LAA-LTE Multicast RTS Coordination for Unlicensed Spectrum

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Solution Overview

Problem

Communications systems using unlicensed spectrum, such as WiFi and LAA-LTE, face interference challenges due to multiple devices competing for the same band, leading to inefficiencies in channel reservation and potential data collisions.

Innovation Solution

Implementing a small cell design with integrated LAA-LTE access points and WiFi access points that utilize a single multicast RTS signal and coordinated transmission schedules to minimize channel reservation overhead and manage interference, allowing multiple small cells to transmit efficiently in the unlicensed spectrum by estimating quality metrics and coordinating transmission windows.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If multiple devices transmit in unlicensed spectrum independently, then device autonomy and simplicity are maintained, but interference increases and channel reservation overhead grows

Engineering Contradiction:

Improvedevice autonomyVSAvoidinterference

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

Multiple small cells merge their channel access coordination by having one small cell act as a representative that performs channel sensing and reservation on behalf of the group, reducing redundant reservations while maintaining autonomous operation of individual devices

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

A coordinating small cell acts as an intermediary that manages channel access for multiple small cells, reducing interference through centralized coordination without removing device autonomy

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If traditional channel reservation is used in unlicensed spectrum, then channel access is secured, but channel reservation overhead increases and spectral efficiency decreases

Engineering Contradiction:

Improvechannel access securityVSAvoidspectral efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

Multiple small cells combine their channel reservation requests into a single reservation signal, reducing overhead while maintaining reliable channel access for all participating small cells

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

A single channel reservation signal serves multiple small cells simultaneously, making the reservation mechanism more efficient by having one signal perform the function of multiple individual reservations

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Device complexity

If small cells transmit simultaneously without coordination, then transmission simplicity is maintained, but data collisions occur and reliability decreases

Engineering Contradiction:

Improvetransmission coordinationVSAvoiddata collision avoidance

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

Small cells perform preliminary channel sensing and coordination before transmission, allowing them to identify suitable transmission opportunities and avoid collisions without complex ongoing coordination during actual data transmission

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS11019654B2LAA-LTE communication in an unlicensed spectrum

Publication Date: 2021.05.25 AVAGO TECHNOLOGIES INTERNATIONAL SALES PTE LTD

AI summary

A method includes transmitting, at an access point configured to transmit data over an unlicensed band, a single message prior to transmitting data over a channel of the unlicensed band. The method further includes receiving, at the access point, a plurality of responses from a plurality of user equipment acknowledging the single message in response to the single message.