COT Sharing Request Signaling for Low-Power RedCap Channel Access

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Solution Overview

Problem

SL-U terminal devices, particularly RedCap terminals, face high power consumption due to the need to perform extensive type-1 LBT procedures for channel access in unlicensed spectrum, which is not optimized for reduced capability devices.

Innovation Solution

The terminal device transmits a first request message to request sharing of a channel occupancy time (COT) from other terminal devices, allowing it to perform a type-2 channel access mechanism instead of a type-1, thereby reducing the need for prolonged listening and conserving power.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a terminal device performs type-1 LBT procedure for channel access in unlicensed spectrum, then channel access is achieved, but power consumption increases significantly

Engineering Contradiction:

Improvechannel accessVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies preliminary action by having one terminal device (first terminal) perform the type-1 LBT procedure in advance to acquire channel occupancy time (COT), then share this pre-acquired channel access with another terminal device (second terminal). This allows the second terminal to perform a simplified type-2 LBT procedure instead of a full type-1 procedure, thereby reducing its power consumption while maintaining reliable channel access.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If a terminal device performs prolonged listening during type-1 LBT procedure, then channel access reliability is improved, but the duration of action increases

Engineering Contradiction:

Improvechannel accessVSAvoidlistening duration

Core Design Contradiction:

ReliabilityVSDuration of action of moving object

Solution Approach 1:

The first terminal device performs the lengthy type-1 LBT listening procedure in advance to acquire COT, then shares this pre-acquired channel access with the second terminal. This transfers the time-consuming listening burden to the first terminal, allowing the second terminal to access the channel quickly through type-2 LBT with minimal listening duration.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If RedCap terminals perform extensive type-1 LBT procedures, then unlicensed spectrum channel access is achieved, but energy efficiency deteriorates

Engineering Contradiction:

Improvechannel accessVSAvoidenergy efficiency

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent enables energy efficiency for RedCap terminals by having a first terminal (which could be a non-RedCap device with more power resources) perform the energy-intensive type-1 LBT procedure in advance, then share the acquired COT with a second RedCap terminal. This allows the RedCap terminal to use the pre-acquired channel access and perform only the low-energy type-2 LBT procedure, significantly improving its energy efficiency while maintaining reliable channel access to unlicensed spectrum.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS20260025844A1Method for transmitting request messages, terminal device, and chip

Publication Date: 2026.01.22 GUANGDONG OPPO MOBILE TELECOMMUNICATIONS CORP LTD

AI summary

Provided is a method for transmitting a request message. The method is performed by a terminal device. The method includes: transmitting a first request message, wherein the first request message is used to request sharing of a channel occupancy time (COT) of at least one other terminal device.