexity increases

Engineering Contradiction:
ImproveHARQ feedback reliabilityVSAvoidresource selection complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The PSSCH resource selection process is segmented into distinct steps: first determining the target PSFCH occasion from multiple mapped occasions, then calculating the minimum time gap based on that target occasion. This segmentation transforms a complex multi-parameter selection problem into a structured two-step process, reducing resource selection complexity while maintaining HARQ feedback reliability.

Inventive Principle:
Principle #1Segmentation

2Reliability

If a minimum time gap is enforced between PSSCH resources, then the HARQ feedback reliability is improved, but the resource utilization efficiency decreases

Engineering Contradiction:
ImproveHARQ feedback reliabilityVSAvoidresource utilization efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The minimum time gap is not fixed but dynamically determined based on the target PSFCH occasion. By changing the parameter calculation method from a static value to a dynamic value derived from the target PSFCH occasion, the system ensures adequate time for HARQ feedback processing while optimizing resource utilization efficiency through adaptive gap adjustment.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If the target PSFCH occasion is determined from multiple mapped occasions, then the HARQ feedback flexibility is improved, but the determination complexity increases

Engineering Contradiction:
ImproveHARQ feedback flexibilityVSAvoiddetermination complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The target PSFCH occasion is determined in advance before the actual PSSCH resource selection. This preliminary determination simplifies subsequent resource selection by providing a fixed reference point for calculating the minimum time gap, thereby reducing overall determination complexity while maintaining HARQ feedback flexibility.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4694466A1Method and apparatus for determining pssch resource, communication device, and storage medium
Publication Date: 2026.02.11 BEIJING XIAOMI MOBILE SOFTWARE CO LTD
  • EP4694466A1 patent drawingFigure 1~2
  • EP4694466A1 patent drawingFigure 3~5
  • EP4694466A1 patent drawingFigure 6~7

AI summary

Embodiments of the present disclosure provide a method and apparatus for determining a physical sidelink shared channel (PSSCH) resource, a communication device, and a storage medium. The method comprises: determining a target physical shared feedback channel (PSFCH) occasion among M PSFCH occasions mapped by a PSSCH where a transport block (TB) is located; and on the basis of the target PSFCH occasion, determining a minimum time interval for any two PSSCH resources selected for the TB, wherein a time interval between any two PSSCH resources selected for one TB is not less than the minimum time interval, the PSSCH resources are unlicensed frequency band resources and are used for transmission and retransmission of the TB, a first PSSCH of any two PSSCHs supports HARQ feedback, and M is an integer greater than 1. In this way, when TB transmission is carried out on the basis of the unlicensed frequency band PSSCH resource, it can be ensured that the minimum time interval is met between any two PSSCH resources selected for the TB, thereby ensuring that the TB supports retransmission based on the HARQ feedback.