PSFCH DTX Counting Across Reception Occasions in SL-U

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Solution Overview

Problem

In sidelink unlicensed spectrum (SL-U), the transmission of physical sidelink feedback channels (PSFCH) frequently fails due to listen before talk (LBT) mechanism, leading to high radio link failure (RLF) rates and disrupted service continuity.

Innovation Solution

A method for determining consecutive discontinuous transmissions (DTXs) based on sets of PSFCH reception occasions, involving statistical counting and resource location determination using various signaling methods, to reduce RLF occurrences.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If LBT mechanism is introduced for SL-U spectrum, then transmission collision is avoided, but PSFCH transmission success rate decreases

Engineering Contradiction:

Improvetransmission collisionVSAvoidPSFCH transmission success rate

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent segments the PSFCH transmission process into multiple reception occasions (at least two) within a set, allowing the terminal to attempt reception across multiple time instances. This segmentation enables the system to overcome temporary LBT failures by providing multiple opportunities for successful PSFCH reception, thereby resolving the contradiction between avoiding transmission collisions and maintaining transmission success rate.

Inventive Principle:

Principle #1Segmentation

2Measurement precision

If statistical method for consecutive DTX frequency is used, then DTX detection capability is improved, but SL RLF frequency increases

Engineering Contradiction:

ImproveDTX detection capabilityVSAvoidSL RLF frequency

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent divides the DTX statistical counting into separate evaluations for each PSFCH reception occasion within a set. By segmenting the evaluation process, the system can accurately detect DTX conditions without prematurely triggering RLF, as it considers the collective outcome of multiple reception occasions rather than treating each individual failure as a definitive DTX event.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces a buffer mechanism by requiring successful PSFCH reception in at least one occasion within a set before confirming DTX. This beforehand cushioning prevents premature RLF declaration by allowing temporary transmission failures due to LBT without immediately triggering failure conditions, thus maintaining system reliability while preserving DTX detection accuracy.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentEP4651544A1Method and device for determining number of times of DTX, and terminal

Publication Date: 2025.11.19 DATANG MOBILE COMM EQUIP CO LTD

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AI summary

A method and an apparatus for determining a number of DTXs, and a terminal are provided. The method executed by a first terminal includes: performing statistics on a number of consecutive discontinuous transmissions (DTXs) for a sidelink interface based on one set of physical sidelink feedback channel (PSFCH) reception occasions, wherein the one set of PSFCH reception occasions comprises at least two PSFCH reception occasions.