Ad-Hoc Network Time Synchronization via Peer-to-Peer Message Exchange

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing methods for time synchronization in ad hoc networks are inefficient due to time delays in cluster formation, hierarchy determination, and master node announcement, leading to increased effort and time required for synchronization.

Innovation Solution

A method where each node continuously sends a 'Hello Message' to signal presence, with acknowledgment messages determining the local time master based on priority, ensuring the highest time accuracy and minimal effort for synchronization across the network.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If cluster formation is used for time synchronization, then time synchronization can be achieved in a distributed manner, but time delay increases due to the time required for cluster formation

Engineering Contradiction:
Improvetime synchronizationVSAvoidtime delay
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent extracts the cluster formation step from the time synchronization process. Nodes directly exchange time synchronization messages with each other without forming clusters first, eliminating the time delay caused by cluster formation while maintaining distributed time synchronization reliability

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent segments the time synchronization process into direct peer-to-peer message exchanges between individual nodes, rather than having all nodes synchronize through cluster structures. This segmentation eliminates the hierarchical overhead and reduces synchronization time delay

Inventive Principle:
Principle #1Segmentation

2Device complexity

If reference network nodes are determined in advance with hierarchy, then time synchronization structure is established, but time delay increases for determining and announcing the hierarchy

Engineering Contradiction:
Improvesynchronization structureVSAvoidtime delay
Core Design Contradiction:
Device complexityVSLoss of time

Solution Approach 1:

The patent implements dynamic time synchronization where nodes can change their reference nodes dynamically based on current network conditions and message exchanges, rather than maintaining fixed hierarchical structures. This dynamic approach eliminates the time delay for determining and announcing static hierarchies

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

Each node independently determines its own reference node and performs time synchronization autonomously through direct message exchanges, without requiring centralized hierarchy determination and announcement. This self-service approach eliminates the time delay for hierarchical setup

Inventive Principle:
Principle #25Self-service

3Reliability

If master-slave principle is used with a specified master node, then time reference is centralized, but time delay increases for determining and announcing the master node

Engineering Contradiction:
Improvetime referenceVSAvoidtime delay
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent extracts the master node determination and announcement step from the time synchronization process. Nodes directly exchange time messages with their chosen reference nodes without requiring master node determination and network-wide announcement, eliminating the associated time delay

Inventive Principle:
Principle #2Taking out (Extraction)

4Reliability

If fixed order for message dispatch is defined in clusters, then time synchronization can be coordinated, but effort for implementation increases

Engineering Contradiction:
Improvetime synchronizationVSAvoidsynchronization effort
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Each node independently manages its own time synchronization by selecting reference nodes and exchanging messages autonomously, without requiring centralized coordination of message dispatch orders within clusters. This self-service approach reduces implementation effort while maintaining synchronization reliability

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP2859766B1Method and system for time synchronization in an ad-hoc network
Publication Date: 2018.05.09 ROHDE & SCHWARZ GMBH & CO KG
  • EP2859766B1 patent drawingFigure 1~2
  • EP2859766B1 patent drawingFigure 3
  • EP2859766B1 patent drawingFigure 4

AI summary

In a method and in a system for time synchronization within a mobile ad-hoc network, every node (31, 32, 33, 34, 35, 36, 37, 38) of the mobile ad-hoc network transmits a message signalling a presence (1), in each case within a given time frame. The received message signalling a presence (1) is acknowledged by every node (31, 32, 33, 34, 35, 36, 37, 38) disposed within the transmission range of the transmitting node (31, 32, 33, 34, 35, 36, 37, 38), in each case with an acknowledgement message (2). On the basis of the information in an acknowledgement message (2) which one of the two nodes (31, 32, 33, 34, 35, 36, 37, 38) receives, that node (31, 32, 33, 34, 35, 36, 37, 38) of two nodes (31, 32, 33, 34, 35, 36, 37, 38) disposed within the transmission range of one another is specified, with the local time of which the respectively other node (31, 32, 33, 34, 35, 36, 37, 3831, 32, 33, 34, 35, 36, 37, 38) synchronizes its local time.