NR-U Cell Reselection Using Occupied Frequency Skipping

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Solution Overview

Problem

In New Radio-Unlicensed Standalone (NR-U SA) communication systems, UE devices waste power by attempting to measure occupied unlicensed frequencies, which are not transmitting reference signals due to listen-before-talk procedures, leading to inefficient cell reselection and potential network congestion.

Innovation Solution

The base station informs UE devices to skip measurements on occupied frequencies or temporarily avoid measuring higher priority frequencies, allowing them to conserve power and reduce network congestion by prioritizing unlicensed frequency usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If UE devices perform measurements on all unlicensed frequencies during cell reselection, then they can find available cells, but they waste power by attempting to measure occupied frequencies that are not transmitting reference signals

Engineering Contradiction:

Improvepower consumptionVSAvoidcell reselection accuracy

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The base station performs preliminary actions by monitoring unlicensed frequencies and identifying occupied frequencies before the UE device needs to measure them. The base station maintains an occupancy status for each frequency and proactively informs the UE device which frequencies are occupied, allowing the UE to skip measurements in advance and conserve power while maintaining reliable cell reselection.

Inventive Principle:

Principle #10Preliminary action

2Productivity

If UE devices continuously search for higher priority frequencies, then they can optimize network load distribution, but they increase power consumption and may cause network congestion through excessive signaling

Engineering Contradiction:

Improvenetwork load distribution efficiencyVSAvoidpower consumption

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The base station provides feedback to the UE device about the occupancy status of unlicensed frequencies through system information blocks. This feedback mechanism allows the UE device to make informed decisions about cell reselection without continuously searching, optimizing network load distribution while reducing power consumption by avoiding unnecessary measurements and signaling on occupied frequencies.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS11800417B2Cell reselection in communication systems using unlicensed frequency bands

Publication Date: 2023.10.24 KYOCERA CORP

AI summary

Cell selection in a New Radio-Unlicensed Standalone (NR-U SA) communication system is managed by allowing UE devices to avoid measurements of frequencies that are occupied. A base station (gNB) may indicate to the UE device frequencies that can be skipped or may allow the UE device to skip frequencies for a temporary period after the frequencies have been determined to be occupied.