Listen-before-talk in shared RF spectrum regions

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Solution Overview

Problem

Listen-before-talk (LBT) procedures in wireless communication systems are associated with high overhead and inefficient use of system resources due to the need for devices to sense channels for potential collisions, leading to suboptimal resource allocation in shared RF spectrum environments.

Innovation Solution

Implementing a method where a user equipment (UE) performs LBT in a first shared RF spectrum region to access resources in a second shared RF spectrum region, allowing for efficient resource usage by mapping LBT resources to smaller RF spectrum regions that overlap with or differ in time from data transmission resources, thereby reducing overhead and improving communication efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If LBT procedures are performed in the same shared RF spectrum region as data transmission, then collision detection capability is improved, but resource usage efficiency deteriorates due to high overhead

Engineering Contradiction:
Improvecollision detection capabilityVSAvoidresource usage efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent segments the RF spectrum into separate first and second shared RF spectrum regions. The LBT procedure is performed in the first region while data transmission occurs in the second region. This spatial segmentation allows collision detection and data transmission to occur simultaneously in different frequency regions, eliminating the overhead of using the same resources for both purposes and thereby resolving the contradiction between reliability and productivity.

Inventive Principle:
Principle #1Segmentation

2Reliability

If resources are allocated for channel sensing in LBT procedures, then collision avoidance is improved, but system resource efficiency deteriorates due to overhead

Engineering Contradiction:
Improvecollision avoidanceVSAvoidsystem resource efficiency
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent divides the spectrum resources into separate first and second shared RF spectrum regions. Channel sensing (LBT procedure) is confined to the first region while data transmission uses the second region. This segmentation ensures that energy spent on sensing does not compete with data transmission resources, maintaining collision avoidance capability while preventing system resource efficiency degradation.

Inventive Principle:
Principle #1Segmentation

3Productivity

If LBT procedure uses the same frequency channel as data transmission, then channel utilization is improved, but overhead increases leading to inefficient resource use

Engineering Contradiction:
Improvechannel utilizationVSAvoidoverhead
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the frequency spectrum into distinct first and second shared RF spectrum regions. The LBT procedure operates in the first region while data transmission occurs in the second region. This segmentation enables the system to maintain high channel utilization in both regions simultaneously without the overhead burden of performing LBT and data transmission on the same channel, as each region can be fully utilized for its designated purpose.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3549382B1Listen-before-talk techniques in synchronous systems
Publication Date: 2021.08.04 QUALCOMM INC
  • EP3549382B1 patent drawingFigure 1
  • EP3549382B1 patent drawingFigure 2
  • EP3549382B1 patent drawingFigure 3

AI summary

Methods, systems, and devices for wireless communication are described. Contention procedures may include a shared radio frequency (RF) spectrum region to access resources in another shared RF spectrum region. For example, a wireless device may operate in a synchronous system and identify a set of target resources for a data transmission. The wireless device may contend for the target resources by performing a procedure, such as a listen-before-talk (LBT) procedure, in a first shared RF spectrum region that is smaller than, and overlaps in frequency with, a second shared RF spectrum region that includes the target resources. Resources used for the LBT procedure may be included in a different time period than the target resources, where LBT resources may correspond to target resources in different time periods. The target resources may also include multiple sub-channels, and LBT resources may be mapped to one or more of the sub-channels.