Deterministic Mesh Node Synchronization via Multi-Agent Reinforcement Learning

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Solution Overview

Problem

Existing Wireless Sensor Networks (WSN) using IEEE 802.15.4e TSCH protocol are vulnerable to timeslot template attacks, which disrupt synchronization and lead to deterministic network failures, especially in Industrial Internet of Things (IIoT) applications, due to the lack of effective distributed synchronization correction mechanisms and adaptive threshold calculations.

Innovation Solution

A method for synchronizing nodes in a deterministic mesh network using a distributed architecture that estimates future synchronization offsets from measured offsets and applies corrections to local clocks, with a catch-up factor to maintain network stability, and employs multi-agent reinforcement learning for adaptive synchronization adjustments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If distributed synchronization correction mechanisms are implemented, then network determinism and reliability are improved, but device complexity increases

Engineering Contradiction:
Improvenetwork determinismVSAvoidsynchronization mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a feedback mechanism where each node continuously measures synchronization offsets with its neighbors, estimates future offsets using linear regression, and applies corrections based on a catch-up factor. This closed-loop feedback system maintains network determinism by constantly adjusting for clock drift and synchronization errors without requiring complex centralized control.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

Each node in the mesh network autonomously performs synchronization measurements, estimates its own offset using linear regression on historical data, and applies corrections to its local clock independently. This self-service approach eliminates the need for complex centralized synchronization management while maintaining network determinism through distributed autonomous operation.

Inventive Principle:
Principle #25Self-service

2Measurement precision

If adaptive synchronization adjustments are applied, then synchronization precision is improved, but computational requirements increase

Engineering Contradiction:
Improvesynchronization offset measurementVSAvoidcomputational power consumption
Core Design Contradiction:
Measurement precisionVSPower

Solution Approach 1:

The patent applies partial correction by using a catch-up factor (alpha) that controls the fraction of estimated offset applied to the local clock. This prevents excessive correction that would cause instability while still improving synchronization precision. The linear regression uses a limited history of offset measurements rather than all past data, balancing precision with computational efficiency.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The synchronization system dynamically adapts to changing network conditions by continuously updating the linear regression model with new offset measurements and adjusting the catch-up factor based on observed synchronization behavior. This dynamic adaptation improves precision without requiring excessive computational power by processing only necessary updates.

Inventive Principle:
Principle #15Dynamics

3Measurement precision

If linear regression is used for offset estimation, then synchronization accuracy is improved, but processing time increases

Engineering Contradiction:
Improvefuture offset estimation accuracyVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent pre-calculates linear regression parameters from historical offset measurements and stores them for rapid retrieval and application. By preparing the regression model in advance with accumulated data, the system achieves accurate future offset estimation without performing complex calculations in real-time, thus reducing processing time while maintaining precision.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS11917046B2Method of synchronizing nodes in a determinist mesh network
Publication Date: 2024.02.27 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • US11917046B2 patent drawing
  • US11917046B2 patent drawing
  • US11917046B2 patent drawing

AI summary

The present invention relates to a method for synchronising a node in a deterministic mesh network, in particular a network of sensors using a channel hopping (TSCH) transmission medium access mode. Each node measures the successive synchronisation offsets of its local clock in relation to those of neighbour nodes with which it enters into communication, the measurement being carried out by detecting a reception event of a packet transmitted by the neighbour node or an acknowledgement of a packet transmitted by said node to the neighbour node. The node estimates from these synchronisation offsets, a synchronisation offset for the timeslot and corrects its local clock by a fraction of the synchronisation offset thus estimated. Said fraction may be determined by means of multi-agent reinforcement learning (MARL), each agent being associated with a node of the network.