Mesh Network Clock Synchronization via Reference Clock Intermediary

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Solution Overview

Problem

In mesh communications networks, particularly in Wireless Sensor Networks and Smart Meter Networks, achieving global clock synchronization is challenging due to clock drift and propagation time issues, which reduce network bandwidth and cause interference, especially in large networks or those with geographical distances.

Innovation Solution

A method where all communication devices, except one designated device, perform distributed consensus-based synchronization, and the given device obtains correction information from the synchronization process to broadcast and align the clock timings, ensuring synchronization without participating in the synchronization process itself.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If distributed consensus-based synchronization is used to avoid propagation time issues, then network bandwidth is improved, but clock drift occurs causing transmission frequency shift

Engineering Contradiction:

Improvenetwork bandwidthVSAvoidclock timing accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent introduces a reference clock as an intermediary that all communication devices use to establish their local clock timings. This reference clock serves as a mediator that prevents clock drift by providing a common time reference, while still allowing devices to communicate and synchronize through the distributed consensus mechanism without direct propagation delays affecting the reference timing.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system performs preliminary action by establishing local clock timings based on a reference clock before actual data transmission occurs. This preliminary synchronization ensures that all devices have pre-aligned timing references, preventing clock drift from affecting subsequent transmissions and eliminating the need for frequent timing corrections during operation.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If distributed consensus-based synchronization is used in clusters sharing transmission resources, then synchronization robustness is improved, but interferences occur between clusters

Engineering Contradiction:

Improvesynchronization robustnessVSAvoidinterference between clusters

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by allowing each cluster to independently establish its own local clock timing based on the reference clock, rather than forcing a single global synchronization scheme. This local autonomy enables each cluster to optimize its timing independently while sharing transmission resources, preventing inter-cluster interference while maintaining robust synchronization within each cluster.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The system segments the network into multiple clusters, each capable of independent distributed consensus-based synchronization. This segmentation allows clusters to operate autonomously with their own timing references derived from the common reference clock, eliminating interference between clusters while maintaining overall network coherence through the shared reference.

Inventive Principle:

Principle #1Segmentation

3Area of stationary object

If multi-hop communication is used for global clock synchronization, then network coverage is improved, but propagation time increases reducing useful bandwidth

Engineering Contradiction:

Improvenetwork coverageVSAvoiduseful bandwidth

Core Design Contradiction:

Area of stationary objectVSProductivity

Solution Approach 1:

The reference clock acts as an intermediary that eliminates the need for multi-hop propagation of timing information. Each device independently establishes its timing based on the reference clock, bypassing the need for sequential timing propagation through multiple hops, thus maintaining full bandwidth utilization while achieving global synchronization across the entire network coverage area.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

Each communication device performs self-service by independently establishing its own local clock timing based on the reference clock, rather than relying on timing information propagated from other devices through the network. This self-service approach eliminates propagation delays and bandwidth consumption associated with multi-hop timing synchronization, while still enabling global network coverage.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS8737379B2Methods and devices for performing synchronization and compensating clock drift among communication devices

Publication Date: 2014.05.27 MITSUBISHI ELECTRIC CORP

AI summary

In order to perform synchronization and compensate clock drift among a plurality of communication devices interconnected to form a mesh communications network, all communication devices, except one given communication device, perform a first distributed consensus-based synchronization. The given communication device performs: obtaining a first correction information derived at least from a difference between a clock timing resulting from the first distributed consensus-based synchronization and a reference clock timing; and transmitting the first correction information through the mesh communications network. All the communication devices, except said given communication device, further perform updating the clock timing resulting from the first distributed consensus-based synchronization by taking into account the transmitted first correction information.