Antenna Beamforming for Spatial LBT in Unlicensed Spectrum

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Solution Overview

Problem

Existing wireless communication technologies, such as LTE and 5G NR, face challenges in deploying Advanced Antenna Systems (AAS) in unlicensed spectrum due to limitations in listen-before-talk (LBT) procedures, which do not account for recent advancements in radio technology, leading to inefficiencies in coverage, data rates, and spectrum utilization.

Innovation Solution

The method involves performing multiple listen-before-talk assessments for disjoint subsets of resources in a shared channel, determining available resource subsets based on size thresholds, and transmitting data only through those subsets, utilizing dynamic antenna beamforming to optimize LBT readiness and improve channel assessment accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If traditional LBT procedures are used in unlicensed spectrum, then coexistence with other devices is achieved, but spectrum utilization and throughput are limited

Engineering Contradiction:
Improvespectrum utilizationVSAvoidLBT success rate
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent segments the channel assessment process by performing LBT on multiple disjoint resource subsets (e.g., different frequency sub-bands or spatial beams) rather than treating the entire channel as a single unit. This allows the system to identify and utilize available resources more efficiently, improving spectrum utilization while maintaining coexistence through selective transmission on clear subsets.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the parameters of LBT assessment by evaluating multiple resource subsets with different characteristics (frequency, spatial direction, time) simultaneously. This enables dynamic adaptation to channel conditions, improving both throughput and LBT success rate by selecting the best available subsets for transmission.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If LBT assessments are performed on the entire channel, then coexistence is ensured, but LBT success rate and throughput decrease

Engineering Contradiction:
ImproveLBT success rateVSAvoidthroughput
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

By dividing the channel into multiple disjoint resource subsets and performing LBT assessments on each subset independently, the system increases the probability of finding available resources. This segmentation approach improves LBT success rate while maintaining fair coexistence, as each subset is assessed and transmitted on according to LBT rules, preventing any single device from monopolizing the entire channel.

Inventive Principle:
Principle #1Segmentation

3Productivity

If Advanced Antenna Systems are deployed in unlicensed spectrum, then coverage and data rates improve, but LBT procedure limitations reduce spectrum utilization

Engineering Contradiction:
Improvedata rateVSAvoidantenna system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent applies local quality by performing LBT assessments and transmissions on specific disjoint resource subsets (e.g., particular frequency sub-bands or spatial beams) rather than uniformly across the entire channel. This allows the AAS to exploit its directional capabilities and transmit at higher data rates on selected subsets while performing LBT only where needed, improving spectrum utilization without requiring complex modifications to the antenna system itself.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3949653B1Advanced antenna systems for spatial listen-before-talk
Publication Date: 2022.07.20 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3949653B1 patent drawingFigure 1A~1B
  • EP3949653B1 patent drawingFigure 2~3
  • EP3949653B1 patent drawingFigure 4

AI summary

Embodiments include methods, performed by a network node, for transmitting data on a shared channel in a wireless network. Such methods include performing a plurality of listen-before-talk (LBT) assessments for a corresponding plurality of substantially disjoint subsets of resources of a shared channel and, based on the plurality of LBT assessments, determining that at least one resource subset is available for transmission. Such methods also include transmitting signals or data to one or more user equipment (UE) using only resources selected from the at least one resource subset. For example, determining availability of resource subsets can be based on a threshold, for each resource subset, that is related to the size of the resource subset. Resource subsets can include adjacent spatial regions having substantially non-overlapping ranges of azimuths and elevations, and/or sub-bandwidths within a bandwidth of the shared channel. Other embodiments include network nodes configured to perform such methods.