Parent Node Selection in 6LoWPAN Mesh Networks
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Solution Overview
Problem
In 6LoWPAN wireless mesh networks, the existing parent node selection method leads to a 'thundering herd effect' where multiple nodes select the same parent node, causing increased transmission failures, retransmissions, and instability due to frequent parent-node switching.
Innovation Solution
A method that determines a target parent node by evaluating candidate parent nodes based on their communication quality, current temporary ETX values, and the number of subnodes connected, ensuring balanced network load and reducing unnecessary parent node switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If nodes select parent nodes based on DODAG rank and ETX calculations, then communication quality is optimized, but a thundering herd effect occurs where multiple nodes select the same parent node simultaneously
Solution Approach 1:
The patent applies preliminary action by having parent nodes broadcast their DIO (DODAG Information Object) containing rank information before child nodes make selection decisions. This allows child nodes to receive and process parent node information in advance, enabling more informed and distributed selection that prevents simultaneous convergence on the same parent node.
Solution Approach 2:
The patent implements feedback mechanisms where parent nodes continuously broadcast their rank and ETX information, and child nodes use this feedback to dynamically adjust their parent selection. The feedback loop includes child nodes reporting their selected parent back to the network, allowing for iterative optimization and preventing thundering herd effects through distributed decision-making.
2Productivity
If parent node switching is performed based on rank differences, then transmission path is optimized, but frequent switching occurs causing network instability
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the threshold for parent node switching based on network conditions. Instead of using a fixed threshold, the system adapts the switching criterion based on current network state, ETX values, and rank differences, thereby optimizing transmission paths while preventing excessive switching that would cause instability.
Solution Approach 2:
The patent implements dynamics by making the parent selection and switching process adaptive rather than static. The system continuously monitors network conditions, ETX values, and rank information, allowing the switching behavior to dynamically adjust to current network state. This dynamic approach enables optimization while maintaining stability through condition-based decision making.
3Ease of operation
If nodes use default ETX values for parent node selection, then selection process is simplified, but transmission failures increase due to poor path selection
Solution Approach 1:
The patent applies partial action by implementing a hybrid approach where default ETX values are used for initial rapid selection, but the system then performs partial verification and optimization based on actual network conditions. This allows the selection process to remain relatively simple while achieving better transmission success rates through targeted refinement rather than complete complexity.
Data Source
AI summary
A parent node selection method includes obtaining, by a network node, an identifier of each of candidate parent nodes, a quantity of subnodes already connected to each candidate parent node and a rank of each candidate parent node; obtaining a candidate rank of the network node that corresponds to each candidate parent node; determining, according to a first preset rule, a first candidate parent node set from the candidate parent nodes based on the identifier of each candidate parent node and the candidate rank of the network node that corresponds to each candidate parent node; and determining, based on a quantity of subnodes already connected to each candidate parent node in the first candidate parent node set, a candidate parent node that is in the first candidate parent node set and that is already connected to a smallest quantity of subnodes as a target parent node of the network node.