Subframe Aligned Listen-Before-Talk for Cellular Unlicensed Bands

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Solution Overview

Problem

Cellular wireless technologies face challenges when operating in unlicensed frequency spectrums, as they are designed for exclusive access and do not account for other devices using different protocols, leading to potential interference and inefficient use of shared channels.

Innovation Solution

Implementing a Listen-Before-Talk (LBT) access scheme with optimized channel sensing and scheduling, allowing cellular wireless devices to assess channel availability and adjust transmission times to minimize interference and optimize resource use in unlicensed bands.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If cellular wireless technologies operate in unlicensed frequency spectrums using traditional licensed protocols, then they can provide cellular service coverage, but they cause interference with other devices using different protocols and fail to efficiently share the spectrum

Engineering Contradiction:

Improveability to operate in unlicensed bandsVSAvoidinterference with other devices

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the operational parameters of cellular devices by implementing LBT mechanisms that dynamically adjust transmission timing and power based on channel sensing results, enabling coexistence with other unlicensed band devices while maintaining cellular service functionality

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces an intermediary LBT protocol layer between the cellular protocol stack and the physical transmission medium, which mediates access to the unlicensed spectrum by sensing channel availability and deferring transmissions when other devices are present

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If cellular devices transmit continuously in unlicensed channels, then they maximize data transmission throughput, but they prevent other devices from utilizing the channel and waste spectrum resources

Engineering Contradiction:

Improvedata transmission throughputVSAvoidwasted spectrum resources

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The patent implements periodic channel sensing and backoff procedures where cellular devices intermittently check for other transmissions before accessing the channel, allowing other devices to utilize the spectrum during periods when cellular devices are not transmitting

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent enables cellular devices to self-regulate their transmission behavior by autonomously sensing channel conditions and adjusting their transmission timing without external control, thereby automatically preventing resource waste while maximizing throughput when the channel is available

Inventive Principle:

Principle #25Self-service

3Object-affected harmful factors

If cellular devices implement LBT access scheme with channel sensing, then they reduce interference with other devices, but they increase device complexity and transmission delay

Engineering Contradiction:

Improveinterference with other devicesVSAvoidcomplexity of LBT implementation

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent segments the LBT implementation into distinct functional layers (sensing layer, decision layer, and transmission layer), where the sensing layer handles channel detection, the decision layer determines transmission timing, and the transmission layer executes the actual data transmission, thereby managing complexity through modular design

Inventive Principle:

Principle #1Segmentation

4Adaptability or versatility

If cellular devices perform backoff procedure to wait for channel availability, then they ensure fair spectrum sharing, but they increase transmission delay and reduce productivity

Engineering Contradiction:

Improvespectrum sharing capabilityVSAvoidtransmission delay

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent implements dynamic backoff mechanisms where the waiting duration is adaptively adjusted based on channel conditions, traffic priority, and historical sensing results, allowing high-priority traffic to experience minimal delay while still ensuring fair spectrum sharing for lower-priority transmissions

Inventive Principle:

Principle #15Dynamics

Data Source

PatentEP3869902A1Subframe aligned listen-before-talk for cellular in unlicensed band

Publication Date: 2021.08.25 INTEL CORP

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AI summary

Disclosed in some examples are systems, machine-readable media, methods, and cellular wireless devices which implement a Listen-Before-Talk (LBT) access scheme for a device operating according to a cellular wireless protocol in an unlicensed channel. A cellular wireless device may utilize the cellular wireless protocol in the unlicensed channel after the LBT access scheme has determined that a channel (a defined range of frequencies) in the unlicensed channel is idle for a particular period of time.