Network Congestion Control via Proactive Contention Window Adjustment

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Solution Overview

Problem

Existing methods for controlling network congestion in wireless local area networks, such as binary exponential backoff, are inefficient as they only enlarge the contention window after collisions occur, leading to prolonged congestion and low efficiency during high traffic scenarios.

Innovation Solution

A method where an access point monitors network congestion levels and sends control frames or beacon frames to stations to proactively enlarge their contention windows before data transmission, using a preset minimum value to determine a new contention window size, ensuring fair channel contention and reducing congestion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If binary exponential backoff is used to control network congestion, then the contention window is enlarged after collisions occur, but the network congestion relief is slow and efficiency is low

Engineering Contradiction:
Improvecongestion control effectivenessVSAvoidcongestion relief time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The access point performs preliminary action by detecting network congestion and proactively notifying stations to enlarge their contention windows before collisions occur. This prevents the reactive approach of binary exponential backoff where stations only respond after experiencing collisions, thereby reducing congestion relief time while maintaining control effectiveness

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements feedback by having the access point continuously monitor network congestion levels and send notifications to stations. This closed-loop feedback mechanism allows the network to adapt dynamically to congestion conditions, improving both the effectiveness and speed of congestion control compared to the open-loop binary exponential backoff approach

Inventive Principle:
Principle #23Feedback

2Ease of operation

If stations contend for channel using random backoff time, then channel access is distributed and fair, but collision probability increases under high traffic load

Engineering Contradiction:
Improvechannel access fairnessVSAvoidcollision probability
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The access point acts as an intermediary that mediates between stations during network congestion. It receives congestion information, determines appropriate contention window adjustments, and notifies stations of the required changes. This intermediary coordination reduces collision probability by ensuring all stations use appropriately enlarged contention windows, while the access point maintains fairness by applying the same adjustment rules to all stations

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP2819456B1Method, and device for controlling network congestion
Publication Date: 2019.06.26 HUAWEI TECH CO LTD
  • EP2819456B1 patent drawingFigure 1~3
  • EP2819456B1 patent drawingFigure 4a~5
  • EP2819456B1 patent drawingFigure 6~7b

AI summary

Embodiments of the present invention provide a method, an apparatus and a system for controlling network congestion, so as to rapidly reduce the congestion level of the network and improve the efficiency of congestion control. The method includes: sending a control frame or a beacon frame to a station in a network when network congestion occurs, so as to instruct the station to enlarge a contention window when the station needs to send data. The method provided by embodiments of the present invention can achieve the congestion control for a network before collision occurs to a station, thereby avoiding more serious network congestion caused by each station still contending for a channel after the network congestion occurs; in another aspect, since an access point can send a control frame or a beacon frame to the station in the network when determining that congestion occurs to the current network, so as to instruct the station which needs to send data to re-determine a backoff time when receiving the control frame or the beacon frame, a rapidly congestion relief of the whole network is achieved from the overall situation, and also a fair channel contention of each station, after re-determining a backoff time, is guaranteed.