PSFCH Transmission Timeline for Sidelink HARQ Feedback Timing

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Solution Overview

Problem

Existing wireless communication systems face inefficiencies in sidelink hybrid automatic repeat request (HARQ) feedback due to a one-size-fits-all time buffer threshold for sidelink HARQ feedback transmission, which can lead to inefficient reporting and potential collisions for UEs with varying capabilities.

Innovation Solution

A configurable transmission timeline for the physical sidelink feedback channel (PSFCH) is introduced, allowing UEs to select or negotiate a time buffer threshold (K value) based on their capabilities, ensuring efficient sidelink HARQ feedback generation and transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a one-size-fits-all time buffer threshold is used for sidelink HARQ feedback transmission, then system simplicity is maintained, but feedback efficiency deteriorates and collisions increase for UEs with varying capabilities

Engineering Contradiction:
Improvesidelink HARQ feedback efficiencyVSAvoidtime buffer threshold configuration complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent implements dynamic time buffer threshold selection where UEs can negotiate and select different K1 values based on their processing capabilities. The time buffer threshold is no longer fixed but adaptable to individual UE requirements, allowing high-capability UEs to use smaller buffers and low-capability UEs to use larger buffers, thereby improving overall feedback efficiency without forcing a one-size-fits-all approach

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of time buffer threshold from a fixed system-wide value to a negotiable parameter that can take different values (K1, K2, etc.) based on UE capability agreements. This parameter change enables the system to adapt to different UE processing speeds and capabilities, resolving the contradiction between maintaining simplicity and improving efficiency

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If a fixed time buffer threshold is used for all UEs, then configuration complexity is reduced, but resource collision probability increases for UEs with different processing capabilities

Engineering Contradiction:
Improvetime buffer threshold configuration easeVSAvoidsidelink feedback collision avoidance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent introduces a feedback mechanism where UEs exchange capability information and negotiate the time buffer threshold value. Each UE provides feedback about its processing capability, and based on this feedback, both UEs agree on an appropriate K1 value. This feedback loop ensures that the configured time buffer is adequate for both UEs' capabilities, preventing resource collisions while maintaining reasonable configuration complexity

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent performs preliminary capability exchange and threshold negotiation before actual sidelink HARQ feedback transmission begins. By establishing the appropriate time buffer threshold in advance based on both UEs' capabilities, the system prevents future collisions without requiring complex real-time adjustments during operation

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4035292B1Configurable transmission timeline for physical sidelink feedback channel
Publication Date: 2026.03.04 QUALCOMM INC
  • EP4035292B1 patent drawingFigure 1
  • EP4035292B1 patent drawingFigure 2
  • EP4035292B1 patent drawingFigure 3A

AI summary

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may transmit, to a second user equipment, an indication of a time buffer threshold associated with providing sidelink hybrid automatic repeat request feedback on a physical sidelink feedback channel. The UE may receive, from the second user equipment, an indication of an agreement to use the time buffer threshold. The UE may transmit, to the second user equipment and based at least in part on the indication of the agreement, sidelink hybrid automatic repeat request feedback for a sidelink communication received from the second user equipment, the sidelink hybrid automatic repeat request feedback being transmitted on the physical sidelink feedback channel based at least in part on the time buffer threshold. Numerous other aspects are provided.