Listen-Before-Talk Duration Indication in Millimeter Wave Uplink Grants

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Solution Overview

Problem

In wireless communications, especially in shared millimeter wave radio frequency spectrum, existing listen-before-talk techniques face challenges in reliably determining channel availability for uplink transmissions, leading to inefficiencies in network resource utilization.

Innovation Solution

The proposed solution involves base stations providing uplink grants with an indication of the duration of a listen-before-talk procedure, allowing user equipment to perform a clear channel assessment using energy detection for a specified observation time, ensuring channel availability before transmitting uplink data, and accommodating synchronization with frame structures to enhance transmission efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If LBT procedure is performed to determine channel availability, then transmission reliability is improved, but network efficiency deteriorates due to additional time consumption

Engineering Contradiction:
Improvechannel availability determinationVSAvoidnetwork efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The base station performs the LBT procedure in advance before allocating uplink resources to the UE. The LBT result and channel availability information are included in the uplink grant message, so the UE does not need to perform separate LBT, thus maintaining reliability while improving efficiency

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If LBT procedure duration is extended for more accurate channel assessment, then measurement precision is improved, but loss of time increases

Engineering Contradiction:
Improvechannel assessment accuracyVSAvoidLBT procedure duration
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The base station copies the LBT measurement results and channel availability information into the uplink grant message, allowing the UE to obtain accurate channel assessment information without performing its own time-consuming LBT procedure

Inventive Principle:
Principle #26Copying

3Device complexity

If uplink resources are allocated without LBT indication, then device complexity is reduced, but transmission reliability deteriorates

Engineering Contradiction:
Improveresource allocation simplicityVSAvoidtransmission reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The base station acts as an intermediary by performing LBT on behalf of the UE and conveying the results through the uplink grant message. This maintains simple resource allocation while ensuring transmission reliability through proper channel assessment

Inventive Principle:
Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach improves network efficiency by ensuring reliable channel availability for uplink transmissions, synchronizing with frame structures, and complying with regulatory requirements for shared millimeter wave spectrum access, thereby optimizing resource utilization and reducing transmission errors.

Implementation Method 1

an indication of a duration of a listen-before-talk (LBT) procedure may be provided in or with the uplink grant. The UE may perform, responsive to receiving the uplink grant, the LBT procedure to determine that the shared mmW radio frequency spectrum band is available for the uplink transmission

Methodology Applied
Scientific EffectEnergy detection:

Data Source

PatentEP3797552B1Listen before talk techniques in shared millimeter wave radio frequency spectrum
Publication Date: 2024.07.03 QUALCOMM INC
  • EP3797552B1 patent drawingFigure 1
  • EP3797552B1 patent drawingFigure 2
  • EP3797552B1 patent drawingFigure 3A~3B

AI summary

Methods, systems, and devices for wireless communications are described in which base stations and user equipment (UEs) may transmit using identified wireless resources in millimeter wave (mmW) radio frequency spectrum. A UE may receive an uplink grant from a base station that indicates uplink resources for transmission of uplink data from the UE to the base station in a shared mmW radio frequency spectrum band. An indication of a duration of a listen-before-talk (LBT) procedure may be provided in or with the uplink grant. The UE may perform, responsive to receiving the uplink grant, the LBT procedure to determine that the shared mmW radio frequency spectrum band is available for the uplink transmission. Based on the outcome of the LBT procedure, the UE may transmit the uplink data to the base station using the uplink resources indicated in the uplink grant.