Wireless Router Contention Window for Fair Bandwidth

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Solution Overview

Problem

Current wireless mesh networks face challenges in fairly allocating bandwidth across multiple interconnected routers and clients, leading to biased bandwidth distribution favoring nodes closer to the gateway, which is not efficiently addressed by conventional ad-hoc routing protocols or existing MAC extensions.

Innovation Solution

A method that dynamically calculates a precise contention window for routers based on information exchanged through control channels, such as the number of hops, total clients, and requested throughput, ensuring fair bandwidth allocation by adjusting the contention window to minimize collisions and provide equal access to the wireless medium.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a predetermined amount of bandwidth is allocated to each client based on total network capacity, then the allocation process is simple and straightforward, but bandwidth distribution becomes biased in favor of nodes nearest to the gateway, causing unfair allocation across the network

Engineering Contradiction:
Improvebandwidth allocation processVSAvoidfairness of bandwidth distribution
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent changes the parameter of contention window size dynamically based on the router's position in the network (number of hops from gateway). Routers farther from the gateway are assigned larger contention windows, which compensates for the cumulative bandwidth consumption along the path and ensures fair bandwidth distribution across all nodes regardless of their location.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If all routers are treated equally as clients with the same bandwidth allocation, then the MAC layer control is simplified, but routers farther from the gateway receive insufficient bandwidth due to cumulative consumption by intermediate nodes

Engineering Contradiction:
ImproveMAC layer controlVSAvoidbandwidth availability for distant routers
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent applies local quality by assigning different contention window sizes to routers based on their specific location (number of hops) from the gateway. Each router's contention window is locally optimized according to its position, ensuring that routers farther from the gateway receive appropriate bandwidth compensation without requiring complex centralized control.

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If conventional ad-hoc routing protocols are used in wireless mesh networks, then implementation is straightforward, but they cannot efficiently address bandwidth allocation fairness issues in multihop scenarios

Engineering Contradiction:
Improveprotocol implementationVSAvoidbandwidth fairness in multihop networks
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent enables routers to autonomously determine their own contention window size based on their hop count from the gateway. Each router independently calculates and configures its parameters without requiring complex centralized coordination or modifications to conventional routing protocols, thus maintaining ease of implementation while achieving fair bandwidth allocation.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP1911205B1Bandwidth allocation in a wireless network
Publication Date: 2019.08.21 BRITISH TELECOM PLC
  • EP1911205B1 patent drawingFigure 1~3
  • EP1911205B1 patent drawingFigure 2~4
  • EP1911205B1 patent drawingFigure 5

AI summary

A method of determining a contention window for allocating bandwidth in a wireless network comprising a plurality of nodes, said nodes comprising at least a first and a second router and at least one client connected to each of said first and second routers, the method comprising the steps of: receiving information at the first router from the other nodes, said information relating to the condition of the other nodes; calculating a contention window for said first router based on the received information; and setting the delay for a retransmission of data by the first router to the calculated contention window, wherein the retransmission of data follows an unsuccessful transmission of said data.