Non-STR Multi-Link Channel Access with Synchronization Delay

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Multi-link devices with non-simultaneous transmitting and receiving capability (non-STR MLDs) experience channel interference and blind states due to signal transmission on one frequency band affecting reception on another, leading to inefficient channel access.

Innovation Solution

Implementing a medium synchronization delay mechanism with conservative channel access methods, including lower energy detection thresholds and restricted channel access on affected links, to mitigate interference and improve channel access efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a non-STR MLD performs transmission on one link, then transmission rate is improved, but channel access on another link is affected due to interference

Engineering Contradiction:
Improvetransmission rateVSAvoidchannel access
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The device performs preliminary channel assessment and identifies potential interference conditions before transmission begins. By detecting the frequency spacing between links and assessing channel conditions in advance, the device can proactively adjust its transmission strategy to prevent interference-related failures, thereby maintaining both high transmission rates and reliable channel access.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The channel access mechanism dynamically adapts based on real-time channel conditions and interference assessments. The device adjusts transmission parameters, selects appropriate access methods, and modifies operating strategies according to the detected frequency spacing and channel state, enabling flexible optimization of both transmission rate and channel access reliability under varying conditions.

Inventive Principle:
Principle #15Dynamics

2Device complexity

If frequency spacing between links is small, then device complexity is reduced, but signal transmission on one link causes channel interference to another link

Engineering Contradiction:
Improvefrequency spacing configurationVSAvoidchannel interference
Core Design Contradiction:
Device complexityVSObject-generated harmful factors

Solution Approach 1:

The device converts the potentially harmful effect of frequency proximity into a beneficial assessment mechanism. By using the small frequency spacing as a criterion for identifying links that require coordinated channel access, the system transforms what would be a source of interference into a trigger for protective channel assessment and coordinated transmission strategies, ultimately improving overall system reliability.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The channel assessment mechanism acts as an intermediary between transmission operations on different links. It evaluates the frequency spacing and channel conditions, then mediates the transmission decisions to prevent interference, allowing the system to maintain simple frequency configurations while avoiding harmful interference effects through intelligent coordination.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If the non-STR MLD is in a blind state on some links, then channel access opportunities are reduced, but allowing simultaneous transmission and reception would cause mutual interference

Engineering Contradiction:
Improvechannel access efficiencyVSAvoidmutual interference
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The device performs preliminary assessment of channel conditions and interference potential before entering transmission states. By evaluating the STR capability and assessing channel conditions in advance, the device can proactively determine whether to allow simultaneous transmission and reception or to implement protective blind states, thereby minimizing unnecessary productivity loss while preventing harmful mutual interference when it would occur.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The channel access mechanism dynamically adjusts the blind state duration and simultaneous transmission/reception permissions based on real-time channel conditions and device capabilities. The system transitions between restrictive and permissive states according to detected interference levels and STR capability, optimizing channel access efficiency while preventing mutual interference under varying operational conditions.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4195857B1Channel access method for multi-link device, and related apparatus
Publication Date: 2025.07.23 HUAWEI TECH CO LTD
  • EP4195857B1 patent drawingFigure 1
  • EP4195857B1 patent drawingFigure 2
  • EP4195857B1 patent drawingFigure 3a~3b

AI summary

This application relates to the field of wireless communication, for example, being applied to a wireless local area network supporting the 802. 1 1be standard, and in particular, relates to a channel access method for a multi-link device and a related apparatus. The method includes: when a length of a first PPDU transmitted on a first link by a first multi-link device is less than or equal to a first value, skipping starting, by the first multi-link device, a medium synchronization delay timer on a second link, where the first multi-link device is not allowed to perform simultaneous transmitting and receiving on the first link and the second link. In embodiments of this application, channel access efficiency can be improved when a non-STR MLD is in a blind state/self-interference state.