SL PRS Timing Flexibility for Unlicensed LBT Access

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Solution Overview

Problem

The uncertainty in completing Listen Before Talk (LBT) on an unlicensed spectrum leads to missed transmission opportunities for sidelink positioning reference signals (SL PRS), affecting positioning accuracy for terminal devices outside cellular network coverage.

Innovation Solution

Configuring sidelink positioning reference signals (SL PRS) and physical channels with multiple starting orthogonal frequency-division multiplexing (OFDM) symbol positions within a slot to enhance transmission probability on unlicensed spectra.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If Listen Before Talk (LBT) mechanism is used on unlicensed spectrum, then channel access is achieved, but transmission opportunity is missed when LBT completion time is uncertain

Engineering Contradiction:

ImproveSL PRS transmission reliabilityVSAvoidLBT completion time uncertainty

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent applies dynamics by making the SL PRS resource configuration flexible and adaptable to LBT outcomes. Multiple starting OFDM symbol positions are configured within a slot, allowing the system to dynamically select an available transmission opportunity based on when LBT is completed, rather than being fixed to a single predetermined time slot.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of starting symbol position from a fixed value to multiple possible values within a slot. By configuring multiple starting OFDM symbol positions for SL PRS resources, the system can adjust the transmission timing parameter based on LBT completion time, thereby resolving the contradiction between reliable transmission and time loss.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If multiple starting OFDM symbol positions are configured for SL PRS resources, then transmission probability is improved, but resource configuration complexity increases

Engineering Contradiction:

ImproveSL PRS transmission probabilityVSAvoidresource configuration complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the SL PRS resource configuration into multiple starting OFDM symbol positions within a slot. Instead of configuring a single resource, the configuration is divided into multiple possible starting positions, allowing the terminal to select from segmented options based on LBT outcomes, thereby improving transmission probability while maintaining manageable configuration complexity.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentEP4642115A1Wireless communication method, terminal device, and network device

Publication Date: 2025.10.29 GUANGDONG OPPO MOBILE TELECOMMUNICATIONS CORP LTD

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AI summary

A wireless communication method, a terminal device, and a network device. The method comprises: in accordance with one or more sidelink positioning reference signal (SL PRS) resources configured in a time slot, a terminal device sending an SL PRS and/or a physical channel, the physical channel being used for indicating the sending of the SL PRS, and the SL PRS resources corresponding to one or more initial orthogonal frequency division multiplexing (OFDM) symbol positions that can be used for sending an SL PRS.