Distributed Channel Availability Check in Shared Spectrum

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Solution Overview

Problem

The 5.600-5.650 GHz radio frequency spectrum band is underutilized due to the requirement for a lengthy 10-minute clear channel assessment (CAC) in wireless communication systems, as many devices are unable or not configured to cease communication for this duration, leading to inefficiencies in shared radio frequency spectrum usage.

Innovation Solution

A distributed channel availability check (CAC) is implemented, where the CAC duration is divided into portions assigned to multiple wireless devices, allowing them to monitor the energy level of the sub-band for shorter periods, reducing the time each device needs to cease communication and enabling more efficient use of the shared spectrum.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a 10-minute clear channel assessment (CAC) is performed to ensure reliable spectrum sharing, then channel availability reliability is improved, but spectrum utilization efficiency deteriorates due to prolonged communication cessation

Engineering Contradiction:
Improvechannel availability reliabilityVSAvoidspectrum utilization efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent divides the 10-minute CAC period into multiple shorter monitoring intervals distributed across different time slots. Multiple wireless devices perform monitoring at different times, and results are aggregated to determine overall channel availability. This segmentation allows the system to maintain reliability through comprehensive monitoring while reducing the time any single device must cease communication.

Inventive Principle:
Principle #1Segmentation

2Reliability

If a 10-minute clear channel assessment (CAC) is performed to ensure reliable spectrum sharing, then channel availability reliability is improved, but communication continuity deteriorates due to prolonged interruption

Engineering Contradiction:
Improvechannel availability reliabilityVSAvoidcommunication continuity
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

The CAC process is segmented into multiple shorter monitoring tasks distributed across different devices and time periods. Each device performs monitoring for a brief interval rather than requiring a continuous 10-minute pause, thereby maintaining communication continuity while still gathering sufficient data for reliable channel availability determination.

Inventive Principle:
Principle #1Segmentation

3Productivity

If the CAC duration is reduced to maintain communication continuity, then communication efficiency is improved, but measurement precision deteriorates due to insufficient monitoring time

Engineering Contradiction:
Improvecommunication efficiencyVSAvoidchannel availability measurement precision
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent merges the monitoring capabilities of multiple wireless devices to achieve comprehensive channel assessment. Each device performs brief monitoring during its assigned time slot, and the individual measurements are combined to form an accurate overall assessment of channel availability, thereby maintaining measurement precision without requiring any single device to pause communication for extended periods.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The monitoring task is segmented into multiple short intervals performed by different devices. The aggregation of these segmented measurements compensates for the reduced individual monitoring duration, maintaining overall measurement precision while improving communication efficiency.

Inventive Principle:
Principle #1Segmentation

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

The distributed CAC approach reduces the overall time devices must cease communication, thereby increasing the utilization of the 5.600-5.650 GHz band by allowing communication to resume sooner and optimizing spectrum usage in wireless communication systems.

Implementation Method 1

monitoring an energy level of the sub-band for a period of time corresponding to the first portion of the distributed CAC

Methodology Applied
Scientific EffectEnergy level monitoring:

Data Source

PatentEP3449657B1Techniques for performing a distributed channel availability check in a shared radio frequency spectrum band
Publication Date: 2022.04.27 QUALCOMM INC
  • EP3449657B1 patent drawingFigure 1
  • EP3449657B1 patent drawingFigure 2
  • EP3449657B1 patent drawingFigure 3

AI summary

Techniques are described for wireless communication at a wireless communication device. One method includes determining an availability of a sub-band of a shared radio frequency spectrum band during a first portion of a distributed channel availability check (CAC); receiving at least one indication that the sub-band is available during remaining portions of the distributed CAC; and communicating over the sub-band based at least in part on determining the sub-band is available during the first portion of the distributed CAC and the at least one indication that the sub-band is available during remaining portions of the distributed CAC.