Relative Time Error Distribution Through Hierarchical PTP Gateways

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Solution Overview

Problem

Existing precision time protocol (PTP) networks struggle to accurately distribute relative time error information, leading to incorrect estimations and increased complexity due to the need for extensive communication and additional functionality among nodes.

Innovation Solution

The method involves defining hierarchical PTP segments and using special TLV fields to distribute relative time error information directly within sub-segments, with gateway devices acting as local grandmasters, ensuring accurate and efficient distribution without additional external communication.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If relative time error information is distributed using existing PTP protocols, then time synchronization is achieved, but the estimation accuracy is incorrect and network complexity increases

Engineering Contradiction:
Improverelative time error estimation accuracyVSAvoidnetwork complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The PTP network is divided into hierarchical segments with gateway devices acting as local grandmasters for sub-segments. Each gateway device independently manages time error distribution within its sub-segment, eliminating the need for complex inter-node communication while improving estimation accuracy through localized time error calculations.

Inventive Principle:
Principle #1Segmentation

2Loss of information

If extensive communication and additional functionality are implemented among network nodes, then time error information can be distributed, but device complexity and implementation cost increase

Engineering Contradiction:
Improvetime error information distributionVSAvoidnode functionality complexity
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

Gateway devices perform self-service by acting as local grandmasters and independently calculating time error information for their sub-segments. This eliminates the need for complex inter-node communication protocols and additional functionality, as each gateway device autonomously manages its own time synchronization domain.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

Gateway devices serve as intermediaries between the main PTP network and sub-segments. They receive absolute time error information from the main network and transform it into relative time error information for local distribution, simplifying the overall network architecture by eliminating direct communication requirements between end nodes.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If hierarchical PTP segments with gateway devices are implemented, then relative time error information is accurately distributed, but software upgrade requirements increase

Engineering Contradiction:
Improverelative time error distribution accuracyVSAvoidsoftware upgrade requirement
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The system implements dynamic software configuration where gateway devices can be flexibly assigned and configured based on network requirements. The software upgrades are minimized by allowing dynamic adaptation of existing devices to gateway functions, reducing the need for hardware changes and extensive software rewrites.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4205313B1Relative time error information distribution in precision time protocol network
Publication Date: 2025.10.01 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP4205313B1 patent drawingFigure 1~2
  • EP4205313B1 patent drawingFigure 3~4
  • EP4205313B1 patent drawingFigure 5A~5B

AI summary

There is provided mechanisms for relative time error (TE) information distribution in a telecommunication network using a precision time protocol (PTP). A method is performed in a gateway device in a telecommunication network having hierarchical segments. The method comprises receiving TE information from a telecom grandmaster (T-GM) of the hierarchical segments. The method comprises preserving a total TE information of the received TE information. The method comprises resetting an accumulated path TE of the received TE information. The method comprises outputting an indication of the reset accumulated path TE and the preserved total TE information to a sub-segment of the hierarchical segments.