UE-Initiated Channel Access for Low-Latency NR-U Uplink

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Solution Overview

Problem

Existing wireless communication systems, particularly in NR-U and URLLC, face inefficiencies with gNB-initiated COT, leading to increased latency and reduced flexibility in uplink transmissions due to dependencies on gNB detection and unnecessary DL signaling, especially in unlicensed bands.

Innovation Solution

Implementing a UE-initiated COT mechanism that allows user equipment to independently initiate channel occupancy time based on configured FFP parameters, enabling flexible uplink transmissions without relying on gNB detection, and harmonizing features between NR-U and URLLC for improved reliability and reduced latency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If gNB-initiated COT is used for uplink transmission, then the base station can control channel access, but the uplink transmission latency increases due to dependency on gNB detection and DL signaling

Engineering Contradiction:

Improvechannel access controlVSAvoiduplink transmission latency

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent inverts the traditional gNB-initiated COT mechanism by enabling UE-initiated COT. Instead of the base station detecting and initiating channel occupancy, the UE autonomously performs LBT and initiates COT when the channel is idle, thereby eliminating the latency caused by gNB detection and DL signaling while maintaining reliable channel access through configured FFP parameters and validation mechanisms.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent applies preliminary action by pre-configuring FFP parameters (frame period, offset, duration) for UE-initiated COT through RRC signaling. The UE prepares and validates these parameters in advance, allowing it to autonomously initiate COT without waiting for gNB detection, thus reducing uplink transmission latency while ensuring controlled channel access.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If gNB-initiated COT is used, then the base station can manage channel occupancy, but the flexibility of uplink scheduling is reduced

Engineering Contradiction:

Improvechannel occupancy managementVSAvoiduplink scheduling flexibility

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent introduces dynamics by allowing the UE to flexibly initiate COT based on configured FFP parameters and channel conditions. The UE can autonomously determine when to initiate COT within the configured parameters, providing dynamic uplink scheduling flexibility while maintaining reliable channel occupancy management through pre-configured FFP parameters and gNB validation mechanisms.

Inventive Principle:

Principle #15Dynamics

3Reliability

If gNB retains acquired COT for downlink transmission, then the base station ensures channel control, but power consumption increases due to unnecessary DL signaling

Engineering Contradiction:

Improvechannel controlVSAvoidbase station power consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent extracts the channel access initiation function from the gNB and transfers it to the UE. The gNB no longer needs to retain acquired COT for downlink transmission or send unnecessary DL signaling to trigger UL transmission. Instead, the UE autonomously initiates COT when needed, reducing base station power consumption while maintaining reliable channel control through configured FFP parameters and validation mechanisms.

Inventive Principle:

Principle #2Taking out (Extraction)

4Reliability

If UE waits for gNB DL transmission to confirm COT acquisition, then channel access is controlled, but additional latency is introduced

Engineering Contradiction:

Improvechannel access confirmationVSAvoidprocessing latency

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent applies self-service by enabling the UE to autonomously perform LBT and initiate COT without waiting for gNB DL transmission. The UE validates the configured FFP parameters and independently determines when to initiate COT, eliminating the processing latency caused by waiting for gNB confirmation while maintaining reliable channel access through pre-configured parameters and validation mechanisms.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS12471138B2Channel access method, user equipment, and base station

Publication Date: 2025.11.11 ESSEN INNOVATION CO LTD

AI summary

A user equipment (UE) executes a semi-static channel access method during a random access procedure in an unlicensed band. A base station transmits configuration information and downlink (DL) information to the UE in a fixed frame period (FFP) according to a set of FFP parameters associated with the base station. The UE determines whether to initiate a channel occupancy time (COT) in an FFP according to a set of FFP parameters associated with the UE based on one or more of: at least one condition in the configuration information, at least one condition in scheduling information, at least one condition in DL information, and a detection result of detecting transmission of the DL information. The base station determines whether to use the UE-initiated COT shared from the UE.