On the Impact of Coarse Synchronization on the Performance of Broadcast/Multicast Single Frequency Network Operation in WCDMA

2008 ◽  
Author(s):  
Christoph A. Jotten ◽  
Christian Sgraja ◽  
Josef J. Blanz
Keyword(s):  
Single Frequency ◽  
Single Frequency Network ◽  
Network Operation ◽  
The Impact

scholarly journals Impact of GPS Interference on Time Synchronization of DVB-T Transmitters

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Juraj Machaj ◽  
Peter Brida ◽  
Norbert Majer ◽  
Roman Sčehovič
Keyword(s):  
Time Synchronization ◽  
Location Based Services ◽  
Single Frequency ◽  
Wireless Transmitters ◽  
Digital Video Broadcasting ◽  
Signal Distribution ◽  
Single Frequency Network ◽  
Video Broadcasting ◽  
Network Operation ◽  
The Impact

Nowadays, the Global Positioning System (GPS) is widely used in all aspects of our lives. GPS signals are not used only in positioning and navigation applications and services in transport and military, but, thanks to quite precise information about time, also for synchronization of world trade and synchronization of wireless transmitters. However, with the recent spread of location-based services, a large number of GPS jammers had appeared. Use of these jammers is prohibited by law; however, their use is gaining popularity especially in the transport segment since jammers can be used to trick vehicle onboard units and help avoid paying toll fees on highways or avoid tracking of company cars when used privately. In this paper, we will investigate the impact of GPS interference caused by jamming and spoofing on the synchronization of Single Frequency Network (SFN) Digital Video Broadcasting–Terrestrial (DVB-T) transmitters. Since GPS signals are used in the DVB-T SFN to provide synchronization which is crucial for the correct network operation, the interference of GPS signals can cause problems with signal distribution. Thus, signals received from a DVB-T SFN network might be out of synchronization and disrupt the service for users.

scholarly journals The Effect of BDS-3 Time Group Delay and Differential Code Bias Corrections on Positioning

2020 ◽  
Vol 11 (1) ◽  
pp. 104
Author(s):  
Peipei Dai ◽  
Jianping Xing ◽  
Yulong Ge ◽  
Xuhai Yang ◽  
Weijin Qin ◽  
...  
Keyword(s):  
Group Delay ◽  
Assessment System ◽  
Convergence Time ◽  
Single Frequency ◽  
Positioning Accuracy ◽  
Differential Code Bias ◽  
Receiver Clock ◽  
Code Bias ◽  
Point Positioning ◽  
The Impact

The timing group delay parameter (TGD) or differential code bias parameter (DCB) is an important factor that affects the performance of GNSS basic services; therefore, TGD and DCB must be taken seriously. Moreover, the TGD parameter is modulated in the navigation message, taking into account the impact of TGD on the performance of the basic service. International GNSS Monitoring and Assessment System (iGMAS) provides the broadcast ephemeris with TGD parameter and the Chinese Academy of Science (CAS) provides DCB products. In this paper, the current available BDS-3 TGD and DCB parameters are firstly described in detail, and the relationship of TGD and DCB for BDS-3 is figured out. Then, correction models of BDS-3 TGD and DCB in standard point positioning (SPP) or precise point positioning (PPP) are given, which can be applied in various situations. For the effects of TGD and DCB in the SPP and PPP solution processes, all the signals from BDS-3 were researched, and the validity of TGD and DCB has been further verified. The experimental results show that the accuracy of B1I, B1C and B2a single-frequency SPP with TGD or DCB correction was improved by approximately 12–60%. TGD will not be considered for B3I single-frequency, because the broadcast satellite clock offset is based on the B3I as the reference signal. The positioning accuracy of B1I/B3I and B1C/B2a dual-frequency SPP showed that the improvement range for horizontal components is 60.2% to 74.4%, and the vertical components improved by about 50% after the modification of TGD and DCB. In addition, most of the uncorrected code biases are mostly absorbed into the receiver clock bias and other parameters for PPP, resulting in longer convergence time. The convergence time can be max increased by up to 50% when the DCB parameters are corrected. Consequently, the positioning accuracy can reach the centimeter level after convergence, but it is critical for PPP convergence time and receiver clock bias that the TGD and DCB correction be considered seriously.

scholarly journals Assessment of mixed-layer height estimation from single-wavelength ceilometer profiles

2017 ◽  
Vol 10 (10) ◽  
pp. 3963-3983 ◽  
Author(s):  
Travis N. Knepp ◽  
James J. Szykman ◽  
Russell Long ◽  
Rachelle M. Duvall ◽  
Jonathan Krug ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Data Collection ◽  
Mixed Layer ◽  
A Priori ◽  
Processing Algorithm ◽  
Height Measurement ◽  
Layer Height ◽  
Network Operation ◽  
Mixed Layer Height ◽  
The Impact

Abstract. Differing boundary/mixed-layer height measurement methods were assessed in moderately polluted and clean environments, with a focus on the Vaisala CL51 ceilometer. This intercomparison was performed as part of ongoing measurements at the Chemistry And Physics of the Atmospheric Boundary Layer Experiment (CAPABLE) site in Hampton, Virginia and during the 2014 Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality (DISCOVER-AQ) field campaign that took place in and around Denver, Colorado. We analyzed CL51 data that were collected via two different methods (BLView software, which applied correction factors, and simple terminal emulation logging) to determine the impact of data collection methodology. Further, we evaluated the STRucture of the ATmosphere (STRAT) algorithm as an open-source alternative to BLView (note that the current work presents an evaluation of the BLView and STRAT algorithms and does not intend to act as a validation of either). Filtering criteria were defined according to the change in mixed-layer height (MLH) distributions for each instrument and algorithm and were applied throughout the analysis to remove high-frequency fluctuations from the MLH retrievals. Of primary interest was determining how the different data-collection methodologies and algorithms compare to each other and to radiosonde-derived boundary-layer heights when deployed as part of a larger instrument network. We determined that data-collection methodology is not as important as the processing algorithm and that much of the algorithm differences might be driven by impacts of local meteorology and precipitation events that pose algorithm difficulties. The results of this study show that a common processing algorithm is necessary for light detection and ranging (lidar)-based MLH intercomparisons and ceilometer-network operation, and that sonde-derived boundary layer heights are higher (10–15 % at midday) than lidar-derived mixed-layer heights. We show that averaging the retrieved MLH to 1 h resolution (an appropriate timescale for a priori data model initialization) significantly improved the correlation between differing instruments and differing algorithms.

Modulation and coding scheme selection in multimedia broadcast over a single frequency network-enabled long-term evolution networks

2011 ◽  
Vol 25 (12) ◽  
pp. 1603-1619 ◽  
Author(s):  
Antonios Alexiou ◽  
Christos Bouras ◽  
Vasileios Kokkinos ◽  
Andreas Papazois ◽  
George Tsichritzis
Keyword(s):  
Long Term Evolution ◽  
Single Frequency ◽  
Single Frequency Network ◽  
Coding Scheme ◽  
Term Evolution ◽  
Scheme Selection

scholarly journals Electric Vehicle Battery Performance Investigation Based on Real World Current Harmonics

Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 489 ◽  
Author(s):  
Sid-Ali Amamra ◽  
Yashraj Tripathy ◽  
Anup Barai ◽  
Andrew D. Moore ◽  
James Marco
Keyword(s):  
Electric Vehicle ◽  
Real World ◽  
Low Frequency ◽  
Single Frequency ◽  
Current Harmonics ◽  
Battery Systems ◽  
Electric Vehicle Battery ◽  
Dc Bus ◽  
Dc Current ◽  
The Impact

Electric vehicle (EV) powertrains consist of power electronic components as well as electric machines to manage the energy flow between different powertrain subsystems and to deliver the necessary torque and power requirements at the wheels. These power subsystems can generate undesired electrical harmonics on the direct current (DC) bus of the powertrain. This may lead to the on-board battery being subjected to DC current superposed with undesirable high- and low- frequency current oscillations, known as ripples. From real-world measurements, significant current harmonics perturbations within the range of 50 Hz to 4 kHz have been observed on the high voltage DC bus of the EV. In the limited literature, investigations into the impact of these harmonics on the degradation of battery systems have been conducted. In these studies, the battery systems were supplied by superposed current signals i.e., DC superposed by a single frequency alternating current (AC). None of these studies considered applying the entire spectrum of the ripple current measured in the real-world scenario, which is focused on in this research. The preliminary results indicate that there is no difference concerning capacity fade or impedance rise between the cells subjected to just DC current and those subjected additionally to a superposed AC ripple current.

scholarly journals Technological Innovation in the Aspect of Safety in the Process of Heat Supply

2019 ◽  
Vol 1 (1) ◽  
pp. 412-418
Author(s):  
Aleksandra Wrzalik ◽  
Matevž Obrecht
Keyword(s):  
Energy Efficiency ◽  
Heat Supply ◽  
Renewable Energy Sources ◽  
District Heating ◽  
High Energy ◽  
The European Union ◽  
Heating Systems ◽  
Operation Conditions ◽  
Network Operation ◽  
The Impact

AbstractIn recent years heating in Poland has been transformed as a result of the priorities of the country's energy policy implemented within the European Union. The increase in energy security, the development of renewable energy sources and the fulfilment of legal and environmental requirements are very important. Exploitation of district heating systems should ensure reliable and safe heat supplies for industrial and municipal customers with high energy efficiency and reduction of environmental impact. The article discusses the conditions and directions of centralized heating systems development as well as technical and economic issues, which are important for the security of heat supply. The Author describes selected technological innovations used in the technical infrastructure for heat transfer and modern IT systems which are improving the management of heating systems. The article includes the results of simulation research with use of IT tools showing the impact of selected innovations on the improvement of network operation conditions. Directions of modernization of heating systems in the aspect of increasing energy efficiency and security of heat supply have also been indicted here.

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