Wi-Fi R-TWT TXOP Timing for Lower Service Latency

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Solution Overview

Problem

The R-TWT technology in IEEE 802.11be requires non-AP EHT STAs to end transmission opportunities (TXOPs) before the start of active R-TWT service periods, leading to increased latency and reduced system efficiency.

Innovation Solution

The method allows stations to set the end time of TXOPs later than the start time of subsequent R-TWT service periods under certain conditions, ensuring continuous data transmission and reducing latency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If non-AP EHT STAs end TXOP before the start of active R-TWT SP, then R-TWT latency assurance is improved, but service latency increases and system efficiency deteriorates

Engineering Contradiction:
ImproveR-TWT latency assuranceVSAvoidservice latency
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies dynamics by making the TXOP end time adjustable based on real-time conditions. Instead of a fixed requirement to end TXOP before R-TWT SP start, the system dynamically determines the end time based on whether the remaining TXOP time is sufficient for subsequent transmissions. This dynamic adjustment resolves the contradiction by maintaining latency assurance when needed while avoiding unnecessary interruptions that increase service latency.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of TXOP end time from a fixed constraint to a flexible parameter. By modifying the end time based on the remaining TXOP duration and transmission needs, the system can adapt to different scenarios. This parameter change allows the system to maintain R-TWT latency assurance while avoiding the penalty of premature TXOP termination, thereby reducing service latency and improving system efficiency.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If non-AP EHT STAs end TXOP before the start of active R-TWT SP, then R-TWT latency assurance is improved, but system efficiency deteriorates

Engineering Contradiction:
ImproveR-TWT latency assuranceVSAvoidsystem efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system dynamically adjusts TXOP end time based on actual transmission conditions rather than following a rigid rule. This dynamic approach allows the system to maximize utilization of TXOP time while ensuring R-TWT latency assurance is maintained, thereby improving system efficiency without sacrificing reliability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

By changing the TXOP end time parameter from a fixed constraint to a flexible value determined by remaining TXOP duration and transmission needs, the system optimizes resource utilization. This parameter change enables the system to maintain latency assurance while avoiding inefficient premature terminations, thus improving overall system efficiency.

Inventive Principle:
Principle #35Parameter changes

3Loss of time

If TXOP end time is extended beyond R-TWT SP start, then service latency is reduced, but R-TWT latency assurance may be compromised

Engineering Contradiction:
Improveservice latencyVSAvoidR-TWT latency assurance
Core Design Contradiction:
Loss of timeVSReliability

Solution Approach 1:

The system dynamically determines whether to extend TXOP beyond R-TWT SP start based on real-time conditions, specifically whether the remaining TXOP time is sufficient for subsequent transmissions. This dynamic decision-making allows the system to extend TXOP when safe (reducing service latency) while maintaining R-TWT latency assurance when necessary.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system uses feedback from the remaining TXOP time calculation to make informed decisions about extending TXOP. By continuously monitoring whether the remaining time is sufficient for subsequent transmissions, the system can safely extend TXOP to reduce service latency without compromising R-TWT latency assurance, thus resolving the contradiction between these two requirements.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4716355A1Communication method and apparatus
Publication Date: 2026.03.25 HUAWEI TECH CO LTD
  • EP4716355A1 patent drawingFigure 1~2
  • EP4716355A1 patent drawingFigure 3
  • EP4716355A1 patent drawingFigure 4

AI summary

A communication method and apparatus are applied to a wireless local area network system supporting 802.11 series protocols such as a next-generation Wi-Fi protocol of IEEE 802.11ax like 802.11be, Wi-Fi 7, or EHT, and Wi-Fi 8. The method includes: When a first condition is met, a first station sets an end time of a first TXOP to be later than a start time of a second SP of a second R-TWT. The first condition includes: The first station is a member of a first R-TWT, the first TXOP is located in a first SP of the first R-TWT, the start time of the second SP is located in the first SP, and a remaining portion of the first TXOP located after the start time of the second SP is used to transmit an uplink frame of an R-TWT uplink traffic identifier of the first R-TWT. The first station does not need to end the first TXOP in advance. Therefore, impact on a transmitted service is avoided, a service latency is reduced, and system efficiency is improved.