Inter-AP RTWT Alignment for Low-Latency WLAN TXOP Continuity

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Solution Overview

Problem

In multi-AP coordination scenarios, communication quality is affected due to the need for a station to terminate transmission opportunities (TXOP) before multiple restricted target wake times (RTWT) of neighboring access points, leading to fragmented time resources and impaired low-latency services.

Innovation Solution

A communication method where a first access point sends a radio frame to a second access point to request modifications to RTWT parameters, such as start times and intervals, to align and optimize RTWT agreements among neighboring access points, reducing TXOP interruptions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a STA terminates TXOP before multiple RTWT SPs of neighboring APs, then low-latency service communication can be ensured, but communication quality deteriorates due to frequent TXOP interruptions

Engineering Contradiction:
Improvelow-latency service communicationVSAvoidcommunication quality
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent merges the RTWT parameters of multiple neighboring APs and performs unified coordination. The first AP collects RTWT parameters from multiple neighboring APs, determines a coordinated RTWT parameter set that aligns service periods across all APs, and sends coordination results to neighboring APs. This consolidation transforms multiple independent RTWT schedules into a unified coordinated schedule, reducing the number of TXOP interruptions while ensuring low-latency service communication.

Inventive Principle:
Principle #5Merging (Combining)

2Productivity

If RTWT parameters of multiple neighboring APs are coordinated, then TXOP interruptions are reduced, but system complexity increases due to inter-AP communication and parameter alignment

Engineering Contradiction:
ImproveTXOP interruption reductionVSAvoidsystem complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The first AP acts as an intermediary that collects RTWT parameters from neighboring APs, performs coordination calculations, and distributes coordinated parameters back to them. This intermediary approach centralizes the complex coordination logic in one AP, avoiding the need for all APs to communicate with each other directly. The intermediary AP simplifies the multi-AP coordination problem into point-to-point communications, reducing overall system complexity while achieving TXOP interruption reduction.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Stability of the object's composition

If RTWT service periods are aligned across neighboring APs, then time resource fragmentation is reduced, but flexibility in individual AP scheduling is limited

Engineering Contradiction:
Improvetime resource alignmentVSAvoidscheduling flexibility
Core Design Contradiction:
Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic RTWT parameter coordination where the first AP collects current RTWT parameters from neighboring APs, determines optimized coordinated parameters based on current network conditions, and updates the coordination results. This dynamic approach allows the system to adapt to changing network conditions while maintaining alignment. The coordinated parameters are not fixed but can be adjusted periodically, preserving scheduling flexibility while achieving time resource alignment.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4697815A1Communication method and communication apparatus
Publication Date: 2026.02.18 HUAWEI TECH CO LTD
  • EP4697815A1 patent drawingFigure 1
  • EP4697815A1 patent drawingFigure 2
  • EP4697815A1 patent drawingFigure 3~5

AI summary

This application relates to the communication field, and in particular, to a communication method and a communication apparatus. The solutions may be applied to a WLAN system that supports a next-generation Wi-Fi protocol of IEEE 802.11ax, for example, 802.11be, Wi-Fi 7, or EHT, and for another example, 802.11 series protocols such as a next-generation protocol of 802.11be, and Wi-Fi 8. According to this application, a first AP may send a first radio frame to a second AP, to request the second AP to modify an RTWT parameter of at least one RTWT agreement. This facilitates enhanced transmission in a multi-AP coordination scenario and improves communication quality.