Multiplexing Multi-RAT Transmissions in Unlicensed Spectrum

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Solution Overview

Problem

Current wireless technologies face inefficiencies when using multiple radio access technologies (RATs) in unlicensed spectra due to the need for channel sensing and maximum channel occupancy time (MCOT), leading to symbol jitter and increased wait times, especially when switching between RATs.

Innovation Solution

Implementing time multiplexing of symbol transmissions across different RATs during a single MCOT interval to avoid interference and reduce wait times, adhering to the Listen-Before-Talk (LBT) protocol to ensure efficient use of unlicensed spectrum.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple RATs perform channel sensing and transmit in unlicensed spectrum according to LBT protocol, then spectrum utilization is improved, but wait times and symbol jitter increase due to MCOT constraints

Engineering Contradiction:

Improvespectrum utilizationVSAvoidwait times

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The patent combines multiple RAT transmissions (e.g., LTE and NR) into a single MCOT interval by performing joint channel sensing and coordinating transmissions. This merging approach allows both RATs to utilize the unlicensed spectrum simultaneously within the same channel occupancy period, improving spectrum utilization while reducing wait times compared to sequential transmissions.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent performs preliminary channel sensing and MCOT acquisition for multiple RATs together before transmissions begin. By securing the channel for the entire duration needed by any RAT in advance, the system eliminates intermediate wait times and symbol jitter that would occur if RATs sensed and acquired channels separately.

Inventive Principle:

Principle #10Preliminary action

2Productivity

If multiple RATs transmit simultaneously in unlicensed spectrum, then network capacity is improved, but interference and channel occupancy conflicts increase

Engineering Contradiction:

Improvenetwork capacityVSAvoidchannel occupancy conflicts

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies different transmission parameters and resource allocations to different RATs within the same MCOT interval. Each RAT is assigned specific time resources, frequency resources, or power levels that are optimized for its requirements, allowing simultaneous transmissions while managing interference through localized parameter differentiation.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent introduces a coordinating mechanism that acts as an intermediary between multiple RATs, managing channel access and transmission timing. This coordinator allocates resources and schedules transmissions to minimize conflicts while maximizing overall network capacity within the MCOT constraints.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS10638512B2Multiplexing multi-radio access technology transmissions

Publication Date: 2020.04.28 VERIZON PATENT & LICENSING INC

AI summary

A device may monitor a frequency band over a time interval; determine that the frequency band is not occupied by transmissions to or from another device based on information obtained from monitoring the frequency band over the time interval; schedule transmissions of a first set of orthogonal frequency division multiple access (OFDM) symbols within a particular time interval over the frequency band, wherein the first set of OFDM symbols is associated with a first radio access technology; and schedule transmissions of a second set of OFDM symbols within the particular time interval over the frequency band, wherein the second set of OFDM symbols is associated with a second radio access technology.