Anchor Master Selection in Neighbor Awareness Networks
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Solution Overview
Problem
In Neighbor Awareness Networking (NAN) clusters, the existing method for anchor master selection fails to effectively manage changes in master rank, leading to persistent recording of outdated anchor master rank values and increased hop counts, which causes the entire cluster to crash and disrupts time synchronization between devices.
Innovation Solution
A method and device for anchor master selection that updates anchor master information based on received beacon frames, where a device switches to or updates its role as an anchor master when its master rank is greater or lesser than the recorded rank, ensuring correct anchor master information is maintained and hop counts are managed within thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the existing anchor master selection method is used, then devices can initially synchronize time, but the hop count increases indefinitely and the cluster crashes over time
Solution Approach 1:
The patent changes the parameter comparison logic from only accepting larger AMR values to accepting both larger and smaller AMR values. When a device receives a sync beacon with an AMR smaller than its recorded AMR, it now compares its own MR with the received AMR and may update its recorded AMR if its MR is larger, preventing the hop count from increasing indefinitely and avoiding cluster crashes.
2Reliability
If the anchor master rank value is only allowed to increase, then synchronization can be maintained initially, but outdated rank values persist and prevent proper anchor master selection
Solution Approach 1:
The patent makes the anchor master rank selection dynamic by allowing the recorded AMR to decrease when appropriate. Instead of monotonically increasing the AMR, the system now dynamically adjusts the recorded AMR based on real-time comparisons between the device's own MR and received AMR values, ensuring the most current and accurate anchor master information is maintained.
Solution Approach 2:
The patent inverts the traditional one-way update mechanism by introducing a bidirectional comparison process. Rather than only updating when receiving a larger AMR, the system now also processes smaller AMR values through reverse logic comparison, allowing outdated information to be replaced and ensuring the anchor master rank reflects current network conditions.
3Measurement precision
If devices discard sync beacons when hop count exceeds threshold, then false information is rejected, but all valid sync beacons are discarded and the cluster crashes
Solution Approach 1:
The patent introduces a feedback mechanism where devices continuously compare their recorded AMR with received AMR values and adjust their recorded AMR accordingly. This feedback loop prevents the hop count from continuously increasing, ensuring that sync beacons remain within the acceptable threshold and the cluster maintains functionality while still rejecting false information.
Data Source
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AI summary
Embodiments of the present invention disclose a method and device for anchor master selection, which can maintain time synchronization between devices in a NAN cluster. The method includes: receiving, by a device, a NAN Beacon frame, where the NAN Beacon frame carries first AM information and first TSF information, and the first AM information includes: a first AMR, a first HC, and a first AMBTT; if the NAN Beacon frame is used for AM selection, when the first AMR is less than a second AMR, and an MR of the device is greater than the first AMR, switching, by the device, a role of the device to AM, where second AM information recorded in the device includes: the second AMR, a second HC, and a second AMBTT; and if the NAN Beacon frame is used for AM selection, when the first AMR is less than the second AMR, and the MR of the device is less than the first AMR, updating, by the device according to the NAN Beacon frame, the second AM information and second TSF information that are recorded in the device.