TXOP Preemption Windows for Low-Latency Priority Traffic

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Solution Overview

Problem

Wireless technologies face challenges in reducing latency for stations (STAs) with high-priority traffic due to exclusive channel access by a transmission opportunity (TXOP) holder, leading to delays in transmitting event-triggered data.

Innovation Solution

Implementing preemption opportunities (PO) with sub-windows, frequency bands, and inter-frame spacing (IFS) to allow prioritized traffic transmission, enabling stations to transmit event-triggered notifications using orthogonal frequency-division multiple access (OFDMA) or single-user (SU) non-OFDMA.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a station holds a transmission opportunity (TXOP) with exclusive channel access, then channel access reliability is improved, but latency for high-priority traffic from other stations increases

Engineering Contradiction:

Improvechannel access reliabilityVSAvoidlatency for high-priority traffic

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The TXOP is segmented into multiple sub-windows, each dedicated to specific access categories. This allows high-priority traffic to be transmitted in dedicated sub-windows without being blocked by lower-priority traffic, reducing latency while maintaining reliable channel access through structured opportunities.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system dynamically adjusts TXOP parameters including the number of sub-windows, sub-window durations, and inter-frame spacings based on traffic conditions and priority requirements. This dynamic configuration enables the system to optimize between reliability and latency depending on current network conditions.

Inventive Principle:

Principle #15Dynamics

2Stability of the object's composition

If transmission opportunity (TXOP) exclusivity is maintained, then channel access stability is improved, but data exchange efficiency for event-triggered traffic deteriorates

Engineering Contradiction:

Improvechannel access stabilityVSAvoiddata exchange efficiency

Core Design Contradiction:

Stability of the object's compositionVSProductivity

Solution Approach 1:

The channel access mechanism is segmented into multiple TXOP types (contention-based, opportunity-based, preemption-based) with different stability characteristics. Event-triggered traffic can utilize preemption-based TXOPs that offer lower stability but higher efficiency, while time-sensitive traffic uses opportunity-based TXOPs for balanced performance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system changes key parameters including TXOP duration, inter-frame spacing, and preemption thresholds based on traffic type and network conditions. This allows optimization of data exchange efficiency for event-triggered traffic while maintaining adequate channel access stability through parameter adjustment rather than structural changes.

Inventive Principle:

Principle #35Parameter changes

3Loss of time

If preemption opportunities with multiple sub-windows are implemented, then latency for prioritized traffic is reduced, but system complexity increases

Engineering Contradiction:

Improvelatency for prioritized trafficVSAvoidsystem complexity

Core Design Contradiction:

Loss of timeVSDevice complexity

Solution Approach 1:

The TXOP is divided into a limited number of sub-windows (e.g., 2-4 sub-windows per TXOP) with each sub-window dedicated to specific access categories. This segmentation reduces latency for prioritized traffic by providing dedicated transmission opportunities, while keeping the number of sub-windows limited to avoid excessive system complexity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system implements partial preemption where only certain sub-windows are dedicated to high-priority traffic rather than preempting the entire TXOP. This partial action approach reduces latency for prioritized traffic in critical sub-windows while maintaining simpler operation in other sub-windows, balancing latency reduction with system complexity.

Inventive Principle:

Principle #16Partial or excessive action

4Adaptability or versatility

If inter-frame spacing is configured between sub-windows, then transmission flexibility is improved, but channel utilization efficiency decreases

Engineering Contradiction:

Improvetransmission flexibilityVSAvoidchannel utilization efficiency

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

The inter-frame spacing between sub-windows is dynamically configured based on traffic conditions and priority requirements. When high-priority traffic is detected, larger inter-frame spacings are used to provide flexibility for preemption. When traffic is steady and predictable, smaller inter-frame spacings are used to maximize channel utilization efficiency.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes inter-frame spacing parameters adaptively based on network conditions, traffic type, and priority levels. This parameter change approach provides transmission flexibility when needed while maintaining high channel utilization efficiency during normal operation, resolving the contradiction between flexibility and efficiency.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS20260082422A1Mechanisms for transmission opportunity preemption

Publication Date: 2026.03.19 NOKIA TECHNOLOGIES OY

AI summary

Apparatuses and methods are disclosed for defining a preemption opportunity (PO) with one or more sub-windows, configuring the PO with one or more bands, defining one or more intersections of the one or more sub-windows and the one or more bands, and/or configuring the PO with inter-frame spacing (IFS) between the one or more sub-windows.