Wi‑Fi Preemption Signaling for Low-Latency Triggered Transmission

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Solution Overview

Problem

Existing communication technologies face challenges in transmitting data requiring low latency outside scheduled periods, necessitating a mechanism beyond Restricted Target Wake Time (R-TWT) to ensure timely data transmission.

Innovation Solution

A communication device is equipped with a first transmission control mechanism that transmits a frame containing acknowledgment information and preemption indications for low-latency data, allowing priority transmission during scheduled opportunities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If data is transmitted during scheduled periods using R-TWT, then communication efficiency is improved, but low-latency data occurring outside scheduled periods cannot be transmitted timely

Engineering Contradiction:
Improvecommunication efficiencyVSAvoidlatency of low-latency data
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent implements dynamic transmission opportunity allocation by allowing stations to request additional TXOPs when low-latency data arrives outside scheduled periods. The access point dynamically grants or denies these requests based on current channel conditions and queue status, enabling the system to adapt between scheduled efficiency and unscheduled responsiveness.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the transmission parameter by introducing a preemption indication field in the frame structure. This field allows the access point to signal stations about preempting scheduled transmissions for low-latency data, effectively changing the transmission timing parameters dynamically based on data urgency.

Inventive Principle:
Principle #35Parameter changes

2Loss of time

If priority transmission is implemented for low-latency data, then latency is reduced, but transmission queue management becomes more complex

Engineering Contradiction:
ImprovelatencyVSAvoidqueue management complexity
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The patent segments the transmission queue into multiple priority levels, with high-priority low-latency data separated from regular data. This segmentation allows independent management of different data types, simplifying the complexity by creating distinct handling paths for different priority levels rather than managing a single mixed queue.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The access point acts as an intermediary that manages the preemption process. It receives preemption requests from stations, checks queue conditions, and sends preemption indication frames to coordinate the interruption of scheduled transmissions. This intermediary role centralizes the complex decision-making logic, reducing the burden on individual stations.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Stability of the object's composition

If scheduled transmission periods are used, then communication organization is improved, but flexibility to handle unexpected low-latency data is reduced

Engineering Contradiction:
Improvecommunication organizationVSAvoidflexibility for unexpected data
Core Design Contradiction:
Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The patent makes the transmission schedule dynamic by allowing stations to request additional transmission opportunities when low-latency data arrives. The access point dynamically adjusts the schedule by granting or denying these requests, maintaining organizational structure while introducing necessary flexibility for unexpected data.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent creates a universal mechanism that handles both scheduled and unscheduled transmissions through the same preemption indication framework. This multi-functional approach allows the system to organize communications systematically while simultaneously accommodating unexpected low-latency data requirements through a unified control mechanism.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP4697842A1Communication device, control method, and program
Publication Date: 2026.02.18 CANON KK
  • EP4697842A1 patent drawingFigure 1
  • EP4697842A1 patent drawingFigure 2
  • EP4697842A1 patent drawingFigure 3

AI summary

A communication device capable of wireless communication based on the IEEE 802.11 standards transmits a frame containing information pertaining to preemption involving low-latency data to an access point to which the communication device is connected. Also, the communication device transmits data to the outside in accordance with the reception of a trigger frame issued after the frame is transmitted to the access point.