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.

μPMU based on wireless IEEE 1588 PTP

Abstract: An important application in the Smart Grid area is the large-scale application of measuring systems in Distribution Networks (DNs) with the Micro Phasor Measurement Unit ($\mu$PMU). The majority of traditional $\mu$PMUs and Phasor Measurement Units (PMUs) use GPS as time synchronization signals. However, this time synchronization system limits the installation of $\mu$PMUs only to outdoor applications and they will remain expensive. In this context, IEEE 1588 comes as an effective way to enhance performance in time synchronization, it can allow microsecond accuracy and is designed for wired and wireless networks. Moreover, the wireless Precision Time Protocol (PTP) reduces the convergence time and the number of packets required for synchronization without compromising on the synchronization accuracy. On the other hand, using the embedded systems the Micro Phasor Measurement Unit ($\mu$PMU) becomes possible since the volume of PMU will be small and easy to be installed. This paper proposes a novel PMU synchronized by a wireless IEEE 1588 Precision Time Protocol (WPTP) which enables precise synchronization of clocks via packet networks.

SDH (Synchronous Digital Hierarchy)-based multi-time source PTP (Precision Time Protocol) data synchronization and time monitoring system

Abstract: The invention provides an SDH (Synchronous Digital Hierarchy)-based multi-time source PTP (Precision Time Protocol) data synchronization and time monitoring system. According to the system, time source signal filtering and protocol conversion are realized based on an FPGA; high-speed analysis, real-time comparison and sorting of multi-time source information can be realized based on a DPS kernel; and most accurate time signals are automatically selected as output time information. When the time monitoring system operates, the IEC61850 standard can be satisfied, a multi-time source information acquisition statistics table can be built, and functions such as remote transmission, on-site check and query of information can be realized.

An enhanced end-to-end transparent clock mechanism for the kernel-based virtual machines

Abstract: Keeping a high-precision time base in cloud clusters is still a big challenge, even using the Precision Time Protocol version 2 (PTPv2) specified in IEEE 1588. One of the main factors on this issue is that too many uncertainties in the network path from the master clock to the slave one, which is likely residing on the Kernel-based Virtual Machine (KVM). The Transparent Clock (TC) of PTPv2 may be useful to solve this issue. However, at present the network I/O path in the virtual machine environment has not been considered in such works, which seriously affect the performance of the synchronization accuracy. In this work, we make improvements in the kernel network stack to manipulate the PTP frames to record the residence time for the path from the physical machine to the virtual machine, making its network I/O architecture an End-to-End Transparent Clock (E2E TC). Although the idea of E2E TC for more accurate synchronization is not new, there is no such implementation publicized for the virtualized environment, as far as we know. The proposed mechanism is specifically tailored to make latency corrections for the neglected routing path between the physical Network Interface Card (NIC) and the virtual machines. Extensive experiments and tests show that this approach makes quite significant improvement of about 50%.

Signal Detection and Estimation for MIMO radar and Network Time Synchronization

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