Critical Path Coordination for Mesh Network PAN Switching

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Solution Overview

Problem

Nodes in mesh networks face inefficiencies when switching PANs due to delayed detection of backhaul connection loss, leading to prolonged unavailability of child nodes during the switching process.

Innovation Solution

Nodes determine the status of backhaul connections prior to joining a PAN and establish a critical path, allowing them to coordinate a seamless switch to a new PAN while maintaining parent-child relationships and timing synchronization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a node determines backhaul connection status after joining a PAN, then the node can join any available PAN, but the node may experience prolonged unavailability when backhaul connection is lost

Engineering Contradiction:
Improvenode availabilityVSAvoiddowntime during PAN switching
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by having the node determine the backhaul connection status before joining the PAN. The node receives beacon frames from potential PANs, checks the backhaul connection status indicated in these beacons, and only joins PANs with available backhaul connections. This prevents the node from joining a PAN that will immediately become unavailable, thereby avoiding downtime and maintaining continuous availability.

Inventive Principle:
Principle #10Preliminary action

2Speed

If a node switches PANs independently without coordinating with child nodes, then the switching node can quickly switch to a new PAN, but child nodes remain unavailable until they locate a new parent

Engineering Contradiction:
ImprovePAN switching speedVSAvoidchild node connectivity
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The patent applies merging by coordinating the PAN switching action between the parent node and all its child nodes. When the parent node decides to switch to a new PAN, it communicates this decision to its child nodes, and they all switch together as a unified group. This ensures that child nodes maintain connectivity to their parent throughout the transition, eliminating periods where child nodes are orphaned and unavailable.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent uses feedback mechanisms where the parent node informs child nodes about the upcoming PAN switch and the identity of the new parent. Child nodes provide feedback by acknowledging the switch and establishing connections to the new parent. This coordinated feedback loop ensures that all nodes switch synchronously and maintain reliability throughout the transition.

Inventive Principle:
Principle #23Feedback

3Stability of the object's composition

If backhaul connection status is not communicated to nodes, then the network topology remains stable with hysteresis, but nodes cannot make informed decisions about PAN switching

Engineering Contradiction:
Improvenetwork topology stabilityVSAvoidnode decision-making capability
Core Design Contradiction:
Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The patent uses beacon frames as an intermediary to communicate backhaul connection status from the PAN to individual nodes. The root node or PAN coordinator includes backhaul connection status information in the beacon frames it broadcasts. This intermediary mechanism allows all nodes to receive real-time information about the backhaul connection status without requiring direct communication between nodes and the backhaul, thereby maintaining topology stability while enabling informed decision-making.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3791627B1Managing connectivity for critical path nodes
Publication Date: 2025.08.06 LANDIS GYR TECH INC
  • EP3791627B1 patent drawingFigure 1~2
  • EP3791627B1 patent drawingFigure 3~4
  • EP3791627B1 patent drawingFigure 5~6

AI summary

Systems and methods for managing nodes in mesh networks are provided. A critical node may determine a status of a backhaul connection prior to joining a PAN. A critical path may be created and maintained that includes the critical node and any intervening nodes between the critical node and the root. A critical node may switch PANs when a backhaul connection becomes unavailable. The switch may be facilitated by a node on the critical path other than the critical node. A node may switch PANs and coordinate the switch with its child nodes.