Mesh Network Channel Access via Scheduled Reservations

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Solution Overview

Problem

Existing mesh network technologies face challenges in coordinating and minimizing interference among devices, particularly when devices are out of range or transmitting short-duration frames, leading to inefficiencies and increased interference.

Innovation Solution

A method for mesh devices to access the wireless channel during reserved periods, utilizing a scheduled mesh access mechanism that includes transmission and retransmission procedures to reduce interfering transmissions, with a scheduled access buffer, quality of service-enabled channel access, and a scheduler to manage reservations and contention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If RTS and CTS control signals are exchanged between transmitter and receiver, then channel access coordination is improved, but transmission time increases and interference vulnerability increases

Engineering Contradiction:
Improvechannel access coordinationVSAvoidtransmission time
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The patent extracts the RTS/CTS handshake mechanism from the transmission process for short-duration frames, allowing direct transmission without the full coordination sequence. This removes the time-consuming control signal exchange while maintaining channel access coordination for longer transmissions.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies partial action by implementing selective RTS/CTS usage - only for frames exceeding a duration threshold. For shorter frames, the full coordination mechanism is omitted, achieving time efficiency while maintaining adequate channel access coordination where needed.

Inventive Principle:
Principle #16Partial or excessive action

2Ease of operation

If RTS and CTS control signals are exchanged, then channel access coordination is improved, but interference susceptibility increases

Engineering Contradiction:
Improvechannel access coordinationVSAvoidinterference susceptibility
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent removes the RTS/CTS control signal exchange from the transmission process for short frames, eliminating the vulnerability to interference during control signal transmission while maintaining direct data frame transmission.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent implements selective coordination - applying RTS/CTS only when frame duration exceeds a threshold. This partial application reduces overall interference susceptibility by minimizing control signal exchanges while maintaining coordination when transmission duration warrants it.

Inventive Principle:
Principle #16Partial or excessive action

3Adaptability or versatility

If mesh devices transmit outside reserved periods, then transmission flexibility is improved, but interfering transmissions increase

Engineering Contradiction:
Improvetransmission flexibilityVSAvoidinterfering transmissions
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The patent implements dynamic transmission scheduling where devices can transmit outside reserved periods when the channel is clear and no other devices have reservations. This creates a flexible system that adapts to real-time channel conditions, allowing opportunistic transmissions without causing interference to scheduled communications.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent uses reservation advertisement mechanisms where devices broadcast their reserved periods to neighbors. This feedback system allows devices to make informed decisions about when to transmit outside reservations, checking against advertised reservation information to avoid interfering with scheduled transmissions.

Inventive Principle:
Principle #23Feedback

4Measurement precision

If routing information is periodically broadcast, then routing accuracy is improved, but information transmission overhead increases

Engineering Contradiction:
Improverouting accuracyVSAvoidinformation transmission overhead
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent implements on-demand routing information exchange instead of periodic broadcasting. Routing information is exchanged only when needed for specific transmissions, reducing the overall quantity of routing information transmitted while maintaining accuracy for active routes through targeted updates.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP2191679B1Method of communicating within a mesh network
Publication Date: 2015.01.21 MOTOROLA SOLUTIONS INC
  • EP2191679B1 patent drawingFigure 1
  • EP2191679B1 patent drawingFigure 2
  • EP2191679B1 patent drawingFigure 3~4

AI summary

A method of communicating within a mesh network comprises scheduling a mesh access reservation time period for transmission of one or more frames by the mesh device on a channel. During the scheduled mesh access reservation time period: contention for the channel is performed with one or more other mesh devices in the network; and at least one frame is transmitted when the mesh device wins the contention. After the scheduled mesh access reservation time period: when one or more frames scheduled for transmission during the scheduled mesh access reservation time period remain to be transmitted; contention for the channel continues; and the one or more frames are transmitted when the mesh device wins the contention for the channel and when another mesh device has not reserved the channel for the time period.