Precision Time Protocol

About: Precision Time Protocol is a research topic. Over the lifetime, 604 publications have been published within this topic receiving 6006 citations. The topic is also known as: PTP & IEEE 1588.

Ethernet passive optical network system and method for implementing end-to-end transparent clock in such system

Abstract: A method for implementing an End-to-End Transparent Clock (E2ETC) in an Ethernet Passive Optical Network (EPON) system is disclosed by the present invention. The method includes: when receiving a Precision Time Protocol (PTP) message, a first network element records a first time when receiving the PTP message, sets the recorded first time in the PTP message and transmits the PTP message to a second network element; and the second network element receives the PTP message, and the PTP message, which will be transmitted to a lower device or an upper device, carries the residence time of the PTP message which is calculated according to the first time and the current time. The EPON system is also disclosed by the present invention. With the present invention, the E2ETC function in the IEEE1588-2008 protocol can be implemented in the condition of without extra hardware assistance.

Minimax Optimum Clock Skew and Offset Estimators for IEEE 1588

Abstract: This paper addresses the problem of clock skew and offset estimation for the IEEE 1588 precision time protocol. Built on the classical two-way message exchange scheme, IEEE 1588 is a prominent synchronization protocol for packet switched networks. It is employed in various applications including cellular base station synchronization in 4G long-term evaluation backhaul networks, substation synchronization in electrical grid networks and industrial control. Due to the presence of random queuing delays in a packet switched network, the recovery of clock skew and offset from the received packet timestamps can be viewed as a statistical estimation problem. Recently, assuming perfect clock skew information, minimax optimum clock offset estimators were developed for IEEE 1588. Building on this work, we develop minimax optimum clock skew and offset estimators for IEEE 1588 in this paper. Simulation results indicate the proposed minimax estimators exhibit a lower mean square estimation error than the estimators available in the literature for various network scenarios.

Modeling and analyzing precision time protocol — Application to prototyping distributed embedded systems

Abstract: Prototyping distributed embedded system can be seen as a collection of many requirements covering many domains. System designers and developers need to describe both functional and non-functional requirements. Building distributed systems is a very tedious task since the application has to be verifiable and analyzable. Architecture Analysis and Design Language (AADL) provides adequate syntax and semantics to express and support distributed embedded systems. This paper studies a general methodology for prototyping distributed applications using the Precision Time Protocol (PTP) for building and translating AADL systems into a distributed application using network communication protocol. This allows simulation of systems specified in AADL to fully assess system viability, to refine and to correct the behavior of the system using the BIP (Behavior Interaction Priority) toolset.

Accurate High-Speed 3D Reconstruction Using an Array of Networked Cameras

Abstract: This paper presents a method for synchronizing a network of camera-based sensors using the precision time protocol. We show the usefulness of this method in a 3D measurement task, where we measure the trajectory of an industrial robot moving at high speed. The accuracy of the synchronized system is compared with that of a non-synchronized system. With synchronized sensors we obtain sub-100 micrometer accuracy, while the non-synchronized sensors produce results with both bias and random spikes.