Channel Access Method for Time-Synchronized Sub-Channel Allocation

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Solution Overview

Problem

In wireless local area networks using the IEEE 802.11 protocol, multiple stations competing for channel resources often experience collisions due to time non-synchronization, leading to interference between signals on adjacent frequency sub-channels, complicating the monitoring process and reducing the effectiveness of channel access.

Innovation Solution

A channel access method where stations monitor the entire channel's busy/idle state and select a sub-channel for request transmission only when the channel is idle, ensuring time synchronization and avoiding interference by uniformly processing requests across sub-channels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the channel is divided into multiple sub-channels in frequency domain, then channel resources can be better utilized and throughput improved, but the monitoring process becomes complex and time non-synchronization occurs

Engineering Contradiction:
Improvechannel throughputVSAvoidmonitoring process complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The channel is divided into multiple sub-channels in the frequency domain, allowing stations to select different sub-channels for transmission. This segmentation enables parallel communication and improves overall channel throughput while maintaining manageable monitoring complexity through the unified channel monitoring approach.

Inventive Principle:
Principle #1Segmentation

2Productivity

If STAs simultaneously monitor multiple sub-channels, then channel access efficiency improves, but time non-synchronization and adjacent band interference occur

Engineering Contradiction:
Improvechannel access efficiencyVSAvoidsignal transmission reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent merges the monitoring function at the channel level rather than maintaining separate monitoring for each sub-channel. This unified monitoring approach ensures time synchronization across all STAs, preventing adjacent band interference while maintaining efficient channel access through coordinated sub-channel selection.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The access point serves as an intermediary that coordinates sub-channel allocation and timing. By centralizing the synchronization function at the access point, the system ensures that multiple STAs accessing different sub-channels do so in a time-synchronized manner, eliminating interference while preserving access efficiency.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Adaptability or versatility

If STAs contend for channel resources on different sub-channels, then channel utilization improves, but adjacent band interference severely degrades signal quality

Engineering Contradiction:
Improvechannel resource utilizationVSAvoidadjacent band interference
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The system performs preliminary channel monitoring and sub-channel selection before actual data transmission begins. STAs monitor the overall channel state and select appropriate sub-channels in advance, ensuring that transmissions on adjacent sub-channels are time-coordinated and do not cause interference, while still achieving high channel utilization.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3035767B1Method, apparatus and system for channel access
Publication Date: 2020.04.15 HUAWEI TECH CO LTD
  • EP3035767B1 patent drawingFigure 1
  • EP3035767B1 patent drawingFigure 2~3
  • EP3035767B1 patent drawingFigure 4~5

AI summary

The present invention discloses a channel access method, apparatus and system, which simplifies a monitoring process of an STA, and can support time synchronization being satisfied when a plurality of STAs perform channel access, thereby avoiding signals at adjacent frequency bands interfere with each other. The method includes: monitoring, by a station STA, a channel state of a channel, wherein the channel comprises at least two sub-channels; sending, when it is monitored that the channel is in an idle state, a request to send frame to an access point AP via at least one sub-channel in the channel; and if an access response frame fed back by the AP is received and the access response frame comprises identification information and channel resource allocation information of the station, determining that channel access succeeds, wherein the identification information and the channel resource allocation information of the station are used for indicating a channel resource allocated to the station for data transmission by the AP.