NR-U Multi-Channel Access for Low-RF User Equipment

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Solution Overview

Problem

In wireless communication networks, especially in 5G NR-U systems, the existing listen-before-talk (LBT) mechanisms face challenges in efficiently managing multi-channel access for low-RF-capable user equipment (UEs), leading to communication inefficiencies and unfairness in spectrum access, particularly when multiple network operators compete for shared resources.

Innovation Solution

Implementing a multi-channel access strategy where base stations detect the presence of other operators and configure primary and secondary channels, allowing low-RF UEs to monitor the primary channel for LBT indicators and re-tune to the secondary channel for communication, thereby maintaining access and reducing interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If low-RF-capable UEs use existing LBT mechanisms for channel access, then they can access the spectrum, but communication efficiency and fairness deteriorate in multi-operator competitive environments

Engineering Contradiction:
Improvespectrum access fairnessVSAvoidcommunication efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent segments the channel access process into two distinct phases: a first phase where the base station performs LBT on a primary channel to acquire initial access rights, and a second phase where the base station performs LBT on a secondary channel to acquire additional access rights. This segmentation allows low-RF-capable UEs to benefit from the base station's sophisticated multi-channel LBT capabilities without requiring them to perform complex medium sensing procedures, thereby improving both communication efficiency and access fairness.

Inventive Principle:
Principle #1Segmentation

2Reliability

If base stations perform multi-channel LBT procedures, then access rights are acquired, but the complexity of channel access management increases

Engineering Contradiction:
Improvechannel access rightsVSAvoidchannel access management
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The base station acts as an intermediary that performs the complex multi-channel LBT procedures on behalf of low-RF-capable UEs. The base station executes LBT on both the primary and secondary channels, acquires the necessary access rights, and then facilitates communication with the UE. This intermediary approach transfers the complexity of channel access management from the UE to the base station, which has the necessary resources and capabilities to handle multi-channel LBT procedures effectively.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If low-RF-capable UEs monitor primary channel for LBT indicators, then access opportunities are identified, but communication delays increase due to re-tuning requirements

Engineering Contradiction:
Improveaccess opportunity identificationVSAvoidcommunication delay
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The base station performs preliminary LBT actions on the primary channel before initiating communication with low-RF-capable UEs. By completing the primary channel LBT procedure in advance and acquiring access rights beforehand, the base station can then quickly proceed to the secondary channel LBT and establish communication, minimizing delays. The UE simply needs to monitor for LBT indicators and re-tune, rather than waiting for the complete LBT process to conclude before access is granted.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3858072B1New radio-unlicensed multi-channel access for low-radio frequency-capable user equipment
Publication Date: 2025.03.26 QUALCOMM INC
  • EP3858072B1 patent drawingFigure 1
  • EP3858072B1 patent drawingFigure 2
  • EP3858072B1 patent drawingFigure 3

AI summary

New radio (NR) unlicensed (NR-U) multi-channel access is disclosed for low-radio frequency (RF)-capable user equipment (UE). A base station may enable multi-channel access when single operator operations cannot be guaranteed within a shared communication spectrum. The primary and secondary channels are defined within the shared communication channel. The base station may then transmit a configuration message to one or more low- RF UEs that identifies the channels and directs the UEs to monitor the primary channel for a successful listen before talk (LBT) indicator. The base station performs an LBT procedure on the primary channel and the secondary channel and signals the low-RF UEs to re-tune to the secondary channel for communication during a current transmission opportunity.