Intelligent Wire Scheduling for LLN Interference Reduction

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Solution Overview

Problem

Low Power and Lossy Networks (LLNs) face challenges in achieving deterministic network communications due to their constrained nature, which makes it difficult to guarantee packet delivery, fixed latency, and low jitter, especially in applications like Smart Grid and Smart Cities, where installation and standardization of wireless access points and sensors are time-consuming and expensive.

Innovation Solution

The introduction of an 'intelligent wire' with embedded network devices at known locations, allowing for a communication schedule to be generated based on device positions, preventing neighboring devices from transmitting on the same frequency and assigning frequency offsets, thereby minimizing interference and enabling deterministic packet delivery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If wireless access points and sensors are installed as part of an LLN, then network coverage and functionality are improved, but installation time and cost increase due to requiring expert personnel

Engineering Contradiction:
Improvenetwork coverageVSAvoidinstallation time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system enables automatic network configuration where devices self-organize into mesh networks without expert intervention. The intelligent wire automatically discovers devices, determines their locations, and configures communication schedules, transforming a service that requires expert installation into a self-configuring system.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The intelligent wire pre-determines device locations and communication schedules before actual network operation begins. By establishing the communication topology and frequency assignments in advance based on device positions along the wire, the system eliminates the need for complex post-installation configuration.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If wireless access points and sensors are installed as part of an LLN, then network coverage and functionality are improved, but installation cost increases due to requiring expert personnel

Engineering Contradiction:
Improvenetwork coverageVSAvoidinstallation cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The system enables automatic network configuration where devices self-organize into mesh networks without expert intervention. The intelligent wire automatically discovers devices, determines their locations, and configures communication schedules, transforming a service that requires expert installation into a self-configuring system.

Inventive Principle:
Principle #25Self-service

3Ease of operation

If devices transmit on the same frequency without coordination, then communication simplicity is maintained, but interference increases and deterministic delivery cannot be guaranteed

Engineering Contradiction:
Improvecommunication simplicityVSAvoiddeterministic delivery
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The system implements periodic time-slot based communication where devices transmit at scheduled intervals rather than continuously or randomly. This periodic structure with assigned time slots and frequency offsets ensures deterministic delivery while maintaining relative simplicity through automated scheduling based on device locations.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The communication schedule is customized for each device based on its specific location along the intelligent wire. Each device receives local optimization with specific time slots and frequency offsets tailored to its position and neighboring devices, ensuring deterministic delivery without requiring complex global coordination.

Inventive Principle:
Principle #3Local quality

4Productivity

If neighboring devices transmit on the same frequency, then frequency utilization is maximized, but interference increases and packet delivery reliability decreases

Engineering Contradiction:
Improvefrequency utilizationVSAvoidpacket delivery
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system implements periodic time-slot based communication where devices transmit at scheduled intervals rather than continuously or randomly. This periodic structure with assigned time slots and frequency offsets ensures deterministic delivery while maintaining relative simplicity through automated scheduling based on device locations.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP3095215B1Intelligent wiring in a low power and lossy network
Publication Date: 2019.03.13 CISCO TECHNOLOGY INC
  • EP3095215B1 patent drawingFigure 1
  • EP3095215B1 patent drawingFigure 2
  • EP3095215B1 patent drawingFigure 3

AI summary

In one embodiment, the locations of a plurality of network devices in a low power and lossy network (LLN) are determined along an intelligent wire. One or more neighboring devices for each network device in the plurality are identified based on the locations of the network devices along the intelligent wire. A communication schedule for the network devices is determined that prevents neighboring devices along the intelligent wire from transmitting on the same frequency. The network devices are assigned to communication time slots based on the communication schedule. The network devices are also assigned frequency offsets based on the communication schedule.