Sidelink COT Sharing via PSFCH RSRP Measurement

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Solution Overview

Problem

In wireless communication networks, especially in unlicensed bands, there is a challenge in efficiently sharing channel occupancy time (COT) for sidelink communications, particularly in mode 2 sidelink operations that support physical sidelink feedback channel (PSFCH) transmissions. This is due to the uncertainty in determining whether a detected PSFCH transmission is part of the COT initiated by a COT-initiating UE, which can lead to premature release of the COT and inefficient resource utilization.

Innovation Solution

A method where a UE measures the reference signal received power (RSRP) of a PSFCH transmission during a COT initiated by another UE. If the measured RSRP exceeds a threshold, the UE infers that the PSFCH transmission is part of the COT, allowing the UE to access and share the COT, thereby preventing premature release.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a UE detects a PSFCH transmission in unlicensed bands, then it may infer the COT is still active, but this can lead to premature COT release due to uncertainty in determining whether the PSFCH is part of the COT

Engineering Contradiction:
ImproveCOT sharing reliabilityVSAvoidCOT availability information
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The patent replaces the mechanical/direct detection method with signal-based measurement. Instead of directly detecting PSFCH transmissions to determine COT activity, the UE measures RSRP of reference signals and compares against thresholds to infer COT status. This substitution of detection mechanism resolves the uncertainty in determining whether detected signals are part of the COT.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces RSRP measurement as an intermediary parameter between PSFCH detection and COT status determination. By measuring the reference signal received power and comparing it to a threshold, the system creates an intermediate verification step that helps accurately determine whether a detected PSFCH transmission is part of the COT, preventing both premature release and false continuation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If a UE releases COT upon detecting any PSFCH transmission, then it avoids interference with other transmissions, but this causes inefficient resource utilization due to premature release

Engineering Contradiction:
ImproveResource utilization efficiencyVSAvoidCOT duration
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent performs preliminary verification before making the COT release decision. Instead of immediately releasing COT upon detecting a PSFCH transmission, the UE first measures the RSRP of the reference signal and compares it against a threshold to verify whether the PSFCH is actually part of the COT. This preliminary action prevents premature release and improves resource utilization efficiency.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If a UE continuously monitors for PSFCH transmissions to determine COT availability, then it can accurately share COT, but this increases detection complexity and processing overhead

Engineering Contradiction:
ImproveCOT status detection accuracyVSAvoidDetection complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies partial monitoring strategy. Instead of continuously monitoring all PSFCH transmissions, the UE monitors for reference signals and only performs full PSFCH detection when the RSRP measurement exceeds the threshold, indicating likely COT activity. This partial approach maintains detection accuracy while reducing overall complexity and processing overhead.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP4298858B1Channel occupancy time (COT) sharing for sidelink communications in unlicensed bands
Publication Date: 2025.04.09 QUALCOMM INC
  • EP4298858B1 patent drawingFigure 1
  • EP4298858B1 patent drawingFigure 2
  • EP4298858B1 patent drawingFigure 3

AI summary

Wireless communications systems and methods related to channel occupancy time (COT) sharing for sidelink communications in unlicensed bands are provided. A method for wireless communication by a first user equipment (UE) may include measuring a first reference signal received power (RSRP) of a physical sidelink feedback channel (PSFCH) transmission transmitted during a channel occupancy time (COT) initiated by a second UE and accessing a first slot of the COT based on the first RSRP.