Trigger Signaling for Uplink Transmission in NR-Unlicensed Spectrum

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Solution Overview

Problem

In NR-Unlicensed spectrum systems, especially in Stand Alone scenarios, the limitations of Max Channel Occupy Time (MCOT) and Listen Before Talk (LBT) make it difficult to accurately predict the transmission time of uplink data based on scheduling and uplink control information, due to varying channel occupation and interference conditions with beamforming.

Innovation Solution

A method involving a trigger signaling to trigger uplink data and control information transmissions, establishing a correlation between the trigger signaling and scheduling signaling, allowing the base station to flexibly determine transmission times and select optimal antenna ports based on specific conditions like LBT results and beamforming directions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If Listen Before Talk (LBT) and Max Channel Occupy Time (MCOT) limitations are enforced on unlicensed spectrum, then channel access reliability is improved, but transmission time prediction accuracy deteriorates

Engineering Contradiction:

Improvechannel access reliabilityVSAvoidtransmission time prediction accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The base station performs LBT and determines channel access timing in advance before sending the trigger signaling. The trigger signaling carries pre-determined timing information that tells the UE when to transmit uplink data, allowing the UE to prepare transmission resources beforehand while the base station has already resolved channel access uncertainty through preliminary LBT action.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

A trigger signaling mechanism is introduced as an intermediary between the base station's scheduling decision and the UE's uplink transmission. This trigger signaling carries timing information that mediates the uncertainty caused by LBT/MCOT limitations, allowing the base station to flexibly determine transmission timing based on channel conditions while providing the UE with clear transmission timing instructions.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If beamforming based on large-scale antenna array is used, then transmission reliability is improved, but channel occupation and interference conditions become more variable across different beam directions

Engineering Contradiction:

Improvetransmission reliabilityVSAvoidchannel occupation condition variability

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The trigger signaling mechanism allows the base station to assess channel conditions and LBT results for each specific beam direction locally, and send targeted trigger signaling to UEs in different beams with timing information appropriate to each local condition. This enables differentiated transmission timing control for different beam directions based on their specific channel occupation and interference characteristics.

Inventive Principle:

Principle #3Local quality

3Adaptability or versatility

If trigger signaling is introduced to flexibly determine transmission time, then adaptability to channel conditions is improved, but signaling overhead increases

Engineering Contradiction:

Improveadaptability to channel conditionsVSAvoidsignaling overhead

Core Design Contradiction:

Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The trigger signaling serves multiple functions simultaneously: it acts as a scheduling command to activate uplink transmission, carries timing information to indicate when transmission should occur, and provides beam indication information. By consolidating these multiple control functions into a single signaling mechanism, the overhead is reduced compared to using separate signaling for each function.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS11792787B2Method and device for wireless communication in UE and base station

Publication Date: 2023.10.17 HONOR DEVICE CO LTD

AI summary

The present disclosure provides a method and a device in a User Equipment (UE) and a base station used for wireless communication. The UE receives a first signaling in a first time window in a first subband; monitors a second signaling in a second time window in a second subband; if successfully receives the second signaling in the second time window in the second subband, transmits a first radio signal in a third time window in a third subband, otherwise drops transmission of the first radio signal in the third time window in the third subband. Herein, the first signaling comprises first-type scheduling information of the first radio signal. The above method allows the base station to flexibly control a transmission time of each uplink transmission on unlicensed spectrum according to specific conditions, such as the result of LBT or the direction of beamforming.