166 research outputs found
Time Synchronization for 5G and TSN Integrated Networking
Emerging industrial applications involving robotic collaborative operations
and mobile robots require a more reliable and precise wireless network for
deterministic data transmission. To meet this demand, the 3rd Generation
Partnership Project (3GPP) is promoting the integration of 5th Generation
Mobile Communication Technology (5G) and Time-Sensitive Networking (TSN). Time
synchronization is essential for deterministic data transmission. Based on the
3GPP's vision of the 5G and TSN integrated networking with interoperability, we
improve the time synchronization of TSN to conquer the multi-gNB competition,
re-transmission, and mobility problems for the integrated 5G time
synchronization. We implemented the improvement mechanisms and systematically
validated the performance of 5G+TSN time synchronization. Based on the
simulation in 500m x 500m industrial environments, the improved time
synchronization achieved a precision of 1 microsecond with interoperability
between 5G nodes and TSN nodes
A Sub-Terahertz Sliding Correlator Channel Sounder with Absolute Timing using Precision Time Protocol over Wi-Fi
Radio channels at mmWave and sub-THz frequencies for 5G and 6G communications
offer large channel bandwidths (hundreds of MHz to several GHz) to achieve
multi-Gbps data rates. Accurate modeling of the radio channel for these wide
bandwidths requires capturing the absolute timing of multipath component (MPC)
propagation delays with sub-nanosecond accuracy. Achieving such timing accuracy
is challenging due to clock drift in untethered transmitter (TX) and receiver
(RX) clocks used in time-domain channel sounders, yet will become vital in many
future 6G applications. This paper proposes a novel solution utilizing
precision time protocol (PTP) and periodic drift correction to achieve absolute
timing for MPCs in power delay profiles (PDPs) --captured as discrete samples
using sliding correlation channel sounders. Two RaspberryPi computers are
programmed to implement PTP over a dedicated Wi-Fi link and synchronize the TX
and RX Rubidium clocks continuously every second. This synchronization
minimizes clock drift, reducing PDP sample drift to 150 samples/hour, compared
to several thousand samples/hour without synchronization. Additionally, a
periodic drift correction algorithm is applied to eliminate PDP sample drift
and achieve sub-nanosecond timing accuracy for MPC delays. The achieved
synchronicity eliminates the need for tedious and sometimes inaccurate ray
tracing to synthesize omnidirectional PDPs from directional measurements. The
presented solution shows promise in myriad applications, including precise
position location and distributed systems that require sub-nanosecond timing
accuracy and synchronization among components.Comment: 6 pages, 7 figures, 3 tables, IEEE Global Communications Conference
(GLOBECOM) 202
Tarkan ja luotettavan ajan siirto kantaverkossa
This master’s thesis is about time distribution that supports substation applications needed for power transmission. The work was done for the Telecommunication department of Finland’s power transmission system operator Fingrid Oyj. This thesis answers to the following question: What is the need for accurate and synchronized time in power substations and how it will be delivered?
Fingrid’s telecommunication network supports the power transmission grid and its operation. Telecommunication network can distribute time to power substations for the applications that need synchronized and accurate time. Current telecommunication equipment used in Fingrid is getting old and new techniques are planned to be implemented. When Fingrid is acquiring new communication equipment, they need to set requirements on the capability to distribute time. This thesis is an initial effort to investigate time distribution requirements for Fingrid’s needs. This thesis aids Fingrid Telecommunication department to define requirements for time distribution.
For this thesis, I met with multiple Fingrid professionals, telecommunication device suppliers and time distribution researchers. This thesis answers to its research questions by means of a literature review and interviews.Tämä diplomityö käsittelee ajansiirron vaikutusta sähköasemasovellusten toimintaan. Työ tehtiin Suomen kantaverkkoyhtiö Fingrid Oyj:n tietoliikenneyksikölle.
Fingridin tietoliikenneverkko on osa kantaverkkoa ja mahdollistaa sähköjärjestelmän toiminteita. Tietoliikenneverkon yksi palvelu on synkronoidun ajan siirtäminen sähköasemille. Nykyinen tietoliikennetekniikka on vanhenemassa ja uutta laitteistoa suunnitellaan hankittavaksi ja testattavaksi. Tämän diplomityön tarkoitus on selvittää mikä on järkevä tapa toteuttaa ajan siirto ja kuinka tarkkaa sen pitää olla. Työ auttaa tietoliikenneyksikköä hankinnan vaatimusmäärittelyssä ajansiirron osalta.
Työtä varten on tavattu monia Fingridin asiantuntijoita, tietoliikennelaitetoimittajia sekä ajansiirron asiantuntijoita. Työ vastaa tutkimuskysymykseen kirjallisuuskatsauksen ja haastattelujen perusteella
Study and Design of Inter-Range Instrumentation Group Time Code B Synchronization of IEC 61850 Sampled Values
Distribution substations are an important part of a chain which delivers energy from power production to customers. They transform the voltage level from transmission levels, usually 35kV and up, to distribution levels ranging between 600 and 35000 V. Recent developments in the instrument transformer field have been toward low-power solutions which use digital measurement values called sampled values in place of analog voltages and currents in substations.
The IEC 61850-9-2 standard and its implementation guideline 9-2 LE by the UCA international users group define an interface for sampled values. This interface is used between an IED and LPIT. The main requirement of using sampled values is accurate time synchronization in order to prevent phase misalignment resulting in unnecessary protection function tripping. 9-2 LE defines two methods for synchronization: 1PPS and PTP. Today, PTP is widely used in the western markets, but due to costs associated with PTP-capable GPS clocks and Ethernet switches as well as vendor inoperability problems, some markets are hesitant to take into use. The purpose of this thesis is to propose a solution to this problem: use IRIG-B as a synchronization method in a PTP grandmaster.
This paper discusses the differences between these two time synchronization topologies, associated costs, disturbance handling, accuracy and it also discusses the design of IRIG-B to PTP conversion done in a bay-level device. The device acts as a PTP grandmaster but the source comes from an IRIG-B clock instead of a GPS PTP grandmaster clock. The results shown in this thesis demonstrate that using IRIG-B as a main or redundant source in synchronization of sampled values is a more cost-effective option, especially if the station is to be retrofitted with sampled values configuration. The proposed bay level device also maintains the desired accuracy levels of ±1 µs set by IEC 61850-5.fi=Opinnäytetyö kokotekstinä PDF-muodossa.|en=Thesis fulltext in PDF format.|sv=Lärdomsprov tillgängligt som fulltext i PDF-format
Timing Signals and Radio Frequency Distribution Using Ethernet Networks for High Energy Physics Applications
Timing networks are used around the world in various applications from telecommunications systems to industrial processes, and from radio astronomy to high energy physics. Most timing networks are implemented using proprietary technologies at high operation and maintenance costs. This thesis presents a novel timing network capable of distributed timing with subnanosecond accuracy. The network, developed at CERN and codenamed “White- Rabbit”, uses a non-dedicated Ethernet link to distribute timing and data packets without infringing the sub-nanosecond timing accuracy required for high energy physics applications. The first part of this thesis proposes a new digital circuit capable of measuring time differences between two digital clock signals with sub-picosecond time resolution. The proposed digital circuit measures and compensates for the phase variations between the transmitted and received network clocks required to achieve the sub-nanosecond timing accuracy. Circuit design, implementation and performance verification are reported. The second part of this thesis investigates and proposes a new method to distribute radio frequency (RF) signals over Ethernet networks. The main goal of existing distributed RF schemes, such as Radio-Over-Fibre or Digitised Radio-Over-Fibre, is to increase the bandwidth capacity taking advantage of the higher performance of digital optical links. These schemes tend to employ dedicated and costly technologies, deemed unnecessary for applications with lower bandwidth requirements. This work proposes the distribution of RF signals over the “White-Rabbit” network, to convey phase and frequency information from a reference base node to a large numbers of remote nodes, thus achieving high performance and cost reduction of the timing network. Hence, this thesis reports the design and implementation of a new distributed RF system architecture; analysed and tested using a purpose-built simulation environment, with results used to optimise a new bespoke FPGA implementation. The performance is evaluated through phase-noise spectra, the Allan-Variance, and signalto- noise ratio measurements of the distributed signals
10 Gigabit White Rabbit: sub-nanosecond timing and data distribution
Time synchronization is a critical feature for many scientific facilities and industrial
infrastructures. The required performance is progressively increasing everyday, for instance, few tens of
nanoseconds for Fifth Generation (5G) networks or sub-nanosecond accuracy on next family of particle
accelerators and astrophysics telescopes. Due to this exigent accuracy, many applications require specific
timing dedicated networks, increasing the system cost and complexity. Under this context, the new IEEE
1588-2019 High Accuracy (HA) default profile is intensively based on White Rabbit (WR) which can
provide sub-nanosecond accurate synchronization for Ethernet networks. However, current WR solutions
have not been designed to work properly with high data bandwidth delivery services even in 1 Gigabit
Ethernet (GbE) links. On this contribution, the authors propose a new architecture design that enables WR
and, consequently, the IEEE 1588-2019 HA profile to be deployed over 10 GbE links solving the already
identified data bandwidth problem. Furthermore, this work addresses different experiments needed to
characterize the system performance in terms of time synchronization and data transfer. As final result, this
contribution presents for the first time in the literature a new WR system which allows high bandwidth data
exchange in 10 GbE networks while providing sub-nanosecond accuracy synchronization. The proposed
solution maintains the time synchronization performance of existing WR 1 GbE devices with significant
advantages in terms of latency and data bandwidth, enabling its deployment in applications that integrate
data and synchronization information in the same network.European Union (EU)
725490H2020 ASTERICS
653477AMIGA7
RTI2018-096228-B-C3
Multichannel Time Synchronization Based on PTP through a High Voltage Isolation Buffer Network Interface for Thick-GEM Detectors
Data logging and complex algorithm implementations acting on multichannel systems with independent devices require the use of time synchronization. In the case of Gas Electron Multipliers (GEM) and Thick-GEM (THGEM) detectors, the biasing potential can be generated at the detector level via DC to DC converters operating at floating voltage. In this case, high voltage isolation buffers may be used to allow communication between the different channels. However, their use add non-negligible delays in the transmission channel, complicating the synchronization. Implementation of a simplified precise time protocol is presented for handling the synchronization on the Field Programmable Gate Array (FPGA) side of a Xilinx SoC Zynq ZC7Z030. The synchronization is done through a high voltage isolated bidirectional network interface built on a custom board attached to a commercial CIAA_ACC carrier. The results of the synchronization are shown through oscilloscope captures measuring the time drift over long periods of time, achieving synchronization in the order of nanoseconds
Aggregated Reverse Time Transfer
Monitoring mechanisms are a critical component of the security and maintenance of high precision timing networks. Any and all guarantees of determinism and correctness are invalidated if a synchronous network malfunctions or is compromised by an attacker. Existing mechanisms allow for a comprehensive view of the distribution of time throughout a network, but they do not scale to large networks. I propose a new method called aggregated reverse time transfer (ARTT), which redefines the existing mechanisms to include a new aggregation scheme that serves the dual purpose of distributed data summarization and anomaly detection for networks of any size. With this thesis I provide a full specification and implementation of the ARTT mechanism, test both the outlier detection and model accuracy on a real timing network, and detail the steps necessary to perform stable-state outlier detection and aggregation on large-scale networks
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