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This paper describes the development of a concept for a European GNSS based robust synchronization service. The service concept is designed upon the infrastructure of the Galileo and EGNOS systems and includes specific features for establishing a robust service suitable for critical infrastructures.
In this paper, we propose a new technique for synchronization and channel estimation in M-QAM OFDM radio over fiber (RoF) system by using constant amplitude zero auto-correlation (CAZAC) sequence based training preamble. Delay and correlate method is used to identify the training sequence in the received signal vector and to correct the symbol timing offset. For an optimum demodulation of OFDM signal,...
Detection and localization of vessels can be carried out by exploiting the radiolocation approach. Nevertheless, the employment of radiolocalization far from the shore can be limited by the lack of enough receivers to perform a correct multi-lateration of the RF source. In order to solve this gap, mobile assets or base stations from different networks need to be exploited. In particular, within a...
DEMETRA aims to be a prototype of an European time dissemination service, based on the timing signal of the European Galileo system, adding particular features like - among the others - certification, calibration, or integrity, that could be of interest to a wide range of users belonging to different sectors as traffic control, energy distribution, finance, telecommunication, and scientific institutions...
White Rabbit (WR) emerged as an OpenSource and OpenHardware project from CERN, due to stringent timing requirements for data recording in the Large Hadron Collider project. It provides picosecond accuracy timing based on a 1 Gigabit Ethernet (1GE) fibre data network, where all routers are specialised White Rabbit hardware. WR is built over the IEEE Precision Time Protocol (PTP IEEE 1588-2008). The...
As an overlay cognitive radio, transform domain communication system (TDCS) has been proposed to support reliable communications with low probability of interception. However, most of research on TDCS assume perfect synchronization to simplify algorithm design. In this paper, we present a low complexity symbol timing offset (STO) and carrier frequency offset (CFO) estimation method for practical TDCS...
Electricity companies will only allow customers to inject power into the grid network if the customer's system is in synch with both frequency and phase as the grid itself. This is normally achieved using a specialised machine sold by the energy provider. It may be possible to achieve this via low cost, low power nodes such as a Raspberry Pi, to synchronize frequency and phase as well as voltage and...
In this paper, a novel timestamp-free synchronization algorithm is proposed where no dedicated timing messages are exchanged; the synchronization algorithm is embedded in the existing network messages. The proposed algorithm is intended for networks where many messages are transferred from the sensor to the central communication node, but only a few messages are transmitted from the central communication...
Device-to-device (D2D) communication is an emerging technique that can reduce device transmission power and enhance cellular capacity, which allows direct communication between two mobile devices. Amount of small packets may exchange between devices in burst mode transmission with the constraint of low overhead and low complexity for energy efficient processing. One of the major challenges for outband...
The paper describes the mechanism of Agilent 3458A sampling time jitter present when external triggering is used at synchronous two channel sampling. Based on measurements it is shown that the master DMM adds approximately 3.2 ns of its own time jitter while triggering the slave DMM and that the effective time jitter for externally triggered DMM remains at 7 ns, well below ±50 ns maximum jitter as...
Low swing clocking is a low power design methodology that scales the clock voltage to decrease power consumption of the clock distribution networks, with an expected degradation in the performance. In this work, a novel low swing clock tree synthesis methodology is combined with a custom low swing clock-aware D flip-flop (DFF) design. The low swing clocking serves to reduce the power dissipation whereas...
Balanced optical-microwave phase detectors (BOMPD) based on fiber Sagnac interferometers and single-ended heterodyne detection are capable of optical-to-RF conversion with sub-femtosecond residual timing jitter. By increasing the BOMPD phase sensitivity and reducing its internal noise down to the thermal noise limit, we achieve an integrated noise floor in the sub-fs regime. Second, we demonstrate...
We present recent progress made in optical, high-precision, long-term stable timing distribution systems for synchronization of next generation X-ray free-electron lasers. Timing jitter characterization of the optical master oscillator shows less than 170 as integrated jitter for frequencies above 10 kHz, limited by the detection noise floor. Timing stabilization of a 3.5-km polarization maintaining...
In this paper, a new and efficient approach for Orthogonal Frequency-Division Multiplexing (OFDM) timing offset error estimation has been presented without using pilot signal. The effect of timing offset on bit error rate (BER) has been analyzed using BPSK, QPSK, 8-PSK modulation scheme and an analytical expression has been derived using probabilistic equation to estimate timing offset. This will...
This paper discusses the use of the Ptides model of computation as a coordination language for the design of deterministic, event-driven, real-time, distributed embedded systems. Specifically, the paper shows how the use of synchronized clocks in the context of Ptides enables explicit, platform independent specification of functionality and timing. From this specification, we generate code for two...
This corrigendum to IEEE Std 802.1AS - 2011 corrects minor errors, bugs, ambiguities, and inconsistencies that were missed when the document was balloted. It does not contain new material.
This paper presents an industry experience and research-based analysis of issues that the deployment of PTP as a service is facing in the finance industry, based on real life examples from a global stock exchange operator. It aims to summarise over three years of author's experience with deploying PTP, highlighting the most common problems encountered: standard specific, implementation specific and...
This paper describes a series of programming assignments associated with a first course on digital communications. The programs build upon one another and progress toward an innovative final programming project that is completed during the last six weeks of the semester. Using black-and-white (1 bit per pixel) images as the message bits to be transmitted, the instructor synthesizes a set of modulated...
Over the last twenty years, many technologies and services have come to rely on the GPS for precise timing. Concern is increasing about the wisdom of being reliant on a single timing solution provided by a single country and because of the susceptibility of the GPS signal to unintentional interference, jamming and spoofing. In this paper, we report on further development of our system for timing signal...
Nowadays, correlator is a crucial part of communication systems. The correlation function has a great practical importance when it is necessary to process a signal in the presence of noise. Use of correlator in modern communication system have more precise frequency and timing synchronization, which improves its ability against interference of multipath and frequency selective fading channels. Even...
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