Coordinated Channel Change in Wireless Mesh Networks
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Solution Overview
Problem
Wireless mesh networks face challenges in maintaining continuous connectivity during Dynamic Frequency Selection (DFS) events, where radar signals require channel changes, leading to potential loss of connectivity due to errors in channel switching processes.
Innovation Solution
A protocol where mesh nodes signal DFS events to a root node or controller, which re-computes and assigns new channels, with parent and child nodes exchanging messages to ensure seamless channel changes, either through a bottom-up or top-down propagation mechanism, ensuring continuous connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If mesh nodes autonomously detect radar signals and change channels independently, then the network can quickly respond to DFS events, but connectivity loss occurs due to lack of coordination between nodes
Solution Approach 1:
The patent introduces a controller as an intermediary that coordinates channel changes across the mesh network. When a node detects radar, it reports to the controller, which then manages the channel change process for the entire network, ensuring all nodes transition together to maintain connectivity while responding to DFS events.
Solution Approach 2:
The controller performs preliminary channel selection and coordination before actual channel changes occur. By pre-planning channel transitions and coordinating the timing of changes across multiple nodes, the system ensures that connectivity is maintained during the transition process while still responding quickly to radar detection.
2Stability of the object's composition
If the entire sub-tree rooted at the gateway node changes frequency simultaneously, then the network maintains consistent operation, but the complexity of managing coordinated changes increases
Solution Approach 1:
The patent segments the mesh network into hierarchical groups (sub-trees rooted at gateway nodes) and manages channel changes at each segment level. This allows consistent operation within each segment while reducing overall coordination complexity by breaking down the large-scale change into smaller, manageable units that can be controlled independently.
Solution Approach 2:
The controller merges the channel change operations of multiple nodes into a coordinated sequence. By combining individual node changes into a unified control process, the system achieves consistent network-wide operation while the controller manages the complexity of coordination centrally, preventing individual nodes from creating conflicts.
3Adaptability or versatility
If channel changes are triggered by radar detection, then DFS requirements are met, but connectivity interruptions occur during the channel switching process
Solution Approach 1:
The controller performs preliminary channel selection and notifies all relevant nodes of the upcoming channel change before the actual transition occurs. This advance notification allows nodes to prepare for the change, and the coordinated timing ensures that all nodes switch together, minimizing connectivity interruptions while still meeting DFS requirements when radar is detected.
Data Source
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AI summary
A coordinated channel change system. In particular implementations, a method includes receiving a prepare-to-change message, wherein the prepare-to-change message indicates instructions to prepare to change channels and includes a designated channel, and forwarding the prepare-to-change message to one or more child nodes. The method also includes receiving a ready-to-change message from the one or more child nodes, and transmitting a change-to-channel message to the one or more child nodes, wherein the change-to-channel message indicates instructions to switch to the designated channel. The method also includes receiving an acknowledgement message from the one or more child nodes, and changing to the designated channel.