Non-LTE effects in inertial confinement fusion target chambers

International Nuclear Information System (INIS)

MacFarlane, J.J.; Moses, G.A.; Peterson, R.R.

1989-01-01

In previous studies of transport processes in inertial confinement fusion target chambers, the radiative properties of the background plasma were calculated under the assumption of local thermodynamic equilibrium (LTE). In this paper, the authors present a study of the equation of state and the radiative properties of high temperature, low-to-moderate density ( 21 cm -3 ) plasmas for the determination of the conditions under which non-LTE effects become important and for an assessment of the importance of non-LTE processes in target chambers during high yield inertial fusion target explosions. For this purpose, two-body (radiative and dielectronic) and three-body (collisional) recombination and de-excitation processes are considered in calculating the steady state ionization and excitation populations. The results of this study indicate that non-LTE processes generally become important at temperatures of > or approx. 1, 10 and 100 eV for plasma densities of 10 18 , 10 19 and 10 21 cm -3 , respectively. Radiation hydrodynamic simulations utilizing the equation of state and the opacities for a non-LTE argon plasma were performed to study the response of a background gas to an inertial fusion target explosion. These calculations indicate that non-LTE processes are often the dominant atomic processes in the background plasma and that they can strongly affect the radiative and shock properties as energy is transported away from the point of the target explosion. (author). 22 refs, 10 figs, 1 tab

Non local-thermodynamical-equilibrium effects in the simulation of laser-produced plasmas

Science.gov (United States)

Klapisch, M.; Bar-Shalom, A.; Oreg, J.; Colombant, D.

1998-05-01

Local thermodynamic equilibrium (LTE) breaks down in directly or indirectly driven laser plasmas because of sharp gradients, energy deposition, etc. For modeling non-LTE effects in hydrodynamical simulations, Busquet's model [Phys. Fluids B 5, 4191 (1993)] is very convenient and efficient. It uses off-line generated LTE opacities and equation of states via an effective, radiation-dependent ionization temperature Tz. An overview of the model is given. The results are compared with an elaborate collisional radiative model based on superconfigurations. The agreements for average charge Z* and opacities are surprisingly good, even more so when the plasma is immersed in a radiation field. Some remaining discrepancy at low density is attributed to dielectronic recombination. Improvement appears possible, especially for emissivities, because the concept of ionization temperature seems to be validated.

Non local-thermodynamical-equilibrium effects in the simulation of laser-produced plasmas

International Nuclear Information System (INIS)

Klapisch, M.; Bar-Shalom, A.; Oreg, J.; Colombant, D.

1998-01-01

Local thermodynamic equilibrium (LTE) breaks down in directly or indirectly driven laser plasmas because of sharp gradients, energy deposition, etc. For modeling non-LTE effects in hydrodynamical simulations, Busquet close-quote s model [Phys. Fluids B 5, 4191 (1993)] is very convenient and efficient. It uses off-line generated LTE opacities and equation of states via an effective, radiation-dependent ionization temperature T z . An overview of the model is given. The results are compared with an elaborate collisional radiative model based on superconfigurations. The agreements for average charge Z * and opacities are surprisingly good, even more so when the plasma is immersed in a radiation field. Some remaining discrepancy at low density is attributed to dielectronic recombination. Improvement appears possible, especially for emissivities, because the concept of ionization temperature seems to be validated. copyright 1998 American Institute of Physics

Influence of condensed species on thermo-physical properties of LTE and non-LTE SF6-Cu mixture

Science.gov (United States)

Chen, Zhexin; Wu, Yi; Yang, Fei; Sun, Hao; Rong, Mingzhe; Wang, Chunlin

2017-10-01

SF6-Cu mixture is frequently formed in high-voltage circuit breakers due to the electrode erosion and metal vapor diffusion. During the interruption process, the multiphase effect and deviation from local thermal equilibrium (non-LTE assumption) can both affect the thermo-physical of the arc plasma and further influence the performance of circuit breaker. In this paper, thermo-physical properties, namely composition, thermodynamic properties and transport coefficients are calculated for multiphase SF6-Cu mixture with and without LTE assumption. The composition is confirmed by combining classical two-temperature mass action law with phase equilibrium condition deduced from second law of thermodynamics. The thermodynamic properties and transport coefficients are calculated using the multiphase composition result. The influence of condensed species on thermo-physical properties is discussed at different temperature, pressure (0.1-10 atm), non-equilibrium degrees (1-10), and copper molar proportions (0-50%). It is found that the multiphase effect has significant influence on specific enthalpy, specific heat and heavy species thermal conductivity in both LTE and non-LTE SF6-Cu system. This paper provides a more accurate database for computational fluid dynamic calculation.

Influence of condensed species on thermo-physical properties of LTE and non-LTE SF6–Cu mixture

International Nuclear Information System (INIS)

Chen, Zhexin; Wu, Yi; Yang, Fei; Sun, Hao; Rong, Mingzhe; Wang, Chunlin

2017-01-01

SF 6 –Cu mixture is frequently formed in high-voltage circuit breakers due to the electrode erosion and metal vapor diffusion. During the interruption process, the multiphase effect and deviation from local thermal equilibrium (non-LTE assumption) can both affect the thermo-physical of the arc plasma and further influence the performance of circuit breaker. In this paper, thermo-physical properties, namely composition, thermodynamic properties and transport coefficients are calculated for multiphase SF 6 –Cu mixture with and without LTE assumption. The composition is confirmed by combining classical two-temperature mass action law with phase equilibrium condition deduced from second law of thermodynamics. The thermodynamic properties and transport coefficients are calculated using the multiphase composition result. The influence of condensed species on thermo-physical properties is discussed at different temperature, pressure (0.1–10 atm), non-equilibrium degrees (1–10), and copper molar proportions (0–50%). It is found that the multiphase effect has significant influence on specific enthalpy, specific heat and heavy species thermal conductivity in both LTE and non-LTE SF 6 –Cu system. This paper provides a more accurate database for computational fluid dynamic calculation. (paper)

Non-LTE line-blanketed model atmospheres of hot stars. 2: Hot, metal-rich white dwarfs

Science.gov (United States)

Lanz, T.; Hubeny, I.

1995-01-01

We present several model atmospheres for a typical hot metal-rich DA white dwarf, T(sub eff) = 60,000 K, log g = 7.5. We consider pure hydrogen models, as well as models with various abundances of two typical 'trace' elements-carbon and iron. We calculte a number of Local Thermodynamic Equilibrium (LTE) and non-LTE models, taking into account the effect of numerous lines of these elements on the atmospheric structure. We demostrate that while the non-LTE effects are notvery significant for pure hydrogen models, except for describing correctly the central emission in H-alpha they are essential for predicting correctly the ionization balance of metals, such as carbon and iron. Previously reported discrepancies in LTE abundances determinations using C III and C IV lines are easily explained by non-LTE effects. We show that if the iron abundance is larger than 10(exp -5), the iron line opacity has to be considered not only for the spectrum synthesis, but also in the model construction itself. For such metal abundances, non-LTE metal line-blanketed models are needed for detailed abundance studies of hot, metal-rich white dwarfs. We also discuss the predicted Extreme Ultraviolet (EUV) spectrum and show that it is very sensitive to metal abundances, as well as to non-LTE effects.

'LTE-diffusion approximation' for arc calculations

International Nuclear Information System (INIS)

Lowke, J J; Tanaka, M

2006-01-01

This paper proposes the use of the 'LTE-diffusion approximation' for predicting the properties of electric arcs. Under this approximation, local thermodynamic equilibrium (LTE) is assumed, with a particular mesh size near the electrodes chosen to be equal to the 'diffusion length', based on D e /W, where D e is the electron diffusion coefficient and W is the electron drift velocity. This approximation overcomes the problem that the equilibrium electrical conductivity in the arc near the electrodes is almost zero, which makes accurate calculations using LTE impossible in the limit of small mesh size, as then voltages would tend towards infinity. Use of the LTE-diffusion approximation for a 200 A arc with a thermionic cathode gives predictions of total arc voltage, electrode temperatures, arc temperatures and radial profiles of heat flux density and current density at the anode that are in approximate agreement with more accurate calculations which include an account of the diffusion of electric charges to the electrodes, and also with experimental results. Calculations, which include diffusion of charges, agree with experimental results of current and heat flux density as a function of radius if the Milne boundary condition is used at the anode surface rather than imposing zero charge density at the anode

Deviations from LTE in a stellar atmosphere

International Nuclear Information System (INIS)

Kalkofen, W.; Klein, R.I.; Stein, R.F.

1979-01-01

Deviations from LTE are investigated in an atmosphere of hydrogen atoms with one bound level, satisfying the equations of radiative, hydrostatic, and statistical equilibrium. The departure coefficient and the kinetic temperature as functions of the frequency dependence of the radiative cross section are studied analytically and numerically. Near the outer boundary of the atmosphere, the departure coefficient b is smaller than unity when the radiative cross section αsub(ν) grows with frequency ν faster than ν 2 ; b exceeds unity otherwise. Far from the boundary the departure coefficient tends to exceed unity for any frequency dependence of αsub(ν). Overpopulation (b > 1) always implies that the kinetic temperature in the statistical equilibrium atmosphere is higher than the temperature in the corresponding LTE atmosphere. Upper and lower bounds on the kinetic temperature are given for an atmosphere with deviations from LTE only in the optically shallow layers when the emergent intensity can be described by a radiation temperature. (author)

Deviations from LTE in a stellar atmosphere

Science.gov (United States)

Kalkofen, W.; Klein, R. I.; Stein, R. F.

1979-01-01

Deviations for LTE are investigated in an atmosphere of hydrogen atoms with one bound level, satisfying the equations of radiative, hydrostatic, and statistical equilibrium. The departure coefficient and the kinetic temperature as functions of the frequency dependence of the radiative cross section are studied analytically and numerically. Near the outer boundary of the atmosphere, the departure coefficient is smaller than unity when the radiative cross section grows with frequency faster than with the square of frequency; it exceeds unity otherwise. Far from the boundary the departure coefficient tends to exceed unity for any frequency dependence of the radiative cross section. Overpopulation always implies that the kinetic temperature in the statistical-equilibrium atmosphere is higher than the temperature in the corresponding LTE atmosphere. Upper and lower bounds on the kinetic temperature are given for an atmosphere with deviations from LTE only in the optically shallow layers when the emergent intensity can be described by a radiation temperature.

Non-LTE radiating acoustic shocks and Ca II K2V bright points

Science.gov (United States)

Carlsson, Mats; Stein, Robert F.

1992-01-01

We present, for the first time, a self-consistent solution of the time-dependent 1D equations of non-LTE radiation hydrodynamics in solar chromospheric conditions. The vertical propagation of sinusoidal acoustic waves with periods of 30, 180, and 300 s is calculated. We find that departures from LTE and ionization recombination determine the temperature profiles of the shocks that develop. In LTE almost all the thermal energy goes into ionization, so the temperature rise is very small. In non-LTE, the finite transition rates delay the ionization to behind the shock front. The compression thus goes into thermal energy at the shock front leading to a high temperature amplitude. Further behind the shock front, the delayed ionization removes energy from the thermal pool, which reduces the temperature, producing a temperature spike. The 180 s waves reproduce the observed temporal changes in the calcium K line profiles quite well. The observed wing brightening pattern, the violet/red peak asymmetry and the observed line center behavior are all well reproduced. The short-period waves and the 5 minute period waves fail especially in reproducing the observed behavior of the wings.

Statistical equilibrium calculations for silicon in early-type model stellar atmospheres

International Nuclear Information System (INIS)

Kamp, L.W.

1976-02-01

Line profiles of 36 multiplets of silicon (Si) II, III, and IV were computed for a grid of model atmospheres covering the range from 15,000 to 35,000 K in effective temperature and 2.5 to 4.5 in log (gravity). The computations involved simultaneous solution of the steady-state statistical equilibrium equations for the populations and of the equation of radiative transfer in the lines. The variables were linearized, and successive corrections were computed until a minimal accuracy of 1/1000 in the line intensities was reached. The common assumption of local thermodynamic equilibrium (LTE) was dropped. The model atmospheres used also were computed by non-LTE methods. Some effects that were incorporated into the calculations were the depression of the continuum by free electrons, hydrogen and ionized helium line blocking, and auto-ionization and dielectronic recombination, which later were found to be insignificant. Use of radiation damping and detailed electron (quadratic Stark) damping constants had small but significant effects on the strong resonance lines of Si III and IV. For weak and intermediate-strength lines, large differences with respect to LTE computations, the results of which are also presented, were found in line shapes and strengths. For the strong lines the differences are generally small, except for the models at the hot, low-gravity extreme of the range. These computations should be useful in the interpretation of the spectra of stars in the spectral range B0--B5, luminosity classes III, IV, and V

Collisional-radiative switching - A powerful technique for converging non-LTE calculations

Science.gov (United States)

Hummer, D. G.; Voels, S. A.

1988-01-01

A very simple technique has been developed to converge statistical equilibrium and model atmospheric calculations in extreme non-LTE conditions when the usual iterative methods fail to converge from an LTE starting model. The proposed technique is based on a smooth transition from a collision-dominated LTE situation to the desired non-LTE conditions in which radiation dominates, at least in the most important transitions. The proposed approach was used to successfully compute stellar models with He abundances of 0.20, 0.30, and 0.50; Teff = 30,000 K, and log g = 2.9.

Improved non-LTE simulation algorithm

Science.gov (United States)

Busquet, Michel; Klapisch, Marcel; Colombant, Denis; Fyfe, David; Gardner, John

2008-11-01

The RAdiation Dependent Ionization Model (RADIOM)- a.k.a Busquet's model-[1] has proven its success in simulating non --LTE effects in laser fusion plasmas [2]. This improved algorithm can take into account Auger effect by a new parameter fitted to SCROLL [3] results. It is independent of the photon binning thanks to a projection on a standard grid. It guarantees smoother convergence to LTE. This algorithm has been implemented in a new way in the hydro-code FASTnD. Hydro simulations on the recent subMJ targets[4], with and without non-LTE corrections will be shown. [1] M. Busquet, Phys. Fluids B 5, 4191(1993). [2] D.G. Colombant et al, Phys. Plas. 7,2046 (2000). [3] A. Bar-Shalom, J. Oreg M. Klapisch, J. Quant. Spectr. Rad. Transf. 65 ,43 (2000). [4] S. P. Obenschain, D. G. Colombant, A. J. Schmitt et al., Phys. Plasmas 13, 056320 (2006).

Radiation dependent ionization model

International Nuclear Information System (INIS)

Busquet, M.

1991-01-01

For laser created plasma simulation, hydrodynamics codes need a non-LTE atomic physics package for both EOS and optical properties (emissivity and opacity). However in XRL targets as in some ICF targets, high Z material can be found. In these cases radiation trapping can induce a significant departure from the optically thin ionization description. The authors present a method to change an existing LTE code into a non-LTE code with coupling of ionization to radiation. This method has very low CPU cost and can be used in 2D simulations

NON-EQUILIBRIUM IONIZATION MODELING OF THE CURRENT SHEET IN A SIMULATED SOLAR ERUPTION

International Nuclear Information System (INIS)

Shen Chengcai; Reeves, Katharine K.; Raymond, John C.; Murphy, Nicholas A.; Ko, Yuan-Kuen; Lin Jun; Mikić, Zoran; Linker, Jon A.

2013-01-01

The current sheet that extends from the top of flare loops and connects to an associated flux rope is a common structure in models of coronal mass ejections (CMEs). To understand the observational properties of CME current sheets, we generated predictions from a flare/CME model to be compared with observations. We use a simulation of a large-scale CME current sheet previously reported by Reeves et al. This simulation includes ohmic and coronal heating, thermal conduction, and radiative cooling in the energy equation. Using the results of this simulation, we perform time-dependent ionization calculations of the flow in a CME current sheet and construct two-dimensional spatial distributions of ionic charge states for multiple chemical elements. We use the filter responses from the Atmospheric Imaging Assembly (AIA) on the Solar Dynamics Observatory and the predicted intensities of emission lines to compute the count rates for each of the AIA bands. The results show differences in the emission line intensities between equilibrium and non-equilibrium ionization. The current sheet plasma is underionized at low heights and overionized at large heights. At low heights in the current sheet, the intensities of the AIA 94 Å and 131 Å channels are lower for non-equilibrium ionization than for equilibrium ionization. At large heights, these intensities are higher for non-equilibrium ionization than for equilibrium ionization inside the current sheet. The assumption of ionization equilibrium would lead to a significant underestimate of the temperature low in the current sheet and overestimate at larger heights. We also calculate the intensities of ultraviolet lines and predict emission features to be compared with events from the Ultraviolet Coronagraph Spectrometer on the Solar and Heliospheric Observatory, including a low-intensity region around the current sheet corresponding to this model

X-RAY SIGNATURES OF NON-EQUILIBRIUM IONIZATION EFFECTS IN GALAXY CLUSTER ACCRETION SHOCK REGIONS

International Nuclear Information System (INIS)

Wong, Ka-Wah; Sarazin, Craig L.; Ji Li

2011-01-01

The densities in the outer regions of clusters of galaxies are very low, and the collisional timescales are very long. As a result, heavy elements will be under-ionized after they have passed through the accretion shock. We have studied systematically the effects of non-equilibrium ionization for relaxed clusters in the ΛCDM cosmology using one-dimensional hydrodynamic simulations. We found that non-equilibrium ionization effects do not depend on cluster mass, but depend strongly on redshift which can be understood by self-similar scaling arguments. The effects are stronger for clusters at lower redshifts. We present X-ray signatures such as surface brightness profiles and emission lines in detail for a massive cluster at low redshift. In general, soft emission (0.3-1.0 keV) is enhanced significantly by under-ionization, and the enhancement can be nearly an order of magnitude near the shock radius. The most prominent non-equilibrium ionization signature we found is the O VII and O VIII line ratio. The ratios for non-equilibrium ionization and collisional ionization equilibrium models are different by more than an order of magnitude at radii beyond half of the shock radius. These non-equilibrium ionization signatures are equally strong for models with different non-adiabatic shock electron heating efficiencies. We have also calculated the detectability of the O VII and O VIII lines with the future International X-ray Observatory (IXO). Depending on the line ratio measured, we conclude that an exposure of ∼130-380 ks on a moderate-redshift, massive regular cluster with the X-ray Microcalorimeter Spectrometer (XMS) on the IXO will be sufficient to provide a strong test for the non-equilibrium ionization model.

Some non-LTE diagnostic methods for hydrogen plasmas

International Nuclear Information System (INIS)

Eddy, T.L.; Cho, K.Y.

1986-01-01

This paper shows that if electric and magnetic fields are not negligible, then the 2-T model assumed by many non-LTE plasma diagnostic techniques may lead to serious errors. Significant difference between T e and T ex have been shown to exist with electric field strengths as low as ∼10 V/cm. Multithermal equilibrium (MTE) calculations show significant deviations in line emission coefficients when T e ≠ T ex compared to equivalent T e ≠ T q . A quasi non-dimentional MTE continuum relation is present to assist in diagnostics. Normalized line emission coefficients verses N e are used to indicate the type and extent of non-LTE. The MTE state diagram for hydrogen is used to show why non-LTE plasmas often appear to be in LTE based on N e determinations

Radio protocols for LTE and LTE-advanced

CERN Document Server

Yi, SeungJune; Lee, YoungDae; Park, SungJun; Jung, SungHoon

2012-01-01

Provides a unique focus on radio protocols for LTE and LTE-Advanced (LTE-A) Giving readers a valuable understanding of LTE radio protocols, this book covers LTE (Long-Term Evolution) Layer 2/3 radio protocols as well as new features including LTE-Advanced. It is divided into two sections to differentiate between the two technologies' characteristics. The authors systematically explain the design principles and functions of LTE radio protocols during the development of mobile handsets. The book also provides essential knowledge on the interaction between mobile networks a

A statistical mechanical model for equilibrium ionization

International Nuclear Information System (INIS)

Macris, N.; Martin, P.A.; Pule, J.

1990-01-01

A quantum electron interacts with a classical gas of hard spheres and is in thermal equilibrium with it. The interaction is attractive and the electron can form a bound state with the classical particles. It is rigorously shown that in a well defined low density and low temperature limit, the ionization probability for the electron tends to the value predicted by the Saha formula for thermal ionization. In this regime, the electron is found to be in a statistical mixture of a bound and a free state. (orig.)

Mass flow and the validity of ionization equilibrium on the sun

International Nuclear Information System (INIS)

Joselyn, J.; Munro, R.H.; Holzer, T.E.

1979-01-01

Ionization equilibrium is a useful assumption which allows temperatures and other plasma properties to be deduced from spectral observations. Inherent to this assumption is the premise that the ion stage densities are determined solely by atomic processes which are local functions of the plasma temperature and electron density. However, if the time scale of plasma flow through a temperature gradient is less than the characteristic time scale for an important atomic process, deviations from the ionization stage densities expected for equilibrium will occur which could introduce serious errors into subsequent analyses. In the past few years, significant flow velocities in the upper solar atmosphere have been inferred from observations of emission lines originating in the transition region (about 10 4 -10 6 K) and corona. In this paper, 3 models of the solar atmosphere (quiet Sun, coronal hole, and a network model) are examined to determine if the emission expected from these model atmospheres could be produced from equilibrium ion populations when steady flows of several kilometers per second are assumed. If the flows are quasi-periodic instead of steady, spatial and temporal averaging inherent in the observations may allow for the construction of satisfactory models based on the assumption of ionization equilibrium. Representative emission lines are analysed for the following ions: C III, IV, O IV, V, VI, Ne VII, VIII, Mg IX, X, Si XII, Fe IX-XIV. Two principle conclusions are drawn. First, only the iron ions are generally in equilibrium for steady flows of 20 kms -1 . For carbon and oxygen, ionization equilibrium is not a valid assumption for steady flows as small as 1 kms -1 . Second, the 3 models representing different solar conditions behave in a qualitatively similar manner, implying that these results are not particularly model dependent over the range of temperature gradients and electron densities thus far inferred for the Sun. In view of the flow velocities

Non-LTE diagnositics of infrared radiation of Titan's atmosphere

Science.gov (United States)

Feofilov, Artem; Rezac, Ladislav; Kutepov, Alexander; Vinatier, Sandrine; Rey, Michael; Nikitin, Andrew; Tyuterev, Vladimir

2016-06-01

Yelle (1991) and Garcia-Comas et al, (2011) demonstrated the importance of accounting for the local thermodynamic equilibrium (LTE) breakdown in the middle and upper atmosphere of Titan for the interpretation of infrared radiances measured at these heights. In this work, we make further advance in this field by: • updating the non-LTE model of CH4 emissions in Titan's atmosphere and including a new extended database of CH4 spectroscopic parameters • studying the non-LTE CH4 vibrational level populations and the impact of non-LTE on limb infrared emissions of various CH4 ro-vibrational bands including those at 7.6 and 3.3 µm • implementing our non-LTE model into the LTE-based retrieval algorithm applied by Vinatier et al., (2015) for processing the Cassini/CIRS spectra. We demonstrate that accounting for non-LTE leads to an increase in temperatures retrieved from CIRS 7.6 µm limb emissions spectra (˜10 K at 600 km altitude) and estimate how this affects the trace gas density retrieval. Finally, we discuss the effects of including a large number of weak one-quantum and combinational bands on the calculated daytime limb 3.3 µm emissions and the impact they may have on the CH4 density retrievals from the Cassini VIMS 3.3 µm limb emission observations.

4G LTE/LTE-advanced for mobile broadband

CERN Document Server

Dahlman, Erik; Skold, Johan

2013-01-01

This book reflects the ongoing success of LTE throughout the world and focuses on LTE with full updates including LTE-Advanced (Release 11) to provide a complete picture of the LTE system. Overviews and detailed explanations are given for the latest LTE standards for radio interface architecture, the physical layer, access procedures, broadcast, relaying, spectrum and RF characteristics, and system performance. Key technologies presented include multi-carrier transmission, advanced single-carrier transmission, advanced receivers, OFDM, MIMO and adaptive antenna solutions, advanced radio res

The equation of state and ionization equilibrium of dense aluminum plasma with conductivity verification

International Nuclear Information System (INIS)

Wang, Kun; Shi, Zongqian; Shi, Yuanjie; Bai, Jun; Wu, Jian; Jia, Shenli

2015-01-01

The equation of state, ionization equilibrium, and conductivity are the most important parameters for investigation of dense plasma. The equation of state is calculated with the non-ideal effects taken into consideration. The electron chemical potential and pressure, which are commonly used thermodynamic quantities, are calculated by the non-ideal free energy and compared with results of a semi-empirical equation of state based on Thomas-Fermi-Kirzhnits model. The lowering of ionization potential, which is a crucial factor in the calculation of non-ideal Saha equation, is settled according to the non-ideal free energy. The full coupled non-ideal Saha equation is applied to describe the ionization equilibrium of dense plasma. The conductivity calculated by the Lee-More-Desjarlais model combined with non-ideal Saha equation is compared with experimental data. It provides a possible approach to verify the accuracy of the equation of state and ionization equilibrium

Assessment of general public exposure to LTE and RF sources present in an urban environment.

Science.gov (United States)

Joseph, Wout; Verloock, Leen; Goeminne, Francis; Vermeeren, Günter; Martens, Luc

2010-10-01

For the first time, in situ electromagnetic field exposure of the general public to fields from long term evolution (LTE) cellular base stations is assessed. Exposure contributions due to different radiofrequency (RF) sources are compared with LTE exposure at 30 locations in Stockholm, Sweden. Total exposures (0.2-2.6 V/m) satisfy the International Commission on Non-Ionizing Radiation Protection (ICNIRP) reference levels (from 28 V/m for frequency modulation (FM), up to 61 V/m for LTE) at all locations. LTE exposure levels up to 0.8 V/m were measured, and the average contribution of the LTE signal to the total RF exposure equals 4%.

New computational method for non-LTE, the linear response matrix

International Nuclear Information System (INIS)

Fournier, K.B.; Grasiani, F.R.; Harte, J.A.; Libby, S.B.; More, R.M.; Zimmerman, G.B.

1998-01-01

My coauthors have done extensive theoretical and computational calculations that lay the ground work for a linear response matrix method to calculate non-LTE (local thermodynamic equilibrium) opacities. I will give briefly review some of their work and list references. Then I will describe what has been done to utilize this theory to create a computational package to rapidly calculate mild non-LTE emission and absorption opacities suitable for use in hydrodynamic calculations. The opacities are obtained by performing table look-ups on data that has been generated with a non-LTE package. This scheme is currently under development. We can see that it offers a significant computational speed advantage. It is suitable for mild non-LTE, quasi-steady conditions. And it offers a new insertion path for high-quality non-LTE data. Currently, the linear response matrix data file is created using XSN. These data files could be generated by more detailed and rigorous calculations without changing any part of the implementation in the hydro code. The scheme is running in Lasnex and is being tested and developed

[Research on the identification method of LTE condition in the laser-induced plasma].

Science.gov (United States)

Fan, Juan-juan; Huang, Dan; Wang, Xin; Zhang, Lei; Ma, Wei-guang; Dong, Lei; Yin, Wang-bao; Jia, Suo-tang

2014-12-01

Because of the poor accuracy of the commonly used Boltzmann plot method and double-line method, the Boltzmann-Maxwell distribution combined with the Saha-Eggert formula is proposed to improve the measurement accuracy of the plasma temperature; the simple algorithm for determining the linewidth of the emission line was established according to the relationship between the area and the peak value of the Gaussian formula, and the plasma electron density was calculated through the Stark broadening of the spectral lines; the method for identifying the plasma local thermal equilibrium (LTE) condition was established based on the McWhirter criterion. The experimental results show that with the increase in laser energy, the plasma temperature and electron density increase linearly; when the laser energy changes within 127~510 mJ, the plasma electron density changes in the range of 1.30532X10(17)~1.87322X10(17) cm(-3), the plasma temperature changes in the range of 12586~12957 K, and all the plasma generated in this experiment meets the LTE condition threshold according to the McWhirter criterion. For element Al, there exist relatively few observable lines at the same ionization state in the spectral region of the spectrometer, thus it is unable to use the Boltzmann plane method to calculate temperature. One hundred sets of Al plasma spectra were used for temperature measurement by employing the Saha-Boltzmann method and the relative standard deviation (RSD) value is 0.4%, and compared with 1.3% of the double line method, the accuracy has been substantially increased. The methods proposed can be used for rapid plasma temperature and electron density calculation, the LTE condition identification, and are valuable in studies such as free calibration, spectral effectiveness analysis, spectral temperature correction, the best collection location determination, LTE condition distribution in plasma, and so on.

MIMO Technologies in 3GPP LTE and LTE-Advanced

Directory of Open Access Journals (Sweden)

Zhang Jianzhong(Charlie

2009-01-01

Full Text Available Abstract 3rd Generation Partnership Project (3GPP has recently completed the specification of the Long Term Evolution (LTE standard. Majority of the world's operators and vendors are already committed to LTE deployments and developments, making LTE the market leader in the upcoming evolution to 4G wireless communication systems. Multiple input multiple output (MIMO technologies introduced in LTE such as spatial multiplexing, transmit diversity, and beamforming are key components for providing higher peak rate at a better system efficiency, which are essential for supporting future broadband data service over wireless links. Further extension of LTE MIMO technologies is being studied under the 3GPP study item "LTE-Advanced" to meet the requirement of IMT-Advanced set by International Telecommunication Union Radiocommunication Sector (ITU-R. In this paper, we introduce various MIMO technologies employed in LTE and provide a brief overview on the MIMO technologies currently discussed in the LTE-Advanced forum.

Size-density relations in dark clouds: Non-LTE effects

Science.gov (United States)

Maloney, P.

1986-01-01

One of the major goals of molecular astronomy has been to understand the physics and dynamics of dense interstellar clouds. Because the interpretation of observations of giant molecular clouds is complicated by their very complex structure and the dynamical effects of star formation, a number of studies have concentrated on dark clouds. Leung, Kutner and Mead (1982) (hereafter LKM) and Myers (1983), in studies of CO and NH3 emission, concluded that dark clouds exhibit significant correlations between linewidth and cloud radius of the form delta v varies as R(0.5) and between mean density and radius of the form n varies as R(-1), as originally suggested by Larson (1981). This result suggests that these objects are in virial equilibrium. However, the mean densities inferred from the CO data of LKM are based on an local thermodynamic equilibrium (LTE) analysis of their 13CO data. At the very low mean densities inferred by LKM for the larger clouds in their samples, the assumption of LTE becomes very questionable. As most of the range in R in the density-size correlation comes from the clouds observed in CO, it seems worthwhile to examine how non-LTE effects will influence the derived densities. One way to assess the validity of LTE-derived densities is to construct cloud models and then to interpret them in the same way as the observed data. Microturbulent models of inhomogeneous clouds of varying central concentration with the linewidth-size and mean density-size relations found by Myers show sub-thermal excitation of the 13CO line in the larger clouds, with the result that LTE analysis considerbly underestimates the actual column density. A more general approach which doesn't require detailed modeling of the clouds is to consider whether the observed T sub R*(13CO)/T sub R*(12CO) ratios in the clouds studied by LKM are in the range where the LTE-derived optical depths (and hence column densities) can be seriously in error due to sub-thermal excitation of the 13CO

Determination of equilibrium composition of thermally ionized monoatomic gas under different physical conditions

Science.gov (United States)

Romanova, M. S.; Rydalevskaya, M. A.

2017-05-01

Perfect gas mixtures that result from thermal ionization of spatially and chemically homogeneous monoatomic gases are considered. Equilibrium concentrations of the components of such mixtures are determined using integration over the momentum space and summation with respect to energy levels of the distribution functions that maximize the entropy of system under condition for constancy of the total number of nuclei and electrons. It is demonstrated that such a method allows significant simplification of the calculation of the equilibrium composition for ionized mixtures at different temperatures and makes it possible to study the degree of ionization of gas versus gas density and number in the periodic table of elements.

An investigation of non-equilibrium effects in thermal argon plasmas

International Nuclear Information System (INIS)

Rosado, R.J.

1981-01-01

This thesis deals with the study of the validity of the assumption of Local Thermal Equilibrium (LTE) in the description of the parameters of a thermal argon plasma. The aim is twofold. As the studied plasma is close to, but not completely in equilibrium, the author first attempts to obtain a simple description of the plasma in terms of an LTE model in which suitable corrections for the deviations of the plasma parameters from their LTE values is introduced. To this end the plasma parameters are studied by means of a diagnostic method in which the assumption of LTE is not made. The evaluation of the usefulness of this method is the second aim of this thesis. (Auth.)

Size-density relations in dark clouds: Non-LTE effects

International Nuclear Information System (INIS)

Maloney, P.

1986-01-01

One of the major goals of molecular astronomy has been to understand the physics and dynamics of dense interstellar clouds. Because the interpretation of observations of giant molecular clouds is complicated by their very complex structure and the dynamical effects of star formation, a number of studies have concentrated on dark clouds. Leung, Kutner and Mead (1982) (hereafter LKM) and Myers (1983), in studies of CO and NH 3 emission, concluded that dark clouds exhibit significant correlations between linewidth and cloud radius of the form delta v varies as R(0.5) and between mean density and radius of the form n varies as R(-1), as originally suggested by Larson (1981). This result suggests that these objects are in virial equilibrium. However, the mean densities inferred from the CO data of LKM are based on an local thermodynamic equilibrium (LTE) analysis of their 13CO data. At the very low mean densities inferred by LKM for the larger clouds in their samples, the assumption of LTE becomes very questionable. As most of the range in R in the density-size correlation comes from the clouds observed in CO, it seems worthwhile to examine how non-LTE effects will influence the derived densities. Microturbulent models of inhomogeneous clouds of varying central concentration with the linewidth-size and mean density-size relations found by Myers show sub-thermal excitation of the 13CO line in the larger clouds, with the result that LTE analysis considerbly underestimates the actual column density. A more general approach which doesn't require detailed modeling of the clouds is to consider whether the observed T/sub R/*(13CO)/T/sub R/*(12CO) ratios in the clouds studied by LKM are in the range where the LTE-derived optical depths be seriously in error due to sub-thermal excitation of the 13CO molecule

The influence of electron collisions on non-LTE Li line formation in stellar atmospheres

International Nuclear Information System (INIS)

Osorio, Yeisson; Barklem, Paul; Lind, Karin; Asplund, Martin

2012-01-01

The influence of the uncertainties in the rate coefficient data for electron-impact excitation and ionization on non-LTE Li line formation in cool stellar atmospheres is investigated. We examine the electron collision data used in previous non-LTE calculations and compare them to our own calculations using the R-matrix with pseudostates (RMPS) method and to other calculations found in the literature.

Non-LTE modeling of the radiative properties of high-Z plasma using linear response methodology

Science.gov (United States)

Foord, Mark; Harte, Judy; Scott, Howard

2017-10-01

Non-local thermodynamic equilibrium (NLTE) atomic processes play a key role in the radiation flow and energetics in highly ionized high temperature plasma encountered in inertial confinement fusion (ICF) and astrophysical applications. Modeling complex high-Z atomic systems, such as gold used in ICF hohlraums, is particularly challenging given the complexity and intractable number of atomic states involved. Practical considerations, i.e. speed and memory, in large radiation-hydrodynamic simulations further limit model complexity. We present here a methodology for utilizing tabulated NLTE radiative and EOS properties for use in our radiation-hydrodynamic codes. This approach uses tabulated data, previously calculated with complex atomic models, modified to include a general non-Planckian radiation field using a linear response methodology. This approach extends near-LTE response method to conditions far from LTE. Comparisons of this tabular method with in-line NLTE simulations of a laser heated 1-D hohlraum will be presented, which show good agreement in the time-evolution of the plasma conditions. This work was performed under the auspices of the U.S. Dept. of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Predicted continuum spectra of type II supernovae - LTE results

Science.gov (United States)

Shaviv, G.; Wehrse, R.; Wagoner, R. V.

1985-01-01

The continuum spectral energy distribution of the flux emerging from type II supernovae is calculated from quasi-static radiative transfer through a power-law density gradient, assuming radiative equilibrium and LTE. It is found that the Balmer jump disappears at high effective temperatures and low densities, while the spectrum resembles that of a dilute blackbody but is flatter with a sharper cutoff at the short-wavelength end. A significant UV excess is found in all models calculated. The calculation should be considered exploratory because of significant effects which are anticipated to arise from departure from LTE.

Non-equilibrium blunt body flows in ionized gases

International Nuclear Information System (INIS)

Nishida, Michio

1981-01-01

The behaviors of electrons and electronically excited atoms in non-equilibrium and partially ionized blunt-body-flows are described. Formulation has been made separately in a shock layer and in a free stream, and then the free stream solution has been connected with the shock layer solution by matching the two solutions at the shock layer edge. The method of this matching is described here. The partially ionized gas is considered to be composed of neutral atoms, ions and electrons. Furthermore, the neutral atoms are divided into atoms in excited levels. Therefore, it is considered that electron energy released due to excitation, and that gained due to de-excitation, contribute to electron energy. Thus, the electron energy equation including these contributions is solved, coupled with the continuity equations of the excited atoms and the electrons. An electron temperature distribution from a free stream to a blunt body wall has been investigated for a case when the electrons are in thermal non-equilibrium with heavy particles in the free stream. In addition, the distributions of the excited atom density are discussed in the present analysis. (author)

Relationship between the induction frequency and LTE in inductively coupled plasmas

International Nuclear Information System (INIS)

Mostaghimi, J.; Boulos, M.I.

1990-01-01

In this paper, the effect of the induction frequency on the local thermodynamic equilibrium (LTE) conditions in an inductively coupled plasma is investigated. Using generators with frequencies ranging from 5 to 56 MHz, a previous study investigated demonstrated the importance of this effect. Their measurements of the excitation temperatures of the iron atomic lines showed a sharp decrease in this temperature as a result of the increase in frequency. Another conclusion was that, all other parameters constant, increase in frequency will help the promotion of non-LTE effects

The Influence of Chemi-Ionization and Recombination Processes on Spectral Line Shapes in Stellar Atmospheres

Directory of Open Access Journals (Sweden)

Mihajlov Anatolij A.

2011-12-01

Full Text Available The chemi-ionization processes in atom - Rydberg atom collisions, as well as the corresponding chemi-recombination processes, are considered as factors of influence on the atom exited-state populations in weakly ionized layers of stellar atmospheres. The presented results are related to the photospheres of the Sun and some M red dwarfs, as well as weakly ionized layers of DB white dwarf atmospheres. It has been found that the mentioned chemi-ionization and recombination processes dominate over the concurrent electron-atom and electron-ion ionization and recombination processes in all parts of the considered stellar atmospheres. The obtained results demonstrate the fact that the considered processes must have significant influence on the optical properties of stellar atmospheres. It is shown that these processes and their importance for non-local thermodynamic equilibrium (non-LTE modeling of the solar atmospheres should be investigated further.

In situ LTE exposure of the general public: Characterization and extrapolation.

Science.gov (United States)

Joseph, Wout; Verloock, Leen; Goeminne, Francis; Vermeeren, Günter; Martens, Luc

2012-09-01

In situ radiofrequency (RF) exposure of the different RF sources is characterized in Reading, United Kingdom, and an extrapolation method to estimate worst-case long-term evolution (LTE) exposure is proposed. All electric field levels satisfy the International Commission on Non-Ionizing Radiation Protection (ICNIRP) reference levels with a maximal total electric field value of 4.5 V/m. The total values are dominated by frequency modulation (FM). Exposure levels for LTE of 0.2 V/m on average and 0.5 V/m maximally are obtained. Contributions of LTE to the total exposure are limited to 0.4% on average. Exposure ratios from 0.8% (LTE) to 12.5% (FM) are obtained. An extrapolation method is proposed and validated to assess the worst-case LTE exposure. For this method, the reference signal (RS) and secondary synchronization signal (S-SYNC) are measured and extrapolated to the worst-case value using an extrapolation factor. The influence of the traffic load and output power of the base station on in situ RS and S-SYNC signals are lower than 1 dB for all power and traffic load settings, showing that these signals can be used for the extrapolation method. The maximal extrapolated field value for LTE exposure equals 1.9 V/m, which is 32 times below the ICNIRP reference levels for electric fields. Copyright © 2012 Wiley Periodicals, Inc.

Updated Collisional Ionization Equilibrium Calculated for Optically Thin Plasmas

Science.gov (United States)

Savin, Daniel Wolf; Bryans, P.; Badnell, N. R.; Gorczyca, T. W.; Laming, J. M.; Mitthumsiri, W.

2010-03-01

Reliably interpreting spectra from electron-ionized cosmic plasmas requires accurate ionization balance calculations for the plasma in question. However, much of the atomic data needed for these calculations have not been generated using modern theoretical methods and their reliability are often highly suspect. We have carried out state-of-the-art calculations of dielectronic recombination (DR) rate coefficients for the hydrogenic through Na-like ions of all elements from He to Zn as well as for Al-like to Ar-like ions of Fe. We have also carried out state-of-the-art radiative recombination (RR) rate coefficient calculations for the bare through Na-like ions of all elements from H to Zn. Using our data and the recommended electron impact ionization data of Dere (2007), we present improved collisional ionization equilibrium calculations (Bryans et al. 2006, 2009). We compare our calculated fractional ionic abundances using these data with those presented by Mazzotta et al. (1998) for all elements from H to Ni. This work is supported in part by the NASA APRA and SHP SR&T programs.

Thermal equilibrium criteria in a nitrogen plasma

International Nuclear Information System (INIS)

Cilliers, W.A.; Hey, J.D.; Rash, J.P.S.

1975-01-01

A method for obtaining the lower electron density limit for LTE in a nitrogen plasma is described, whereby the experimentally determined ratio of the collisional-radiative ionization and recombination coefficients (S/α) is compared with the corresponding LTE value (Saha ratio). It is argued that if the electron density is increased from values of about 10 16 cm -3 , S/α should tend to the Saha ratio as LTE is approached For NII and NIII spectral lines, this is found to happen at an electron density of a few times 10 16 cm -3 when the electron temperature is about 3 eV, in good agreement with the LTE criterion of Griem. (author)

Departure from Local Thermodynamic Equilibrium in argon plasmas sustained in a Torche à Injection Axiale sur Guide d'Ondes

International Nuclear Information System (INIS)

Rincón, R.; Muñoz, J.; Calzada, M.D.

2015-01-01

Plasma torches are suitable plasma sources for a wide range of applications. The capability of these discharges to produce processes like sample excitation or decomposition of molecules inside them depends on the density of the plasma species and their energies (temperatures). The relation between these parameters determines the specific state of thermodynamic equilibrium in the discharge. Thus, the understanding of plasma possibilities for application purposes is related to the knowledge of the plasma thermodynamic equilibrium degree. In this paper a discussion about the equilibrium state for Ar plasmas generated by using a Torche à Injection Axiale sur Guide d'Ondes, TIAGO device, is presented. Emission spectroscopy techniques were used to measure gas temperature and electron density at the exit of the nozzle torch and along the dart. Boltzmann-plots as well as b p parameters were calculated to characterize the type and degree of departure from partial Local Saha Equilibrium (pLSE). This study indicates that the closer situation to Local Thermodynamic Equilibrium (LTE) of the plasma corresponds to larger Ar flows which highlights the importance of the nitrogen (atmosphere surrounding the plasma) in the kinetics of Ar-TIAGO discharges. - Highlights: • Discharges sustained in Ar using a TIAGO Torch show a significant departure from Local Thermodynamic Equilibrium. • Nitrogen entrance from surrounding air highly influences Thermodynamic Equilibrium. • Departure from LTE has been studied by means of Boltzmann plots and b p parameters. • The discharge is ionizing at the nozzle exit plasma, while along the dart it becomes recombining

The Evolution of the Large-Scale ISM: Bubbles, Superbubbles and Non-Equilibrium Ionization

Science.gov (United States)

de Avillez, M. A.; Breitschwerdt, D.

2010-12-01

The ISM, powered by SNe, is turbulent and permeated by a magnetic field (with a mean and a turbulent component). It constitutes a frothy medium that is mostly out of equilibrium and is ram pressure dominated on most of the temperature ranges, except for T 106K, where magnetic and thermal pressures dominate, respectively. Such lack of equilibrium is also imposed by the feedback of the radiative processes into the ISM flow. Many models of the ISM or isolated phenomena, such as bubbles, superbubbles, clouds evolution, etc., take for granted that the flow is in the so-called collisional ionization equilibrium (CIE). However, recombination time scales of most of the ions below 106 K are longer than the cooling time scale. This implies that the recombination lags behind and the plasma is overionized while it cools. As a consequence cooling deviates from CIE. This has severe implications on the evolution of the ISM flow and its ionization structure. Here, besides reviewing several models of the ISM, including bubbles and superbubbles, the validity of the CIE approximation is discussed, and a presentation of recent developments in modeling the ISM by taking into account the time-dependent ionization structure of the flow in a full-blown numerical 3D high resolution simulation is presented.

Two-temperature chemically non-equilibrium modelling of transferred arcs

International Nuclear Information System (INIS)

Baeva, M; Kozakov, R; Gorchakov, S; Uhrlandt, D

2012-01-01

A two-temperature chemically non-equilibrium model describing in a self-consistent manner the heat transfer, the plasma chemistry, the electric and magnetic field in a high-current free-burning arc in argon has been developed. The model is aimed at unifying the description of a thermionic tungsten cathode, a flat copper anode, and the arc plasma including the electrode sheath regions. The heat transfer in the electrodes is coupled to the plasma heat transfer considering the energy fluxes onto the electrode boundaries with the plasma. The results of the non-equilibrium model for an arc current of 200 A and an argon flow rate of 12 slpm are presented along with results obtained from a model based on the assumption of local thermodynamic equilibrium (LTE) and from optical emission spectroscopy. The plasma shows a near-LTE behaviour along the arc axis and in a region surrounding the axis which becomes wider towards the anode. In the near-electrode regions, a large deviation from LTE is observed. The results are in good agreement with experimental findings from optical emission spectroscopy. (paper)

An introduction to LTE LTE, LTE-advanced, SAE, VoLTE and 4G mobile communications

CERN Document Server

Cox, Christopher

2014-01-01

Following on from the successful first edition (March 2012), this book gives a clear explanation of what LTE does and how it works. The content is expressed at a systems level, offering less technically experienced readers the opportunity to grasp the key factors which make LTE the hot topic amongst vendors and operators across the globe. Assuming no more than a basic knowledge of mobile telecommunication systems, the reader is not expected to already understand complex mathematical operations.  This second edition both updates and introduces new material for the current state of the industry

Ionization equilibrium and radiation losses of molybdenum in a high temperature plasma

International Nuclear Information System (INIS)

1976-11-01

The ionization equilibrium and the associated radiation losses of molybdenum have been calculated as a function of the electron temperature. In the 1-2keV range the computed fractional abundances are supported by experimental facts obtained in T.F.R. Tokamak plasmas

Local thermodynamic equilibrium and related metrological issues involving collisional-radiative model in laser-induced aluminum plasmas

International Nuclear Information System (INIS)

Travaille, G.; Peyrusse, O.; Bousquet, B.; Canioni, L.; Pierres, K. Michel-Le; Roy, S.

2009-01-01

We present a collisional-radiative approach of the theoretical analysis of laser-induced breakdown spectroscopy (LIBS) plasmas. This model, which relies on an optimized effective potential atomic structure code, was used to simulate a pure aluminum plasma. The description of aluminum involved a set of 220 atomic levels representative of three different stages of ionization (Al 0 , Al + and Al ++ ). The calculations were carried for stationary plasmas, with input parameters (n e and T e ) ranging respectively between 10 13-18 cm -3 and 0.3-2 eV. A comparison of our atomic data with some existing databases is made. The code was mainly developed to address the validity of the local thermodynamic equilibrium (LTE) assumption. For usual LIBS plasma parameters, we did not reveal a sizeable discrepancy of the radiative equilibrium of the plasma towards LTE. For cases where LTE was firmly believed to stand, the Boltzmann plot outputs of this code were used to check the physical accuracy of the Boltzmann temperature, as it is currently exploited in several calibration-free laser-induced breakdown spectroscopy (CF-LIBS) studies. In this paper, a deviation ranging between 10 and 30% of the measured Boltzmann temperature to the real excitation temperature is reported. This may be due to the huge dispersion induced on the line emissivities, on which the Boltzmann plots are based to extract this parameter. Consequences of this fact on the CF-LIBS procedure are discussed and further insights to be considered for the future are introduced.

Improvements to Busquet's Non LTE algorithm in NRL's Hydro code

Science.gov (United States)

Klapisch, M.; Colombant, D.

1996-11-01

Implementation of the Non LTE model RADIOM (M. Busquet, Phys. Fluids B, 5, 4191 (1993)) in NRL's RAD2D Hydro code in conservative form was reported previously(M. Klapisch et al., Bull. Am. Phys. Soc., 40, 1806 (1995)).While the results were satisfactory, the algorithm was slow and not always converging. We describe here modifications that address the latter two shortcomings. This method is quicker and more stable than the original. It also gives information about the validity of the fitting. It turns out that the number and distribution of groups in the multigroup diffusion opacity tables - a basis for the computation of radiation effects in the ionization balance in RADIOM- has a large influence on the robustness of the algorithm. These modifications give insight about the algorithm, and allow to check that the obtained average charge state is the true average. In addition, code optimization resulted in greatly reduced computing time: The ratio of Non LTE to LTE computing times being now between 1.5 and 2.

Non-LTE considerations in spectral diagnostics of thermal transport and implosion experiments

International Nuclear Information System (INIS)

Epstein, R.; Skupsky, S.; Delettrez, J.; Yaakobi, B.

1984-01-01

Recent thermal-transport and target-implosion experiments have used the emission of radiation from highly-ionized ions to signal the advance of laser-driven heat fronts and to mark the trajectories and stagnation points of imploding shells. We examine the results of such experiments with particular attention given to non-LTE effects of non-Maxwellian electrons and of finite ionization times on the populations of signature-emitting atomic species and on the formation of signature spectra and x-ray images in these experiments

Estudio comparativo entre redes LTE Advanced y LTE a nivel de CORE.

OpenAIRE

Castillo Contreras, David Oswaldo

2017-01-01

El presente trabajo de titulación contiene un estudio y análisis de las tecnologías LTE y LTE -Advanced a nivel de CORE de voz. Mediante la metodología de investigación descriptiva, se expondrán profundamente las principales características tecnológicas de las redes LTE y LTE Advanced, haciendo un enfoque hacia la arquitectura del CORE de voz y sus principales procesos para la administración de la movilidad, llamadas originadas y llamadas terminadas. Se detallará paso a paso ...

Electron equilibrium for parallel plate ionization chambers in gamma radiation fields

International Nuclear Information System (INIS)

Caldas, L.; Albuquerque, M. da P.P.

1989-08-01

Parallel plate ionization chambers, designed and constructed for use in low energy X-radiation fields, were tested in gamma radiation beams ( 6 Co and 137 Cs) of two different Calibration Laboratories, in order to study the electron equilibrium occurrence and to verify the possibility of their use for the detection of the kind of radiation too. (author) [pt

Assessment of general public exposure to lte signals compared to other cellular networks present in Thessaloniki, Greece

International Nuclear Information System (INIS)

Gkonis, Fotios; Boursianis, Achilles; Samaras, Theodoros

2017-01-01

To assess general public exposure to electromagnetic fields from Long Term Evolution (LTE) base stations, measurements at 10 sites in Thessaloniki, Greece were performed. Results are compared with other mobile cellular networks currently in use. All exposure values satisfy the guidelines for general public exposure of the International Commission on Non-Ionizing Radiation Protection (ICNIRP), as well as the reference levels by the Greek legislation at all sites. LTE electric field measurements were recorded up to 0.645 V/m. By applying the ICNIRP guidelines, the exposure ratio for all LTE signals is between 2.9 x 10"-"5 and 2.8 x 10"-"2. From the measurements results it is concluded that the average and maximum power density contribution of LTE down-link signals to the overall cellular networks signals are 7.8% and 36.7%, respectively. (authors)

Non-Equilibrium Radiative Transfer in Structured Atmospheres

National Research Council Canada - National Science Library

Picard, R. H; Winick, J. R; Wintersteiner, P. P

2002-01-01

... passage of both atmospheric gravity waves and transient frontal disturbances or bores. The infrared emissions from this part of the atmosphere are already typically not in local thermodynamic equilibrium (LTE...

Non-equilibrium ionization by a periodic electron beam. I. Synthetic coronal spectra and implications for interpretation of observations

Science.gov (United States)

Dzifčáková, E.; Dudík, J.; Mackovjak, Š.

2016-05-01

Context. Coronal heating is currently thought to proceed via the mechanism of nanoflares, small-scale and possibly recurring heating events that release magnetic energy. Aims: We investigate the effects of a periodic high-energy electron beam on the synthetic spectra of coronal Fe ions. Methods: Initially, the coronal plasma is assumed to be Maxwellian with a temperature of 1 MK. The high-energy beam, described by a κ-distribution, is then switched on every period P for the duration of P/ 2. The periods are on the order of several tens of seconds, similar to exposure times or cadences of space-borne spectrometers. Ionization, recombination, and excitation rates for the respective distributions are used to calculate the resulting non-equilibrium ionization state of Fe and the instantaneous and period-averaged synthetic spectra. Results: Under the presence of the periodic electron beam, the plasma is out of ionization equilibrium at all times. The resulting spectra averaged over one period are almost always multithermal if interpreted in terms of ionization equilibrium for either a Maxwellian or a κ-distribution. Exceptions occur, however; the EM-loci curves appear to have a nearly isothermal crossing-point for some values of κs. The instantaneous spectra show fast changes in intensities of some lines, especially those formed outside of the peak of the respective EM(T) distributions if the ionization equilibrium is assumed. Movies 1-5 are available in electronic form at http://www.aanda.org

Assessing the existence of non-LTE behavior in aluminum K-shell diagnostic lines from dynamic hohlraum driven experiments

International Nuclear Information System (INIS)

Sherrill, M E

2015-01-01

We describe in this work a study designed to obtain insight into the sensitivity of foil targets driven out of local thermodynamic equilibrium (LTE) by an idealized dynamic hohlraum during its brightest phase. This work is motivated by a perceived over-prediction of the plasma temperature by current LTE spectral modeling of opacity experiments performed by Bailey et al at the Sandia Z facility. Although several aspects of this modeling study parallel the SNL/LANL opacity experiments, this work is primarily intended to gain insight into radiatively over-driven systems. The results from this idealized study suggest that a non-LTE population distribution with qualities similar to an LTE distribution at higher material temperatures are possible, and therefore support a further theoretical investigation with experimental parameters. (special issue paper)

Measurement of Stark width of some Ar I transitions and the investigation of local thermodynamic equilibrium (LTE) in an atmospheric d.c. argon plasma jet

International Nuclear Information System (INIS)

Bakshi, V.

1988-01-01

The Stark widths of seven Ar I transitions are reported. Axial line shape data from an atmospheric d.c. argon plasma jet were Abel-inverted to obtain radial line shapes. The electron-density was determined by Stark width measurements of the hydrogen H β transition. In the electron-density region of ≤6 x 10 22 m -3 the experimental Ar I Stark widths are fitted to a linear dependence on the electron-density. Values of Stark width extrapolated to other electron densities are compared to measurements reported in the literature on the 4s-4p array. Experimental values are up to 45% smaller than those predicted by Griem's theory of Stark broadening. Conditions for local thermodynamic equilibrium (LTE) to exist in an atmospheric argon plasma jet were studied. The experiment measures the emission coefficient of seven Ar I transitions and the line shape of the hydrogen H beta transition. After transforming the side-on data into radial space the excited neutral argon atom-density and the electron-density are determined. It is found LTE does not exist below an electron-density of 6 x 10 33 m -3 in the experimental conditions

A theoretical analysis of local thermal equilibrium in fibrous materials

Directory of Open Access Journals (Sweden)

Tian Mingwei

2015-01-01

Full Text Available The internal heat exchange between each phase and the Local Thermal Equilibrium (LTE scenarios in multi-phase fibrous materials are considered in this paper. Based on the two-phase heat transfer model, a criterion is proposed to evaluate the LTE condition, using derived characteristic parameters. Furthermore, the LTE situations in isothermal/adiabatic boundary cases with two different heat sources (constant heat flux and constant temperature are assessed as special transient cases to test the proposed criterion system, and the influence of such different cases on their LTE status are elucidated. In addition, it is demonstrated that even the convective boundary problems can be generally estimated using this approach. Finally, effects on LTE of the material properties (thermal conductivity, volumetric heat capacity of each phase, sample porosity and pore hydraulic radius are investigated, illustrated and discussed in our study.

Experiments on the Scaling of Ionization Balance vs. Electron and Radiation Temperature in Non-LTE Gold Plasmas

International Nuclear Information System (INIS)

Heeter, R.F.; Hansen, S.B.; Beiersdorfer, P.; Foord, M.E.; Fournier, K.B.; Froula, D.H.; Mackinnon, A.J.; May, M.J.; Schneider, M.B.; Young, B.K.F.

2004-01-01

Understanding and predicting the behavior of high-Z non-LTE plasmas is important for developing indirect-drive inertial confinement fusion. Extending earlier work from the Nova laser, we present results from experiments using the Omega laser to study the ionization balance of gold as a function of electron and radiation temperature. In these experiments, gold samples embedded in Be disks expand under direct laser heating to ne ≅ 1021cm-3, with Te varying from 0.8 to 2.5 keV. An additional finite radiation field with effective temperature Tr up to 150 eV is provided by placing the gold Be disks inside truncated 1.2 mm diameter tungsten-coated cylindrical hohlraums with full laser entrance holes. Densities are measured by imaging of plasma expansion. Electron temperatures are diagnosed with either 2ω or 4ω Thomson scattering, and also K-shell spectroscopy of KCl tracers co-mixed with the gold. Hohlraum flux and effective radiation temperature are measured using an absolutely-calibrated multichannel filtered diode array. Spectroscopic measurements of the M-shell gold emission in the 2.9-4 keV spectral range provide ionization balance and charge state distribution information. The spectra show strong variation with Te, strong variation with the applied Tr, at Te below 1.6 keV, and relatively little variation with Tr at higher Te (upwards of 2 keV). We summarize our most recent spectral analyses and discuss emerging and outstanding issues

A non-LTE study of neutral calcium in late-type stars with special reference to Pollux

International Nuclear Information System (INIS)

Drake, J.J.; Texas Univ., Austin, TX

1991-01-01

Detailed simultaneous radiative transfer-statistical equilibrium calculations have been undertaken for neutral calcium using model stellar atmospheres corresponding to a variety of late spectral types. The results are used to investigate non-LTE effects and trends with differing stellar parameters, and to estimate the likely influence of departures from LTE on model atmosphere analyses. The behaviour of individual Ca I atomic levels and lines are discussed in connection with calculations carried out for a model atmosphere corresponding to the KO III giant Pollux (β Gem). (author)

Effects of deviations from local thermodynamic equilibrium in the atmospheres of F supergiants. I. Overionization of Fe I atoms

International Nuclear Information System (INIS)

Boyarchuk, A.A.; Lyubimkov, L.S.; Sakhibullin, N.A.

1985-01-01

For a number of class F supergiants and dwarfs, non-LTE calculations have been made of the Fe I-Fe II ionization balance. It is shown that deviations from local thermodynamic equilibrium lead to a strong overionization of the Fe I atoms in the upper layers of the atmosphere. This confirms the conclusion obtained by Lyubimkov and Boyarchuk on the basis of an investigation of microturbulence in F supergiants. The reason for the overionization (compared with LTE) is the nonequality of the recombination and photoionization temperatures: To recombination processes there corresponds a local temperature T(/tau/), whereas the photoionization takes place under the influence of ultraviolet radiation from deeper and hotter layers of the atmosphere. The equivalent widths of some Fe I lines have been calculated. It is shown that neglect of the overionization in the analysis of sufficiently strong lines may lead to an underestimation of the iron abundance by an order of magnitude

H TO Zn IONIZATION EQUILIBRIUM FOR THE NON-MAXWELLIAN ELECTRON κ-DISTRIBUTIONS: UPDATED CALCULATIONS

International Nuclear Information System (INIS)

Dzifčáková, E.; Dudík, J.

2013-01-01

New data for the calculation of ionization and recombination rates have been published in the past few years, most of which are included in the CHIANTI database. We used these data to calculate collisional ionization and recombination rates for the non-Maxwellian κ-distributions with an enhanced number of particles in the high-energy tail, which have been detected in the solar transition region and the solar wind. Ionization equilibria for elements H to Zn are derived. The κ-distributions significantly influence both the ionization and recombination rates and widen the ion abundance peaks. In comparison with the Maxwellian distribution, the ion abundance peaks can also be shifted to lower or higher temperatures. The updated ionization equilibrium calculations result in large changes for several ions, notably Fe VIII-Fe XIV. The results are supplied in electronic form compatible with the CHIANTI database.

Departures from radiative equilibrium in stellar atmospheres grey absorption

International Nuclear Information System (INIS)

Cram, L.E.

1978-01-01

We discuss some of the consequences of departures from radiative equilibrium in stellar atmospheres. Using a discrete ordinates method we solve the radiative transfer equation in a grey atmosphere subjected to a specified distribution of mechanical heating, and determine the resulting temperature changes in LTE and non LTE conditions. We show how radiative transfer leads to temperature changes in regions that are not directly heated, and how non LTE effects lead to an amplification of the temperature rise produced by a given distribution of heating. An attempt is made to resolve a controversy surrounding the estimation of excess radiative losses in the solar chromosphere. (orig.) [de

Assessment of General Public Exposure to LTE signals compared to other Cellular Networks Present in Thessaloniki, Greece.

Science.gov (United States)

Gkonis, Fotios; Boursianis, Achilles; Samaras, Theodoros

2017-07-01

To assess general public exposure to electromagnetic fields from Long Term Evolution (LTE) base stations, measurements at 10 sites in Thessaloniki, Greece were performed. Results are compared with other mobile cellular networks currently in use. All exposure values satisfy the guidelines for general public exposure of the International Commission on Non-Ionizing Radiation Protection (ICNIRP), as well as the reference levels by the Greek legislation at all sites. LTE electric field measurements were recorded up to 0.645 V/m. By applying the ICNIRP guidelines, the exposure ratio for all LTE signals is between 2.9 × 10-5 and 2.8 × 10-2. From the measurements results it is concluded that the average and maximum power density contribution of LTE downlink signals to the overall cellular networks signals are 7.8% and 36.7%, respectively. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Non-local Thermodynamic Equilibrium Abundance Analyses of the Extreme Helium Stars V652 Her and HD 144941

International Nuclear Information System (INIS)

Pandey, Gajendra; Lambert, David L.

2017-01-01

Optical high-resolution spectra of V652 Her and HD 144941, the two extreme helium stars with exceptionally low C/He ratios, have been subjected to a non-LTE abundance analysis using the tools TLUSTY and SYNSPEC. Defining atmospheric parameters were obtained from a grid of non-LTE atmospheres and a variety of spectroscopic indicators including He i and He ii line profiles, and the ionization equilibrium of ion pairs such as C ii/C iii and N ii/N iii. The various indicators provide a consistent set of atmospheric parameters: T eff = 25,000 ± 300 K, log g = 3.10 ± 0.12(cgs), and ξ = 13 ± 2 km s −1 are provided for V652 Her, and T eff = 22,000 ± 600 K, log g = 3.45 ± 0.15 (cgs), and ξ = 10 km s −1 are provided for HD 144941. In contrast to the non-LTE analyses, the LTE analyses—LTE atmospheres and an LTE line analysis—with the available indicators do not provide a consistent set of atmospheric parameters. The principal non-LTE effect on the elemental abundances is on the neon abundance. It is generally considered that these extreme helium stars with their very low C/He ratio result from the merger of two helium white dwarfs. Indeed, the derived composition of V652 Her is in excellent agreement with predictions by Zhang and Jeffery, who model the slow merger of helium white dwarfs; a slow merger results in the merged star having the composition of the accreted white dwarf. In the case of HD 144941, which appears to have evolved from metal-poor stars, a slow merger is incompatible with the observed composition but variations of the merger rate may account for the observed composition. More detailed theoretical studies of the merger of a pair of helium white dwarfs are to be encouraged.

Non-local Thermodynamic Equilibrium Abundance Analyses of the Extreme Helium Stars V652 Her and HD 144941

Energy Technology Data Exchange (ETDEWEB)

Pandey, Gajendra [Indian Institute of Astrophysics, Bangalore, 560034 (India); Lambert, David L., E-mail: pandey@iiap.res.in, E-mail: dll@astro.as.utexas.edu [The W.J. McDonald Observatory and Department of Astronomy, University of Texas at Austin, Austin, TX 78712-1083 (United States)

2017-10-01

Optical high-resolution spectra of V652 Her and HD 144941, the two extreme helium stars with exceptionally low C/He ratios, have been subjected to a non-LTE abundance analysis using the tools TLUSTY and SYNSPEC. Defining atmospheric parameters were obtained from a grid of non-LTE atmospheres and a variety of spectroscopic indicators including He i and He ii line profiles, and the ionization equilibrium of ion pairs such as C ii/C iii and N ii/N iii. The various indicators provide a consistent set of atmospheric parameters: T {sub eff} = 25,000 ± 300 K, log g = 3.10 ± 0.12(cgs), and ξ = 13 ± 2 km s{sup −1} are provided for V652 Her, and T {sub eff} = 22,000 ± 600 K, log g = 3.45 ± 0.15 (cgs), and ξ = 10 km s{sup −1} are provided for HD 144941. In contrast to the non-LTE analyses, the LTE analyses—LTE atmospheres and an LTE line analysis—with the available indicators do not provide a consistent set of atmospheric parameters. The principal non-LTE effect on the elemental abundances is on the neon abundance. It is generally considered that these extreme helium stars with their very low C/He ratio result from the merger of two helium white dwarfs. Indeed, the derived composition of V652 Her is in excellent agreement with predictions by Zhang and Jeffery, who model the slow merger of helium white dwarfs; a slow merger results in the merged star having the composition of the accreted white dwarf. In the case of HD 144941, which appears to have evolved from metal-poor stars, a slow merger is incompatible with the observed composition but variations of the merger rate may account for the observed composition. More detailed theoretical studies of the merger of a pair of helium white dwarfs are to be encouraged.

Non-equilibrium ionization by a periodic electron beam. II. Synthetic Si IV and O IV transition region spectra

Science.gov (United States)

Dzifčáková, Elena; Dudík, Jaroslav

2018-03-01

Context. Transition region (TR) spectra typically show the Si IV 1402.8 Å line to be enhanced by a factor of 5 or more compared to the neighboring O IV 1401.2 Å, contrary to predictions of ionization equilibrium models and the Maxwellian distribution of particle energies. Non-equilibrium effects in TR spectra are therefore expected. Aims: To investigate the combination of non-equilibrium ionization and high-energy particles, we apply the model of the periodic electron beam, represented by a κ-distribution that recurs at periods of several seconds, to plasma at chromospheric temperatures of 104 K. This simple model can approximate a burst of energy release involving accelerated particles. Methods: Instantaneous time-dependent charge states of silicon and oxygen were calculated and used to synthesize the instantaneous and period-averaged spectra of Si IV and O IV. Results: The electron beam drives the plasma out of equilibrium. At electron densities of Ne = 1010 cm-3, the plasma is out of ionization equilibrium at all times in all cases we considered, while for a higher density of Ne = 1011 cm-3, ionization equilibrium can be reached toward the end of each period, depending on the conditions. In turn, the character of the period-averaged synthetic spectra also depends on the properties of the beam. While the case of κ = 2 results in spectra with strong or even dominant O IV, higher values of κ can approximate a range of observed TR spectra. Spectra similar to typically observed spectra, with the Si IV 1402.8 Å line about a factor 5 higher than O IV 1401.2 Å, are obtained for κ = 3. An even higher value of κ = 5 results in spectra that are exclusively dominated by Si IV, with negligible O IV emission. This is a possible interpretation of the TR spectra of UV (Ellerman) bursts, although an interpretation that requires a density that is 1-3 orders of magnitude lower than for equilibrium estimates. Movies associated to Fig. A.1 are available at http://https://www.aanda.org

A Laser Induced Breakdown Spectroscopy application based on Local Thermodynamic Equilibrium assumption for the elemental analysis of alexandrite gemstone and copper-based alloys

Energy Technology Data Exchange (ETDEWEB)

De Giacomo, A. [Department of Chemistry, University of Bari, Via Orabona 4, 70126 Bari (Italy); Institute of Inorganic Methodologies and Plasmas - CNR, U.O.S. Bari, Via Amendola 122/D, 70126 Bari (Italy); Dell' Aglio, M. [Institute of Inorganic Methodologies and Plasmas - CNR, U.O.S. Bari, Via Amendola 122/D, 70126 Bari (Italy); Gaudiuso, R., E-mail: rosalba.gaudiuso@ba.imip.cnr.it [Institute of Inorganic Methodologies and Plasmas - CNR, U.O.S. Bari, Via Amendola 122/D, 70126 Bari (Italy); Santagata, A. [Institute of Inorganic Methodologies and Plasmas - CNR, U.O.S. Potenza, Via S. Loja, Zona Ind., 85050 Tito Scalo (PZ) (Italy); Senesi, G.S. [Institute of Inorganic Methodologies and Plasmas - CNR, U.O.S. Bari, Via Amendola 122/D, 70126 Bari (Italy); Rossi, M.; Ghiara, M.R. [Department of Earth Sciences, University of Naples ' Federico II' , Via Mezzocannone 8, 80134 Naples (Italy); Capitelli, F. [Institute of Crystallography - CNR, Via Salaria Km 29.300, 00015 Monterotondo (Roma) (Italy); De Pascale, O. [Institute of Inorganic Methodologies and Plasmas - CNR, U.O.S. Bari, Via Amendola 122/D, 70126 Bari (Italy)

2012-04-04

Graphical abstract: Self-calibrated analytical techniques based on the approximation of Local Thermodynamic Equilibrium (LTE) have been employed for the analysis of gemstones and copper-based alloys by LIBS (Laser Induced Breakdown Spectroscopy), with a special focus on LTE conditions in laser induced plasmas. Highlights: Black-Right-Pointing-Pointer Discussion of Local Thermodynamic Equilibrium (LTE) condition in laser-induced plasmas. Black-Right-Pointing-Pointer LIBS enables elemental analysis with self-calibrated LTE-based methods. Black-Right-Pointing-Pointer Be detection in alexandrite gemstone is made possible by LIBS. - Abstract: Laser Induced Breakdown Spectroscopy (LIBS) is an appealing technique to study laser-induced plasmas (LIPs), both from the basic diagnostics point of view and for analytical applications. LIPs are complex dynamic systems, expanding at supersonic velocities and undergoing a transition between different plasma regimes. If the Local Thermodynamic Equilibrium (LTE) condition is valid for such plasmas, several analytical methods can be employed and fast quantitative analyses can be performed on a variety of samples. In the present paper, a discussion about LTE is carried out and an innovative application to the analysis of the alexandrite gemstone is presented. In addition, a study about the influence of plasma parameters on the performance of LTE-based methods is reported for bronze and brass targets.

Deviations from excitation equilibrium in optically thick mercury arc plasmas

International Nuclear Information System (INIS)

Karabourniotis, D.; Couris, S.; Damelincourt, J.J.

1989-01-01

Up to date mercury arcs at pressure greater than 1 atm have been investigated as plasma systems in local thermodynamic equilibrium (LTE) state. These studies have been motivated by the applications of mercury arcs, e.g., in the lighting industry. The LTE-assumption simplifies the use of spectroscopic diagnostics and the performance of species-concentration calculations. A high pressure mercury arc of about 1 atm had been considered in two possibilities: excitation and gas temperatures are the same, the electron temperature is higher and excitation and electron temperatures are the same, the gas temperature is lower. Recent measurements in mercury arcs reveal the existence of severe departures from thermal equilibrium and suggest the absence of excitation equilibrium in the axis and in the periphery in such an arc. The deviation from equilibrium leads to complicated distributions, such that the system cannot be described correctly by any single temperature. This becomes quite complicated when plasma inhomogeneity and strong reabsorption of the radiation are present

The chromospheric structure of cool carbon stars

International Nuclear Information System (INIS)

Luttermoser, D.G.

1988-01-01

The temperature-density structure of the outer atmospheres of the N-type carbon stars are investigated through computer generated synthetic spectra from model atmospheres. The synthetic spectra are compared to spectra obtained with the International Ultraviolet Explorer (IUE) spacecraft and ground-based photometry. The nature of the severe violet flux falloff seen in cool carbon stars is investigated through photospheric synthetic flux calculations with the assumption of local thermodynamic equilibrium (LTE). A new candidate for the unknown opacity source that causes this flux falloff is proposed-a preponderance of neutral metal bound-bound and bound-free transitions from low energy states. The chromospheric structure of these stars is also investigated through a semi-empirical modeling technique. Such a technique involves attaching a chromospheric temperature rise to a radiative equilibrium model photosphere and generating a synthetic spectrum of chromospheric spectral lines using non-LTE radiative transfer. The chromospheric temperature-density structure is then altered until the synthetic spectrum matches the IUE observations of the singly ionized magnesium resonance lines and the intercombination lines of singly ionized carbon. Through the above mentioned non-LTE analysis of the atmospheric structure of these stars, the excitation and ionization equilibria are investigated. The excited levels of H I, C I, Na I, Mg I, and Ca I are over-populated with respect to LTE in the middle and upper photosphere of these stars, and all are over-ionized with respect to LTE. Photons from the chromosphere greatly influence the excitation and ionization of H I, C I, and Mg I

Weak Acid Ionization Constants and the Determination of Weak Acid-Weak Base Reaction Equilibrium Constants in the General Chemistry Laboratory

Science.gov (United States)

Nyasulu, Frazier; McMills, Lauren; Barlag, Rebecca

2013-01-01

A laboratory to determine the equilibrium constants of weak acid negative weak base reactions is described. The equilibrium constants of component reactions when multiplied together equal the numerical value of the equilibrium constant of the summative reaction. The component reactions are weak acid ionization reactions, weak base hydrolysis…

A NON-LTE STUDY OF SILICON ABUNDANCES IN GIANT STARS FROM THE Si i INFRARED LINES IN THE zJ -BAND

International Nuclear Information System (INIS)

Tan, Kefeng; Shi, Jianrong; Zhao, Gang; Takada-Hidai, Masahide; Takeda, Yoichi

2016-01-01

We investigate the feasibility of Si i infrared (IR) lines as Si abundance indicators for giant stars. We find that Si abundances obtained from the Si i IR lines based on the local thermodynamic equilibrium (LTE) analysis show large line-to-line scatter (mean value of 0.13 dex), and are higher than those from the optical lines. However, when non-LTE effects are taken into account, the line-to-line scatter reduces significantly (mean value of 0.06 dex), and the Si abundances are consistent with those from the optical lines. The typical average non-LTE correction of [Si/Fe] for our sample stars is about −0.35 dex. Our results demonstrate that the Si i IR lines could be reliable abundance indicators, provided that the non-LTE effects are properly taken into account.

Target simulations with SCROLL non-LTE opacity/emissivity databases.

Science.gov (United States)

Klapisch, M.; Colombant, D.; Bar-Shalom, A.

2001-10-01

SCROLL[1], a collisional radiative model and code based on superconfigurations, is able to compute high Z non-LTE opacities and emissivities accurately and efficiently. It was used to create opacity/emissivity databases for Pd, Lu, Au on a 50 temperatures/80 densities grid. Incident radiation field was shown to have no effect on opacities in the case of interest, and was not taken into account. These databases were introduced in the hydrocode FAST1D[2]. SCROLL also gives an ionization temperature Tz which is used in FAST1D to obtain non-LTE corrections to the equation of state. Results will be compared to those of a previous version using Busquet’s algorithm[3]. Work supported by USDOE under a contract with NRL. [1] A. Bar-Shalom, J. Oreg and M. Klapisch, J. Quant. Spectrosc. Radiat. Transfer, 65, 43(2000). [2] J. H. Gardner, A. J. Schmitt, J. P. Dahlburg, C. J. Pawley, S. E. Bodner, S. P. Obenschain, V. Serlin and Y. Aglitskiy, Phys. Plasmas, 5, 1935 (1998). [3] M. Busquet, Phys. Fluids B, 5, 4191 (1993).

LTE-Advanced Relay Technology and Standardization

CERN Document Server

Yuan, Yifei

2013-01-01

LTE-Advanced Relay Technology and Standardization provides a timely reference work for relay technology with the finalizing of LTE Release 10 specifications. LTE-Advanced is quickly becoming the global standard for 4G cellular communications. The relay technology, as one of the key features in LTE-Advanced, helps not only to improve the system coverage and capacity, but also to save the costs of laying wireline backhaul. As a leading researcher in the field of LTE-Advanced standards, the author provides an in-depth description of LTE-A relay technology, and explains in detail the standard specification and design principles.     Readers from both academic and industrial fields can find sections of interest to them: Sections 2 & 4 could benefit researchers in academia and those who are engaged in exploratory work, while Sections 3 & 4 are more useful to engineers. Dr. Yifei Yuan is the Technical Director at the Standards Department of ZTE Inc.

Wi-Fi Coexistence with Duty Cycled LTE-U

Directory of Open Access Journals (Sweden)

Yimin Pang

2017-01-01

Full Text Available Coexistence of Wi-Fi and LTE-Unlicensed (LTE-U technologies has drawn significant concern in industry. In this paper, we investigate the Wi-Fi performance in the presence of duty cycle based LTE-U transmission on the same channel. More specifically, one LTE-U cell and one Wi-Fi basic service set (BSS coexist by allowing LTE-U devices to transmit their signals only in predetermined duty cycles. Wi-Fi stations, on the other hand, simply contend the shared channel using the distributed coordination function (DCF protocol without cooperation with the LTE-U system or prior knowledge about the duty cycle period or duty cycle of LTE-U transmission. We define the fairness of the above scheme as the difference between Wi-Fi performance loss ratio (considering a defined reference performance and the LTE-U duty cycle (or function of LTE-U duty cycle. Depending on the interference to noise ratio (INR being above or below −62 dbm, we classify the LTE-U interference as strong or weak and establish mathematical models accordingly. The average throughput and average service time of Wi-Fi are both formulated as functions of Wi-Fi and LTE-U system parameters using probability theory. Lastly, we use the Monte Carlo analysis to demonstrate the fairness of Wi-Fi and LTE-U air time sharing.

The ALI-ARMS Code for Modeling Atmospheric non-LTE Molecular Band Emissions: Current Status and Applications

Science.gov (United States)

Kutepov, A. A.; Feofilov, A. G.; Manuilova, R. O.; Yankovsky, V. A.; Rezac, L.; Pesnell, W. D.; Goldberg, R. A.

2008-01-01

The Accelerated Lambda Iteration (ALI) technique was developed in stellar astrophysics at the beginning of 1990s for solving the non-LTE radiative transfer problem in atomic lines and multiplets in stellar atmospheres. It was later successfully applied to modeling the non-LTE emissions and radiative cooling/heating in the vibrational-rotational bands of molecules in planetary atmospheres. Similar to the standard lambda iterations ALI operates with the matrices of minimal dimension. However, it provides higher convergence rate and stability due to removing from the iterating process the photons trapped in the optically thick line cores. In the current ALI-ARMS (ALI for Atmospheric Radiation and Molecular Spectra) code version additional acceleration of calculations is provided by utilizing the opacity distribution function (ODF) approach and "decoupling". The former allows replacing the band branches by single lines of special shape, whereas the latter treats non-linearity caused by strong near-resonant vibration-vibrational level coupling without additional linearizing the statistical equilibrium equations. Latest code application for the non-LTE diagnostics of the molecular band emissions of Earth's and Martian atmospheres as well as for the non-LTE IR cooling/heating calculations are discussed.

A partially ionized plasma modeling; Un modele de plasma partiellement ionise

Energy Technology Data Exchange (ETDEWEB)

Le Thanh, K.C.; Raviart, P.A

2003-07-01

We propose a model for the partially ionized plasma sheaths near the anode of an anodic spot electric arc where the cathode is considered as an electron emitter. A fluid description takes into account the heating and the ionization of the plasma induced by the electron beam. As physical hypothesis we assume that the condition of charge neutrality is valid. According that the electron mass can be neglected compared to the ion mass, we can assume that ions and atoms have the same velocity and the same temperature. Electrons and heavy particles are then regarded as two separate fluids coexisting in the plasma. Governing equations are then multi-fluid equations with relaxation correction to the local thermodynamic equilibrium (LTE) and heating by Joule effect. Equations are solved by an operator splitting procedure. That is we first discretize the homogeneous conservation laws (i.e. without source terms) by a finite volume method. The second step is to solve the ordinary differential system (i.e, governing equation without transport terms) with an implicit scheme. (authors)

Limb-darkening coefficients from line-blanketed non-LTE hot-star model atmospheres

Science.gov (United States)

Reeve, D. C.; Howarth, I. D.

2016-02-01

We present grids of limb-darkening coefficients computed from non-local thermodynamic equilibrium (non-LTE), line-blanketed TLUSTY model atmospheres, covering effective-temperature and surface-gravity ranges of 15-55 kK and 4.75 dex (cgs) down to the effective Eddington limit, at 2×, 1×, 0.5× (Large Magellanic Cloud), 0.2× (Small Magellanic Cloud), and 0.1× solar. Results are given for the Bessell UBVRICJKHL, Sloan ugriz, Strömgren ubvy, WFCAM ZYJHK, Hipparcos, Kepler, and Tycho passbands, in each case characterized by several different limb-darkening `laws'. We examine the sensitivity of limb darkening to temperature, gravity, metallicity, microturbulent velocity, and wavelength, and make a comparison with LTE models. The dependence on metallicity is very weak, but limb darkening is a moderately strong function of log g in this temperature regime.

Global low-frequency modes in weakly ionized magnetized plasmas: effects of equilibrium plasma rotation

International Nuclear Information System (INIS)

Sosenko, P.; Pierre, Th.; Zagorodny, A.

2004-01-01

The linear and non-linear properties of global low-frequency oscillations in cylindrical weakly ionized magnetized plasmas are investigated analytically for the conditions of equilibrium plasma rotation. The theoretical results are compared with the experimental observations of rotating plasmas in laboratory devices, such as Mistral and Mirabelle in France, and KIWI in Germany. (authors)

On the Way towards Fourth-Generation Mobile: 3GPP LTE and LTE-Advanced

Directory of Open Access Journals (Sweden)

Martín-Sacristán David

2009-01-01

Full Text Available Abstract Long-Term Evolution (LTE is the new standard recently specified by the 3GPP on the way towards fourth-generation mobile. This paper presents the main technical features of this standard as well as its performance in terms of peak bit rate and average cell throughput, among others. LTE entails a big technological improvement as compared with the previous 3G standard. However, this paper also demonstrates that LTE performance does not fulfil the technical requirements established by ITU-R to classify one radio access technology as a member of the IMT-Advanced family of standards. Thus, this paper describes the procedure followed by the 3GPP to address these challenging requirements. Through the design and optimization of new radio access techniques and a further evolution of the system, the 3GPP is laying down the foundations of the future LTE-Advanced standard, the 3GPP candidate for 4G. This paper offers a brief insight into these technological trends.

On the Way towards Fourth-Generation Mobile: 3GPP LTE and LTE-Advanced

Directory of Open Access Journals (Sweden)

David Martín-Sacristán

2009-01-01

Full Text Available Long-Term Evolution (LTE is the new standard recently specified by the 3GPP on the way towards fourth-generation mobile. This paper presents the main technical features of this standard as well as its performance in terms of peak bit rate and average cell throughput, among others. LTE entails a big technological improvement as compared with the previous 3G standard. However, this paper also demonstrates that LTE performance does not fulfil the technical requirements established by ITU-R to classify one radio access technology as a member of the IMT-Advanced family of standards. Thus, this paper describes the procedure followed by the 3GPP to address these challenging requirements. Through the design and optimization of new radio access techniques and a further evolution of the system, the 3GPP is laying down the foundations of the future LTE-Advanced standard, the 3GPP candidate for 4G. This paper offers a brief insight into these technological trends.

Non-LTE population probabilities of the excited ionic levels in a steady state plasma

International Nuclear Information System (INIS)

Salzmann, D.

1982-01-01

A Complete-Staedy-State (CSS) model for the charge state distribution and the ionic levels population probabilities of ions in hot non-LTE plasmas is described. The following properties of this model are described: (i) it is shown that CSS covers LTE and Corona Equilibrium (CE) in the high and low electron density regimes respectively, (ii) an explicit expression is found for the low electron density asymptotic behaviour of the population probabilities, (iii) it is shown that at intermediate density regions the CSS model predicts results similar to that of the Quasi-Steady-State model, (iv) new validity limits are derived for LTE and CE, (v) the population distribution of the excited levels is revised, (vi) an analytical expression is found for the high electron density asymptotic behaviour of the population distribution, (vii) the influence of the radiation reabsorption in a spherically symmetric CSS plasma is briefly described, and (viii) the effect of the inaccuracies in the rate-coefficients on the results of CSS calculations is evaluated. (author)

Studying effects of non-equilibrium radiative transfer via HPC

Energy Technology Data Exchange (ETDEWEB)

Holladay, Daniel [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2018-01-24

This report presents slides on Ph.D. Research Goals; Local Thermodynamic Equilibrium (LTE) Implications; Calculating an Opacity; Opacity: Pictographic Representation; Opacity: Pictographic Representation; Opacity: Pictographic Representation; Collisional Radiative Modeling; Radiative and Collisional Excitation; Photo and Electron Impact Ionization; Autoionization; The Rate Matrix; Example: Total Photoionization rate; The Rate Coefficients; inlinlte version 1.1; inlinlte: Verification; New capabilities: Rate Matrix – Flexibility; Memory Option Comparison; Improvements over previous DCA solver; Inter- and intra-node load balancing; Load Balance – Full Picture; Load Balance – Full Picture; Load Balance – Internode; Load Balance – Scaling; Description; Performance; xRAGE Simulation; Post-process @ 2hr; Post-process @ 4hr; Post-process @ 8hr; Takeaways; Performance for 1 realization; Motivation for QOI; Multigroup Er; Transport and NLTE large effects (1mm, 1keV); Transport large effect, NLTE lesser (1mm, 750eV); Blastwave Diagnostici – Description & Performance; Temperature Comparison; NLTE has effect on dynamics at wall; NLTE has lesser effect in the foam; Global Takeaways; The end.

Coronal and local thermodynamic equilibriums in a hollow cathode discharge

International Nuclear Information System (INIS)

Zheng Xutao

2005-01-01

A characteristic two-section profile of excited-state populations is observed in a hollow cathode discharge and is explained by coexistence of the coronal equilibrium (CE) and the local thermodynamic equilibrium (LTE). At helium pressure 0.1 Torr and cathode current 200-300 mA, vacuum ultraviolet radiations from He I 1snp 1 P (n=2-16) and He II np 2 P (n=2-14) are resolved with a 2.2-M McPherson spectrometer. Relative populations of these states are deduced from the discrete line intensities and are plotted against energy levels. For both the He I and He II series, as energy level increases, populations of high-n (n>10) states are found to decrease much more quickly than low-n (n<7) populations. While low-n populations are described with the CE dominated by direct electron-impact excitations, high-n populations are fitted with the LTE to calculate the population temperatures of gas atoms and ions. Validities of the CE and LTE in different n-ranges are considered on the competition between radiative decays of the excited states and their collisions with gas atoms. (author)

Local Thermodynamic Equilibrium in Laser-Induced Breakdown Spectroscopy: Beyond the McWhirter criterion

International Nuclear Information System (INIS)

Cristoforetti, G.; De Giacomo, A.; Dell'Aglio, M.; Legnaioli, S.; Tognoni, E.; Palleschi, V.; Omenetto, N.

2010-01-01

In the Laser-Induced Breakdown Spectroscopy (LIBS) technique, the existence of Local Thermodynamic Equilibrium (LTE) is the essential requisite for meaningful application of theoretical Boltzmann-Maxwell and Saha-Eggert expressions that relate fundamental plasma parameters and concentration of analyte species. The most popular criterion reported in the literature dealing with plasma diagnostics, and usually invoked as a proof of the existence of LTE in the plasma, is the McWhirter criterion [R.W.P. McWhirter, in: Eds. R.H. Huddlestone, S.L. Leonard, Plasma Diagnostic Techniques, Academic Press, New York, 1965, pp. 201-264]. However, as pointed out in several papers, this criterion is known to be a necessary but not a sufficient condition to insure LTE. The considerations reported here are meant to briefly review the theoretical analysis underlying the concept of thermodynamic equilibrium and the derivation of the McWhirter criterion, and to critically discuss its application to a transient and non-homogeneous plasma, like that created by a laser pulse on solid targets. Specific examples are given of theoretical expressions involving relaxation times and diffusion coefficients, as well as a discussion of different experimental approaches involving space and time-resolved measurements that could be used to complement a positive result of the calculation of the minimum electron number density required for LTE using the McWhirter formula. It is argued that these approaches will allow a more complete assessment of the existence of LTE and therefore permit a better quantitative result. It is suggested that the mere use of the McWhirter criterion to assess the existence of LTE in laser-induced plasmas should be discontinued.

Effect of configuration widths on the spectra of local thermodynamic equilibrium plasmas

International Nuclear Information System (INIS)

Bar-Shalom, A.; Oreg, J.; Goldstein, W.H.

1995-01-01

We present the extension of the supertransition-array (STA) theory to include configuration widths in the spectra of local thermodynamic equilibrium (LTE) plasmas. Exact analytic expressions for the moments of a STA are given, accounting for the detailed contributions of individual levels within the configurations that belong to a STA. The STA average energy is shifted and an additional term appears in its variance. Various cases are presented, demonstrating the effect of these corrections on the LTE spectrum

LTE UE Power Consumption Model

DEFF Research Database (Denmark)

Jensen, Anders Riis; Lauridsen, Mads; Mogensen, Preben

2012-01-01

is based on a review of the major power consuming parts in an LTE UE radio modem. The model includes functions of UL and DL power and data rate. Measurements on a commercial LTE USB dongle were used to assign realistic power consumption values to each model parameter. Verification measurements......In this work a novel LTE user equipment (UE) power consumption model is presented. It was developed for LTE system level optimization, because it is important to understand how network settings like scheduling of resources and transmit power control affect the UE’s battery life. The proposed model...... on the dongle show that the model results in an average error of 2.6%. The measurements show that UL transmit power and DL data rate determines the overall power consumption, while UL data rate and DL receive power have smaller impact....

Ionization equilibrium in dense plasmas

International Nuclear Information System (INIS)

Ying, R.

1987-01-01

The average degree of ionization for a strongly coupled plasma is investigated and calculated. Two widely used approaches: the Saha equation method and the Thomas-Fermi (TF) statistical atomic model are adopted to determine the degree of ionization. Both methods are modified in a number of ways to include the strong-coupling effect in the plasma. In the Saha equation approach, the strong-coupling effects are introduced through: (i) a replacement of the Coulomb potential by a screened Debye potential; (ii) adoption of the Planck-Larkin partition function; (iii) description of the electron component by Fermi-Dirac statistics. The calculated degree of ionization exceeds that obtained from the original Saha equation, exhibits a minimum as a function of the density and shows an abrupt phase transition from weakly ionized to a fully ionized state. The zero-temperature TF model for compressed ions and the finite-temperature TF model for ions are investigated for the first time. In order to take into account the strong-coupling effect in a systematic way, a strong-coupling TF model is set up. Favorable results with the relatively simple approximations indicate that the newly established strong-coupling TF model is a more systematic and physically consistent approach

Configuration interaction in LTE spectra of heavy elements

International Nuclear Information System (INIS)

Bar-Shalom, A.; Oreg, J.; Goldstein, W.

1992-11-01

We present a method for including the effects of configuration interaction (CI) between relativistic subconfigurations of an electron configuration in the calculation of emission and absorption spectra of plasmas in local thermodynamic equilibrium (LTE). Analytical expressions for the correction to the intensities, owing to Cl, of an unresolved transition array (UTA) and of a supertransition array (STA) are obtained when the correction is small compared to the spin-orbit splitting, bypassing the need to diagonalize energy matrices. These expressions serve as working formulas in the STA model and, in addition, reveal a priori the conditions under which CI effects are significant. Examples of the effect are presented

Coexistence of 3G repeaters with LTE base stations.

Science.gov (United States)

Yeo, Woon-Young; Lee, Sang-Min; Hwang, Gyung-Ho; Kim, Jae-Hoon

2013-01-01

Repeaters have been an attractive solution for mobile operators to upgrade their wireless networks at low cost and to extend network coverage effectively. Since the first LTE commercial deployment in 2009, many mobile operators have launched LTE networks by upgrading their 3G and legacy networks. Because all 3G frequency bands are shared with the frequency bands for LTE deployment and 3G mobile operators have an enormous number of repeaters, reusing 3G repeaters in LTE networks is definitely a practical and cost-efficient solution. However, 3G repeaters usually do not support spatial multiplexing with multiple antennas, and thus it is difficult to reuse them directly in LTE networks. In order to support spatial multiplexing of LTE, the role of 3G repeaters should be replaced with small LTE base stations or MIMO-capable repeaters. In this paper, a repeater network is proposed to reuse 3G repeaters in LTE deployment while still supporting multilayer transmission of LTE. Interestingly, the proposed network has a higher cluster throughput than an LTE network with MIMO-capable repeaters.

Local thermal equilibrium and KMS states in curved spacetime

International Nuclear Information System (INIS)

Solveen, Christoph

2012-01-01

On the example of a free massless and conformally coupled scalar field, it is argued that in quantum field theory in curved spacetimes with the time-like Killing field, the corresponding KMS states (generalized Gibbs ensembles) at parameter β > 0 need not possess a definite temperature in the sense of the zeroth law. In fact, these states, although passive in the sense of the second law, are not always in local thermal equilibrium (LTE). A criterion characterizing LTE states with sharp local temperature is discussed. Moreover, a proposal is made for fixing the renormalization freedom of composite fields which serve as ‘thermal observables’ and a new definition of the thermal energy of LTE states is introduced. Based on these results, a general relation between the local temperature and the parameter β is established for KMS states in (anti) de Sitter spacetime. (paper)

Checking the validity of Busquet's ionization temperature with detailed collisional radiative models.

Science.gov (United States)

Klapisch, M.; Bar-Shalom, A.

1997-12-01

Busquet's RADIOM model for effective ionization temperature Tz is an appealing and simple way to introduce non LTE effects in hydrocodes. The authors report checking the validity of RADIOM in the optically thin case by comparison with two collisional radiative models, MICCRON (level-by-level) for C and Al and SCROLL (superconfiguration- by-superconfiguration) for Lu and Au. MICCRON is described in detail. The agreement between the average ion charge >ZBusquet is very good in most cases. There is however room for improvement when the departure from LTE is more pronounced for heavy atoms and for emissivity. Improvement appears possible because the concept of ionization temperature seems to hold in a broader range of parameters.

LTE-verkon mittaus

OpenAIRE

Summanen, Mika

2013-01-01

Tämän insinöörityön tarkoituksena oli esitellä LTE-verkon rakennetta ja radiorajapinnassa käytettäviä parametreja, sekä suorittaa muutamia nopeusmittauksia verkossa. Parametrien mittaukseen käytettiin Ascomin TEMS Investigation -ohjelmiston versiota 14.4. Nopeustestit puolestaan suoritettiin matkapuhelimeen asennetun Ookla speedtest sovelluksen avulla. Työssä käydään läpi LTE-verkon arkkitehtuuria ja siinä sijaitsevia elementtejä, sekä esitellään radiotien standardoinnissa valittuja tekn...

Single Carrier Transmission for UTRA LTE Uplink

DEFF Research Database (Denmark)

Priyanto, Basuki Endah; Berardinelli, Gilberto; Sørensen, Troels Bundgaard

2009-01-01

In this chapter, we have presented the key techniques for LTE uplink as well as presented the baseline performance. Radio access technology is the key aspect in LTE uplink and two radio access schemes, SC-FDMA and OFDMA, are studied. The performance results are obtained from a detailed UTRA LTE...

A Zero Dimensional Time-Dependent Model of High-Pressure Ablative Capillary Discharge (Preprint)

National Research Council Canada - National Science Library

Pekker, Leonid

2008-01-01

... plasma core and the ablative capillary walls. The model includes the thermodynamics of partially ionized plasmas and non-ideal effects taking place in the high density plasma and assumes local thermodynamic equilibrium (LTE...

From LTE to 5G for Connected Mobility

DEFF Research Database (Denmark)

Lauridsen, Mads; Gimenez, Lucas Chavarria; Rodriguez Larrad, Ignacio

2017-01-01

been initiated. In this article, we measure how current LTE network implementations perform in comparison with the initial LTE requirements. The target is to identify certain key performance indicators that have suboptimal implementations and therefore lend themselves to careful consideration when...... time, and coverage of four operational LTE networks based on 19,000 km of drive tests covering a mixture of rural, suburban, and urban environments. The measurements have been collected using commercial radio network scanners and measurement smartphones. Even though LTE has low air interface delays......, the measurements reveal that core network delays compromise the overall round-trip time design requirement. LTE's breakbefore- make handover implementation causes a data interruption at each handover of 40 ms at the median level. While this is in compliance with the LTE requirements, and lower values are certainly...

Direct evidence of departure from local thermodynamic equilibrium in a free-burning arc-discharge plasma

International Nuclear Information System (INIS)

Snyder, S.C.; Lassahn, G.D.; Reynolds, L.D.

1993-01-01

Radial profiles of gas temperature, electron temperature, and electron density were measured in a free-burning atmospheric-pressure argon arc-discharge plasma using line-shape analysis of scattered laser light. This method yields gas temperature, electron temperature, and electron density directly, with no reliance on the assumption of local thermodynamic equilibrium (LTE). Our results show a significant departure from LTE in the center of the discharge, contrary to expectations

Analysis of LTE 800MHz Network Deployment Strategy%LTE 800MHz网络部署策略分析

Institute of Scientific and Technical Information of China (English)

余扬尧; 陈杨; 杨芙蓉

2016-01-01

Starting ifrst with the current mobile user development situation of the three operators, the paper analyzed the necessity of China telecom LTE 800 MHz network construction, the network coverage, terminal market, construction speed, the business competition, and etc., concluded the short-term, mid-term and long-term deployment strategy for LTE 800 MHz.%首先从当前三大运营商的移动业务用户发展情况入手，分析了中国电信LTE 800 MHz网络建设的必要性，对LTE 800 MHz的网络覆盖、终端市场、建设速度、业务竞争等几个方面进行分析，得出了LTE 800 MHz近、中、远期的部署策略。

Energy Flow in Dense Off-Equilibrium Plasma

Science.gov (United States)

2016-07-15

brings the electron density and light emission into LTE at the measured spectral temperature while leaving the ions cold. Because of their large mass... measurements of ionization potential lowering and collision times indense plasmas, allowing us to distinguish between competing dense-plasma models...Hydrodynamic analysis of shockwaves generated by sparks yielded similar measurements ina different, more accessible system. Ultra-fast observations

Dynamic Relaying in 3GPP LTE-Advanced Networks

DEFF Research Database (Denmark)

Teyeb, Oumer Mohammed; Van Phan, Vinh; Redana, Simone

2009-01-01

Relaying is one of the proposed technologies for LTE-Advanced networks. In order to enable a flexible and reliable relaying support, the currently adopted architectural structure of LTE networks has to be modified. In this paper, we extend the LTE architecture to enable dynamic relaying, while...... maintaining backward compatibility with LTE Release 8 user equipments, and without limiting the flexibility and reliability expected from relaying.With dynamic relaying, relays can be associated with base stations on a need basis rather than in a fixed manner which is based only on initial radio planning....... Proposals are also given on how to further improve a relay enhanced LTE network by enabling multiple interfaces between the relay nodes and their controlling base stations, which can possibly be based on technologies different from LTE, so that load balancing can be realized. This load balancing can...

Non-LTE hydrogen-line formation in moving prominences

Science.gov (United States)

Heinzel, P.; Rompolt, B.

1986-01-01

The behavior of hydrogen-line brightness variations, depending on the prominence-velocity changes were investigated. By solving the NON-Local thermodynamic equilibrium (LTE) problem for hydrogen researchers determine quantitatively the effect of Doppler brightening and/or Doppler dimming (DBE, DDE) in the lines of Lyman and Balmer series. It is demonstrated that in low-density prominence plasmas, DBE in H alpha and H beta lines can reach a factor of three for velocities around 160 km/sec, while the L alpha line exhibits typical DDE. L beta brightness variations follow from a combined DBE in the H alpha and DDE in L alpha and L beta itself, providing that all relevant multilevel interlocking processes are taken into account.

Multi-Group Reductions of LTE Air Plasma Radiative Transfer in Cylindrical Geometries

Science.gov (United States)

Scoggins, James; Magin, Thierry Edouard Bertran; Wray, Alan; Mansour, Nagi N.

2013-01-01

Air plasma radiation in Local Thermodynamic Equilibrium (LTE) within cylindrical geometries is studied with an application towards modeling the radiative transfer inside arc-constrictors, a central component of constricted-arc arc jets. A detailed database of spectral absorption coefficients for LTE air is formulated using the NEQAIR code developed at NASA Ames Research Center. The database stores calculated absorption coefficients for 1,051,755 wavelengths between 0.04 µm and 200 µm over a wide temperature (500K to 15 000K) and pressure (0.1 atm to 10.0 atm) range. The multi-group method for spectral reduction is studied by generating a range of reductions including pure binning and banding reductions from the detailed absorption coefficient database. The accuracy of each reduction is compared to line-by-line calculations for cylindrical temperature profiles resembling typical profiles found in arc-constrictors. It is found that a reduction of only 1000 groups is sufficient to accurately model the LTE air radiation over a large temperature and pressure range. In addition to the reduction comparison, the cylindrical-slab formulation is compared with the finite-volume method for the numerical integration of the radiative flux inside cylinders with varying length. It is determined that cylindrical-slabs can be used to accurately model most arc-constrictors due to their high length to radius ratios.

Non equilibrium atomic processes and plasma spectroscopy

International Nuclear Information System (INIS)

Kato, Takako

2003-01-01

Along with the technical progress in plasma spectroscopy, non equilibrium ionization processes have been recently observed. We study non local thermodynamic equilibrium and non ionization equilibrium for various kinds of plasmas. Specifically we discuss non equilibrium atomic processes in magnetically confined plasmas, solar flares and laser produced plasmas using a collisional radiative model based on plasma spectroscopic data. (author)

Dynamic Relaying in 3GPP LTE-Advanced Networks

Directory of Open Access Journals (Sweden)

Van Phan Vinh

2009-01-01

Full Text Available Relaying is one of the proposed technologies for LTE-Advanced networks. In order to enable a flexible and reliable relaying support, the currently adopted architectural structure of LTE networks has to be modified. In this paper, we extend the LTE architecture to enable dynamic relaying, while maintaining backward compatibility with LTE Release 8 user equipments, and without limiting the flexibility and reliability expected from relaying. With dynamic relaying, relays can be associated with base stations on a need basis rather than in a fixed manner which is based only on initial radio planning. Proposals are also given on how to further improve a relay enhanced LTE network by enabling multiple interfaces between the relay nodes and their controlling base stations, which can possibly be based on technologies different from LTE, so that load balancing can be realized. This load balancing can be either between different base stations or even between different networks.

Method for traceable measurement of LTE signals

Science.gov (United States)

Sunder Dash, Soumya; Pythoud, Frederic; Leuchtmann, Pascal; Leuthold, Juerg

2018-04-01

This contribution presents a reference setup to measure the power of the cell-specific resource elements present in downlink long term evolution (LTE) signals in a way that the measurements are traceable to the international system of units. This setup can be used to calibrate the LTE code-selective field probes that are used to measure the radiation of base stations for mobile telephony. It can also be used to calibrate LTE signal generators and receivers. The method is based on traceable scope measurements performed directly at the output of a measuring antenna. It implements offline digital signal processing demodulation algorithms that consider the digital down-conversion, timing synchronization, frequency synchronization, phase synchronization and robust LTE cell identification to produce the downlink time-frequency LTE grid. Experimental results on conducted test scenarios, both single-input-single-output and multiple-input-multiple-output antenna configuration, show promising results confirming measurement uncertainties of the order of 0.05 dB with a coverage factor of 2.

LTE for public safety

CERN Document Server

Liebhart, Rainer; Wong, Curt; Merkel , Jürgen

2015-01-01

The aim of the book is to educate government agencies, operators, vendors and other regulatory institutions how LTE can be deployed to serve public safety market and offer regulatory / public safety features. It is written in such a way that it can be understood by both technical and non-technical personnel with just introductory knowledge in wireless communication. Some sections and chapters about public safety services offered by LTE network are intended to be understood by anyone with no knowledge in wireless communication.

A non-equilibrium simulation of thermal constriction in a cascaded arc hydrogen plasma

International Nuclear Information System (INIS)

Peerenboom, K S C; Goedheer, W J; Van Dijk, J; Kroesen, G M W

2014-01-01

The cascaded arc hydrogen plasma of Pilot-PSI is studied in a non-LTE model. We demonstrate that the effect of vibrationally excited molecules on the heavy-particle-assisted dissociation is crucial for obtaining thermal constriction. To the best of our knowledge, thermal constriction has not been obtained before in a non-LTE simulation. Probably, realistic numerical studies of this type of plasma were hindered by numerical problems, preventing the non-LTE simulations to show characteristic physical mechanisms such as thermal constriction. In this paper we show that with the help of appropriate numerical strategies thermal constriction can be obtained in a non-LTE simulation. To this end, a new source term linearization technique is developed, which ensures physical solutions even near chemical equilibrium where the composition is dominated by chemical source terms. Results of the model are compared with experiments on Pilot-PSI and show good agreement with pressure and voltage measurements in the source. (paper)

The continuous UV flux of alpha lyrae: NON-LTE results

International Nuclear Information System (INIS)

Snijders, M.A.J.

1977-01-01

Non--LTE calculations for the ultraviolet C I and Si I continuous opacity show that LTE results overestimate the importance of these sources of opacity and underestimate the emergent flux in α Lyr. The largest errors occur between 1100 and 1160 A where the predicted flux in non--LTE is as much as 50 times larger than in LTE, in reasonable accord with Copernicus observations.The discrepancy between LTE models and observations has been interpreted by Praderie et al. to result from the existence of a chromosphere. Until a self--consistent non-LTE model atmosphere becomes available, such an interpretation is premature

The continuous UV flux of Alpha Lyrae - Non-LTE results

Science.gov (United States)

Snijders, M. A. J.

1977-01-01

Non-LTE calculations for the ultraviolet C I and Si I continuous opacity show that LTE results overestimate the importance of these sources of opacity and underestimate the emergent flux in Alpha Lyr. The largest errors occur between 1100 and 1160 A, where the predicted flux in non-LTE is as much as 50 times larger than in LTE, in reasonable accord with Copernicus observations. The discrepancy between LTE models and observations has been interpreted to result from the existence of a chromosphere. Until a self-consistent non-LTE model atmosphere becomes available, such an interpretation is premature.

Random access procedures and radio access network (RAN) overload control in standard and advanced long-term evolution (LTE and LTE-A) networks

DEFF Research Database (Denmark)

Kiilerich Pratas, Nuno; Thomsen, Henning; Popovski, Petar

2015-01-01

In this chapter, we describe and discuss the current LTE random access procedure and the Radio Access Network Load Control solution within LTE/LTE-A. We provide an overview of the several considered load control solutions and give a detailed description of the standardized Extended Access Class B...

LTE uplink scheduling - flow level analysis

NARCIS (Netherlands)

Dimitrova, D.C.; van den Berg, J.L.; Heijenk, G.; Litjens, R.; Sacchi, Claudio; Bellalta, Boris; Vinel, Alexey; Schlegel, Christian; Granelli, Fabrizio; Zhang, Yan

Long Term Evolution (LTE) is a cellular technology foreseen to extend the capacity and improve the performance of current 3G cellular networks. A key mechanism in the LTE traffic handling is the packet scheduler, which is in charge of allocating resources to active flows in both the frequency and

LTE uplink scheduling - Flow level analysis

NARCIS (Netherlands)

Dimitrova, D.C.; Berg, J.L. van den; Heijenk, G.; Litjens, R.

2011-01-01

Long Term Evolution (LTE) is a cellular technology foreseen to extend the capacity and improve the performance of current 3G cellular networks. A key mechanism in the LTE traffic handling is the packet scheduler, which is in charge of allocating resources to active flows in both the frequency and

Handover Framework for Relay Enhanced LTE Networks

DEFF Research Database (Denmark)

Teyeb, Oumer Mohammed; Van Phan, Vinh; Raaf, Bernhard

2009-01-01

Relaying is one of the proposed technologies for future releases of UTRAN Long Term Evolution (LTE) networks. Introducing relaying is expected to increase the coverage and capacity of LTE networks. In order to enable relaying, the architecture, protocol and radio resource management procedures...... of LTE, such as handover, have to be modified. A user can be handed over not only between two base stations, but also between relays and base stations, and between two relays. With the introduction of relaying, there is a need for a new procedure to hand over a relay and all its associated users...... to another base station, allowing a flexible and dynamic relay deployment. In this paper, we extend the LTE release 8 handover mechanisms so that it can accommodate these new handover functionalities in a flexible manner....

Effect of non-local equilibrium on minimal thermal resistance porous layered systems

International Nuclear Information System (INIS)

Leblond, Genevieve; Gosselin, Louis

2008-01-01

In this paper, the cooling of a heat-generating surface by a stacking of porous media (e.g., metallic foam) through which fluid flows parallel to the surface is considered. A two-temperature model is proposed to account for non-local thermal equilibrium (non-LTE). A scale analysis is performed to determine temperatures profiles in the boundary layer regime. The hot spot temperature is minimized with respect to the three design variables of each layer: porosity, pore diameter, and material. Global cost and mass are constrained. The optimization is performed with a hybrid genetic algorithm (GA) including local search to enhance convergence and repeatability. Results demonstrate that the optimized stacks do not operate in LTE. Therefore, we show that assuming LTE might result in underestimation of the hot spot temperature, and into different final designs as well

Enhanced cognitive Radio Resource Management for LTE systems

KAUST Repository

Alqerm, Ismail

2013-10-01

The explosive growth in mobile Internet and related services has increased the need for more bandwidth in cellular networks. The Long-Term Evolution (LTE) technology is an attractive solution for operators and subscribers to meet such need since it provides high data rates and scalable bandwidth. Radio Resource Management (RRM) is essential for LTE to provide better communication quality and meet the application QoS requirements. Cognitive resource management is a promising solution for LTE RRM as it improves network efficiency by exploiting radio environment information, intelligent optimization algorithms to configure transmission parameters, and mitigate interference. In this paper, we propose a cognitive resource management scheme to adapt LTE network parameters to the environment conditions. The scheme optimizes resource blocks assignment, modulation selection and bandwidth selection to maximize throughput and minimize interference. The scheme uses constrained optimization for throughput maximization and interference control. It is also enhanced by learning mechanism to reduce the optimization complexity and improve the decision-making quality. Our evaluation results show that our scheme achieved significant improvements in throughput and LTE system capacity. Results also show the improvement in the user satisfaction over other techniques in LTE RRM.

Towards a QoE-Driven Resource Control in LTE and LTE-A Networks

Directory of Open Access Journals (Sweden)

Gerardo Gómez

2013-01-01

Full Text Available We propose a novel architecture for providing quality of experience (QoE awareness to mobile operator networks. In particular, we describe a possible architecture for QoE-driven resource control for long-term evolution (LTE and LTE-advanced networks, including a selection of KPIs to be monitored in different network elements. We also provide a description and numerical results of the QoE evaluation process for different data services as well as potential use cases that would benefit from the rollout of the proposed framework.

NON-EQUILIBRIUM CHEMISTRY OF DYNAMICALLY EVOLVING PRESTELLAR CORES. II. IONIZATION AND MAGNETIC FIELD

International Nuclear Information System (INIS)

Tassis, Konstantinos; Willacy, Karen; Yorke, Harold W.; Turner, Neal J.

2012-01-01

We study the effect that non-equilibrium chemistry in dynamical models of collapsing molecular cloud cores has on measurements of the magnetic field in these cores, the degree of ionization, and the mean molecular weight of ions. We find that OH and CN, usually used in Zeeman observations of the line-of-sight magnetic field, have an abundance that decreases toward the center of the core much faster than the density increases. As a result, Zeeman observations tend to sample the outer layers of the core and consistently underestimate the core magnetic field. The degree of ionization follows a complicated dependence on the number density at central densities up to 10 5 cm –3 for magnetic models and 10 6 cm –3 in non-magnetic models. At higher central densities, the scaling approaches a power law with a slope of –0.6 and a normalization which depends on the cosmic-ray ionization rate ζ and the temperature T as (ζT) 1/2 . The mean molecular weight of ions is systematically lower than the usually assumed value of 20-30, and, at high densities, approaches a value of 3 due to the asymptotic dominance of the H + 3 ion. This significantly lower value implies that ambipolar diffusion operates faster.

Two-temperature transport coefficients of SF6–N2 plasma

International Nuclear Information System (INIS)

Yang, Fei; Chen, Zhexin; Wu, Yi; Rong, Mingzhe; Wang, Chunlin; Guo, Anxiang; Liu, Zirui

2015-01-01

Sulfur hexafluoride (SF 6 ) is widely adopted in electric power industry, especially in high-voltage circuit breakers and gas-insulated switchgear. However, the use of SF 6 is limited by its high liquidation temperature and high global warming potential. Recently, research shows SF 6 –N 2 mixture, which shows environmental friendliness and good electrical properties, may be a feasible substitute for pure SF 6 . This paper is devoted to the calculation of and transport coefficients of SF 6 –N 2 mixture under both LTE (local thermodynamic equilibrium) and non-LTE condition. The two–temperature mass action law was used to determine the composition. The transport coefficients were calculated by classical Chapman–Enskog method simplified by Devoto. The thermophysical properties are presented for electron temperatures of 300–40 000 K, ratios of electron to heavy species temperature of 1–10 and N 2 mole fraction of 0%–100% at atmospheric pressure. The ionization processes under both LTE and non-LTE have been discussed. The results show that deviations from local thermodynamic equilibrium significantly affect the properties of SF 6 –N 2 plasma, especially before the plasma is fully ionized. The different influence of N 2 on properties for SF 6 –N 2 plasma in and out of LTE has been found. The results will serve as reliable reference data for computational simulation of the behavior of SF 6 –N 2 plasmas

Kesiapan Operator Seluler dalam Mengimplementasikan Teknologi Long Term Evolution (LTE

Directory of Open Access Journals (Sweden)

Sri Ariyanti

2012-06-01

Full Text Available Penelitian ini bertujuan untuk mengetahui seberapa besar kesiapan operator seluler dalam mengimplementasikan teknologi Long Term Evolution (LTE. Model penelitian dengan menggunakan mengadopsi teknik Net Readiness Framwork. Adapun kriteria pengukurannya terdiri dari Leadership, Governance, Competencies dan Technology. Pengumpulan data dilakukan dengan menyebarkan kuesioner kepada operator seluler di Indonesia dan melakukan wawancara kepada regulator. Kajian ini menggunakan teknik analisis data kuantitatif deskriptif. Hasil penelitian menunjukkan bahwa PT. Axis, PT. HCPT dan PT. Telkomsel mempunyai tingkat kesiapan LTE Visionary yang berarti perusahaan sangat antusias dalam perubahan dan lebih dahulu mengambil resiko untuk mengimplementasikan LTE dalam organisasinya yang merupakan bagian yang tak terpisahkan proses bisnis perusahaan. PT. Indosat dan PT. XL mempunyai nilai kesiapan LTE leader  yang berarti perusahaan mampu mengadaptasi perubahan dan menginspirasi organsiasi lain dalam penerapan LTE. PT. Smartfren pada tingkat kesiapan LTE savvy yang berarti operator seluler memahami sebab dan efek dari perubahan dari munculnya LTE terhadap organisasi, namun belum melakukan adaptasi.

Analysis of non-equilibrium phenomena in inductively coupled plasma generators

Energy Technology Data Exchange (ETDEWEB)

Zhang, W.; Panesi, M., E-mail: mpanesi@illinois.edu [University of Illinois at Urbana-Champaign, Urbana, Illinois 61822 (United States); Lani, A. [Von Karman Institute for Fluid Dynamics, Rhode-Saint-Genèse (Belgium)

2016-07-15

This work addresses the modeling of non-equilibrium phenomena in inductively coupled plasma discharges. In the proposed computational model, the electromagnetic induction equation is solved together with the set of Navier-Stokes equations in order to compute the electromagnetic and flow fields, accounting for their mutual interaction. Semi-classical statistical thermodynamics is used to determine the plasma thermodynamic properties, while transport properties are obtained from kinetic principles, with the method of Chapman and Enskog. Particle ambipolar diffusive fluxes are found by solving the Stefan-Maxwell equations with a simple iterative method. Two physico-mathematical formulations are used to model the chemical reaction processes: (1) A Local Thermodynamics Equilibrium (LTE) formulation and (2) a thermo-chemical non-equilibrium (TCNEQ) formulation. In the TCNEQ model, thermal non-equilibrium between the translational energy mode of the gas and the vibrational energy mode of individual molecules is accounted for. The electronic states of the chemical species are assumed in equilibrium with the vibrational temperature, whereas the rotational energy mode is assumed to be equilibrated with translation. Three different physical models are used to account for the coupling of chemistry and energy transfer processes. Numerical simulations obtained with the LTE and TCNEQ formulations are used to characterize the extent of non-equilibrium of the flow inside the Plasmatron facility at the von Karman Institute. Each model was tested using different kinetic mechanisms to assess the sensitivity of the results to variations in the reaction parameters. A comparison of temperatures and composition profiles at the outlet of the torch demonstrates that the flow is in non-equilibrium for operating conditions characterized by pressures below 30 000 Pa, frequency 0.37 MHz, input power 80 kW, and mass flow 8 g/s.

Detailed non-LTE calculations of the iron emission from NGC 1068

Science.gov (United States)

Band, David L.; Klein, Richard I.; Castor, John I.; Nash, J. K.

1989-01-01

The X-ray iron line emission from NGC 1068 observed by the Ginga satellite is modeled using the new multiline, multilevel, non-LTE radiative transport code ALTAIR and a detailed atomic model for Ne-like through stripped iron. The parameter space of the obscured type 1 Seyfert nucleus model for this object is studied. The equivalent width is greater than previously predicted. It is found that detailed radiative transfer can have a significant effect on the observed line flux both for the K alpha line and for the L-shell emission. The ionization of the iron increases with temperature. Therefore the K alpha equivalent width and energy is a function not only of the ionization parameter, but also of the column depth and temperature. For a likely model of NGC 1068 it is found that the iron abundance is about twice solar, but that modifications of this model may permit a smaller abundance.

Physical phenomena in a low-temperature non-equilibrium plasma and in MHD generators with non-equilibrium conductivity

International Nuclear Information System (INIS)

Velikhov, E.P.; Golubev, V.S.; Dykhne, A.M.

1976-01-01

The paper assesses the position in 1975 of theoretical and experimental work on the physics of a magnetohydrodynamic generator with non-equilibrium plasma conductivity. This research started at the beginning of the 1960s; as work on the properties of thermally non-equilibrium plasma in magnetic fields and also in MHD generator ducts progressed, a number of phenomena were discovered and investigated that had either been unknown in plasma physics or had remained uninvestigated until that time: ionization instability and ionization turbulence of plasma in a magnetic field, acoustic instability of a plasma with anisotropic conductivity, the non-equilibrium ionization wave and the energy balance of a non-equilibrium plasma. At the same time, it was discovered what physical requirements an MHD generator with non-equilibrium conductivity must satisfy to achieve high efficiency in converting the thermal or kinetic energy of the gas flow into electric energy. The experiments on MHD power generation with thermally non-equilibrium plasma carried out up to 1975 indicated that it should be possible to achieve conversion efficiencies of up to 20-30%. (author)

Level population measurements on analyte atom and ion excited states in the inductively coupled plasma

International Nuclear Information System (INIS)

Walker, Z.H.; Blades, M.W.

1986-01-01

During the past decade a number of publications dealing with fundamental studies of the inductively coupled plasma (ICP) have appeared in the literature. The purpose of many of these investigations has been to understand the nature of the interaction between the plasma gas and the analyte. The general conclusion drawn from these studies has been that the ICP is very close to Local Thermodynamic Equilibrium (LTE), but that some deviations from LTE do occur. Recent studies by the authors' have been directed towards the measurement of analyte atom and ion excited state level populations with the objective of obtaining a better understanding of both ionization and excitation in the ICP discharge and the extent to which such processes contribute to a non-equilibrium state. Further discussion is drawn from similar measurements made on elements with low ionization potentials, such as Barium, as well as on elements such as Iron in the presence of Easily Ionizable Elements (EIE's). The spatial and power dependences of such measurements are also discussed

Wall ablation of heated compound-materials into non-equilibrium discharge plasmas

Science.gov (United States)

Wang, Weizong; Kong, Linghan; Geng, Jinyue; Wei, Fuzhi; Xia, Guangqing

2017-02-01

The discharge properties of the plasma bulk flow near the surface of heated compound-materials strongly affects the kinetic layer parameters modeled and manifested in the Knudsen layer. This paper extends the widely used two-layer kinetic ablation model to the ablation controlled non-equilibrium discharge due to the fact that the local thermodynamic equilibrium (LTE) approximation is often violated as a result of the interaction between the plasma and solid walls. Modifications to the governing set of equations, to account for this effect, are derived and presented by assuming that the temperature of the electrons deviates from that of the heavy particles. The ablation characteristics of one typical material, polytetrafluoroethylene (PTFE) are calculated with this improved model. The internal degrees of freedom as well as the average particle mass and specific heat ratio of the polyatomic vapor, which strongly depends on the temperature, pressure and plasma non-equilibrium degree and plays a crucial role in the accurate determination of the ablation behavior by this model, are also taken into account. Our assessment showed the significance of including such modifications related to the non-equilibrium effect in the study of vaporization of heated compound materials in ablation controlled arcs. Additionally, a two-temperature magneto-hydrodynamic (MHD) model accounting for the thermal non-equilibrium occurring near the wall surface is developed and applied into an ablation-dominated discharge for an electro-thermal chemical launch device. Special attention is paid to the interaction between the non-equilibrium plasma and the solid propellant surface. Both the mass exchange process caused by the wall ablation and plasma species deposition as well as the associated momentum and energy exchange processes are taken into account. A detailed comparison of the results of the non-equilibrium model with those of an equilibrium model is presented. The non-equilibrium results

Studi Pemanfaatan Digital Dividend Untuk Layanan Long Term Evolution (LTE

Directory of Open Access Journals (Sweden)

Sri Ariyanti

2013-09-01

Full Text Available Sesuai dengan Permen kominfo No. 22/PER/M/KOMINFO/11/2011 tentang Penyelenggaraan Penyiaran Televisi Digital Terestrial Penerimaan Tetap Tidak Berbayar (Free To Air, pada tahun 2018 semua TV analog migrasi secara penuh ke TV digital. Dengan demikian ada alokasi tersisa sebesar 2 x 45 Mhz FDD yang disebut sebagai digital dividend. Frekuensi tersebut rencananya akan digunakan untuk teknologi LTE. Namun sebelum digelar teknologi LTE pada frekuensi digital dividend tersebut maka perlu dikaji bagaimana penggunaan digital dividend untuk layanan LTE. Penelitian ini bertujuan untuk mengetahui hasil perhitungan link budget frekuensi 700 MHz untuk LTE, mengetahui perbandingan kapasitas user pada daerah tipe dense-urban, urban, sub-urban dan rural, mengetahui estimasi jumlah pelanggan LTE, mengetahui jumlah operator LTE optimum dan pembagian bandwidthnya.  Metode penelitian dengan menggunakan studi literatur. Kajian ini menggunakan teknik analisis kuantitatif deskriptif.  Hasil penelitian menunjukkan bahwa jangkauan paling besar yaitu daerah rural kemudian disusul berturut-turut daerah sub urban, dense urban dan urban. Kapasitas user per site dalam 1 Km2 dari urutan terbesar ke kecil berturut-turut yaitu daerah rural, sub urban, urban dan dense urban. Estimasi jumlah pelanggan LTE di Indonesia paling besar yaitu di daerah dense-urban yaitu mencapai 500 user/Km2 pada tahun ke 8. Jumlah operator LTE-700 MHz paling optimum sebanyak 3 operator dengan pembagian bandwidth masing-masing 15 MHz.

Analisis Kelayakan Implementasi Teknologi LTE 1.8 GHz Bagi Operator Seluler di Indonesia [Feasibility Analysis of LTE 1.8 GHz for Mobile Operators in Indonesia

Directory of Open Access Journals (Sweden)

Sri Ariyanti

2015-06-01

Full Text Available Peningkatan kebutuhan layanan data mendorong operator telekomunikasi berusaha mengimplementasikan jaringan akses broadband yang lebih handal.  Teknologi LTE merupakan salah satu teknologi dengan kecepatan mencapai tiga kali dibanding teknologi HSDPA, sehingga diharapkan dapat memenuhi kebutuhan pelanggan data mobile. Refarming frekuensi 1.8 GHz  untuk penerapan teknologi LTE memberikan efisiensi karena tidak perlu membayar BHP lagi untuk menyewa frekuensi baru. Teknologi 2G GSM selama ini juga semakin ditinggalkan, masyarakat di daerah perkotaan cenderung lebih banyak menggunakan layanan data.  Sebelum diterapkannya teknologi LTE pada frekuensi 1.8 GHz perlu adanya kajian untuk mengetahui kelayakan teknologi LTE pada frekuensi 1.8 GHz. Penelitian ini bertujuan untuk melakukan cost-benefit analysis implementasi LTE pada frekuensi 1.8 GHz.  Metode penelitian menggunakan pendekatan kualitataif yang didukung dengan data kuantitatif.  Hasil penelitian menunjukkan bahwa minimal bandiwdth yang diperlukan agar implementasi LTE layak digunakan adalah 15 MHz.  Meskipun tanpa Global Frequency Returning, penggunaan bandwidth 10 MHz tidak layak digunakan untuk implementasi LTE.      *****The incresing of data demand drives mobile operators to implement more reliable broadband access network. LTE technology has downlink peak rate up to three times than HSDPA,  hence it may fulfill the mobile data user requirement. Frequency 1.8 GHz refarming can be implemented to provide efficiency because They do not need to pay licence fee for leasing new frequency. GSM technology will be abandoned since it is not growing anymore. Besides that, dense urban users tend to use data mobile.  Before implementing LTE technology  on 1.8 GHz frequency, It is necessary to analysis the feasibility such technology. This research used qualitative method supported by quantitative  approach.  The result of this research showed that minimum bandwidth to implement 1.8 GHz LTE

Uplink scheduling and adjacent-channel coupling loss analysis for TD-LTE deployment.

Science.gov (United States)

Yeo, Woon-Young; Moon, Sung Ho; Kim, Jae-Hoon

2014-01-01

TD-LTE, one of the two duplexing modes in LTE, operates in unpaired spectrum and has the advantages of TDD-based technologies. It is expected that TD-LTE will be more rapidly deployed in near future and most of WiMax operators will upgrade their networks to TD-LTE gradually. Before completely upgrading to TD-LTE, WiMax may coexist with TD-LTE in an adjacent frequency band. In addition, multiple TD-LTE operators may deploy their networks in adjacent bands. When more than one TDD network operates in adjacent frequency bands, severe interference may happen due to adjacent channel interference (ACI) and unsynchronized operations. In this paper, coexistence issues between TD-LTE and other systems are analyzed and coexistence requirements are provided. This paper has three research objectives. First, frame synchronization between TD-LTE and WiMax is discussed by investigating possible combinations of TD-LTE and WiMax configurations. Second, an uplink scheduling algorithm is proposed to utilize a leakage pattern of ACI in synchronized operations. Third, minimum requirements for coexistence in unsynchronized operations are analyzed by introducing a concept of adjacent-channel coupling loss. From the analysis and simulation results, we can see that coexistence of TD-LTE with other TDD systems is feasible if the two networks are synchronized. For the unsynchronized case, some special cell-site engineering techniques may be required to reduce the ACI.

Equilibrium solubility measurement of ionizable drugs – consensus recommendations for improving data quality

Directory of Open Access Journals (Sweden)

Alex Avdeef

2016-06-01

Full Text Available This commentary addresses data quality in equilibrium solubility measurement in aqueous solution. Broadly discussed is the “gold standard” shake-flask (SF method used to measure equilibrium solubility of ionizable drug-like molecules as a function of pH. Many factors affecting the quality of the measurement are recognized. Case studies illustrating the analysis of both solution and solid state aspects of solubility measurement are presented. Coverage includes drug aggregation in solution (sub-micellar, micellar, complexation, use of mass spectrometry to assess aggregation in saturated solutions, solid state characterization (salts, polymorphs, cocrystals, polymorph creation by potentiometric method, solubility type (water, buffer, intrinsic, temperature, ionic strength, pH measurement, buffer issues, critical knowledge of the pKa, equilibration time (stirring and sedimentation, separating solid from saturated solution, solution handling and adsorption to untreated surfaces, solubility units, and tabulation/graphic presentation of reported data. The goal is to present cohesive recommendations that could lead to better assay design, to result in improved quality of measurements, and to impart a deeper understanding of the underlying solution chemistry in suspensions of drug solids.

VoLTE performance in railway scenarios

DEFF Research Database (Denmark)

Sniady, Aleksander; Sønderskov, Morten; Soler, José

2015-01-01

GSM-Railways (GSM-R) is the current standard for railway voice and data communication. GSM-R provides railway specific voice services, such as Railway Emergency Call (REC). GSM-R provides also the European Train Control System (ETCS), which offers in-cab signaling and Automatic Train Protection...... (ATP). Despite these features and services, GSM-R has various major shortcomings. Therefore, alternative technologies are considered to replace GSM-R and become the next generation railway mobile communication network. 3GPP Long Term Evolution (LTE) is a likely candidate for GSM-R replacement. LTE...... is more efficient, flexible and offers much higher capacity, which allows the railway network to provide new communication-based applications for railways. Most of the research on LTE in railways has been focused on data-based railway applications (ETCS signaling and other). Nevertheless, voice...

VoLTE Performance in Railway Scenarios

DEFF Research Database (Denmark)

Sniady, Aleksander; Sønderskov, Morten; Soler, José

2015-01-01

GSM-Railways (GSM-R) is the current standard for railway voice and data communication. GSM-R provides railway specific voice services, such as Railway Emergency Call (REC). GSM-R provides also the European Train Control System (ETCS), which offers in-cab signaling and Automatic Train Protection...... (ATP). Despite these features and services, GSM-R has various major shortcomings. Therefore, alternative technologies are considered to replace GSM-R and become the next generation railway mobile communication network. 3GPP Long Term Evolution (LTE) is a likely candidate for GSM-R replacement. LTE...... is more efficient, flexible and offers much higher capacity, which allows the railway network to provide new communication-based applications for railways. Most of the research on LTE in railways has been focused on data-based railway applications (ETCS signaling and other). Nevertheless, voice...

Capacity gain with an alternative LTE railway communication network

DEFF Research Database (Denmark)

Sniady, Aleksander; Soler, José

2014-01-01

, such as 3GPP Long Term Evolution (LTE). T his paper describe s how to adapt the reversible multi - chain/channel queuing system to model an LTE cell serving ETCS - equipped trains . It is proposed to use the multiple user chains available in the model to represent varying bitrate in LTE radio access network....... Usin g this model , LTE and GSM - R are compare d in terms of capacity on an example at Copenhagen Main Train Station . The purpose of this work is to demonstrate the benefits that railway operators and infrastructure managers can expect from the introduc tion of LTE , as a telecommunication technology...... Control System (ETCS) signaling , the capacity of GSM - R turns out to be insufficient . GSM - R cannot ful fill the railway requirements , in terms of the number of simultaneous ETCS connections . This is why , alternative , more efficient communication technologies should be considered by railways...

A conservative multicomponent diffusion algorithm for ambipolar plasma flows in local thermodynamic equilibrium

International Nuclear Information System (INIS)

Peerenboom, Kim; Van Boxtel, Jochem; Janssen, Jesper; Van Dijk, Jan

2014-01-01

The usage of the local thermodynamic equilibrium (LTE) approximation can be a very powerful assumption for simulations of plasmas in or close to equilibrium. In general, the elemental composition in LTE is not constant in space and effects of mixing and demixing have to be taken into account using the Stefan–Maxwell diffusion description. In this paper, we will introduce a method to discretize the resulting coupled set of elemental continuity equations. The coupling between the equations is taken into account by the introduction of the concept of a Péclet matrix. It will be shown analytically and numerically that the mass and charge conservation constraints can be fulfilled exactly. Furthermore, a case study is presented to demonstrate the applicability of the method to a simulation of a mercury-free metal-halide lamp. The source code for the simulations presented in this paper is provided as supplementary material (stacks.iop.org/JPhysD/47/425202/mmedia). (paper)

Quad Band Handset Antenna for LTE MIMO and WLAN Application

Directory of Open Access Journals (Sweden)

H. S. Wong

2014-01-01

Full Text Available A compact quad band antenna for long-term evolution (LTE MIMO and WLAN application in the handset is presented in this paper. The proposed antenna comprises two symmetrical quarter wavelength radiating strips and a slotted ground plane. On the ground plane, a T-shaped slot is cut from the bottom. Two symmetrical P-shaped slots are etched at both sides of the ground plane. The radiating strips and slots generate a lower resonant at 780 MHz and an upper resonant at 2.350 GHz to cover LTE 700 Band 14, LTE 2300, 2.4 GHz WLAN, and LTE 2500. A novel isolation technique by placing a rectangular patch between the radiating strips is presented. The rectangular patch creates a dedicated current path for each radiating strip. The proposed antenna has high isolation of less than −18 dBi at LTE 2300, 2.4 GHz WLAN, and LTE 2500 band.

Resilience of LTE networks against smart jamming attacks

KAUST Repository

Aziz, Farhan M.; Shamma, Jeff S.; Stuber, Gordon L.

2014-01-01

Commercial LTE networks are being studied for mission-critical applications, such as public safety and smart grid communications. In this paper, LTE networks are shown vulnerable to Denial-of-Service (DOS) and loss of service attacks from smart

Two-temperature transport coefficients of SF{sub 6}–N{sub 2} plasma

Energy Technology Data Exchange (ETDEWEB)

Yang, Fei; Chen, Zhexin; Wu, Yi, E-mail: wuyic51@mail.xjtu.edu.cn; Rong, Mingzhe; Wang, Chunlin [State Key Laboratory of Electrical Insulation and Power Equipment, School of Electrical Engineering, Xi' an Jiaotong University, Xi' an 710049 (China); Guo, Anxiang; Liu, Zirui [Electric Power Research Institute of State Grid Shaanxi Electric Power Company, Xian (China)

2015-10-15

Sulfur hexafluoride (SF{sub 6}) is widely adopted in electric power industry, especially in high-voltage circuit breakers and gas-insulated switchgear. However, the use of SF{sub 6} is limited by its high liquidation temperature and high global warming potential. Recently, research shows SF{sub 6}–N{sub 2} mixture, which shows environmental friendliness and good electrical properties, may be a feasible substitute for pure SF{sub 6}. This paper is devoted to the calculation of and transport coefficients of SF{sub 6}–N{sub 2} mixture under both LTE (local thermodynamic equilibrium) and non-LTE condition. The two–temperature mass action law was used to determine the composition. The transport coefficients were calculated by classical Chapman–Enskog method simplified by Devoto. The thermophysical properties are presented for electron temperatures of 300–40 000 K, ratios of electron to heavy species temperature of 1–10 and N{sub 2} mole fraction of 0%–100% at atmospheric pressure. The ionization processes under both LTE and non-LTE have been discussed. The results show that deviations from local thermodynamic equilibrium significantly affect the properties of SF{sub 6}–N{sub 2} plasma, especially before the plasma is fully ionized. The different influence of N{sub 2} on properties for SF{sub 6}–N{sub 2} plasma in and out of LTE has been found. The results will serve as reliable reference data for computational simulation of the behavior of SF{sub 6}–N{sub 2} plasmas.

Gold emissivities for hydrocode applications

International Nuclear Information System (INIS)

Bowen, C.; Wagon, F.; Galmiche, D.; Loiseau, P.; Dattolo, E.; Babonneau, D.

2004-01-01

The Radiom model [M. Busquet, Phys Fluids B 5, 4191 (1993)] is designed to provide a radiative-hydrodynamic code with non-local thermodynamic equilibrium (non-LTE) data efficiently by using LTE tables. Comparison with benchmark data [M. Klapisch and A. Bar-Shalom, J. Quant. Spectrosc. Radiat. Transf. 58, 687 (1997)] has shown Radiom to be inaccurate far from LTE and for heavy ions. In particular, the emissivity was found to be strongly underestimated. A recent algorithm, Gondor [C. Bowen and P. Kaiser, J. Quant. Spectrosc. Radiat. Transf. 81, 85 (2003)], was introduced to improve the gold non-LTE ionization and corresponding opacity. It relies on fitting the collisional ionization rate to reproduce benchmark data given by the Averroes superconfiguration code [O. Peyrusse, J. Phys. B 33, 4303 (2000)]. Gondor is extended here to gold emissivity calculations, with two simple modifications of the two-level atom line source function used by Radiom: (a) a larger collisional excitation rate and (b) the addition of a Planckian source term, fitted to spectrally integrated Averroes emissivity data. This approach improves the agreement between experiments and hydrodynamic simulations

LTE HetNet Mobility Performance Through Emulation with Commercial Smartphones

DEFF Research Database (Denmark)

Jensen, Anders Riis; Pedersen, Klaus I.; Lauridsen, Mads

2014-01-01

In this paper we introduce a laboratory emulation setup for evaluation of Long Term Evolution (LTE) mobility performance in a co-channel heterogeneous network (HetNet). The setup consists of two eNodeB emulators, signal faders and release 9 LTE User Equipment (UE). It is shown how the LTE HetNet ...

A novel multiphysic model for simulation of swelling equilibrium of ionized thermal-stimulus responsive hydrogels

Science.gov (United States)

Li, Hua; Wang, Xiaogui; Yan, Guoping; Lam, K. Y.; Cheng, Sixue; Zou, Tao; Zhuo, Renxi

2005-03-01

In this paper, a novel multiphysic mathematical model is developed for simulation of swelling equilibrium of ionized temperature sensitive hydrogels with the volume phase transition, and it is termed the multi-effect-coupling thermal-stimulus (MECtherm) model. This model consists of the steady-state Nernst-Planck equation, Poisson equation and swelling equilibrium governing equation based on the Flory's mean field theory, in which two types of polymer-solvent interaction parameters, as the functions of temperature and polymer-network volume fraction, are specified with or without consideration of the hydrogen bond interaction. In order to examine the MECtherm model consisting of nonlinear partial differential equations, a meshless Hermite-Cloud method is used for numerical solution of one-dimensional swelling equilibrium of thermal-stimulus responsive hydrogels immersed in a bathing solution. The computed results are in very good agreements with experimental data for the variation of volume swelling ratio with temperature. The influences of the salt concentration and initial fixed-charge density are discussed in detail on the variations of volume swelling ratio of hydrogels, mobile ion concentrations and electric potential of both interior hydrogels and exterior bathing solution.

A tightly coupled non-equilibrium model for inductively coupled radio-frequency plasmas

International Nuclear Information System (INIS)

Munafò, A.; Alfuhaid, S. A.; Panesi, M.; Cambier, J.-L.

2015-01-01

The objective of the present work is the development of a tightly coupled magneto-hydrodynamic model for inductively coupled radio-frequency plasmas. Non Local Thermodynamic Equilibrium (NLTE) effects are described based on a hybrid State-to-State approach. A multi-temperature formulation is used to account for thermal non-equilibrium between translation of heavy-particles and vibration of molecules. Excited electronic states of atoms are instead treated as separate pseudo-species, allowing for non-Boltzmann distributions of their populations. Free-electrons are assumed Maxwellian at their own temperature. The governing equations for the electro-magnetic field and the gas properties (e.g., chemical composition and temperatures) are written as a coupled system of time-dependent conservation laws. Steady-state solutions are obtained by means of an implicit Finite Volume method. The results obtained in both LTE and NLTE conditions over a broad spectrum of operating conditions demonstrate the robustness of the proposed coupled numerical method. The analysis of chemical composition and temperature distributions along the torch radius shows that: (i) the use of the LTE assumption may lead to an inaccurate prediction of the thermo-chemical state of the gas, and (ii) non-equilibrium phenomena play a significant role close the walls, due to the combined effects of Ohmic heating and macroscopic gradients

System Level Analysis of LTE-Advanced

DEFF Research Database (Denmark)

Wang, Yuanye

This PhD thesis focuses on system level analysis of Multi-Component Carrier (CC) management for Long Term Evolution (LTE)-Advanced. Cases where multiple CCs are aggregated to form a larger bandwidth are studied. The analysis is performed for both local area and wide area networks. In local area...... reduction. Compared to the case of reuse-1, they achieve a gain of 50∼500% in cell edge user throughput, with small or no loss in average cell throughput. For the wide area network, effort is devoted to the downlink of LTE-Advanced. Such a system is assumed to be backwards compatible to LTE release 8, i...... scheme is recommended. It reduces the CQI by 94% at low load, and 79∼93% at medium to high load, with reasonable loss in downlink performance. To reduce the ACK/NACK feedback, multiple ACK/NACKs can be bundled, with slightly degraded downlink throughput....

Acoustic waves in the solar atmosphere. VII - Non-grey, non-LTE H(-) models

Science.gov (United States)

Schmitz, F.; Ulmschneider, P.; Kalkofen, W.

1985-01-01

The propagation and shock formation of radiatively damped acoustic waves in the solar chromosphere are studied under the assumption that H(-) is the only absorber; the opacity is non-grey. Deviations from local thermodynamic equilibrium (LTE) are permitted. The results of numerical simulations show the depth dependence of the heating by the acoustic waves to be insensitive to the mean state of the atmosphere. After the waves have developed into shocks, their energy flux decays exponentially with a constant damping length of about 1.4 times the pressure scale height, independent of initial flux and wave period. Departures from LTE have a strong influence on the mean temperature structure in dynamical chromosphere models; this is even more pronounced in models with reduced particle density - simulating conditions in magnetic flux tubes - which show significantly increased temperatures in response to mechanical heating. When the energy dissipation of the waves is sufficiently large to dissociate most of the H(-) ions, a strong temperature rise is found that is reminiscent of the temperature structure in the transition zone between chromosphere and corona; the energy flux remaining in the waves then drives mass motions.

Pramana – Journal of Physics | Indian Academy of Sciences

Indian Academy of Sciences (India)

Effects of non-local thermodynamic equilibrium (non-LTE) condition on emission and hydrodynamics of typical inertial confinement fusion (ICF) plasmas are studied. The average degree of ionization at high temperatures is seen to be much lower compared to the values obtained from Thomas–Fermi scaling or Saha ...

Scheduling strategies for LTE uplink with flow behaviour analysis

OpenAIRE

Dimitrova, D.C.; Berg, J.L. van den; Litjens, R.; Heijenk, G.

2010-01-01

Long Term Evolution (LTE) is a cellular technology developed to support diversity of data traffic at potentially high rates. It is foreseen to extend the capacity and improve the performance of current 3G cellular networks. A key mechanism in the LTE traffic handling is the packet scheduler, which is in charge of allocating resources to active flows in both the frequency and time dimension. In this paper we present a performance comparison of two distinct scheduling schemes for LTE uplink (fa...

Resilience of LTE networks against smart jamming attacks: Wideband model

KAUST Repository

Aziz, Farhan M.

2015-12-03

LTE/LTE-A networks have been successfully providing advanced broadband services to millions of users worldwide. Lately, it has been suggested to use LTE networks for mission-critical applications like public safety, smart grid and military communications. We have previously shown that LTE networks are vulnerable to Denial-of-Service (DOS) and loss of service attacks from smart jammers. In this paper, we extend our previous work on resilience of LTE networks to wideband multipath fading channel, SINR estimation in frequency domain and computation of utilities based on observable parameters under the framework of single-shot and repeated games with asymmetric information. In a single-shot game formulation, network utility is severely compromised at its solutions, i.e. at the Nash Equilibria (NE). We propose evolved repeated-game strategy algorithms to combat smart jamming attacks that can be implemented in existing deployments using current technology. © 2015 IEEE.

Performance of Flow-Aware Networking in LTE backbone

DEFF Research Database (Denmark)

Sniady, Aleksander; Soler, José

2012-01-01

technologies, such as Long Term Evolution (LTE). This paper proposes usage of a modified Flow Aware Networking (FAN) technique for enhancing Quality of Service (QoS) in the all-IP transport networks underlying LTE backbone. The results obtained with OPNET Modeler show that FAN, in spite of being relatively...

Performance of multi-rate equalizer with lte standard turbo code

OpenAIRE

Du, D. (Dongyang)

2014-01-01

Abstract In the uplink channel of the 3GPP long term evolution (LTE) and LTE-Advanced (LTE-A) systems, signal carrier frequency-division multiplexing access (SC-FDMA) transmission scheme is employed instead of orthogonal frequency-division multiplexing (OFDM) to reduce the peak-to-average power ratio (PAPR). However, compared to OFDM, SC-FDMA has lower channel throughput, since it suffers from inter-symbol interference (ISI...

Mobility management in LTE heterogeneous networks

CERN Document Server

Karandikar, Abhay; Mehta, Mahima

2017-01-01

This book is the first of its kind, compiling information on the Long-Term Evolution (LTE) standards, which are enhanced to address new mobility-related challenges in Heterogeneous Networks (HetNets). It identifies the related challenges and discusses solutions and the simulation methodology for modeling HetNet mobility – cutting-edge information that was previously accessible only in the form of 3GPP specifications and documents, and research papers. The book reviews the current LTE mobility framework and discusses some of the changes for enhancing mobility management in HetNets. It describes the measurement procedures, handover (HO) mechanisms and HO success/failure scenarios. HetNets are intended to provide very high spectral efficiency while ensuring seamless coverage by deploying low-power nodes within the umbrella macrocell network. While mobility management in homogeneous networks is well understood, LTE standards are being enhanced to address the HetNet-specific mobility management challenges emergi...

Power Saving Scheduling Scheme for Internet of Things over LTE/LTE-Advanced Networks

Directory of Open Access Journals (Sweden)

Yen-Wei Kuo

2015-01-01

Full Text Available The devices of Internet of Things (IoT will grow rapidly in the near future, and the power consumption and radio spectrum management will become the most critical issues in the IoT networks. Long Term Evolution (LTE technology will become a promising technology used in IoT networks due to its flat architecture, all-IP network, and greater spectrum efficiency. The 3rd Generation Partnership Project (3GPP specified the Discontinuous Reception (DRX to reduce device’s power consumption. However, the DRX may pose unexpected communication delay due to missing Physical Downlink Control Channel (PDCCH information in sleep mode. Recent studies mainly focus on optimizing DRX parameters to manage the tradeoff between the energy consumption and communication latency. In this paper, we proposed a fuzzy-based power saving scheduling scheme for IoT over the LTE/LTE-Advanced networks to deal with the issues of the radio resource management and power consumption from the scheduling and resource allocation perspective. The proposed scheme considers not only individual IoT device’s real-time requirement but also the overall network performance. The simulation results show that our proposed scheme can meet the requirements of the DRX cycle and scheduling latency and can save about half of energy consumption for IoT devices compared to conventional approaches.

LTE/Wi-Fi Coexistence in 5 GHz ISM Spectrum: Issues, Solutions and Perspectives

DEFF Research Database (Denmark)

Abinader, Fuad; A. de Sousa Jr., Vicente; Choudhurry, Sayantan

2018-01-01

solutions is the aggregation of ISM unlicensed spectrum to licensed bands, using wireless networks defined by IEEE and 3GPP. While Wi-Fi networks are aggregated to LTE small cells via LTE/WLAN Aggregation (LWA), in proposals like LTE-U and LAA-LTE, the LTE air interface itself is used for transmission...... on the unlicensed band. Wi-Fi technology is widespread and also operates in the 5 GHz ISM spectrum bands, which may bring performance issues due to the coexistence of both technologies in the same spectrum band. This work is dedicated to the study of coexistence between LTE and Wi-Fi access systems operating in 5...

Understanding LTE with Matlab from mathematical modeling to simulation and prototyping

CERN Document Server

Zarrinkoub, Houman

2014-01-01

An introduction to technical details related to the Physical Layer of the LTE standard with MATLAB® The LTE (Long Term Evolution) and LTE-Advanced are among the latest mobile communications standards, designed to realize the dream of a truly global, fast, all-IP-based, secure broadband mobile access technology. This book examines the Physical Layer (PHY) of the LTE standards by incorporating three conceptual elements: an overview of the theory behind key enabling technologies; a concise discussion regarding standard specifications; and the MATLAB® algorithms needed to simulate the standard.

Location-assured, multifactor authentication on smartphones via LTE communication

Science.gov (United States)

Kuseler, Torben; Lami, Ihsan A.; Al-Assam, Hisham

2013-05-01

With the added security provided by LTE, geographical location has become an important factor for authentication to enhance the security of remote client authentication during mCommerce applications using Smartphones. Tight combination of geographical location with classic authentication factors like PINs/Biometrics in a real-time, remote verification scheme over the LTE layer connection assures the authenticator about the client itself (via PIN/biometric) as well as the client's current location, thus defines the important aspects of "who", "when", and "where" of the authentication attempt without eaves dropping or man on the middle attacks. To securely integrate location as an authentication factor into the remote authentication scheme, client's location must be verified independently, i.e. the authenticator should not solely rely on the location determined on and reported by the client's Smartphone. The latest wireless data communication technology for mobile phones (4G LTE, Long-Term Evolution), recently being rolled out in various networks, can be employed to enhance this location-factor requirement of independent location verification. LTE's Control Plane LBS provisions, when integrated with user-based authentication and independent source of localisation factors ensures secure efficient, continuous location tracking of the Smartphone. This feature can be performed during normal operation of the LTE-based communication between client and network operator resulting in the authenticator being able to verify the client's claimed location more securely and accurately. Trials and experiments show that such algorithm implementation is viable for nowadays Smartphone-based banking via LTE communication.

Potential of dynamic spectrum allocation in LTE macro networks

NARCIS (Netherlands)

Hoffmann, H.; Ramachandra, P.; Kovacs, I.Z.; Jorguseski, L.; Gunnarsson, F.; Kurner, T.

2015-01-01

In recent years Mobile Network Operators (MNOs) worldwide are extensively deploying LTE networks in different spectrum bands and utilising different bandwidth configurations. Initially, the deployment is coverage oriented with macro cells using the lower LTE spectrum bands. As the offered traffic

Resource allocation using ANN in LTE

Science.gov (United States)

Yigit, Tuncay; Ersoy, Mevlut

2017-07-01

LTE is the 4th generation wireless network technology, which provides flexible bandwidth, higher data speeds and lower delay. Difficulties may be experienced upon an increase in the number of users in LTE. The objective of this study is to ensure a faster solution to any such resource allocation problems which might arise upon an increase in the number of users. A fast and effective solution has been obtained by making use of Artificial Neural Network. As a result, fast working artificial intelligence methods may be used in resource allocation problems during operation.

Physics of Solar Prominences: I-Spectral Diagnostics and Non-LTE Modelling

Science.gov (United States)

Labrosse, N.; Heinzel, P.; Vial, J.-C,; Kucera, T.; Parenti, S.; Gunar, S.; Schmieder, B.; Kilper, G.

2010-01-01

This review paper outlines background information and covers recent advances made via the analysis of spectra and images of prominence plasma and the increased sophistication of non-LTE (i.e. when there is a departure from Local Thermodynamic Equilibrium) radiative transfer models. We first describe the spectral inversion techniques that have been used to infer the plasma parameters important for the general properties of the prominence plasma in both its cool core and the hotter prominence-corona transition region. We also review studies devoted to the observation of bulk motions of the prominence plasma and to the determination of prominence mass. However, a simple inversion of spectroscopic data usually fails when the lines become optically thick at certain wavelengths. Therefore, complex

Local thermodynamic equilibrium considerations in powerchip laser-induced plasmas

Energy Technology Data Exchange (ETDEWEB)

Merten, Jonathan A., E-mail: jmerten@astate.edu; Smith, Benjamin W., E-mail: bwsmith@chem.ufl.edu; Omenetto, Nicoló, E-mail: omenetto@chem.ufl.edu

2013-05-01

Time-resolved emission experiments are reported in the fast-decaying transient plasma induced by a microchip laser on an aluminum target in three different cover gases, i.e., air, argon and helium. The laser operates at 532 nm, with a repetition frequency of 1 kHz and a pulse width of less than 0.5 ns. The overall persistence of plasma emission is of the order of 100 ns. We examine the existence of local thermodynamic equilibrium (LTE) by evaluating the temporal criteria required (in addition to the McWhirter criterion), as recommended by Cristoforetti et al. (Spectrochim. Acta Part B 65, 2010, 86–95). The temporal criteria examine the evolution of temperature and electron number density and compare their rate of change to the rate at which electron collisions can thermalize the change. These considerations are used to determine time windows in which LTE may be present. Our results suggest that calibration-free LIBS measurements with these lasers may be possible for some elements at early times, especially under argon. - Highlights: ► Powerchip laser-induced plasma evolution is affected by cover gas. ► Plasma often out of LTE, despite fulfilling the McWhirter criterion ► Calibration-free LIBS may be possible with powerchip laser plasmas.

Local thermodynamic equilibrium considerations in powerchip laser-induced plasmas

International Nuclear Information System (INIS)

Merten, Jonathan A.; Smith, Benjamin W.; Omenetto, Nicoló

2013-01-01

Time-resolved emission experiments are reported in the fast-decaying transient plasma induced by a microchip laser on an aluminum target in three different cover gases, i.e., air, argon and helium. The laser operates at 532 nm, with a repetition frequency of 1 kHz and a pulse width of less than 0.5 ns. The overall persistence of plasma emission is of the order of 100 ns. We examine the existence of local thermodynamic equilibrium (LTE) by evaluating the temporal criteria required (in addition to the McWhirter criterion), as recommended by Cristoforetti et al. (Spectrochim. Acta Part B 65, 2010, 86–95). The temporal criteria examine the evolution of temperature and electron number density and compare their rate of change to the rate at which electron collisions can thermalize the change. These considerations are used to determine time windows in which LTE may be present. Our results suggest that calibration-free LIBS measurements with these lasers may be possible for some elements at early times, especially under argon. - Highlights: ► Powerchip laser-induced plasma evolution is affected by cover gas. ► Plasma often out of LTE, despite fulfilling the McWhirter criterion ► Calibration-free LIBS may be possible with powerchip laser plasmas

Calculation of opacities and emissivities for carbon plasmas under NLTE and LTE conditions

International Nuclear Information System (INIS)

Gil, J.M.; Rodriguez, R.; Florido, R.; Rubiano, J.G.; Martel, P.; Sauvan, P.; Minguez, E.

2006-01-01

We calculate different optical properties for carbon plasma in a wide range of temperatures and densities by using ATOM3R-OP code which has been recently developed. In this code we have implemented the rate equations, the Saha equation (for local thermodynamic equilibrium) and the coronal equilibrium model. We have calculated average ionizations, level populations, opacities and emissivities and we focus our study on the identification with our code of coronal equilibrium, non-local thermodynamic equilibrium and local thermodynamic equilibrium regions for this kind of plasma. Moreover, we analyse the differences in the optical properties when they are calculated in non-local thermodynamic equilibrium and local thermodynamic equilibrium. (authors)

Calculation of opacities and emissivities for carbon plasmas under NLTE and LTE conditions

Energy Technology Data Exchange (ETDEWEB)

Gil, J.M.; Rodriguez, R.; Florido, R.; Rubiano, J.G.; Martel, P. [Las Palmas de Gran Canaria Univ., Dept. de Fisica (Spain); Sauvan, P. [Universidad Nacional de Educacion a Distancia, Dept. de Ingenieria Energetica, Madrid (Spain); Minguez, E. [Madrid Univ. Politecnica, Instituto de Fusion Nuclear-DENIM (Spain)

2006-06-15

We calculate different optical properties for carbon plasma in a wide range of temperatures and densities by using ATOM3R-OP code which has been recently developed. In this code we have implemented the rate equations, the Saha equation (for local thermodynamic equilibrium) and the coronal equilibrium model. We have calculated average ionizations, level populations, opacities and emissivities and we focus our study on the identification with our code of coronal equilibrium, non-local thermodynamic equilibrium and local thermodynamic equilibrium regions for this kind of plasma. Moreover, we analyse the differences in the optical properties when they are calculated in non-local thermodynamic equilibrium and local thermodynamic equilibrium. (authors)

LTE Micro-cell Deployment for High-Density Railway Areas

DEFF Research Database (Denmark)

Sniady, Aleksander; Kassab, Mohamed; Soler, José

2014-01-01

Long Term Evolution (LTE) is a serious candidate for the future releases of the European Rail Traffic Management System (ERTMS). LTE offers more capacity and supports new communication-based applications and services for railways. Nevertheless, even with this technology, the classical macro...

Software Defined Networking to support IP address mobility in future LTE network

NARCIS (Netherlands)

Karimzadeh Motallebi Azar, Morteza; Valtulina, Luca; van den Berg, Hans Leo; Pras, Aiko; Liebsch, Marco; Taleb, Tarik

2017-01-01

The existing LTE network architecture dose not scale well to increasing demands due to its highly centralized and hierarchical composition. In this paper we discuss the major modifications required in the current LTE network to realize a decentralized LTE architecture. Next, we develop two IP

Double-NAT Based Mobility Management for Future LTE Networks

NARCIS (Netherlands)

Karimzadeh Motallebi Azar, Morteza; Valtulina, Luca; Pras, Aiko; Liebsch, Marco; Taleb, Tarik

2017-01-01

In this paper we discuss the major modifications required in the current LTE network to realize a decentralized LTE architecture and develop a novel IP mobility management solution for it. The proposed solution can handle traffic redirecting and IP address continuity above the distributed anchor

Design, deployment and performance of 4G-LTE networks a practical approach

CERN Document Server

ElNashar, Ayman; Sherif, Mahmoud

2014-01-01

This book provides an insight into the key practical aspects and best practice of 4G-LTE network design, performance, and deployment Design, Deployment and Performance of 4G-LTE Networks addresses the key practical aspects and best practice of 4G networks design, performance, and deployment. In addition, the book focuses on the end-to-end aspects of the LTE network architecture and different deployment scenarios of commercial LTE networks. It describes the air interface of LTE focusing on the access stratum protocol layers: PDCP, RLC, MAC, and Physical Layer. The air interface described in this book covers the concepts of LTE frame structure, downlink and uplink scheduling, and detailed illustrations of the data flow across the protocol layers. It describes the details of the optimization process including performance measurements and troubleshooting mechanisms in addition to demonstrating common issues and case studies based on actual field results. The book provides detailed performance analysis of key fe...

Gold emissivities for hydrocode applications

Science.gov (United States)

Bowen, C.; Wagon, F.; Galmiche, D.; Loiseau, P.; Dattolo, E.; Babonneau, D.

2004-10-01

The Radiom model [M. Busquet, Phys Fluids B 5, 4191 (1993)] is designed to provide a radiative-hydrodynamic code with non-local thermodynamic equilibrium (non-LTE) data efficiently by using LTE tables. Comparison with benchmark data [M. Klapisch and A. Bar-Shalom, J. Quant. Spectrosc. Radiat. Transf. 58, 687 (1997)] has shown Radiom to be inaccurate far from LTE and for heavy ions. In particular, the emissivity was found to be strongly underestimated. A recent algorithm, Gondor [C. Bowen and P. Kaiser, J. Quant. Spectrosc. Radiat. Transf. 81, 85 (2003)], was introduced to improve the gold non-LTE ionization and corresponding opacity. It relies on fitting the collisional ionization rate to reproduce benchmark data given by the Averroès superconfiguration code [O. Peyrusse, J. Phys. B 33, 4303 (2000)]. Gondor is extended here to gold emissivity calculations, with two simple modifications of the two-level atom line source function used by Radiom: (a) a larger collisional excitation rate and (b) the addition of a Planckian source term, fitted to spectrally integrated Averroès emissivity data. This approach improves the agreement between experiments and hydrodynamic simulations.

New RADIOM algorithm using inverse EOS

Science.gov (United States)

Busquet, Michel; Sokolov, Igor; Klapisch, Marcel

2012-10-01

The RADIOM model, [1-2], allows one to implement non-LTE atomic physics with a very low extra CPU cost. Although originally heuristic, RADIOM has been physically justified [3] and some accounting for auto-ionization has been included [2]. RADIOM defines an ionization temperature Tz derived from electronic density and actual electronic temperature Te. LTE databases are then queried for properties at Tz and NLTE values are derived from them. Some hydro-codes (like FAST at NRL, Ramis' MULTI, or the CRASH code at U.Mich) use inverse EOS starting from the total internal energy Etot and returning the temperature. In the NLTE case, inverse EOS requires to solve implicit relations between Te, Tz, and Etot. We shall describe these relations and an efficient solver successively implemented in some of our codes. [4pt] [1] M. Busquet, Radiation dependent ionization model for laser-created plasmas, Ph. Fluids B 5, 4191 (1993).[0pt] [2] M. Busquet, D. Colombant, M. Klapisch, D. Fyfe, J. Gardner. Improvements to the RADIOM non-LTE model, HEDP 5, 270 (2009).[0pt] [3] M.Busquet, Onset of pseudo-thermal equilibrium within configurations and super-configurations, JQSRT 99, 131 (2006)

Exploring Chemical and Thermal Non-equilibrium in Nitrogen Arcs

International Nuclear Information System (INIS)

Ghorui, S; Das, A K

2012-01-01

Plasma torches operating with nitrogen are of special importance as they can operate with usual tungsten based refractory electrodes and offer radical rich non-oxidizing high temperature environment for plasma chemistry. Strong gradients in temperature as well as species densities and huge convective fluxes lead to varying degrees of chemical non-equilibrium in associated regions. An axi-symmetric two-temperature chemical non-equilibrium model of a nitrogen plasma torch has been developed to understand the effects of thermal and chemical non-equilibrium in arcs. A 2-D finite volume CFD code in association with a non-equilibrium property routine enabled extraction of steady state self-consistent distributions of various plasma quantities inside the torch under various thermal and chemical non-equilibrium conditions. Chemical non-equilibrium has been incorporated through computation of diffusive and convective fluxes in each finite volume cell in every iteration and associating corresponding thermodynamic and transport properties through the scheme of 'chemical non-equilibrium parameter' introduced by Ghorui et. al. Recombination coefficient data from Nahar et. al. and radiation data from Krey and Morris have been used in the simulation. Results are presented for distributions of temperature, pressure, velocity, current density, electric potential, species densities and chemical non-equilibrium effects. Obtained results are compared with similar results under LTE.

Potential of dynamic spectrum allocation in LTE macro networks

Science.gov (United States)

Hoffmann, H.; Ramachandra, P.; Kovács, I. Z.; Jorguseski, L.; Gunnarsson, F.; Kürner, T.

2015-11-01

In recent years Mobile Network Operators (MNOs) worldwide are extensively deploying LTE networks in different spectrum bands and utilising different bandwidth configurations. Initially, the deployment is coverage oriented with macro cells using the lower LTE spectrum bands. As the offered traffic (i.e. the requested traffic from the users) increases the LTE deployment evolves with macro cells expanded with additional capacity boosting LTE carriers in higher frequency bands complemented with micro or small cells in traffic hotspot areas. For MNOs it is crucial to use the LTE spectrum assets, as well as the installed network infrastructure, in the most cost efficient way. The dynamic spectrum allocation (DSA) aims at (de)activating the available LTE frequency carriers according to the temporal and spatial traffic variations in order to increase the overall LTE system performance in terms of total network capacity by reducing the interference. This paper evaluates the DSA potential of achieving the envisaged performance improvement and identifying in which system and traffic conditions the DSA should be deployed. A self-optimised network (SON) DSA algorithm is also proposed and evaluated. The evaluations have been carried out in a hexagonal and a realistic site-specific urban macro layout assuming a central traffic hotspot area surrounded with an area of lower traffic with a total size of approximately 8 × 8 km2. The results show that up to 47 % and up to 40 % possible DSA gains are achievable with regards to the carried system load (i.e. used resources) for homogenous traffic distribution with hexagonal layout and for realistic site-specific urban macro layout, respectively. The SON DSA algorithm evaluation in a realistic site-specific urban macro cell deployment scenario including realistic non-uniform spatial traffic distribution shows insignificant cell throughput (i.e. served traffic) performance gains. Nevertheless, in the SON DSA investigations, a gain of up

Scheduling strategies for LTE uplink with flow behaviour analysis

NARCIS (Netherlands)

Dimitrova, D.C.; Berg, J.L. van den; Litjens, R.; Heijenk, G.

2010-01-01

Long Term Evolution (LTE) is a cellular technology developed to support diversity of data traffic at potentially high rates. It is foreseen to extend the capacity and improve the performance of current 3G cellular networks. A key mechanism in the LTE traffic handling is the packet scheduler, which

Scheduling strategies for LTE uplink with flow behaviour analysis

NARCIS (Netherlands)

Dimitrova, D.C.; van den Berg, Hans Leo; Litjens, R.; Brogle, Marc; Osipov, Evgeny; Heijenk, Gerhard J.

Long Term Evolution (LTE) is a cellular technology developed to support diversity of data traffic at potentially high rates. It is foreseen to extend the capacity and improve the performance of current 3G cellular networks. A key mechanism in the LTE traffic handling is the packet scheduler, which

Analysis of the LTE Access Reservation Protocol for Real-Time Traffic

DEFF Research Database (Denmark)

Thomsen, Henning; Kiilerich Pratas, Nuno; Stefanovic, Cedomir

2013-01-01

LTE is increasingly seen as a system for serving real-time Machine-to-Machine (M2M) communication needs. The asynchronous M2M user access in LTE is obtained through a two-phase access reservation protocol (contention and data phase). Existing analysis related to these protocols is based...... of the two-phase LTE reservation protocol and asses its performance, when assumptions (1) and (2) do not hold....

The center-to-limb behavior of CaI lambda 6573 and [Ca II] lambda 7324

International Nuclear Information System (INIS)

Ayres, T.R.; Testerman, L.

1978-01-01

Center-to-limb measurements of the Ca I lambda 6573 intercombination line and the Ca II lambda 7324 forbidden line are compared with synthetic profiles based on a simple representation of the non-LTE Ca-Ca + ionization equilibrium. The effects of photoionization from low lying excited states of neutral calcium are found to reduce the sensitivity of the lambda 6573 center-to-limb behavior as a thermal structure diagnostic. The synthetic center-to-limb behavior is also sensitive to uncertainties in the nonthermal broadening. Nevertheless, the measured center-to-limb behavior of lambda 6573 favors a 'cool' photospheric model similar to the Vernazza, Avrett, and Loeser model M over hotter models based on the Ca II K wings. The non-LTE calcium abundance obtained from the disk center equivalent widths of lambda 6573 and lambda 7324 using the best fit model is Asub(Ca)approximately=2.1+-0.2x10 -6 (by number relative to hydrogen). Applications of these lines as diagnostics of the Ca-Ca + ionization equilibrium in other stars are briefly discussed. (Auth.)

Novel Miniaturized Octaband Antenna for LTE Smart Handset Applications

Directory of Open Access Journals (Sweden)

Haixia Liu

2015-01-01

Full Text Available A novel octaband LTE mobile phone antenna is presented, which has a compact size with the overall dimension of 35 mm × 9 mm × 3 mm. The miniaturized octaband antenna is implemented by a simple prototype of three parts which include a folded monopole as feeding element, main radiator element, and parasitic radiator element. The main and parasitic radiator elements are excited by the folded monopole feeding element coupling and shorting to the handset ground plane. A wide bandwidth in low-frequency bands covering from 747 MHz to 960 MHz (LTE Band13/GSM850/GSM900 is contributed by both main and parasitic radiator elements. In addition, the folded monopole is designed to resonate at 2530 MHz, and the coupling between the feeding element and main radiator element is designed to resonate at 1840 MHz. Subsequently, the wide bandwidth in high-frequency bands covering from 1710 MHz to 2690 MHz (DCS1800/PCS1900/WCDMA2100/LTE2300/LTE2500 is contributed by both structures. The antenna has the total efficiency up to 30% in low bands and up to 75% in high bands, respectively. At the same time, the proposed miniaturized octaband LTE mobile phone antenna is fabricated and tested to verify the design.

Kajian Implementasi Standar Long-Term Evolution (LTE pada Sistem Komunikasi Taktis Militer

Directory of Open Access Journals (Sweden)

Aris Pradana

2012-09-01

Full Text Available Sistem komunikasi taktis memungkinkan banyak pengguna dengan mobilitas tinggi, memiliki kemampuan network recovery dan network entry yang baik, serta diperkuat dengan sistem keamanan transmisi yang tahan terhadap jamming. Di sisi lain kemajuan telekomunikasi mendorong dikembangkannya LTE (Long-Term Evolution. LTE meningkatkan kapasitas sistem, cakupan area, high peak data rates, didukung dengan sistem keamanan yang baik guna mewujudkan pelayanan komunikasi menjadi lebih baik. Pada penelitian ini dilakukan simulasi dan pengkajian penggunaan standar teknologi LTE agar mampu mendukung dan meningkatkan kualitas sistem komunikasi taktis militer. Simulasi dilakukan untuk menguji kemampuan LTE terhadap jamming. Dari hasil simulasi dan pengkajian didapatkan bahwa sistem uplink LTE, dengan penambahan convolutional coding dan interleaver 8×8, memiliki ketahanan terhadap jamming dengan amplitudo di bawah 2,5 V, serta lebih tahan terhadap multitone-jamming pada sub-carrier yang berbeda daripada multitone-jamming pada sub-carrier yang sama. Arsitektur LTE dengan dukungan teknik AMC, AAA server, dan fast cell selection mampu mendukung sistem super network, network entry, dan network recovery pada sistem komunikasi taktis.

Non-LTE line-blanketed model atmospheres of hot stars. 1: Hybrid complete linearization/accelerated lambda iteration method

Science.gov (United States)

Hubeny, I.; Lanz, T.

1995-01-01

A new munerical method for computing non-Local Thermodynamic Equilibrium (non-LTE) model stellar atmospheres is presented. The method, called the hybird complete linearization/accelerated lambda iretation (CL/ALI) method, combines advantages of both its constituents. Its rate of convergence is virtually as high as for the standard CL method, while the computer time per iteration is almost as low as for the standard ALI method. The method is formulated as the standard complete lineariation, the only difference being that the radiation intensity at selected frequency points is not explicity linearized; instead, it is treated by means of the ALI approach. The scheme offers a wide spectrum of options, ranging from the full CL to the full ALI method. We deonstrate that the method works optimally if the majority of frequency points are treated in the ALI mode, while the radiation intensity at a few (typically two to 30) frequency points is explicity linearized. We show how this method can be applied to calculate metal line-blanketed non-LTE model atmospheres, by using the idea of 'superlevels' and 'superlines' introduced originally by Anderson (1989). We calculate several illustrative models taking into accont several tens of thosands of lines of Fe III to Fe IV and show that the hybrid CL/ALI method provides a robust method for calculating non-LTE line-blanketed model atmospheres for a wide range of stellar parameters. The results for individual stellar types will be presented in subsequent papers in this series.

Power-Consumption Measurements for LTE User Equipment

DEFF Research Database (Denmark)

Lauridsen, Mads

wireless communications test set and the Agilent N6705B DC power analyzer to establish a power consumption model for LTE user equipment (UE). The model is useful when you need to examine the UE battery life in system-level simulations. We will explain how the Agilent equipment can be used in manual tests......, but we do not discuss how to make automated tests (for example, using VEE software). In this application note, we analyze smartphones adhering to the 3GPP LTE standard [1]....

Resilience of LTE networks against smart jamming attacks: Wideband model

KAUST Repository

Aziz, Farhan M.; Shamma, Jeff S.; Stuber, Gordon L.

2015-01-01

communications. We have previously shown that LTE networks are vulnerable to Denial-of-Service (DOS) and loss of service attacks from smart jammers. In this paper, we extend our previous work on resilience of LTE networks to wideband multipath fading channel

A non-local thermodynamical equilibrium line formation for neutral and singly ionized titanium in model atmospheres of reference A-K stars

Science.gov (United States)

Sitnova, T. M.; Mashonkina, L. I.; Ryabchikova, T. A.

2016-09-01

We construct a model atom for Ti I-II using more than 3600 measured and predicted energy levels of Ti I and 1800 energy levels of Ti II, and quantum mechanical photoionization cross-sections. Non-local thermodynamical equilibrium (NLTE) line formation for Ti I and Ti II is treated through a wide range of spectral types from A to K, including metal-poor stars with [Fe/H] down to -2.6 dex. NLTE leads to weakened Ti I lines and positive abundance corrections. The magnitude of NLTE corrections is smaller compared to the literature data for FGK atmospheres. NLTE leads to strengthened Ti II lines and negative NLTE abundance corrections. For the first time, we have performed NLTE calculations for Ti I-II in the 6500 ≤ Teff ≤ 13 000 K range. For four A-type stars, we derived in LTE an abundance discrepancy of up to 0.22 dex between Ti I and Ti II, which vanishes in NLTE. For four other A-B stars, with only Ti II lines observed, NLTE leads to a decrease of line-to-line scatter. An efficiency of inelastic Ti I + H I collisions was estimated from an analysis of Ti I and Ti II lines in 17 cool stars with -2.6 ≤ [Fe/H] ≤ 0.0. Consistent NLTE abundances from Ti I and Ti II were obtained by applying classical Drawinian rates for the stars with log g ≥ 4.1, and neglecting inelastic collisions with H I for the very metal-poor (VMP) giant HD 122563. For the VMP turn-off stars ([Fe/H] ≤ -2 and log g ≤ 4.1), we obtained the positive abundance difference Ti I-II already in LTE, which increases in NLTE. Accurate collisional data for Ti I and Ti II are necessary to help solve this problem.

Non-LTE calculations of Al III line strengths in early-type stars

International Nuclear Information System (INIS)

Dufton, P.L.; Brown, P.J.F.; Lennon, D.J.; Lynas-Gray, A.E.

1986-01-01

Non-LTE line formation calculations, based on the 'complete linearization method' are presented for the Al III ion in early-type stars. Equivalent widths, together with the corresponding LTE values, are tabulated for 15 ultraviolet and visible region transitions, for effective temperatures from 20 000 to 35 000 K, logarithmic gravities of 3.5, 4.0 and 4.5, microturbulent velocities of 0 and 5 km s -1 and logarithmic aluminium abundances of 6.0, 6.5 and 7.0. The non-LTE line strengths are significantly larger than the LTE values particularly for the visible region transitions and the implications of this are briefly discussed. (author)

Parametrization of the average ionization and radiative cooling rates of carbon plasmas in a wide range of density and temperature

International Nuclear Information System (INIS)

Gil, J.M.; Rodriguez, R.; Florido, R.; Rubiano, J.G.; Mendoza, M.A.; Nuez, A. de la; Espinosa, G.; Martel, P.; Minguez, E.

2013-01-01

In this work we present an analysis of the influence of the thermodynamic regime on the monochromatic emissivity, the radiative power loss and the radiative cooling rate for optically thin carbon plasmas over a wide range of electron temperature and density assuming steady state situations. Furthermore, we propose analytical expressions depending on the electron density and temperature for the average ionization and cooling rate based on polynomial fittings which are valid for the whole range of plasma conditions considered in this work. -- Highlights: ► We compute the average ionization, cooling rates and emissivities of carbon plasmas. ► We compare LTE and NLTE calculations of these magnitudes. ► We perform a parametrization of these magnitudes in a wide range of plasma conditions. ► We provide information about where LTE regime assumption is accurate

Analysis And Augmentation Of Timing Advance Based Geolocation In Lte Cellular Networks

Science.gov (United States)

2016-12-01

measurements to validate TA-based positioning approaches in LTE . Their approach did not, however, focus on characterizing the TA. Rather, similar to...UE will measure the time difference of arrival of the LTE Positioning Reference Signal (PRS) from multiple eNBs. This information is then sent to a...NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA DISSERTATION ANALYSIS AND AUGMENTATION OF TIMING ADVANCE-BASED GEOLOCATION IN LTE CELLULAR NETWORKS by

Network performance and fault analytics for LTE wireless service providers

CERN Document Server

Kakadia, Deepak; Gilgur, Alexander

2017-01-01

 This book is intended to describe how to leverage emerging technologies big data analytics and SDN, to address challenges specific to LTE and IP network performance and fault management data in order to more efficiently manage and operate an LTE wireless networks. The proposed integrated solutions permit the LTE network service provider to operate entire integrated network, from RAN to Core , from UE to application service, as one unified system and correspondingly collect and align disparate key metrics and data, using an integrated and holistic approach to network analysis. The LTE wireless network performance and fault involves the network performance and management of network elements in EUTRAN, EPC and IP transport components, not only as individual components, but also as nuances of inter-working of these components. The key metrics for EUTRAN include radio access network accessibility, retainability, integrity, availability and mobility. The key metrics for EPC include MME accessibility, mobility and...

Non-LTE models of Titan's upper atmosphere

Science.gov (United States)

Yelle, Roger V.

1991-01-01

Models for the thermal structure of Titan's upper atmosphere, between 0.1 mbar and 0.01 nbar are presented. The calculations include non-LTE heating/cooling in the rotation-vibration bands of CH4, C2H2, and C2H6, absorption of solar IR radiation in the near-IR bands of CH4 and subsequent cascading to the nu-4 band of CH4, absorption of solar EUV and UV radiation, thermal conduction and cooling by HCN rotational lines. Unlike earlier models, the calculated exospheric temperature agrees well with observations, because of the importance of HCN cooling. The calculations predict a well-developed mesopause with a temperature of 135-140 K at an altitude of approximately 600 km and pressure of about 0.1 microbar. The mesopause is at a higher pressure than predicted by earlier calculations because non-LTE radiative transfer in the rotation-vibration bands of CH4, C2H2, and C2H6 is treated in an accurate manner. The accuracy of the LTE approximation for source functions and heating rates is discussed.

Recent developments in the super transition array model for spectral simulation of LTE plasmas

International Nuclear Information System (INIS)

Bar-Shalom, A.; Oreg, J.; Goldstein, W.H.

1992-01-01

Recently developed sub-picosecond pulse lasers have been used to create hot, near solid density plasmas. Since these plasmas are nearly in local thermodynamic equilibrium (LTE), their emission spectra involve a huge number of populated configurations. A typical spectrum is a combination of many unresolved clusters of emission, each containing an immense number of overlapping, unresolvable bound-bound and bound-free transitions. Under LTE, or near LTE conditions, traditional detailed configuration or detailed term spectroscopic models are not capable of handling the vast number of transitions involved. The average atom (AA) model, on the other hand, accounts for all relevant transitions, but in an oversimplified fashion that ignores all spectral structure. The Super Transition Array (STA) model, which has been developed in recent years, combines the simplicity and comprehensiveness of the AA model with the accuracy of detailed term accounting. The resolvable structure of spectral clusters is revealed by successively increasing the number of distinct STA's, until convergence is attained. The limit of this procedure is a detailed unresolved transition array (UTA) spectrum, with a term-broadened line for each accessible configuration-to-configuration transition, weighted by the relevant Boltzman population. In practice, this UTA spectrum is actually obtained using only a few thousand to tens of thousands of STA's (as opposed, typically, to billions of UTAs). The central result of STA theory is a set of formulas for the moments (total intensity, average transition energy, variance) of an STA. In calculating the moments, detailed relativistic first order quantum transition energies and probabilities are used. The energy appearing in the Boltzman factor associated with each level in a superconfiguration is the zero order result corrected by a superconfiguration averaged first order correction. Examples and application to recent measurements are presented

``Statistical treatment of the spectral properties of plasmas in local thermodynamical equilibrium using a screened hydrogenic model``; ``Traitement statistique des proprietes spectrales des plasmas a l`equilibre thermodynamique local dans le cadre du modele hydrogenique ecrante``

Energy Technology Data Exchange (ETDEWEB)

Faussurier, G.

1996-12-31

A new screened hydrogenic model is presented. The screening constants depend both on the principal n and orbital l quantum numbers. They have been obtained from numerical fits over a large data base containing ionization potentials and one-electron excitation energies of ions. A rapid and original method to compute the bound-bound and bound-free oscillator strengths is proposed. The discrete spectrum and the series continuum are connected by continuity, and the sum rules are respected. The screened hydrogenic average atom is well-adapted to describe multicharged ion plasmas in local thermodynamic equilibrium (LTE). Using the key principle of statistical mechanics, it is shown first that this model is properly defined and thermodynamically coherent. Secondly, a new method of detailed ionization stage accounting of a LTE plasma is explained. It can be used to reconstruct the distribution of integer charge states in such a plasma from any average atom model. The l -splitting allows one-electron transitions between two subshells with the same principal quantum number n. They may be of great importance when the Rosseland opacity is computed. Though, methods of classical statistical mechanics are required to calculate the distribution of the configurations around the average atom one and so to improve the spectral opacities. The splitting in integer ionic stages can be easily included. The formalism is tested by comparisons with theoretical and experimental results published in the literature. From the photoabsorption spectra encountered, the main results are the correct estimations of both the Rosseland opacity and the detailed charge degrees accounting. (author).

A Compact Frequency Reconfigurable Antenna for LTE Mobile Handset Applications

Directory of Open Access Journals (Sweden)

Munyong Choi

2015-01-01

Full Text Available A compact (8 × 62 × 5 mm3; 2.48 cc frequency reconfigurable antenna that uses electrical switching with PIN diodes is proposed for the low frequency LTE band (699 MHz–862 MHz, high frequency LTE band (2496 MHz–2690 MHz, GSM850/900 bands (824 MHz–960 MHz, and DCS/PCS/WCDMA bands (1710 MHz–2170 MHz. The penta-band PIFA is first designed for GSM850/900/DCS/PCS/WCDMA bands by using two slits and ground pins within a limited antenna volume (8 × 54.6 × 5 mm3; 2.18 cc. The frequency reconfigurable antenna based on this penta-band PIFA is thus proposed to additionally cover all LTE bands. The proposed antenna has two PIN diodes with an optimal location. For State 1 (PIN diode 1: ON state, PIN diode 2: OFF state, the proposed antenna covers the low frequency LTE band, DCS/PCS/WCDMA bands, and high frequency LTE band. For State 2 (PIN diode 1: OFF state, PIN diode 2: ON state, the antenna covers the GSM850/900 bands. Simulated and measured results show that the total efficiency of the proposed antenna was greater than 40% for all operating frequency bands.

LTE, WiMAX and WLAN network design, optimization and performance analysis

CERN Document Server

Korowajczuk, Leonhard

2011-01-01

A technological overview of LTE and WiMAX LTE, WiMAX and WLAN Network Design, Optimization and Performance Analysis provides a practical guide to LTE and WiMAX technologies introducing various tools and concepts used within. In addition, topics such as traffic modelling of IP-centric networks, RF propagation, fading, mobility, and indoor coverage are explored; new techniques which increase throughput such as MIMO and AAS technology are highlighted; and simulation, network design and performance analysis are also examined. Finally, in the latter part of the book Korowajczuk gives a step-by-step

Towards detecting methanol emission in low-mass protoplanetary discs with ALMA: the role of non-LTE excitation

Science.gov (United States)

Parfenov, S. Yu.; Semenov, D. A.; Sobolev, A. M.; Gray, M. D.

2016-08-01

The understanding of organic content of protoplanetary discs is one of the main goals of the planet formation studies. As an attempt to guide the observational searches for weak lines of complex species in discs, we modelled the (sub)millimetre spectrum of gaseous methanol (CH3OH), one of the simplest organic molecules, in the representative T Tauri system. We used 1+1D disc physical model coupled to the gas-grain ALCHEMIC chemical model with and without 2D-turbulent mixing. The computed CH3OH abundances along with the CH3OH scheme of energy levels of ground and excited torsional states were used to produce model spectra obtained with the non-local thermodynamic equilibrium (non-LTE) 3D line radiative transfer code LIME. We found that the modelled non-LTE intensities of the CH3OH lines can be lower by factor of >10-100 than those calculated under assumption of LTE. Though population inversion occurs in the model calculations for many (sub)millimetre transitions, it does not lead to the strong maser amplification and noticeably high line intensities. We identify the strongest CH3OH (sub)millimetre lines that could be searched for with the Atacama Large Millimeter Array (ALMA) in nearby discs. The two best candidates are the CH3OH 50 - 40A+ (241.791 GHz) and 5-1 - 4-1E (241.767 GHz) lines, which could possibly be detected with the ˜5σ signal-to-noise ratio after ˜3 h of integration with the full ALMA array.

Jammer Type Estimation in LTE with a Smart Jammer Repeated Game

KAUST Repository

Aziz, Farhan; Shamma, Jeff S.; Stuber, Gordon L.

2017-01-01

LTE/LTE-Advanced networks are known to be vulnerable to denial-of-service (DOS) and loss-of-service attacks from smart jammers. The interaction between the network and the smart jammer has been modeled as an infinite-horizon general-sum (non

Pricing Resources in LTE Networks through Multiobjective Optimization

Science.gov (United States)

Lai, Yung-Liang; Jiang, Jehn-Ruey

2014-01-01

The LTE technology offers versatile mobile services that use different numbers of resources. This enables operators to provide subscribers or users with differential quality of service (QoS) to boost their satisfaction. On one hand, LTE operators need to price the resources high for maximizing their profits. On the other hand, pricing also needs to consider user satisfaction with allocated resources and prices to avoid “user churn,” which means subscribers will unsubscribe services due to dissatisfaction with allocated resources or prices. In this paper, we study the pricing resources with profits and satisfaction optimization (PRPSO) problem in the LTE networks, considering the operator profit and subscribers' satisfaction at the same time. The problem is modelled as nonlinear multiobjective optimization with two optimal objectives: (1) maximizing operator profit and (2) maximizing user satisfaction. We propose to solve the problem based on the framework of the NSGA-II. Simulations are conducted for evaluating the proposed solution. PMID:24526889

Pricing resources in LTE networks through multiobjective optimization.

Science.gov (United States)

Lai, Yung-Liang; Jiang, Jehn-Ruey

2014-01-01

The LTE technology offers versatile mobile services that use different numbers of resources. This enables operators to provide subscribers or users with differential quality of service (QoS) to boost their satisfaction. On one hand, LTE operators need to price the resources high for maximizing their profits. On the other hand, pricing also needs to consider user satisfaction with allocated resources and prices to avoid "user churn," which means subscribers will unsubscribe services due to dissatisfaction with allocated resources or prices. In this paper, we study the pricing resources with profits and satisfaction optimization (PRPSO) problem in the LTE networks, considering the operator profit and subscribers' satisfaction at the same time. The problem is modelled as nonlinear multiobjective optimization with two optimal objectives: (1) maximizing operator profit and (2) maximizing user satisfaction. We propose to solve the problem based on the framework of the NSGA-II. Simulations are conducted for evaluating the proposed solution.

Pricing Resources in LTE Networks through Multiobjective Optimization

Directory of Open Access Journals (Sweden)

Yung-Liang Lai

2014-01-01

Full Text Available The LTE technology offers versatile mobile services that use different numbers of resources. This enables operators to provide subscribers or users with differential quality of service (QoS to boost their satisfaction. On one hand, LTE operators need to price the resources high for maximizing their profits. On the other hand, pricing also needs to consider user satisfaction with allocated resources and prices to avoid “user churn,” which means subscribers will unsubscribe services due to dissatisfaction with allocated resources or prices. In this paper, we study the pricing resources with profits and satisfaction optimization (PRPSO problem in the LTE networks, considering the operator profit and subscribers' satisfaction at the same time. The problem is modelled as nonlinear multiobjective optimization with two optimal objectives: (1 maximizing operator profit and (2 maximizing user satisfaction. We propose to solve the problem based on the framework of the NSGA-II. Simulations are conducted for evaluating the proposed solution.

Adaptive Modulation and Coding for LTE Wireless Communication

Science.gov (United States)

Hadi, S. S.; Tiong, T. C.

2015-04-01

Long Term Evolution (LTE) is the new upgrade path for carrier with both GSM/UMTS networks and CDMA2000 networks. The LTE is targeting to become the first global mobile phone standard regardless of the different LTE frequencies and bands use in other countries barrier. Adaptive Modulation and Coding (AMC) is used to increase the network capacity or downlink data rates. Various modulation types are discussed such as Quadrature Phase Shift Keying (QPSK), Quadrature Amplitude Modulation (QAM). Spatial multiplexing techniques for 4×4 MIMO antenna configuration is studied. With channel station information feedback from the mobile receiver to the base station transmitter, adaptive modulation and coding can be applied to adapt to the mobile wireless channels condition to increase spectral efficiencies without increasing bit error rate in noisy channels. In High-Speed Downlink Packet Access (HSDPA) in Universal Mobile Telecommunications System (UMTS), AMC can be used to choose modulation types and forward error correction (FEC) coding rate.

Physical Layer Multi-Core Prototyping A Dataflow-Based Approach for LTE eNodeB

CERN Document Server

Pelcat, Maxime; Piat, Jonathan; Nezan, Jean-François

2013-01-01

Base stations developed according to the 3GPP Long Term Evolution (LTE) standard require unprecedented processing power. 3GPP LTE enables data rates beyond hundreds of Mbits/s by using advanced technologies, necessitating a highly complex LTE physical layer. The operating power of base stations is a significant cost for operators, and is currently optimized using state-of-the-art hardware solutions, such as heterogeneous distributed systems. The traditional system design method of porting algorithms to heterogeneous distributed systems based on test-and-refine methods is a manual, thus time-expensive, task.   Physical Layer Multi-Core Prototyping: A Dataflow-Based Approach for LTE eNodeB provides a clear introduction to the 3GPP LTE physical layer and to dataflow-based prototyping and programming. The difficulties in the process of 3GPP LTE physical layer porting are outlined, with particular focus on automatic partitioning and scheduling, load balancing and computation latency reduction, specifically in sys...

Handoff mechanisms in LTE networks

Science.gov (United States)

Lal, Preeti; Yamini, Vidhu; Mohammed, V. Noor

2017-11-01

In this paper, we have analysed and studied the handoff mechanism in Long Term Evaluation (LTE) network. A LTE network has been defined with a set number of macro-cells, micro-cells and mobile devices. In this handoff mechanism distance and speed has been considered as an important parameters. The speed has been detected using the Gauss Markov Mobility Model, and from that distances have been predicted at different instances. In the handover process, Received Signal Power (RSP) for various users has been calculated with respect to base stations at various time intervals and the path loss between transmitter and receiver. A comparative study between path loss models is done in order to improve the signal power. A detailed study has been done on unnecessary handoff probability and handoff failure probability. Simulation results shows that there is an improvement in performance of the above mentioned parameters in the defined network.

Determination of absolute oscillator strengths for doubly-ionized vanadium

International Nuclear Information System (INIS)

Goly, A.

1978-01-01

Oscillator strengths of thirty V III lines in the wavelength region from 2300A to 2600A were determined by the emission method using a modified wallstabilized cascade are operating at atmospheric pressure in helium with traces of VOCl 3 -vapour. The plasma radiation was analyzed by using a high dispersion grating spectrograph (0.7 A/mm) and Kodak IIaO-plates. Conventional techniques of intensity measurement were employed. Under the physical conditions created the helium plasma was found more or less distant from LTE, but for singly- and doubly-ionized vanadium according to Drawin's criteria, a Boltzmann distribution of level population can be assumed (and has been proved for VII). Measuring a set of intensities of V II lines (with different energies of upper levels) and using gf-values, obtained previously in an argon-vanadium plasma in LTE, excitation temperatures were determined from slopes of Boltzmann plots. (orig.) 891 WL [de

EXTRAPOLATION METHOD FOR MAXIMAL AND 24-H AVERAGE LTE TDD EXPOSURE ESTIMATION.

Science.gov (United States)

Franci, D; Grillo, E; Pavoncello, S; Coltellacci, S; Buccella, C; Aureli, T

2018-01-01

The Long-Term Evolution (LTE) system represents the evolution of the Universal Mobile Telecommunication System technology. This technology introduces two duplex modes: Frequency Division Duplex and Time Division Duplex (TDD). Despite having experienced a limited expansion in the European countries since the debut of the LTE technology, a renewed commercial interest for LTE TDD technology has recently been shown. Therefore, the development of extrapolation procedures optimised for TDD systems becomes crucial, especially for the regulatory authorities. This article presents an extrapolation method aimed to assess the exposure to LTE TDD sources, based on the detection of the Cell-Specific Reference Signal power level. The method introduces a βTDD parameter intended to quantify the fraction of the LTE TDD frame duration reserved for downlink transmission. The method has been validated by experimental measurements performed on signals generated by both a vector signal generator and a test Base Transceiver Station installed at Linkem S.p.A facility in Rome. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

LTE UE Energy Saving by Applying Carrier Aggregation in a HetNet Scenario

DEFF Research Database (Denmark)

Lauridsen, Mads; Wang, Hua; Mogensen, Preben

2013-01-01

In this work it is examined if downlink Carrier Aggregation (CA) can be used to save UE energy. A dual-receiver LTE release 10 UE is compared with a single-receiver LTE release 8 UE. The models are based on scaling of an existing LTE release 8 UE power model. The energy consumption of the UEs...... is examined in a Heterogeneous Network scenario consisting of macro and small cells. The unexpected conclusion is that CA UEs can save energy, compared to LTE release 8 UEs, if they, depending on cell load, experience a throughput gain of 20%. However if the UE throughput is unaltered the energy consumption...

LTE Adaptation for Mobile Broadband Satellite Networks

Directory of Open Access Journals (Sweden)

Bastia Francesco

2009-01-01

Full Text Available One of the key factors for the successful deployment of mobile satellite systems in 4G networks is the maximization of the technology commonalities with the terrestrial systems. An effective way of achieving this objective consists in considering the terrestrial radio interface as the baseline for the satellite radio interface. Since the 3GPP Long Term Evolution (LTE standard will be one of the main players in the 4G scenario, along with other emerging technologies, such as mobile WiMAX; this paper analyzes the possible applicability of the 3GPP LTE interface to satellite transmission, presenting several enabling techniques for this adaptation. In particular, we propose the introduction of an inter-TTI interleaving technique that exploits the existing H-ARQ facilities provided by the LTE physical layer, the use of PAPR reduction techniques to increase the resilience of the OFDM waveform to non linear distortion, and the design of the sequences for Random Access, taking into account the requirements deriving from the large round trip times. The outcomes of this analysis show that, with the required proposed enablers, it is possible to reuse the existing terrestrial air interface to transmit over the satellite link.

Time-dependent simulation of plasma and electrodes in high-intensity discharge lamps with different electrode shapes

CERN Document Server

Flesch, P

2003-01-01

The subject of this paper is the modelling of d.c. and a.c. high-intensity Hg-discharge lamps with differently shaped electrodes. Different arc attachments on the electrodes are studied and insight for the development of new electrodes is gained. The model includes the entire discharge plasma (plasma column, hot plasma spots in front of electrodes, near-electrode non-LTE-plasma) as well as anode and cathode. No subdivision of the discharge space into different regions is necessary (like space charge layer, ionization zone, plasma column). This is achieved by using a differential equation for a non-LTE electrical conductivity which is applicable for local thermal equilibrium (LTE-)regions as well as for non-LTE plasma regions close to the electrodes in a high pressure plasma. Modelling results for a 0.6 MPa mercury discharge considering six different electrode shapes (anode and cathode) are presented and compared with experimental results. The electrodes have different diameters and different electrode tips, s...

Enabling LTE and WiFi Coexisting in 5 GHz for Efficient Spectrum Utilization

Directory of Open Access Journals (Sweden)

Hongyu Sun

2017-01-01

Full Text Available Due to the increasing mobile traffic demands in cellular network, researchers have proposed the coexistence of LTE and WiFi technologies in 5 GHz unlicensed bands. Therefore, how to efficiently utilize the spectrum in 5 GHz becomes extremely important. To avoid the channel access conflicts, current LTE Unlicensed (LTE-U technology introduces the duty cycle of LTE, while License-Assisted Access (LAA technology introduces Listen-Before-Talk (LBT mechanism. While these two technologies improve the spectrum utilization by using time division access schema, we believe that more efficient spectrum utilization can be achieved by enabling simultaneous transmissions from LTE and WiFi. In this paper, we propose a novel method (i.e., Low Amplitude Stream Injection (LASI method to enable the simultaneous transmissions of WiFi and LTE frames in the same channel and recover the data from the conflicts. To further utilize the LASI method, we introduce the Conflict-Tolerant Channel Allocation (CTCA algorithm to optimize the channel allocation and achieve more efficient spectrum utilization in 5 GHz. Extensive simulation results show that our approach achieves lower latency and higher throughput. Compared with the state-of-the-art LTE-U and LAA technologies, our approach can improve the spectrum efficiency 2.9 times.

CO2 non-LTE limb emissions in Mars' atmosphere as observed by OMEGA/Mars Express

Science.gov (United States)

Piccialli, A.; López-Valverde, M. A.; Määttänen, A.; González-Galindo, F.; Audouard, J.; Altieri, F.; Forget, F.; Drossart, P.; Gondet, B.; Bibring, J. P.

2016-06-01

We report on daytime limb observations of Mars upper atmosphere acquired by the OMEGA instrument on board the European spacecraft Mars Express. The strong emission observed at 4.3 μm is interpreted as due to CO2 fluorescence of solar radiation and is detected at a tangent altitude in between 60 and 110 km. The main value of OMEGA observations is that they provide simultaneously spectral information and good spatial sampling of the CO2 emission. In this study we analyzed 98 dayside limb observations spanning over more than 3 Martian years, with a very good latitudinal and longitudinal coverage. Thanks to the precise altitude sounding capabilities of OMEGA, we extracted vertical profiles of the non-local thermodynamic equilibrium (non-LTE) emission at each wavelength and we studied their dependence on several geophysical parameters, such as the solar illumination and the tangent altitude. The dependence of the non-LTE emission on solar zenith angle and altitude follows a similar behavior to that predicted by the non-LTE model. According to our non-LTE model, the tangent altitude of the peak of the CO2 emission varies with the thermal structure, but the pressure level where the peak of the emission is found remains constant at ˜0.03 ± 0.01 Pa, . This non-LTE model prediction has been corroborated by comparing SPICAM and OMEGA observations. We have shown that the seasonal variations of the altitude of constant pressure levels in SPICAM stellar occultation retrievals correlate well with the variations of the OMEGA peak emission altitudes, although the exact pressure level cannot be defined with the spectroscopy for the investigation of the characteristics of the atmosphere of Venus (SPICAM) nighttime data. Thus, observed changes in the altitude of the peak emission provide us information on the altitude of the 0.03 Pa pressure level. Since the pressure at a given altitude is dictated by the thermal structure below, the tangent altitude of the peak emission represents

User-Location Aware Downlink Performance Analysis of LTE Networks

OpenAIRE

Olaifa, John Olorunfemi

2016-01-01

In order to evaluate the performance of Long Term Evolution (LTE) networks, system-level simulation with detailed focus on network related effects such as mobility, scheduling and interference management must be emphasized. Existing studies evaluate user throughput and dimension LTE networks usually assuming uniform distribution of users within the cell. These studies report average user throughputs over the cell and the 5th percentile throughputs as estimates of the performance of the users ...

Reducing LTE Uplink Transmission Energy by Allocating Resources

DEFF Research Database (Denmark)

Lauridsen, Mads; Jensen, Anders Riis; Mogensen, Preben

2011-01-01

The effect of physical resource block (PRB) allocation on an LTE modem's transmit power and total modem energy consumption is examined. In this paper the uplink resource blocks are scheduled in either a Frequency Division Multiple Access (FDMA) or Time Division Multiple Access (TDMA) manner......, to determine if low transmission power & long transmission time or high transmission power & short transmission time is most energy efficient. It is important to minimize the LTE modem's energy consumption caused by uplink transmission because it affects phone battery time, and because researchers rarely focus...

CBRS Spectrum Sharing between LTE-U and WiFi: A Multiarmed Bandit Approach

Directory of Open Access Journals (Sweden)

Imtiaz Parvez

2016-01-01

Full Text Available The surge of mobile devices such as smartphone and tablets requires additional capacity. To achieve ubiquitous and high data rate Internet connectivity, effective spectrum sharing and utilization of the wireless spectrum carry critical importance. In this paper, we consider the use of unlicensed LTE (LTE-U technology in the 3.5 GHz Citizens Broadband Radio Service (CBRS band and develop a multiarmed bandit (MAB based spectrum sharing technique for a smooth coexistence with WiFi. In particular, we consider LTE-U to operate as a General Authorized Access (GAA user; hereby MAB is used to adaptively optimize the transmission duty cycle of LTE-U transmissions. Additionally, we incorporate downlink power control which yields a high energy efficiency and interference suppression. Simulation results demonstrate a significant improvement in the aggregate capacity (approximately 33% and cell-edge throughput of coexisting LTE-U and WiFi networks for different base station densities and user densities.

A non-LTE study of silicon line formation in early-type main-sequence atmospheres.

Science.gov (United States)

Kamp, L. W.

1973-01-01

We have computed populations of 16 levels of Si III-V and radiation fields in all connecting transitions; in particular the first six Si III triplet levels, including the 4553 line, and the first six Si IV levels including 4089. The computations were done for four non-LTE H-He model atmospheres, provided by Auer and Mihalas. Estimates of corresponding MK types are B1.5 V, B0.5 V, O9 V, and O6. Solutions were obtained by iterating the linearized equations of radiative transfer and statistical equilibrium, except that for less important lines an approximate equivalent two-level atom treatment was used. Continuous opacities of C, N, O, and Ne were included. All abundances were solar values.

Experimental approaches for studying non-equilibrium atmospheric plasma jets

Energy Technology Data Exchange (ETDEWEB)

Shashurin, A., E-mail: ashashur@purdue.edu [School of Aeronautics & Astronautics, Purdue University, West Lafayette, Indiana 47907 (United States); Keidar, M. [Department of Mechanical and Aerospace Engineering, The George Washington University, Washington, District of Columbia 20052 (United States)

2015-12-15

This work reviews recent research efforts undertaken in the area non-equilibrium atmospheric plasma jets with special focus on experimental approaches. Physics of small non-equilibrium atmospheric plasma jets operating in kHz frequency range at powers around few Watts will be analyzed, including mechanism of breakdown, process of ionization front propagation, electrical coupling of the ionization front with the discharge electrodes, distributions of excited and ionized species, discharge current spreading, transient dynamics of various plasma parameters, etc. Experimental diagnostic approaches utilized in the field will be considered, including Rayleigh microwave scattering, Thomson laser scattering, electrostatic streamer scatterers, optical emission spectroscopy, fast photographing, etc.

Mobility and Bandwidth prediction in virtualized LTE systems: architecture and challenges

NARCIS (Netherlands)

Karagiannis, Georgios; Jamakovic, Almerima; Briggs, Keith; Karimzadeh Motallebi Azar, Morteza; Parada, Carlos; Iulian Corici, Marius; Taleb, Tarik; Edmonds, Andy; Bohnert, Thomas Michael

2014-01-01

Long Term Evolution (LTE) represents the fourth generation (4G) technology which is capable of providing high data rates as well as support of high speed mobility. The EU FP7 Mobile Cloud Networking (MCN) project integrates the use of cloud computing concepts in LTE mobile networks in order to

LTE and the evolution to 4G wireless design and measurement challenges

CERN Document Server

Rumney, Moray

2013-01-01

A practical guide to LTE design, test and measurement, this new edition has been updated to include the latest developments This book presents the latest details on LTE from a practical and technical perspective. Written by Agilent's measurement experts, it offers a valuable insight into LTE technology and its design and test challenges. Chapters cover the upper layer signaling and system architecture evolution (SAE). Basic concepts such as MIMO and SC-FDMA, the new uplink modulation scheme, are introduced and explained, and the authors look into the challenges of verifying the

Final Report on DTRA Basic Research Project #BRCALL08-Per3-C-2-0006 "High-Z Non-Equilibrium Physics and Bright X-ray Sources with New Laser Targets"

Energy Technology Data Exchange (ETDEWEB)

Colvin, Jeffrey D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2016-06-01

This project had two major goals. Final Goal: obtain spectrally resolved, absolutely calibrated x-ray emission data from uniquely uniform mm-scale near-critical-density high-Z plasmas not in local thermodynamic equilibrium (LTE) to benchmark modern detailed atomic physics models. Scientific significance: advance understanding of non-LTE atomic physics. Intermediate Goal: develop new nano-fabrication techniques to make suitable laser targets that form the required highly uniform non-LTE plasmas when illuminated by high-intensity laser light. Scientific significance: advance understanding of nano-science. The new knowledge will allow us to make x-ray sources that are bright at the photon energies of most interest for testing radiation hardening technologies, the spectral energy range where current x-ray sources are weak. All project goals were met.

Deviation from local thermodynamic equilibrium in a cesium-seeded argon plasma

International Nuclear Information System (INIS)

Stefanov, B.; Zarkova, L.

1985-11-01

The possibility of deviations from local thermodynamic equilibrium of a cesium seeded argon plasma has been analyzed. A four level model of cesium has been employed. Overpopulations of the ground state and the first excited state as well as the corresponding reduction of the electron density are calculated for cylindrical discharge structures by solving stationary rate equations. Numerical results are presented. These results indicate that in a large regime of plasma conditions the LTE assumption is valid for electron temperatures larger than 3000 K. (orig.)

Synchronized RACH-less Handover Solution for LTE Heterogeneous Networks

DEFF Research Database (Denmark)

Barbera, Simone; Pedersen, Klaus I.; Rosa, Claudio

2015-01-01

reductions in the data connectivity interruption time at each handover, no need for random access in the target cell, and reduced overall handover execution time. Laboratory handover measurement results, using commercial LTE equipment, are presented and analyzed to justify the latency benefits......Some of the most recent LTE features require synchronous base stations, and time-synchronized base stations also offer opportunities for improved handover mechanisms by introducing a new synchronized RACH-less handover scheme. The synchronized RACH-less handover solution offers significant...

Aerospace Applications of Non-Equilibrium Plasma

Science.gov (United States)

Blankson, Isaiah M.

2016-01-01

Nonequilibrium plasma/non-thermal plasma/cold plasmas are being used in a wide range of new applications in aeronautics, active flow control, heat transfer reduction, plasma-assisted ignition and combustion, noise suppression, and power generation. Industrial applications may be found in pollution control, materials surface treatment, and water purification. In order for these plasma processes to become practical, efficient means of ionization are necessary. A primary challenge for these applications is to create a desired non-equilibrium plasma in air by preventing the discharge from transitioning into an arc. Of particular interest is the impact on simulations and experimental data with and without detailed consideration of non-equilibrium effects, and the consequences of neglecting non-equilibrium. This presentation will provide an assessment of the presence and influence of non-equilibrium phenomena for various aerospace needs and applications. Specific examples to be considered will include the forward energy deposition of laser-induced non-equilibrium plasmoids for sonic boom mitigation, weakly ionized flows obtained from pulsed nanosecond discharges for an annular Hall type MHD generator duct for turbojet energy bypass, and fundamental mechanisms affecting the design and operation of novel plasma-assisted reactive systems in dielectric liquids (water purification, in-pipe modification of fuels, etc.).

Surface-ionization field mass-spectrometry studies of nonequilibrium surface ionization

International Nuclear Information System (INIS)

Blashenkov, Nikolai M; Lavrent'ev, Gennadii Ya

2007-01-01

The ionization of polyatomic molecules on tungsten and tungsten oxide surfaces is considered for quasiequilibrium or essentially nonequilibrium conditions (in the latter case, the term nonequilibrium surface ionization is used for adsorbate ionization). Heterogeneous reactions are supposed to proceed through monomolecular decay of polyatomic molecules or fragments of multimolecular complexes. The nonequilibrium nature of these reactions is established. The dependences of the current density of disordered ions on the surface temperature, electric field strength, and ionized particle energy distribution are obtained in analytical form. Heterogeneous dissociation energies, the ionization potentials of radicals, and the magnitude of reaction departure from equilibrium are determined from experimental data, as are energy exchange times between reaction products and surfaces, the number of molecules in molecular complexes, and the number of effective degrees of freedom in molecules and complexes. In collecting the data a new technique relying on surface-ionization field mass-spectrometry was applied. (instruments and methods of investigation)

Modelling of synchronisation and energy performance of FBE- and LBE-based standalone LTE-U networks

Directory of Open Access Journals (Sweden)

Jiamin Li

2017-06-01

Full Text Available Without the aid of licensed channel, deploying long-term evolution (LTE networks over unlicensed spectrum (named standalone LTE-U networks faces the difficulty of establishing and maintaining synchronisation between user equipments and base stations. In this work, considering the two modes of listen-before-talk-based channel access scheme, frame-based equipment (FBE and load-based equipment (LBE, the authors propose analytical frameworks to study the successful probability of synchronisation and the energy consumption of synchronisation in a standalone LTE-U network. Specifically, for the LBE mode, the authors also propose a Lattice-Poisson algorithm-based approach to derive the distribution of the channel non-occupancy period of a standalone LTE-U network. Furthermore, the authors explore the impact of diverse protocol parameters of both FBE and LBE modes on the two studied performance metrics. Simulation results demonstrate the accuracy of the analysis, and shed some light on the selection of FBE and LBE for standalone LTE-U networks, in terms of synchronisation, energy consumption, and throughput of standalone LTE-U and Wi-Fi networks.

LTE for Railways: Impact on Performance of ETCS Railway Signaling

DEFF Research Database (Denmark)

Sniady, Aleksander; Soler, José

2014-01-01

The Global System for Mobile Communications-Railways (GSM-R) is an obsolete mobile technology with considerable shortcomings in terms of capacity and data transmission capabilities. Because of these shortcomings, GSM-R is becoming the element limiting the number of running trains in areas with high...... train concentration, such as major train stations. Moreover, GSM-R cannot support advanced data services. Hence, modern technologies, such as long-term evolution (LTE), have to be evaluated as possible railway communication technologies to replace GSM-R in the future. This article analyzes...... the characteristics of the LTE railway radio access network in terms of eNodeB (LTE base station) density and eNodeB transmission power. Based on this analysis, a set of computer-based simulation scenarios (e.g., OPNET) with varying numbers of eNodeBs is evaluated regarding the achieved transfer delay and data...

Python Radiative Transfer Emission code (PyRaTE): non-LTE spectral lines simulations

Science.gov (United States)

Tritsis, A.; Yorke, H.; Tassis, K.

2018-05-01

We describe PyRaTE, a new, non-local thermodynamic equilibrium (non-LTE) line radiative transfer code developed specifically for post-processing astrochemical simulations. Population densities are estimated using the escape probability method. When computing the escape probability, the optical depth is calculated towards all directions with density, molecular abundance, temperature and velocity variations all taken into account. A very easy-to-use interface, capable of importing data from simulations outputs performed with all major astrophysical codes, is also developed. The code is written in PYTHON using an "embarrassingly parallel" strategy and can handle all geometries and projection angles. We benchmark the code by comparing our results with those from RADEX (van der Tak et al. 2007) and against analytical solutions and present case studies using hydrochemical simulations. The code will be released for public use.

An Empirical LTE Smartphone Power Model with a View to Energy Efficiency Evolution

DEFF Research Database (Denmark)

Lauridsen, Mads; Noël, Laurent; Sørensen, Troels Bundgaard

2014-01-01

measurements made on state-of-the-art LTE smartphones. Discontinuous Reception (DRX) sleep mode is also modeled, because it is one of the most effective methods to improve smartphone battery life. Energy efficiency has generally improved with each Radio Access Technology (RAT) generation, and to see......Smartphone users struggle with short battery life, and this affects their device satisfaction level and usage of the network. To evaluate how chipset manufacturers and mobile network operators can improve the battery life, we propose a Long Term Evolution (LTE) smartphone power model. The idea...... this evolution, we compare the energy efficiency of the latest LTE devices with devices based on Enhanced Data rates for GSM Evolution (EDGE), High Speed Packet Access (HSPA), and Wi-Fi*. With further generations of RAT systems we expect further improvements. To this end, we discuss the new LTE features, Carrier...

Non-LTE treatment of beryllium lines: Misidentification of the solar Be I feature at 2650 A

International Nuclear Information System (INIS)

Shipman, H.L.; Auer, L.H.

1979-01-01

We investigated the formation of beryllium lines, with particular reference to the solar Be spectrum, in a non-LTE context with a 25-level model atom in which 15 levels were allowed to depart from LTE. In some transitions, particularly the Be I lambda2650 line, the non-LTE effects can be quite dramatic, changing the deduced abundances by a factor of 4. Based on our non-LTE calculations and Copernicus observations of other stars, we find that a solar spectral feature at 2650 A, previously identified by numerous investigators as a Be I line, cannot be produced by Be I. Non-LTE effects on the Be II lambda3131 A line, used for most Be abundance determinations in the literature, are small by comparison

Low-cost extrapolation method for maximal LTE radio base station exposure estimation: test and validation.

Science.gov (United States)

Verloock, Leen; Joseph, Wout; Gati, Azeddine; Varsier, Nadège; Flach, Björn; Wiart, Joe; Martens, Luc

2013-06-01

An experimental validation of a low-cost method for extrapolation and estimation of the maximal electromagnetic-field exposure from long-term evolution (LTE) radio base station installations are presented. No knowledge on downlink band occupation or service characteristics is required for the low-cost method. The method is applicable in situ. It only requires a basic spectrum analyser with appropriate field probes without the need of expensive dedicated LTE decoders. The method is validated both in laboratory and in situ, for a single-input single-output antenna LTE system and a 2×2 multiple-input multiple-output system, with low deviations in comparison with signals measured using dedicated LTE decoders.

A Multistage Control Mechanism for Group-Based Machine-Type Communications in an LTE System

Directory of Open Access Journals (Sweden)

Wen-Chien Hung

2013-01-01

Full Text Available When machine-type communication (MTC devices perform the long-term evolution (LTE attach procedure without bit rate limitations, they may produce congestion in the core network. To prevent this congestion, the LTE standard suggests using group-based policing to regulate the maximum bit rate of all traffic generated by a group of MTC devices. However, previous studies on the access point name-aggregate maximum bit rate based on group-based policing are relatively limited. This study proposes a multistage control (MSC mechanism to process the operations of maximum bit rate allocation based on resource-use information. For performance evaluation, this study uses a Markov chain with to analyze MTC application in a 3GPP network. Traffic flow simulations in an LTE system indicate that the MSC mechanism is an effective bandwidth allocation method in an LTE system with MTC devices. Experimental results show that the MSC mechanism achieves a throughput 22.5% higher than that of the LTE standard model using the group-based policing, and it achieves a lower delay time and greater long-term fairness as well.

Efficient LTE Access with Collision Resolution for Massive M2M Communications

DEFF Research Database (Denmark)

Madueño, Germán Corrales; Stefanovic, Cedomir; Popovski, Petar

2014-01-01

outage. In this work we propose a LTE RACH scheme tailored for delay-sensitive M2M services with synchronous traffic arrivals. The key idea is, upon detection of a RACH overload, to apply a collision resolution algorithm based on splitting trees. The solution is implemented on top of the existing LTE...

The Effects of a Dynamic Spectrum Access Overlay in LTE-Advanced Networks

Energy Technology Data Exchange (ETDEWEB)

Juan D. Deaton; Ryan E. lrwin; Luiz A. DaSilva

2011-05-01

As early as 2014, wireless network operators spectral capacity will be overwhelmed by a data tsunami brought on by new devices and applications. To augment spectral capacity, operators could deploy a Dynamic Spectrum Access (DSA) overlay. In the light of the many planned Long Term Evolution (LTE) network deployments, the affects of a DSA overlay have not been fully considered into the existing LTE standards. Coalescing many different aspects of DSA, this paper develops the Spectrum Accountability (SA) framework. The SA framework defines specific network element functionality, protocol interfaces, and signaling flow diagrams for LTE to support service requests and enforce rights of responsibilities of primary and secondary users, respectively. We also include a network simulation to quantify the benefits of using DSA channels to augment capacity. Based on our simulation we show that, network operators can benefit up to %40 increase in operating capacity when sharing DSA bands to augment spectral capacity. With our framework, this paper could serve as an guide in developing future LTE network standards that include DSA.

Design and optimization of LTE 1800 MIMO antenna.

Science.gov (United States)

Wong, Huey Shin; Islam, Mohammad Tariqul; Kibria, Salehin

2014-01-01

A multiple input and multiple output (MIMO) antenna that comprises a printed microstrip antenna and a printed double-L sleeve monopole antenna for LTE 1800 wireless application is presented. The printed double-L sleeve monopole antenna is fed by a 50 ohm coplanar waveguide (CPW). A novel T-shaped microstrip feedline printed on the other side of the PCB is used to excite the waveguide's outer shell. Isolation characteristics better than -15 dB can be obtained for the proposed MIMO antenna. The proposed antenna can operate in LTE 1800 (1710 MHz-1880 MHz). This antenna exhibits omnidirectional characteristics. The efficiency of the antenna is greater than 70% and has high gain of 2.18 dBi.

Uplink multi-cluster scheduling with MU-MIMO for LTE-advanced with carrier aggregation

DEFF Research Database (Denmark)

Wang, Hua; Nguyen, Hung Tuan; Rosa, Claudio

2012-01-01

-Advanced requirements and are being considered as part of LTE Release 10. In this paper, some of the physical layer enhancement techniques for LTE-Advanced have been studied including carrier aggregation (CA), uplink multi-cluster scheduling, and uplink multi-user multiple-input multiple-output (MU-MIMO) transmission....... A system-level simulation was conducted to investigate the performance gains that can be achieved in uplink CA with multi-cluster scheduling and MU-MIMO. Simulation results show that with proper separation between power-limited and non-power-limited LTE-A users, multi-cluster scheduling with CA has similar...

Analisa Performansi Algoritma Penjadwalan Proportional Fairness Dan Log Rule Dengan Skenario Multicell Pada Sistem 3GPP LTE

Directory of Open Access Journals (Sweden)

Muhammad Dimas Arfianto

2016-05-01

Full Text Available Teknologi Long Term Evolution (LTE dikembangkan dengan tujuan untuk mengurangi biaya yang dikeluarkan oleh pengguna maupun operator jasa telekomunikasi, memperluas daerah jangkauan, menambah kapasitas sistem, dan mengurangi delay. Dengan spesifikasi yang tinggi, LTE diharapkan mampu memberikan kemudahan pelanggan dalam mengakses layanan Voice over IP, Streaming, dan Video Conference. LTE diharapkan mampu memberikan layanan dengan besar throughput yang tinggi dan delay yang rendah. Padahal tidak semua user membutuhkan throughput yang sama besar namun yang dibutuhkan adalah kesesuaian pengendalian delay dan fairness index untuk setiap user dengan tetap memperhatikan batasan throughput. Untuk mendapatkan kinerja dan hasil yang maksimal tersebut pada LTE diperlukan sistem algoritma penjadwalan yang baik. Pada penelitian ini, dianalisis performansi LTE dengan parameter Delay, Packet loss, Throughput, dan Fairness Index menggunakan algoritma penjadwalan Proportional Fairness dan Log Rule pada LTE-Simulator dengan skenario menggunakan trafik VoIP, Video dan Best Effort. Hasil penelitian ini menunjukan bahwa penjadwalan algoritma Proportional Fairness lebih baik dalam menangani layanan VoIP, sedangkan algoritma Log Rule lebih baik dalam menangani layanan Video. Hal ini menandakan kedua algoritma ini sangat cocok digunakan untuk jaringan LTE dengan kondisi trafik layanan real-time, tetapi tidak untuk layanan non real-time seperti layanan Best Effort

Low-cost extrapolation method for maximal lte radio base station exposure estimation: Test and validation

International Nuclear Information System (INIS)

Verloock, L.; Joseph, W.; Gati, A.; Varsier, N.; Flach, B.; Wiart, J.; Martens, L.

2013-01-01

An experimental validation of a low-cost method for extrapolation and estimation of the maximal electromagnetic-field exposure from long-term evolution (LTE) radio base station installations are presented. No knowledge on down-link band occupation or service characteristics is required for the low-cost method. The method is applicable in situ. It only requires a basic spectrum analyser with appropriate field probes without the need of expensive dedicated LTE decoders. The method is validated both in laboratory and in situ, for a single-input single-output antenna LTE system and a 2x2 multiple-input multiple-output system, with low deviations in comparison with signals measured using dedicated LTE decoders. (authors)

The Vienna LTE-advanced simulators up and downlink, link and system level simulation

CERN Document Server

Rupp, Markus; Taranetz, Martin

2016-01-01

This book introduces the Vienna Simulator Suite for 3rd-Generation Partnership Project (3GPP)-compatible Long Term Evolution-Advanced (LTE-A) simulators and presents applications to demonstrate their uses for describing, designing, and optimizing wireless cellular LTE-A networks. Part One addresses LTE and LTE-A link level techniques. As there has been high demand for the downlink (DL) simulator, it constitutes the central focus of the majority of the chapters. This part of the book reports on relevant highlights, including single-user (SU), multi-user (MU) and single-input-single-output (SISO) as well as multiple-input-multiple-output (MIMO) transmissions. Furthermore, it summarizes the optimal pilot pattern for high-speed communications as well as different synchronization issues. One chapter is devoted to experiments that show how the link level simulator can provide input to a testbed. This section also uses measurements to present and validate fundamental results on orthogonal frequency division multiple...

A non-LTE treatment of beryllium lines - Misidentification of the solar Be I feature at 2650 A

Science.gov (United States)

Shipman, H. L.; Auer, L. H.

1979-01-01

The formation of beryllium lines, with particular reference to the solar Be spectrum, is investigated in a non-LTE context with a 25-level model atom in which 15 levels are allowed to depart from LTE. In some transitions, particularly the Be I 2650-A line, the non-LTE effects can be quite dramatic, changing the deduced abundances by a factor of 4. Based on the non-LTE calculations and Copernicus observations of other stars, it is found that a solar spectral feature at 2650 A, previously identified by numerous investigators as a Be I line, cannot be produced by Be I. Non-LTE effects on the Be II 3131-A line, used for most Be abundance determinations in the literature, are small by comparison.

Utilizing ICN/CCN for service and VM migration support in virtualized LTE systems

NARCIS (Netherlands)

Karimzadeh Motallebi Azar, Morteza; Satria, Triadimas; Karagiannis, Georgios

2014-01-01

One of the most important concepts used in mobile networks, like LTE (Long Term Evolution) is service continuity. A mobile user moving from one network to another network should not lose an on-going service. In cloud-based (virtualized) LTE systems, services are hosted on Virtual Machines (VMs) that

Using adaptive antenna array in LTE with MIMO for space-time processing

Directory of Open Access Journals (Sweden)

Abdourahamane Ahmed Ali

2015-04-01

Full Text Available The actual methods of improvement the existent wireless transmission systems are proposed. Mathematical apparatus is considered and proved by models, graph of which are shown, using the adaptive array antenna in LTE with MIMO for space-time processing. The results show that improvements, which are joined with space-time processing, positively reflects on LTE cell size or on throughput

Non-LTE profiles of the Al I autoionization lines. [for solar model atmospheres

Science.gov (United States)

Finn, G. D.; Jefferies, J. T.

1974-01-01

A non-LTE formulation is given for the transfer of radiation in the autoionizing lines of neutral aluminum at 1932 and 1936 A through both the Bilderberg and Harvard-Smithsonian model atmospheres. Numerical solutions for the common source function of these lines and their theoretical line profiles are calculated and compared with the corresponding LTE profiles. The results show that the non-LTE profiles provide a better match with the observations. They also indicate that the continuous opacity of the standard solar models should be increased in this wavelength region if the center-limb variations of observed and theoretical profiles of these lines are to be in reasonable agreement.

Correlation Evaluation on Small LTE Handsets

DEFF Research Database (Denmark)

Barrio, Samantha Caporal Del; Pedersen, Gert Frølund

2012-01-01

This paper presents measurements of the first MIMO handset on the market. It investigates the correlation coefficient computed from coaxial cable measurements and from optical fiber measurements. The results are compared and discussed. The question of the actual feasibility of low correlation...... for the LTE-700 band in small terminals is raised....

A Tractable Model of the LTE Access Reservation Procedure for Machine-Type Communications

DEFF Research Database (Denmark)

Nielsen, Jimmy Jessen; Min Kim, Dong; Madueño, Germán Corrales

2015-01-01

A canonical scenario in Machine-Type Communications (MTC) is the one featuring a large number of devices, each of them with sporadic traffic. Hence, the number of served devices in a single LTE cell is not determined by the available aggregate rate, but rather by the limitations of the LTE access...

Power Saving Scheduling Scheme for Internet of Things over LTE/LTE-Advanced Networks

OpenAIRE

Kuo, Yen-Wei; Chou, Li-Der

2015-01-01

The devices of Internet of Things (IoT) will grow rapidly in the near future, and the power consumption and radio spectrum management will become the most critical issues in the IoT networks. Long Term Evolution (LTE) technology will become a promising technology used in IoT networks due to its flat architecture, all-IP network, and greater spectrum efficiency. The 3rd Generation Partnership Project (3GPP) specified the Discontinuous Reception (DRX) to reduce device’s power consumption. Howev...

Influence of external radiation on non-LTE opacities of Xe

Science.gov (United States)

Klapisch, Marcel; Busquet, Michel

2010-11-01

In Laboratory Astrophysics, where astrophysics phenomena are scaled down to the laboratory, Xenon is commonly used. In most cases, astrophysical plasmas are not dense enough to warrant LTE. However, they are surrounded by radiation fields. Extensive detailed level computations of non-LTE Xe around Te = 100eV were performed with HULLAC [1], with different radiation temperatures and/or dilution factors. Generally, the effects are very important, even with small dilution factors. [4pt] [1] M. Klapisch and M. Busquet, High Ener. Dens. Phys.5, (2009) 105-9; Bull. Am. Phys. Soc.54, (2009) 210.

LTE modem power consumption, SAR and RF signal strength emulation

DEFF Research Database (Denmark)

Musiige, Deogratius; Vincent, Laulagnet; Anton, François

2012-01-01

This paper presents a new methodology for emulating the LTE modem power consumption, emitted SAR and RF signal strength when transmitting an LTE signal. The inputs of the methodology are: modem logical/protocol commands, time advance, near-field specifier, and antenna characteristics. The power...... emulation model(s) are computed by a two layer 451 neural network based on physical power measurements. SAR is emulated by polynomial interpolation models based on FDTD simulations. The accuracies of the mathematical function approximations for the emulation models of power and SAR are 5.19% and 3...

Adaptive Antenna System for Both 4G LTE and 5G Cellular Systems

Science.gov (United States)

Henderson, Kendrick Q. T.

Given the steep increase in the use of mobile communication systems, the current 4G/LTE (Long Term Evolution), cellular system will not be able to handle the increase in data. It is estimated that by 2020 the bandwidth requirements will be 10 times greater than what LTE can sustain. A new 5th generation (5G) communication system has been proposed to meet this demand. The physical layer or the antenna is the most critical part of any wireless communication systems as it is the interface between the free space medium and an electrical circuit. It sets the margin for almost all design parameters in the system such as the system noise and bandwidth. Several interactions of antennas have been proposed over the years for cellular services. These antennas are of various geometries, bandwidths, and radiation patterns with almost all having linear polarization. This thesis attempts to solve the multiple LTE antenna problem by creating a simple antenna that covers most of the LTE bands (850-2700 MHz) as well as introducing an antenna system at the 28 GHz 5G band. This allows for a greater educated hypothesis into what 5G can offer at the physical layer. The proposed concept will provide a solution to the co-existence problem of upcoming 5G wireless systems to be interoperable with existing 4G/LTE system.

Comparing two non-equilibrium approaches to modelling of a free-burning arc

International Nuclear Information System (INIS)

Baeva, M; Uhrlandt, D; Benilov, M S; Cunha, M D

2013-01-01

Two models of high-pressure arc discharges are compared with each other and with experimental data for an atmospheric-pressure free-burning arc in argon for arc currents of 20–200 A. The models account for space-charge effects and thermal and ionization non-equilibrium in somewhat different ways. One model considers space-charge effects, thermal and ionization non-equilibrium in the near-cathode region and thermal non-equilibrium in the bulk plasma. The other model considers thermal and ionization non-equilibrium in the entire arc plasma and space-charge effects in the near-cathode region. Both models are capable of predicting the arc voltage in fair agreement with experimental data. Differences are observed in the arc attachment to the cathode, which do not strongly affect the near-cathode voltage drop and the total arc voltage for arc currents exceeding 75 A. For lower arc currents the difference is significant but the arc column structure is quite similar and the predicted bulk plasma characteristics are relatively close to each other. (paper)

Coordinated Dynamic Spectrum Management of LTE-U and Wi-Fi Networks

OpenAIRE

Sagari, Shweta; Baysting, Samuel; Saha, Dola; Seskar, Ivan; Trappe, Wade; Raychaudhuri, Dipankar

2015-01-01

This paper investigates the co-existence of Wi-Fi and LTE in emerging unlicensed frequency bands which are intended to accommodate multiple radio access technologies. Wi-Fi and LTE are the two most prominent access technologies being deployed today, motivating further study of the inter-system interference arising in such shared spectrum scenarios as well as possible techniques for enabling improved co-existence. An analytical model for evaluating the baseline performance of co-existing Wi-Fi...

Spectrum Sensing Experimentation for LTE and WiFi Unlicensed Band Operation

Directory of Open Access Journals (Sweden)

N. Milošević

2016-11-01

Full Text Available If several different systems operate in the same frequency band, a coordination between them is needed for effective use of the available spectrum. The coordination is especially important if the systems are not designed to operate in such an environment. The very important initial phase of the coordination process is acquiring of the spectrum usage map or spectrum sensing. The paper describes the spectrum sensing experimentation in the unlicensed 5 GHz band during the WiFi or LTE transmission. It describes the experiment workflow and depicts the obtained results. The experiments were performed at NITOS testbed at the University of Thessaly, Greece, and show that it is possible to determine whether WiFi or LTE transmission is sensed. Therefore, based on spectrum sensing it will be possible to coordinate a shared access of WiFi and LTE users in the unlicensed 5 GHz band.

Enhanced cognitive Radio Resource Management for LTE systems

KAUST Repository

Alqerm, Ismail; Shihada, Basem; Shin, Kang G.

2013-01-01

as it improves network efficiency by exploiting radio environment information, intelligent optimization algorithms to configure transmission parameters, and mitigate interference. In this paper, we propose a cognitive resource management scheme to adapt LTE

Frequency Reconfigurable Antenna for Deca-Band 5 G/LTE/WWAN Mobile Terminal Applications

Science.gov (United States)

Yang, Lingsheng; Cheng, Biyu; Jia, Hongting

2018-04-01

In this paper, a frequency reconfigurable antenna for 5 G/LTE/WWAN mobile terminal applications is presented. The proposed antenna consists of a radiation element which is folded on a dielectric cuboid. Four PIN diodes located on the antenna element are used for frequency reconfigration. By controlling the states of four PIN diodes with an 8-bit microcontroller, a broad band which can cover deca-band as LTE700/2300/2500, GSM850/900/1800/1900, UMTS 2100, WLAN2400 and the future 5 G or LTE3600 is obtained with a compacted size of 40×8×5mm3. The antenna gain, efficiency and radiation characteristics are also shown.

Light element opacities of astrophysical interest from ATOMIC

Energy Technology Data Exchange (ETDEWEB)

Colgan, J.; Kilcrease, D. P.; Magee, N. H. Jr.; Armstrong, G. S. J.; Abdallah, J. Jr.; Sherrill, M. E. [Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Fontes, C. J.; Zhang, H. L.; Hakel, P. [Computational Physics Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

2013-07-11

We present new calculations of local-thermodynamic-equilibrium (LTE) light element opacities from the Los Alamos ATOMIC code for systems of astrophysical interest. ATOMIC is a multi-purpose code that can generate LTE or non-LTE quantities of interest at various levels of approximation. Our calculations, which include fine-structure detail, represent a systematic improvement over previous Los Alamos opacity calculations using the LEDCOP legacy code. The ATOMIC code uses ab-initio atomic structure data computed from the CATS code, which is based on Cowan's atomic structure codes, and photoionization cross section data computed from the Los Alamos ionization code GIPPER. ATOMIC also incorporates a new equation-of-state (EOS) model based on the chemical picture. ATOMIC incorporates some physics packages from LEDCOP and also includes additional physical processes, such as improved free-free cross sections and additional scattering mechanisms. Our new calculations are made for elements of astrophysical interest and for a wide range of temperatures and densities.

Capacity planning for Carrier Ethernet LTE backhaul networks

DEFF Research Database (Denmark)

Checko, Aleksandra; Ellegaard, Lars; Berger, Michael Stübert

2012-01-01

With the introduction of LTE networks operators need to plan a new, IP-based mobile backhaul. In this paper, we provide recommendation on dimensioning LTE backhaul networks links using three methods: delay-, dimensioning formula- and overbooking factor-based. Results are obtained from OPNET simul...... and verified. Simulation in this work proves that Carrier Ethernet, one of the candidate technologies for mobile backhaul, protects the network from users that want to flood the network with their data and manages to keep the delay experienced by other users low....... simulations with traffic model based on traffic forecast for 2015. A delay-based approach gives recommended bandwidth for expected number of users. A dimensioning formula is proposed to calculate link bandwidth when mean value of aggregated traffic in the network is known. An overbooking factor is calculated...

Brazilian cross-cultural adaptation and validation of the List of Threatening Events Questionnaire (LTE-Q).

Science.gov (United States)

Abreu, Patrícia B de; Cogo-Moreira, Hugo; Pose, Regina A; Laranjeira, Ronaldo; Caetano, Raul; Gaya, Carolina M; Madruga, Clarice S

2017-01-01

To perform a construct validation of the List of Threatening Events Questionnaire (LTE-Q), as well as convergence validation by identifying its association with drug use in a sample of the Brazilian population. This is a secondary analysis of the Second Brazilian National Alcohol and Drugs Survey (II BNADS), which used a cross-cultural adaptation of the LTE-Q in a probabilistic sample of 4,607 participants aged 14 years and older. Latent class analysis was used to validate the latent trait adversity (which considered the number of events from the list of 12 item in the LTE experienced by the respondent in the previous year) and logistic regression was performed to find its association with binge drinking and cocaine use. The confirmatory factor analysis returned a chi-square of 108.341, weighted root mean square residual (WRMR) of 1.240, confirmatory fit indices (CFI) of 0.970, Tucker-Lewis index (TLI) of 0.962, and root mean square error approximation (RMSEA) score of 1.000. LTE-Q convergence validation showed that the adversity latent trait increased the chances of binge drinking by 1.31 time and doubled the chances of previous year cocaine use (adjusted by sociodemographic variables). The use of the LTE-Q in Brazil should be encouraged in different research fields, including large epidemiological surveys, as it is also appropriate when time and budget are limited. The LTE-Q can be a useful tool in the development of targeted and more efficient prevention strategies.

A non-LTE model for the Jovian methane infrared emissions at high spectral resolution

Science.gov (United States)

Halthore, Rangasayi N.; Allen, J. E., Jr.; Decola, Philip L.

1994-01-01

High resolution spectra of Jupiter in the 3.3 micrometer region have so far failed to reveal either the continuum or the line emissions that can be unambiguously attributed to the nu(sub 3) band of methane (Drossart et al. 1993; Kim et al. 1991). Nu(sub 3) line intensities predicted with the help of two simple non-Local Thermodynamic Equilibrium (LTE) models -- a two-level model and a three-level model, using experimentally determined relaxation coefficients, are shown to be one to three orders of magnitude respectively below the 3-sigma noise level of these observations. Predicted nu(sub 4) emission intensities are consistent with observed values. If the methane mixing ratio below the homopause is assumed as 2 x 10(exp -3), a value of about 300 K is derived as an upper limit to the temperature of the high stratosphere at microbar levels.

Voice over LTE via Generic access (Volga) as a possible solution of mobile networks transformation

OpenAIRE

Stepaniuk, Oleg

2010-01-01

This paper is focused on Voice over LTE via Generic Access Network, which concept is to connect the already existing Mobile Switching Centers to the LTE network via a gateway supporting 2G or 3G voice environment.

Non-LTE model atmospheres for supersoft X-ray sources

Science.gov (United States)

Rauch, T.; Werner, K.

2010-02-01

In the last decade, X-ray observations of hot stellar objects became available with unprecedented resolution and S/N ratio. For an adequate interpretation, fully metal-line blanketed Non-LTE model-atmospheres are necessary. The Tübingen Non-LTE Model Atmosphere Package (TMAP) can calculate such model atmospheres at a high level of sophistication. Although TMAP is not especially designed for the calculation of spectral energy distributions (SEDs) at extreme photospheric parameters, it can be employed for the spectral analysis of burst spectra of novae like V4743 Sgr or line identifications in observations of neutron stars with low magnetic fields in low-mass X-ray binaries (LMXBs) like EXO 0748-676.

Visualization of electromagnetic exposure near LTE antennae

Science.gov (United States)

Zvezdina, M. Yu; Shokova, Yu A.; Nazarova, O. Yu; Al-Ali, H. T. A.; Al-Farhan, G. H. A.

2018-01-01

Technical progress in wireless data transfer has given an opportunity to apply information and communication technologies in various areas of economics. Digital economy is linked to the 4th and 5th generation mobile network deployment. The peculiarities of the abovementioned standards decrease BTS antenna range three times in dense developed areas and worsen electromagnetic background in big cities. In the paper the comparative assessment results for rooftop electromagnetic exposure near BTS LTE and BTS GSM antennae are given. It is shown, that at the same level of transmitter power, energy flux density for LTE standard is three times less than the one for GSM. Moreover, the conclusion is made that the rooftop could be considered safe for people for indefinite time if antenna is placed more than 5 meters above the rooftop. The value of antenna height is taken to be on the safe side, as it is required by an application of “preventive principle”.

Wave propagation in a quasi-chemical equilibrium plasma

Science.gov (United States)

Fang, T.-M.; Baum, H. R.

1975-01-01

Wave propagation in a quasi-chemical equilibrium plasma is studied. The plasma is infinite and without external fields. The chemical reactions are assumed to result from the ionization and recombination processes. When the gas is near equilibrium, the dominant role describing the evolution of a reacting plasma is played by the global conservation equations. These equations are first derived and then used to study the small amplitude wave motion for a near-equilibrium situation. Nontrivial damping effects have been obtained by including the conduction current terms.

LTE Radiated Data Throughput Measurements, Adopting MIMO 2x2 Reference Antennas

DEFF Research Database (Denmark)

Szini, Istvan Janos; Pedersen, Gert Frølund; Barrio, Samantha Caporal Del

2012-01-01

Long Term Evolution (LTE) requires Multiple Input Multiple Output (MIMO) antenna systems. Consequently a new over-the-air (OTA) test methodology need to be created to make proper assessment of LTE devices radiated performance. The antenna specific parameters i.e. total antenna efficiency, gain...... imbalance and correlation coefficient, are essential for a proper MIMO antenna system design. However it can't be use directly to assess the LTE device system performance, since a multiplicity of other factors are involved, e.g. power amplifier load- pull, low noise amplifier source-pull, self interference...... noise, baseband algorithm and other factors. Several standard organizations are working towards a consensus over the proper OTA MIMO test method, however so far results of measurement campaigns have ambiguous results not allowing a desirable progress [1]. Initially presented at one of several MIMO OTA...

MIH based mobility for TETRA-LTE network

DEFF Research Database (Denmark)

Popovska Avramova, Andrijana

2013-01-01

TETRA is a digital trunked mobile radio standard, devel- oped to meet the needs of traditional Professional Mobile Radio user or-ganizations. As TETRA does not provide for broadband services, many companies are looking into integration of LTE and TETRA in order to provide support for real time mu...

Non-LTE model atmosphere analysis of Nova Cygni 1992

Science.gov (United States)

Hauschildt, P. H.; Starrfield, S.; Austin, S.; Wagner, R. M.; Shore, S. N.; Sonneborn, G.

1994-01-01

We use spherically symmetric non-local thermodynamic equilibrium (non-LTE), line-blanketed, expanding model atmospheres to analyze the International Ultraviolet Explorer (IUE) and optical spectra of Nova Cygni 1992 during the early phases of its outburst. We find that the first IUE spectrum obtained just after discovery on 1992 February 20, is best reproduced by a model atmosphere with a steep density gradient and homologous expansion, whereas the IUE and optical spectra obtained on February 24 show an extended, optically thick, wind structure. Therefore, we distinguish two phases of the early evolution of the nova photosphere: the initial, rapid, 'fireball' phase and the subsequent, much longer, optically thick 'wind' phase. The importance of line-blanketing in nova spectra is demonstrated. Our preliminary abundance analysis implies that hydrogen is depeleted in the ejecta, corresponding to abundance enhancements of Fe by a factor of approximately 2 and of CNO by more than a factor of 10 when compared to solar abundances. The synthetic spectra reproduce both the observed pseudo-continua as well as most of the observed features from the UV to the optical spectral range and demonstrate the importance of obtaining nearly simultaneous UV and optical spectra for performing accurate analyses of expanding stellar atmospheres (for both novae and supernovae).

Resilience of LTE networks against smart jamming attacks

KAUST Repository

Aziz, Farhan M.

2014-12-08

Commercial LTE networks are being studied for mission-critical applications, such as public safety and smart grid communications. In this paper, LTE networks are shown vulnerable to Denial-of-Service (DOS) and loss of service attacks from smart jammers, who may employ simple narrowband jamming techniques to attack without any need to hack the network or its users. We modeled the utilities of jamming and anti-jamming actions played by the jammer and the network under the framework of single-shot and repeated Bayesian games. In a single-shot game formulation the only Nash Equilibria (NE) are pure strategy equilibria at which network utility is severely compromised. We propose a repeated-game learning and strategy algorithm for the network that outperforms single-shot games by a significant margin. Furthermore, all of our proposed actions and algorithms can be implemented with current technology.

Ionization of anisothermal plasmas

International Nuclear Information System (INIS)

Dennery, F.M.

1994-01-01

During this last mid-century, only the temperature of electrons has been involved in the Saha's mass action law, whatever be the other ionic and neutral ones in any isothermal or anisothermal plasma. In order to set aside this underlying paradox in the case of argon ionization, it is necessary to improve this equation of partial equilibrium after having defined: - the basic Gibbs-Duhem's relations for such a polythermal mixture, - the inhomogeneous equilibrium issued from chemical reactions according to Le Chatelier's principle. (author). 3 refs

NonLTE ANALYSIS OF THE NaI LINES IN THE SOLAR SPECTRUM

OpenAIRE

Ivanova, D. V.; Shimansky, V. V.

2017-01-01

Solar spectrum of Nal lines by method of the nonLTE analysis is investigated. It shown, that in atmosphere of the Sun the Nal is in moderate ”overrecombination”. The analysis of influence of atomic data, models of atmospheres and damping constants for nonLTE deviation and sodium abundances is made. Observational solar spectrum of strong lines Nal has been synthesized in good approximation. On summary data of 15 lines the sodium abundance is determined:-5.78dex.

Novel Architecture for LTE World-Phones

DEFF Research Database (Denmark)

Barrio, Samantha Caporal Del; Tatomirescu, Alexandru; Pedersen, Gert Frølund

2013-01-01

The 4th Generation of mobile communications (4G) came with new challenges on the antenna bandwidth and on the front-end architecture of mobile phones. This letter proposes a novel architecture overcoming these challenges. It includes narrow-band tunable antennas, co-designed with a tunable Front-......- End (FE). Simulations and measurements demonstrate the concept for low and high bands of the LTE frequency spectrum....

The Influence of Non-Equilibrium Excitation on the Electron Density in One-Dimensional MFD Channel Flow

Energy Technology Data Exchange (ETDEWEB)

Eichert, K.; Kaeppeler, H. J. [Institut fuer Plasmaforschung der Technischen Hochschule Stuttgart, Federal Republic of Germany (Germany)

1966-10-15

In previous publications, a system of equations was derived from the gas-kinetic description of a multi-component reacting plasma and employed for the calculation of one-dimensional subsonic flows. This system is now extended to include non-equilibrium excitation. No thermal or chemical equilibrium between the various components of the plasma is assumed. The components of the plasma considered are a non-reacting working fluid, an alkali metal vapour as a seeding material, ions of this seeding substance, and electrons. Three levels for the excited states are introduced. The reactions considered are excitation and ionization by electron collisions, and photo-ionization, as well as the corresponding reverse processes. For the reaction velocities, analytical equations are introduced permitting insertion of any excitation or ionization cross-sections of either experimental or theoretical origin. The method employed had been previously suggested by one of the authors. As examples, the degrees of excitation and ionization in the flow of a helium working fluid with 1% caesium seeding through a channel against transverse magnetic fields of 15 and 40 kg at Mach numbers of 0.7 and 0.8, respectively, were calculated. The results of the calculations show that for relatively small magnetic fields there is no rapid rise of the ionization to Saha-equilibrium as a function of electron temperature. A comparison with the results of a calculation neglecting excitation shows that especially for relatively large magnetic fields non-equilibrium excitation has an essential influence on the electron density and its approach to equilibrium. Neglecting excitation, there results a nearly frozen behaviour of the degree of ionization within channel lengths of technical interest for small magnetic fields. (author)

Non-local thermodynamic equilibrium effects on isentropic coefficient in argon and helium thermal plasmas

International Nuclear Information System (INIS)

Sharma, Rohit; Singh, Kuldip

2014-01-01

In the present work, two cases of thermal plasma have been considered; the ground state plasma in which all the atoms and ions are assumed to be in the ground state and the excited state plasma in which atoms and ions are distributed over various possible excited states. The variation of Zγ, frozen isentropic coefficient and the isentropic coefficient with degree of ionization and non-equilibrium parameter θ(= T e /T h ) has been investigated for the ground and excited state helium and argon plasmas at pressures 1 atm, 10 atm, and 100 atm in the temperature range from 6000 K to 60 000 K. For a given value of non-equilibrium parameter, the relationship of Zγ with degree of ionization does not show any dependence on electronically excited states in helium plasma whereas in case of argon plasma this dependence is not appreciable till degree of ionization approaches 2. The minima of frozen isentropic coefficient shifts toward lower temperature with increase of non-equilibrium parameter for both the helium and argon plasmas. The lowering of non-equilibrium parameter decreases the frozen isentropic coefficient more emphatically in helium plasma at high pressures in comparison to argon plasma. The increase of pressure slightly reduces the ionization range over which isentropic coefficient almost remains constant and it does not affect appreciably the dependence of isentropic coefficient on non-equilibrium parameter

Scheduler-dependent inter-cell interference and its impact on LTE uplink performance at flow level

NARCIS (Netherlands)

Dimitrova, D.C.; Heijenk, G.; Berg, J.L. van den; Yankov, S.

2011-01-01

The Long Term Evolution (LTE) cellular technology is expected to extend the capacity and improve the performance of current 3G cellular networks. Among the key mechanisms in LTE responsible for traffic management is the packet scheduler, which handles the allocation of resources to active flows in

On local thermal equilibrium and potential gradient vs current characteristic in wall-stabilized argon plasma arc at 0.1 atm pressure

International Nuclear Information System (INIS)

Shindo, Haruo; Imazu, Shingo; Inaba, Tsuginori.

1979-01-01

In wall-stabilized arc which is a very useful means for determining the transport characteristics of high temperature gases, it is the premise that the inside of arc column is in complete local thermal equilibrium (LTE). In general, the higher the gas pressure, the easier the establishment of LTE, accordingly the experimental investigations on the characteristics of arc discharge as well as the transport characteristics so far were limited to the region of relatively high pressure. However, the authors have found that the theoretical potential vs. current characteristic obtained by the transport characteristic was greatly different from the actually measured one in low pressure region, as the fundamental characteristic of wall-stabilized argon plasma arc below atmospheric pressure. This time, they have clarified this discrepancy at 0.1 atm using the plasma parameters obtained through the spectroscopic measurements. The spectroscopic measurements have been performed through the side observation window at the position 5.5 cm away from the cathode, when arc was ignited vertically at the electrodes distant by 11 cm. Arc radius was 0.5 cm. Electron density and temperature, gas temperature and the excitation density of argon neutral atoms have been experimentally measured. The investigations showed that, in the region of low arc current, where the ratio of current to arc radius is less than 200 A/cm, the fall of gas temperature affected greatly on the decrease of axial electric field of arc column. The non-equilibrium between electron temperature and gas temperature decreased with the increase of arc current, and it was concluded that LTE has been formed at the center portion of arc column above I/R = 300 A/cm. (Wakatsuki, Y.)

Coverage and Capacity Analysis of LTE-M and NB-IoT in a Rural Area

DEFF Research Database (Denmark)

Lauridsen, Mads; Kovács, István; Mogensen, Preben Elgaard

2016-01-01

equipped with either of the newly standardized technologies. The study is made for a site specific network deployment of a Danish operator, and the simulation is calibrated using drive test measurements. The results show that LTE-M can provide coverage for 99.9% of outdoor and indoor devices, if the latter......The 3GPP has introduced the LTE-M and NB-IoT User Equipment categories and made amendments to LTE release 13 to support the cellular Internet of Things. The contribution of this paper is to analyze the coverage probability, the number of supported devices, and the device battery life in networks...... is experiencing 10 dB additional loss. However, for deep indoor users NB-IoT is required and provides coverage for about 95% of the users. The cost is support for more than 10 times fewer devices and a 2-6 times higher device power consumption. Thus both LTE-M and NB-IoT provide extended support for the cellular...

Analisis Performansi Algoritma Penjadwalan Log Rule dan Frame Level Schedule Skenario Multicell Pada Layer Mac LTE

Directory of Open Access Journals (Sweden)

Ridwan

2016-03-01

Full Text Available Mobile telecommunications technology gradually evolved to support better services such as voice, data, and video to users of telecommunications services. LTE (Long Term Evolution is a network based on Internet Protocol (IP standardized by 3rd Generation Partnership Project (3GPP. To support it, LTE requires a mechanism that can support. One of them by applying methods of scheduling packets in each service. Scheduling is a different treatment to packets that come in accordance with the priorities of the scheduling algorithm. In this research, to analyze the performance of LTE with paramater delay, packet loss ratio, throughput and fairness index uses a scheduling algorithms Frame Level Schedule (FLS and Log Rule on LTE-Simulator with scenarios using Voip traffic, Video and Best Effort (BE. The results is scheduling algorithms FLS is better than log rule in term of throughput values, while of scheduling algorithms log rule is better than FLS in terms of delay based on the number and speed of the users. This indicates that both scheduling algorithms suitable for use in LTE networks within conditions of traffic real time services, but not for non real time services such as BE.

Non-LTE line formation of Fe in late-type stars - III. 3D non-LTE analysis of metal-poor stars

DEFF Research Database (Denmark)

Amarsi, A. M.; Lind, K.; Asplund, M.

2016-01-01

As one of the most important elements in astronomy, iron abundance determinations need to be as accurate as possible. We investigate the accuracy of spectroscopic iron abundance analyses using archetypal metal-poor stars. We perform detailed 3D non-LTE radiative transfer calculations based on 3D...

Scheduler-dependent inter-cell interference and its impact on LTE uplink performance at flow level

NARCIS (Netherlands)

Dimitrova, D.C.; Heijenk, Geert; van den Berg, Hans Leo; Yankov, S.; Masip Bruin, Xavier; Verchere, Dominique; Tsaoussidis, Vassilis; Yannuzzi, Marcelo

The Long Term Evolution (LTE) cellular technology is ex- pected to extend the capacity and improve the performance of current 3G cellular networks. Among the key mechanisms in LTE responsible for traffic management is the packet scheduler, which handles the al- location of resources to active flows

In-Band Interference Effects on UTRA LTE Uplink Resource Block Allocation

DEFF Research Database (Denmark)

Priyanto, Basuki Endah; Sørensen, Troels Bundgaard; Jensen, Ole Kiel

2008-01-01

In this paper we investigate the impact of in-band interference on the uplink multiple access of UMTS Terrestrial Radio Access, long term evolution (UTRA LTE). In- band and out-of-band interference arise as a result of transmitter imperfections. Out-of- band, or adjacent channel, interference can......, and when the interfering signal is received at higher power spectral density (PSD). The effect of frequency offset and different PSD level from the UE interferers to a victim UE is studied. The impact on different UE resource block size allocation is also investigated. The results are obtained from an LTE...

Interference analysis for UAV connectivity over LTE using aerial radio measurements

DEFF Research Database (Denmark)

Kovacs, Istvan; Amorim, Rafhael Medeiros de; Nguyen, Huan Cong

2017-01-01

. In this paper, we use empirical measurements in live rural LTE networks to assess the impact of uplink and downlink radio interference on the UAV radio connectivity performance. Further, we provide a baseline analysis on the potential of interference mitigation schemes, needed to provide a reliable radio...... for these services is that the radio communication link must reliably cover a wide(er) area, when compared to the visual-line-of-sight range radio links currently used. Standardized cellular systems such as Long Term Evolution UMTS (LTE), are an obvious candidate to provide the radio communication link to UAVs...

Method for Detection of Airborne UEs based on LTE Radio Measurements

DEFF Research Database (Denmark)

Wigard, Jeroen; Amorim, Rafhael Medeiros de; Nguyen, Huan Cong

2017-01-01

management can be optimized for UAVs separately from terrestrial UEs. In this paper, we present a classification algorithm using existing LTE UE radio measurements to identify whether a UE is airborne or terrestrial. The method is verified with LTE measurements made in a rural area at different heights......, including terrestrial measurements and it is shown that the method in 3 out of the 4 different measurement cases can detect a UE to be airborne with 99% likelihood, while the fourth case still can classify a UE correctly in 95% of the cases. The right classification can further be improved by taking...

RRM Strategies in LTE&WiMAX Interworking System

DEFF Research Database (Denmark)

Zakrzewska, Anna; Ruepp, Sarah Renée; Berger, Michael Stübert

, that could be applied in 4G systems (LTE interworking with WiMAX is considered). Furthermore, it will also discuss the Radio Resource Management (RRM) problem addressing the challenges of designing a RRM system for such a multi-RAT wireless environment. Different functionalities and possibilities...

TD-LTE Wireless Private Network QoS Transmission Protection

Science.gov (United States)

Zhang, Jianming; Cheng, Chao; Wu, Zanhong

With the commencement of construction of the smart grid, the demand power business for reliability and security continues to improve, the reliability transmission of power TD-LTE Wireless Private Network are more and more attention. For TD-LTE power private network, it can provide different QoS services according to the user's business type, to protect the reliable transmission of business. This article describes in detail the AF module of PCC in the EPC network, specifically introduces set up AF module station and QoS mechanisms in the EPS load, fully considers the business characteristics of the special power network, establishing a suitable architecture for mapping QoS parameters, ensuring the implementation of each QoS business. Through using radio bearer management, we can achieve the reliable transmission of each business on physical channel.

Non-equilbrium behavior of low-pressure plasma jets

International Nuclear Information System (INIS)

Chang, C.H.; Pfender, E.

1989-01-01

After establishing the basic equations, some sample calculations are presented to examine the thermodynamic state of the plasma from atmospheric to low pressures (80 mbar). These results indicate the validity of local thermodynamic equilibrium (LTE) at atmospheric pressure as well as strong deviations from LTE at lower pressures especially in terms of chemical equilibrium. Departures from kinetic equilibrium are not as severe as those from chemical equilibrium along the centerline of the jet. However, there are some departures from transitional equilibrium in the fringes of the jet. It is demonstrated that conventional methods based on the LTE assumption are not appropriate for describing low-pressure plasma jets

An arc facility for investigating non-LTE thermodynamic and transport phenomena in low and high pressure plasmas

International Nuclear Information System (INIS)

Sedghinisab, A.; Eddy, T.L.; Murray, R.T.

1986-01-01

This paper discusses a high pressure arc facility modified for computerized control and data acquisition to simplify measurements of non-LTE plasmas. The non-LTE methods have shown that numerous spectral lines and continuum must be accurately, precisely and quickly measured.The instrumentation uses a 1-m monochrometer with programmed wavelength slews and scans; oplasma scans; and monitoring of chamber pressure, current, voltages, and location. Multiple flows of various gases can be provided simultaneously. Plasma self absorption is determined via a concave back mirror and shutter with final alignment via computer plots. The raw data is corrected for absorption, zeroed, centered and smoothed. The net line intensity is then determined and Abeled prior to feeding into LTE or non-LTE analysis methods. Sample results are presented at 0.1,1 and 10 atm

Exploring the physical layer frontiers of cellular uplink: The Vienna LTE-A Uplink Simulator.

Science.gov (United States)

Zöchmann, Erich; Schwarz, Stefan; Pratschner, Stefan; Nagel, Lukas; Lerch, Martin; Rupp, Markus

Communication systems in practice are subject to many technical/technological constraints and restrictions. Multiple input, multiple output (MIMO) processing in current wireless communications, as an example, mostly employs codebook-based pre-coding to save computational complexity at the transmitters and receivers. In such cases, closed form expressions for capacity or bit-error probability are often unattainable; effects of realistic signal processing algorithms on the performance of practical communication systems rather have to be studied in simulation environments. The Vienna LTE-A Uplink Simulator is a 3GPP LTE-A standard compliant MATLAB-based link level simulator that is publicly available under an academic use license, facilitating reproducible evaluations of signal processing algorithms and transceiver designs in wireless communications. This paper reviews research results that have been obtained by means of the Vienna LTE-A Uplink Simulator, highlights the effects of single-carrier frequency-division multiplexing (as the distinguishing feature to LTE-A downlink), extends known link adaptation concepts to uplink transmission, shows the implications of the uplink pilot pattern for gathering channel state information at the receiver and completes with possible future research directions.

Self-Optimization of LTE Networks Utilizing Celnet Xplorer

CERN Document Server

Buvaneswari, A; Polakos, Paul; Buvaneswari, Arumugam

2010-01-01

In order to meet demanding performance objectives in Long Term Evolution (LTE) networks, it is mandatory to implement highly efficient, autonomic self-optimization and configuration processes. Self-optimization processes have already been studied in second generation (2G) and third generation (3G) networks, typically with the objective of improving radio coverage and channel capacity. The 3rd Generation Partnership Project (3GPP) standard for LTE self-organization of networks (SON) provides guidelines on self-configuration of physical cell ID and neighbor relation function and self-optimization for mobility robustness, load balancing, and inter-cell interference reduction. While these are very important from an optimization perspective of local phenomenon (i.e., the eNodeB's interaction with its neighbors), it is also essential to architect control algorithms to optimize the network as a whole. In this paper, we propose a Celnet Xplorer-based SON architecture that allows detailed analysis of network performan...

Dual Connectivity in LTE HetNets with Split Control- and User-Plane

DEFF Research Database (Denmark)

Zakrzewska, Anna; López-Pérez, David; Kucera, Stepan

2013-01-01

a detailed description of our dual connectivity framework based on the latest LTE-Advanced enhancements, in which macrocellassisted (MA) small cells use different channel state informationreference signals (CSI-RS) to differentiate among each other and allow User Equipment (UE) to take adequate measurements......Recently, a new network architecture with split control-plane and user-plane has been proposed and gained a lot of momentum in the standardisation of Long Term Evolution (LTE) Release 12. In this new network architecture, the controlplane, which transmits system information and handles user...

Empirical LTE Smartphone Power Model with DRX Operation for System Level Simulations

DEFF Research Database (Denmark)

Lauridsen, Mads; Noël, Laurent; Mogensen, Preben

2013-01-01

An LTE smartphone power model is presented to enable academia and industry to evaluate users’ battery life on system level. The model is based on empirical measurements on a smartphone using a second generation LTE chipset, and the model includes functions of receive and transmit data rates...... and power levels. The first comprehensive Discontinuous Reception (DRX) power consumption measurements are reported together with cell bandwidth, screen and CPU power consumption. The transmit power level and to some extent the receive data rate constitute the overall power consumption, while DRX proves...

Why is observable radio recombination line emission from galactic HII regions always close to LTE

International Nuclear Information System (INIS)

Shaver, P.A.

1980-01-01

There is no evidence for significant deviations from LTE in single-dish observations of radio recombination line emission from galactic HII regions. This is in agreement with the known properties of HII regions, particularly their density variations and limited range of excitation parameters; the optimum configuration for strong observable non-LTE effects, low electron density and high emission measure, simply does not exist in galactic HII regions, and the observed lines are emitted under near-LTE conditions. Models of the Orion Nebulae and NGC 6604 are presented which fit all available data and show only weak stimulated emission. It is concluded that reliable electron temperatures can indeed be obtained from straightforward analysis of appropriate radio recombination lines. (orig.)

Evidence of non-LTE Effects in Mesospheric Water Vapor from Spectrally-Resolved Emissions Observed by CIRRIS-1A

Science.gov (United States)

Zhou, D. K.; Mlynczak, M. G.; Lopez-Puertas, M.; Zaragoza, G.

1999-01-01

Evidence of non-LTE effects in mesospheric water vapor as determined by infrared spectral emission measurements taken from the space shuttle is reported. A cryogenic Michelson interferometer in the CIRRIS-1A shuttle payload yielded high quality, atmospheric infrared spectra. These measurements demonstrate the enhanced daytime emissions of H2O (020-010) which are the result of non-LTE processes and in agreement with non-LTE models. The radiance ratios of H2O (010 to 000) and (020 to 010) Q(1) transitions during daytime are compared with non-LTE model calculations to assess the vibration-to-vibration exchange rate between H2O and O2 in the mesosphere. An exchange rate of 1.2 x 10(exp -12)cc/s is derived.

On the impact of D2D traffic offloading on energy efficiency in green LTE-A HetNets

KAUST Repository

Yaacoub, Elias E.

2014-08-11

In this paper, the interplay between cooperative device-to-device (D2D) communications and green cellular communications in the long term evolution (LTE) and LTE-advanced (LTE-A) cellular systems is investigated. An efficient approach for grouping mobile terminals (MTs) into cooperative clusters is described. In each cluster, MTs cooperate via D2D communications to share content of common interest. In addition, an energy-efficient approach for putting base stations in sleep mode in an LTE-A heterogeneous network is presented. Finally, both methods are combined in order to ensure green communications for both the users\\' MTs and the operator\\'s base stations. The presented techniques are investigated in the framework of orthogonal frequency division multiple access-based state-of-the-art LTE cellular networks, while taking resource allocation and intercell interference into account. Results show that the proposed approach leads to energy savings for both the operator and the MTs, while leading to enhanced quality of service for mobile users. Copyright © 2014 John Wiley & Sons, Ltd.

Role of recombination, ionization, diffusion and convection in a decaying argon plasma

International Nuclear Information System (INIS)

Gleizes, A.

1981-01-01

A theoretical study of a decaying argon arc plasma, at atmospheric pressure, has been performed to determine the plasma state during the decay. The method is based on the transport equations combined with the knowledge of the electron density previously measured. The comparison between calculated and experimental results allows the analysis of the main processes responsible for the particle density evolutions. It is shown that departures from LTE are important and that thermal equilibrium is not even achieved in the plasma. This result is due to the role of elastic collisions between electrons and heavy particles in the electron energy balance. (orig.)

LTE-A cellular networks multi-hop relay for coverage, capacity and performance enhancement

CERN Document Server

Yahya, Abid

2017-01-01

In this book, three different methods are presented to enhance the capacity and coverage area in LTE-A cellular networks. The scope involves the evaluation of the effect of the RN location in terms of capacity and the determination of the optimum location of the relay that provides maximum achievable data rate for users with limited interference at the cell boundaries. This book presents a new model to enhance both capacity and coverage area in LTE-A cellular network by determining the optimum location for the RN with limited interference. The new model is designed to enhance the capacity of the relay link by employing two antennas in RN. This design enables the relay link to absorb more users at cell edge regions. An algorithm called the Balance Power Algorithm (BPA) is developed to reduce MR power consumption. The book pertains to postgraduate students and researchers in wireless & mobile communications. Provides a variety of methods for enhancing capacity and coverage in LTE-A cellular networks Develop...

TD-LTE产业发展策略之我见%Analysis of TD-LTE Industry Development Strategy

Institute of Scientific and Technical Information of China (English)

杨骅; 吴慧敏

2013-01-01

In view of the TD-LTE industry development status, the leading role of market demand for TD-LTE industry is analyzed. Based on the development experiences of mobile communication industry over the world, the development strategy of TD-LTE single market in the early stage is expounded, in the meantime, the TD-LTE spectrum planning is analyzed.%　　结合TD-LTE产业发展现状，分析了市场需求对TD-LTE产业规模发展的拉动作用，基于国际国内移动通信产业的发展经验，阐述了产业发展初期采用单一TD-LTE市场模式的发展策略，并对TD-LTE频段规划使用进行分析。

Impact of the traffic load on performance of an alternative LTE railway communication network

DEFF Research Database (Denmark)

Sniady, Aleksander; Soler, José

2013-01-01

communication infrastructure supporting railway signaling. This work is based on OPNET realistic network simulations, which show the relation between the traffic load (the number of trains transmitting and receiving data in an LTE cell) and the delay performance of the European Train Control System (ETCS......Although many countries only now begin to invest in deployment of GSM-Railways (GSM-R) networks, this technology is already obsolete and reveals its significant shortcomings. The most troublesome one is the insufficient number of communication channels offered by GSM-R. This is a major problem...... obstructing railway operations at big train stations and junctions. Hence, other technologies, such as Long Term Evolution (LTE), need to be considered as an alternative to GSM-R. The goal of this paper is to demonstrate the capacity increase that railways can expect, from the introduction of LTE as internal...

Cloudified Mobility and Bandwidth Prediction in Virtualized LTE Networks

NARCIS (Netherlands)

Zhao, Zongliang; Karimzadeh Motallebi Azar, Morteza; Braun, Torsten; Pras, Aiko; van den Berg, Hans Leo

Network Function Virtualization involves implementing network functions (e.g., virtualized LTE component) in software that can run on a range of industry standard server hardware, and can be migrated or instantiated on demand. A prediction service hosted on cloud infrastructures enables consumers to

A Wireless Location System in LTE Networks

OpenAIRE

Liu, Qi; Hu, Rongyi; Liu, Shan

2017-01-01

Personal location technologies are becoming important with the rapid development of Mobile Internet services. In traditional cellular networks, the key problems of user location technologies are high-precision synchronization among different base stations, inflexible processing resources, and low accuracy positioning, especially for indoor environment. In this paper, a new LTE location system in Centralized Radio Access Network (C-RAN) is proposed, which makes channel and location measurement...

3D Multi-Level Non-LTE Radiative Transfer for the CO Molecule

Science.gov (United States)

Berkner, A.; Schweitzer, A.; Hauschildt, P. H.

2015-01-01

The photospheres of cool stars are both rich in molecules and an environment where the assumption of LTE can not be upheld under all circumstances. Unfortunately, detailed 3D non-LTE calculations involving molecules are hardly feasible with current computers. For this reason, we present our implementation of the super level technique, in which molecular levels are combined into super levels, to reduce the number of unknowns in the rate equations and, thus, the computational effort and memory requirements involved, and show the results of our first tests against the 1D implementation of the same method.

Interference Coordination for E-MBMS Transmissions in LTE-Advanced

Directory of Open Access Journals (Sweden)

Alberto A. Lopes

2010-01-01

Full Text Available Interference coordination methods for Evolved-Multimedia Broadcast/Multicast Service (E-MBMS in Long-Term Evolution Advanced (LTE-A are presented. In addition, we consider signal space diversity based on Rotation Matrices (RM known to provide good performance gains over uncorrelated Rayleigh fading channels. OFDM/OFDMA systems can make the use of RM very attractive both for single and multiple antenna transmissions. In this paper, OFDM/OFDMA signals based on LTE parameters are combined with RM, MIMO, Turbo, or LDPC codes. We have considered different types of receivers, namely, we used an MMSE (Minimum Mean Squared Error equalizer and a Maximum Likelihood Soft Output criterion (MLSO. Frequency, signal, and space diversity gains are evaluated for different spatial channel models (SCM based on ITU multipath propagation channels. Different adaptive frequency reuse and schedulers are considered to evaluate the E-MBMS spectral efficiency at the cell borders.

Physics of partially ionized plasmas

CERN Document Server

Krishan, Vinod

2016-01-01

Plasma is one of the four fundamental states of matter; the other three being solid, liquid and gas. Several components, such as molecular clouds, diffuse interstellar gas, the solar atmosphere, the Earth's ionosphere and laboratory plasmas, including fusion plasmas, constitute the partially ionized plasmas. This book discusses different aspects of partially ionized plasmas including multi-fluid description, equilibrium and types of waves. The discussion goes on to cover the reionization phase of the universe, along with a brief description of high discharge plasmas, tokomak plasmas and laser plasmas. Various elastic and inelastic collisions amongst the three particle species are also presented. In addition, the author demonstrates the novelty of partially ionized plasmas using many examples; for instance, in partially ionized plasma the magnetic induction is subjected to the ambipolar diffusion and the Hall effect, as well as the usual resistive dissipation. Also included is an observation of kinematic dynam...

Heterogeneous LTE-Advanced Network Expansion for 1000x Capacity

DEFF Research Database (Denmark)

Hu, Liang; Sanchez, Maria Laura Luque; Maternia, Michal

2013-01-01

this paper studies LTE (Long-Term Evolution)-Advanced heterogeneous network expansion in a dense urban environment for a 1000 times capacity increase and a 10 times increase in minimum user data rate requirements. The radio network capacity enhancement via outdoor and indoor small cell densificat...

Performance of Uplink Carrier Aggregation in LTE-Advanced Systems

DEFF Research Database (Denmark)

Wang, Hua; Rosa, Claudio; Pedersen, Klaus

2010-01-01

Carrier aggregation (CA) has been proposed to aggregate two or more component carriers (CCs) to support a much wider transmission bandwidth for LTE-Advanced systems. With carrier aggregation, it is possible to schedule a user equipment (UE) on multiple component carriers simultaneously. In this p...

Retrieval of Kinetic Temperature and Carbon Dioxide Abundance from Non-Local Thermodynamic Equilibrium Limb Emission Measurements made by the SABER Experiment on the TIMED Satellite

Science.gov (United States)

Mertens, Christopher J.; Mlynczak, Martin G.; Lopez-Puertas, Manuel; Wintersteiner, Peter P.; Picard, Richard H.; Winick, Jeremy R.; Gordley, Larry L.; Russell, James M., III

2002-01-01

The Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) experiment was launched onboard the TIMED satellite in December, 2001. SABER is designed to provide measurements of the key radiative and chemical sources and sinks of energy in the mesosphere and lower thermosphere (MLT). SABER measures Earth limb emission in 10 broadband radiometer channels ranging from 1.27 micrometers to 17 micrometers. Measurements are made both day and night over the latitude range from 54 deg. S to 87 deg. N with alternating hemisphere coverage every 60 days. In this paper we concentrate on retrieved profiles of kinetic temperature (T(sub k)) and CO2 volume mixing ratio (vmr), inferred from SABER-observed 15 micrometer and 4.3 micrometer limb emissions, respectively. SABER-measured limb radiances are in non-local thermodynamic equilibrium (non-LTE) in the MLT region. The complexity of non-LTE radiation transfer combined with the large volume of data measured by SABER requires new retrieval approaches and radiative transfer techniques to accurately and efficiently retrieve the data products. In this paper we present the salient features of the coupled non-LTE T(sub k)/CO2 retrieval algorithm, along with preliminary results.

Non-LTE spectral analysis and model constraints on SN 1993J

Science.gov (United States)

Baron, E.; Hauschildt, P. H.; Branch, D.; Austin, S.; Garnavich, P.; Ann, Hong Bae; Wagner, R. M.; Filippenko, A. V.; Matheson, T.; Liebert, James

1995-01-01

We present non-Local Thermodynamic Equilibrium (LTE) synthetic spectra for a time series of observations of SN 1993J obtained on 1993 March 30-31, April 7, April 13-15, and June 13 UT. The spectra are dominated by hydrogen Balmer lines; neutral helium lines, which have been nonthermally excited; and Fe II features. The density profile evolves from an extremely steep 'brick wall' structure with an equivalent power-law index of about 50 on March 30 to a more typical SN II profile with a power law index of about 10. The early spectra are well fitted by a solar composition of metals, although an enhanced abundance of helium is required in order to fit the neutral helium lines. By June 13, the photosphere has receded deep into the helium layer, although there appears to be a layer of hydrogen at higher velocity. The distance is estimated for each epoch. While consistent results are found for spectra obtained in the month of April, the spread in distances from March to June is quite large. Our value for April is mu = 28.0 +/- 0.3 mag, consistent with the recent Cepheid distance to the host galaxy M81. We also compare our results to other implementations of the expanding photosphere method.

Using LTE Networks for UAV Command and Control Link

DEFF Research Database (Denmark)

Nguyen, Huan Cong; Amorim, Rafhael Medeiros de; Wigard, Jeroen

2017-01-01

In this paper we investigate the ability of Long-Term Evolution (LTE) network to provide coverage for Unmanned Aerial Vehicles (UAVs) in a rural area, in particular for the Command and Control (C2) downlink. The study takes into consideration the dependency of the large-scale path loss on the hei......In this paper we investigate the ability of Long-Term Evolution (LTE) network to provide coverage for Unmanned Aerial Vehicles (UAVs) in a rural area, in particular for the Command and Control (C2) downlink. The study takes into consideration the dependency of the large-scale path loss...... on the height of the UAV, which is derived from actual measurements, and a real-world cellular network layout and configuration. The results indicate that interference is the dominant factor limiting the cellular coverage for UAVs in the downlink: outage level increases from 4.2% at 1.5 m height to 51.7% at 120...

LTE-Advanced/WLAN testbed

OpenAIRE

Plaisner, Denis

2017-01-01

Táto práca sa zaoberá skúmaním a vyhodnocovaním komunikácie štandardov LTE-Advance a WiFi (IEEE 802.11n/ac). Pri jednotlivých štandardoch je preskúmaný chybový parameter EVM. Pre prácu s jednotlivými štandardmi je navrhnuté univerzálne pracovisko (testbed). Toto univerzálne pracovisko slúži na nastavovanie vysielacieho a prijímacieho zariadenia a na spracovávanie prenášaných signálov a ich vyhodnocovanie. Pre túto prácu je vybrané prostredie Matlab, cez ktoré sa ovládajú použité prístroje ako...

Mobility Performance in Slow- and High-Speed LTE Real Scenarios

DEFF Research Database (Denmark)

Gimenez, Lucas Chavarria; Cascino, Maria Carmela; Stefan, Maria

2016-01-01

Mobility performance and handover data interruption times in real scenarios are studied by means of field measurements in an operational LTE network. Both slow- and high-speed scenarios are analyzed by collecting results from two different areas: Aalborg downtown and the highway which encircles...... in the city center as cells on the same site often cover different non-crossing street canyons. Moreover, no handover failures are experienced in the measurements which confirms robust LTE mobility performance. The average interruption time, which is at least equal to the handover execution time, lays within...... the same city. Measurements reveal that the terminal is configured by the network with different handover parametrization depending on the serving cell, which indicates the use of mobility robustness optimization. Although the network is dominated by three sector sites, no intra-site handovers are observed...

Feedback Compression Schemes for Downlink Carrier Aggregation in LTE-Advanced

DEFF Research Database (Denmark)

Nguyen, Hung Tuan; Kovac, Istvan; Wang, Yuanye

2011-01-01

With full channel state information (CSI) available, it has been shown that carrier aggregation (CA) in the downlink can significantly improve the data rate experienced at the user equipments (UE) [1], [2], [3], [4]. However, full CSI feedback in all component carriers (CCs) requires a large...... portion of the uplink bandwidth and the feedback information increases linearly with the number of CCs. Therefore, the performance gain brought by deploying CA could be easily hindered if the amount of CSI feedback is not thoroughly controlled. In this paper we analyze several feedback overhead...... compression schemes in CA systems. To avoid a major re-design of the feedback schemes, only CSI compression schemes closely related to the ones specified in LTE-Release 8 and LTE-Release 9 are considered. Extensive simulations at system level were carried out to evaluate the performance of these feedback...

Heterogeneous LTE/802.11a mobile relays for data rate enhancement and energy-efficiency in high speed trains

KAUST Repository

Atat, Rachad; Yaacoub, Elias E.; Alouini, Mohamed-Slim; Abu-Dayya, Adnan A.

2012-01-01

(LTE) long range links and with the mobile terminals (MTs) inside the train cars using IEEE 802.11a short range links. Scenarios with unicasting and multicasting from the BS are studied, both in the presence and absence of the relays. In addition, LTE

Absolute, time-resolved emission of non-LTE L-shell spectra from Ti-doped aerogels

International Nuclear Information System (INIS)

Back, C.A.; Feldman, U.; Weaver, J.L.; Seely, J.F.; Constantin, C.; Holland, G.; Lee, R.W.; Chung, H.-K.; Scott, H.A.

2006-01-01

Outstanding discrepancies between data and calculations of laser-produced plasmas in recombination have been observed since the 1980s. Although improvements in hydrodynamic modeling may reduce the discrepancies, there are indications that non-LTE atomic kinetics may be the dominant cause. Experiments to investigate non-LTE effects were recently performed at the NIKE KrF laser on low-density Ti-doped aerogels. The laser irradiated a 2mm diameter, cylindrical sample of various lengths with a 4-ns square pulse to create a volumetrically heated plasma. Ti L-shell spectra spanning a range of 0.47-3keV were obtained with a transmission grating coupled to Si photodiodes. The diagnostic can be configured to provide 1-dimensional spatial resolution at a single photon energy, or 18 discrete energies with a resolving power, λ/δλ of 3-20. The data are examined and compared to calculations to develop absolute emission measurements that can provide new tests of the non-LTE physics

Absolute, time-resolved emission of non-LTE L-shell spectra from Ti-doped aerogels

Energy Technology Data Exchange (ETDEWEB)

Back, C.A. [Lawrence Livermore National Laboratory, P.O. Box 808, L-21, Livermore, CA 94551 (United States)]. E-mail: tinaback@llnl.gov; Feldman, U. [Artep Inc. 2922 Excelsior Ct., Ellicott City, MD 21042 (United States); Weaver, J.L. [Naval Research Laboratory, 4555 Overlook Drive, SW, Washington DC 20375 (United States); Seely, J.F. [Naval Research Laboratory, 4555 Overlook Drive, SW, Washington DC 20375 (United States); Constantin, C. [Lawrence Livermore National Laboratory, P.O. Box 808, L-21, Livermore, CA 94551 (United States); Holland, G. [Naval Research Laboratory, 4555 Overlook Drive, SW, Washington DC 20375 (United States); Lee, R.W. [Lawrence Livermore National Laboratory, P.O. Box 808, L-21, Livermore, CA 94551 (United States); Chung, H.-K. [Lawrence Livermore National Laboratory, P.O. Box 808, L-21, Livermore, CA 94551 (United States); Scott, H.A. [Lawrence Livermore National Laboratory, P.O. Box 808, L-21, Livermore, CA 94551 (United States)

2006-05-15

Outstanding discrepancies between data and calculations of laser-produced plasmas in recombination have been observed since the 1980s. Although improvements in hydrodynamic modeling may reduce the discrepancies, there are indications that non-LTE atomic kinetics may be the dominant cause. Experiments to investigate non-LTE effects were recently performed at the NIKE KrF laser on low-density Ti-doped aerogels. The laser irradiated a 2mm diameter, cylindrical sample of various lengths with a 4-ns square pulse to create a volumetrically heated plasma. Ti L-shell spectra spanning a range of 0.47-3keV were obtained with a transmission grating coupled to Si photodiodes. The diagnostic can be configured to provide 1-dimensional spatial resolution at a single photon energy, or 18 discrete energies with a resolving power, {lambda}/{delta}{lambda} of 3-20. The data are examined and compared to calculations to develop absolute emission measurements that can provide new tests of the non-LTE physics.

Variability of OH rotational temperatures on time scales from hours to 15 years by kinetic temperature variations, emission layer changes, and non-LTE effects

Science.gov (United States)

Noll, Stefan

2016-07-01

Rotational temperatures derived from hydroxyl (OH) line emission are frequently used to study atmospheric temperatures at altitudes of about 87 km. While the measurement only requires intensities of a few bright lines of an OH band, the interpretation can be complicated. Ground-based temperatures are averages for the entire, typically 8 km wide emission layer. Variations in the rotational temperature are then caused by changes of the kinetic temperature and the OH emission profile. The latter can also be accompanied by differences in the layer-averaged efficiency of the thermalisation of the OH rotational level populations. Since this especially depends on the frequency of collisions with O_2, which is low at high altitudes, the non-local thermodynamic equilibrium (non-LTE) contribution to the measured temperatures can be significant and variable. In order to understand the impact of the different sources of OH rotational temperature variations from time scales of hours to a solar cycle, we have studied spectra from the astronomical echelle spectrographs X-shooter and UVES located at Cerro Paranal in Chile. While the X-shooter data spanning 3.5 years allowed us to measure temperatures for 25 OH and two O_2 bands, the UVES spectra cover no more than 10 OH bands simultaneously but a period of about 15 years. These data have been complemented by kinetic temperature and OH and O_2 emission profiles from the multi-channel radiometer SABER on the TIMED satellite. Taking the O_2 and SABER kinetic temperatures as reference and considering the different band-dependent emission profiles, we could evaluate the contribution of non-LTE effects to the measured OH rotational temperatures depending on line set, band, and time. Non-LTE contributions are significant for most bands and can exceed 10 K. The amplitudes of their average nocturnal and seasonal variation are of the order of 1 to 2 K.

Psychometric properties of the List of Threatening Experiences--LTE and its association with psychosocial factors and mental disorders according to different scoring methods.

Science.gov (United States)

Motrico, Emma; Moreno-Küstner, Berta; de Dios Luna, Juan; Torres-González, Francisco; King, Michael; Nazareth, Irwin; Montón-Franco, Carmen; Gilde Gómez-Barragán, María Josefa; Sánchez-Celaya, Marta; Díaz-Barreiros, Miguel Ángel; Vicens, Catalina; Moreno-Peral, Patricia; Bellón, Juan Ángel

2013-09-25

The List of Threatening Experiences (LTE) questionnaire is frequently used to assess stressful events; however, studies of its psychometric properties are scarce. We examined the LTE's reliability, factorial structure, construct validity and explored the association between LTE scores and psychosocial variables and mental disorders. This study involved interviewing 5442 primary care attendees from Spain. Associations between four different methods of quantifying LTE scores, psychosocial factors, major depression (CIDI), anxiety disorders (PRIME-MD), alcohol misuse and dependence (AUDIT) were measured. The LTE showed high test-retest reliability (Kappa range=0.61-0.87) and low internal consistency (α=0.44). Tetrachoric factorial analysis yielded four factors (spousal and relational problems; employment and financial problems; personal problems; illness and bereavement in close persons). Logistic multilevel regression found a strong association between greater social support and a lower occurrence of stressful events (OR range=0.36-0.79). The association between religious-spiritual beliefs and the LTE, was weaker. The association between mental disorders and LTE scores was greater for depression (OR range=1.64-2.57) than anxiety (OR range=1.35-1.97), though the highest ORs were obtained with alcohol dependence (OR range=2.86-4.80). The ordinal score (ordinal regression) was more sensitive to detect the strength of association with mental disorders. We are unable to distinguish the direction of the association between stressful events, psychosocial factors and mental disorders, due to our cross-sectional design of the study. The LTE is a valid and reliable measure of stress in mental health, and the strength of association with mental disorders depends on the method of quantifying LTE scores. © 2013 Elsevier B.V. All rights reserved.

Quantum statistical mechanics of dense partially ionized hydrogen.

Science.gov (United States)

Dewitt, H. E.; Rogers, F. J.

1972-01-01

The theory of dense hydrogenic plasmas beginning with the two component quantum grand partition function is reviewed. It is shown that ionization equilibrium and molecular dissociation equilibrium can be treated in the same manner with proper consideration of all two-body states. A quantum perturbation expansion is used to give an accurate calculation of the equation of state of the gas for any degree of dissociation and ionization. In this theory, the effective interaction between any two charges is the dynamic screened potential obtained from the plasma dielectric function. We make the static approximation; and we carry out detailed numerical calculations with the bound and scattering states of the Debye potential, using the Beth-Uhlenbeck form of the quantum second virial coefficient. We compare our results with calculations from the Saha equation.

Characterization of dual-polarization LTE radio over a free-space optical turbulence channel.

Science.gov (United States)

Bohata, J; Zvanovec, S; Korinek, T; Mansour Abadi, M; Ghassemlooy, Z

2015-08-10

A dual polarization (DP) radio over a free-space optical (FSO) communication link using a long-term evolution (LTE) radio signal is proposed and analyzed under different turbulence channel conditions. Radio signal transmission over the DP FSO channel is experimentally verified by means of error vector magnitude (EVM) statistics. We demonstrate that such a system, employing a 64 quadrature amplitude modulation at the frequency bands of 800 MHz and 2.6 GHz, evinces reliability with LTE signal over the FSO channel is a potential solution for last-mile access or backbone networks, when using multiple-input multiple-output based DP signals.

Transport coefficients in high-temperature ionized air flows with electronic excitation

Science.gov (United States)

Istomin, V. A.; Oblapenko, G. P.

2018-01-01

Transport coefficients are studied in high-temperature ionized air mixtures using the modified Chapman-Enskog method. The 11-component mixture N2/N2+/N /N+/O2/O2+/O /O+/N O /N O+/e- , taking into account the rotational and vibrational degrees of freedom of molecules and electronic degrees of freedom of both atomic and molecular species, is considered. Using the PAINeT software package, developed by the authors of the paper, in wide temperature range calculations of the thermal conductivity, thermal diffusion, diffusion, and shear viscosity coefficients for an equilibrium ionized air mixture and non-equilibrium flow conditions for mixture compositions, characteristic of those in shock tube experiments and re-entry conditions, are performed. For the equilibrium air case, the computed transport coefficients are compared to those obtained using simplified kinetic theory algorithms. It is shown that neglecting electronic excitation leads to a significant underestimation of the thermal conductivity coefficient at temperatures higher than 25 000 K. For non-equilibrium test cases, it is shown that the thermal diffusion coefficients of neutral species and the self-diffusion coefficients of all species are strongly affected by the mixture composition, while the thermal conductivity coefficient is most strongly influenced by the degree of ionization of the flow. Neglecting electronic excitation causes noticeable underestimation of the thermal conductivity coefficient at temperatures higher than 20 000 K.

Cooperation Techniques between LTE in Unlicensed Spectrum and Wi-Fi towards Fair Spectral Efficiency.

Science.gov (United States)

Maglogiannis, Vasilis; Naudts, Dries; Shahid, Adnan; Giannoulis, Spilios; Laermans, Eric; Moerman, Ingrid

2017-08-31

On the road towards 5G, a proliferation of Heterogeneous Networks (HetNets) is expected. Sensor networks are of great importance in this new wireless era, as they allow interaction with the environment. Additionally, the establishment of the Internet of Things (IoT) has incredibly increased the number of interconnected devices and consequently the already massive wirelessly transmitted traffic. The exponential growth of wireless traffic is pushing the wireless community to investigate solutions that maximally exploit the available spectrum. Recently, 3rd Generation Partnership Project (3GPP) announced standards that permit the operation of Long Term Evolution (LTE) in the unlicensed spectrum in addition to the exclusive use of the licensed spectrum owned by a mobile operator. Alternatively, leading wireless technology developers examine standalone LTE operation in the unlicensed spectrum without any involvement of a mobile operator. In this article, we present a classification of different techniques that can be applied on co-located LTE and Wi-Fi networks. Up to today, Wi-Fi is the most widely-used wireless technology in the unlicensed spectrum. A review of the current state of the art further reveals the lack of cooperation schemes among co-located networks that can lead to more optimal usage of the available spectrum. This article fills this gap in the literature by conceptually describing different classes of cooperation between LTE and Wi-Fi. For each class, we provide a detailed presentation of possible cooperation techniques that can provide spectral efficiency in a fair manner.

Wideband PIFA antenna for higher LTE band applications

Directory of Open Access Journals (Sweden)

Carlos Arturo Suárez-Fajardo

2015-01-01

Full Text Available Este artículo presenta una antena plana F invertida (PIFA de b anda ancha con la técnica de excitación capacitiva en U para ap licaciones en la banda alta de LTE. La ante na propuesta se basa en una sim ple PIFA, donde las placas de excitación capacitiva, de radiaci ón y de tierra se modifican a una geometrí a en U de tal manera que la a ntena puede poseer características de ancho de banda amplio. Me diante el uso de la configuración de excitación propuesta, la antena mues tra un ancho de banda amplio de diagrama e impedancia del 81.6 % para un VSWR ≤ 2.0 desde 1.66GHz a 3.95GHz la cual puede cubrir apli caciones en la banda alta de LTE (1.71GHz3.8GHz, DCS 1800, DCS 1900, UCDMA, UMTS, IMT 2000, DMB, WiFi, 2.4GHz, WiMAX (2.3 –2.5 GHz, WiMAX (3.4–3 .5 GHz y Bl uetooth.

Privacy-Enhancing Security Protocol in LTE Initial Attack

Directory of Open Access Journals (Sweden)

Uijin Jang

2014-12-01

Full Text Available Long-Term Evolution (LTE is a fourth-generation mobile communication technology implemented throughout the world. It is the communication means of smartphones that send and receive all of the private date of individuals. M2M, IOT, etc., are the base technologies of mobile communication that will be used in the future cyber world. However, identification parameters, such as International Mobile Subscriber Identity (IMSI, Radio Network Temporary Identities (RNTI, etc., in the initial attach section for accessing the LTE network are presented with the vulnerability of being exposed as clear text. Such vulnerability does not end in a mere identification parameter, but can lead to a secondary attack using the identification parameter, such as replication of the smartphone, illegal use of the mobile communication network, etc. This paper proposes a security protocol to safely transmit identification parameters in different cases of the initial attach. The proposed security protocol solves the exposed vulnerability by encrypting the parameters in transmission. Using an OPNET simulator, it is shown that the average rate of delay and processing ratio are efficient in comparison to the existing process.

An Efficient Live TV Scheduling System for 4G LTE Broadcast

KAUST Repository

Lau, Chun Pong; Alabbasi, AbdulRahman; Shihada, Basem

2016-01-01

Traditional live television (TV) broadcasting systems are proven to be spectrum inefficient. Therefore, researchers propose to provide TV services on fourth-generation (4G) long-term evolution (LTE) networks. However, static broadcast, a typical

TD-LTE maritime trunking communication system based on TVWS

Science.gov (United States)

Ren, Chunxiang; Chen, Xing; Li, Wanchao; Chen, Baodan

2014-10-01

This paper collects the measurement results of 470 MHZ-960MHZ spectrum in the coastal areas, and analyzes the characteristics of TV broadcast spectrum occupancy in the measurement region. Moreover, this article proposes construct the TD-LTE maritime trunking communication system using geolocation database, television database (TVDB) and cognitive radio (CR) technology.

DSRC versus 4G-LTE for Connected Vehicle Applications: A Study on Field Experiments of Vehicular Communication Performance

Directory of Open Access Journals (Sweden)

Zhigang Xu

2017-01-01

Full Text Available Dedicated short-range communication (DSRC and 4G-LTE are two widely used candidate schemes for Connected Vehicle (CV applications. It is thus of great necessity to compare these two most viable communication standards and clarify which one can meet the requirements of most V2X scenarios with respect to road safety, traffic efficiency, and infotainment. To the best of our knowledge, almost all the existing studies on comparing the feasibility of DRSC or LTE in V2X applications use software-based simulations, which may not represent realistic constraints. In this paper, a Connected Vehicle test-bed is established, which integrates the DSRC roadside units, 4G-LTE cellular communication stations, and vehicular on-board terminals. Three Connected Vehicle application scenarios are set as Collision Avoidance, Traffic Text Message Broadcast, and Multimedia File Download, respectively. A software tool is developed to record GPS positions/velocities of the test vehicles and record certain wireless communication performance indicators. The experiments have been carried out under different conditions. According to our results, 4G-LTE is more preferred for the nonsafety applications, such as traffic information transmission, file download, or Internet accessing, which does not necessarily require the high-speed real-time communication, while for the safety applications, such as Collision Avoidance or electronic traffic sign, DSRC outperforms the 4G-LTE.

Adaptive MCS selection and resource planning for energy-efficient communication in LTE-M based IoT sensing platform.

Science.gov (United States)

Dao, Nhu-Ngoc; Park, Minho; Kim, Joongheon; Cho, Sungrae

2017-01-01

As an important part of IoTization trends, wireless sensing technologies have been involved in many fields of human life. In cellular network evolution, the long term evolution advanced (LTE-A) networks including machine-type communication (MTC) features (named LTE-M) provide a promising infrastructure for a proliferation of Internet of things (IoT) sensing platform. However, LTE-M may not be optimally exploited for directly supporting such low-data-rate devices in terms of energy efficiency since it depends on core technologies of LTE that are originally designed for high-data-rate services. Focusing on this circumstance, we propose a novel adaptive modulation and coding selection (AMCS) algorithm to address the energy consumption problem in the LTE-M based IoT-sensing platform. The proposed algorithm determines the optimal pair of MCS and the number of primary resource blocks (#PRBs), at which the transport block size is sufficient to packetize the sensing data within the minimum transmit power. In addition, a quantity-oriented resource planning (QORP) technique that utilizes these optimal MCS levels as main criteria for spectrum allocation has been proposed for better adapting to the sensing node requirements. The simulation results reveal that the proposed approach significantly reduces the energy consumption of IoT sensing nodes and #PRBs up to 23.09% and 25.98%, respectively.

A Study of the Polycondensation of (Tetrahydroxy(TetraarylCyclotetrasiloxanes under Equilibrium and Non-Equilibrium Conditions in the Presence and Absence of Montmorillonite

Directory of Open Access Journals (Sweden)

Nataliya N. Makarova

2018-04-01

Full Text Available Oligo- and polycyclosiloxanes were obtained by the polycondensation of (tetrahydroxy(tetraarylcyclotetrasiloxanes in equilibrium and non-equilibrium conditions in the presence and absence of montmorillonite (MMT. Their composition and the structures of their components were investigated by infrared (IR spectroscopy, 29Si nuclear magnetic resonance (NMR spectroscopy, atmospheric pressure chemical ionization (APCI mass spectrometry, powder X-ray diffraction (XRD, and gel-penetrating chromatography (GPC. Also, a comparison of polymers formed in the presence of MMT and via anionic polymerization was performed showing differences in their structures.

Research on insulating material affecting the property of gas ionization chamber

International Nuclear Information System (INIS)

Wang Liqiang; Wang Zhentao; Zheng Jian

2014-01-01

The insulating material in ionization chamber affects the internal gas pressure and ionic pulse shape in the research process of the ion drift velocity in high pressure gas ionization chamber. It will affect the ion drift velocity measurement. It is required to isolate by insulating material between electrode to electrode and between electrodes to the shell of gas ionization chamber. Insulating material in gas ionization chamber is indispensable. Therefore it needs to carefully study the insulating material affecting the performance of gas ionization chamber. First of all, it is found that Teflon can slowly adsorb the working gas in ionization chamber, and the gas pressure in it is reduced when we measure the sensitivity of gas ionization chamber over time. It is verified by experiment that insulating materials absorbing and releasing gas is dynamically reversible process. Then the adsorbing gas property of 95% aluminium oxide ceramic and Teflon is studied through experimental comparision. Gas adsorption equilibrium time of ceramic material is faster, generally it is about a few hours, and the gas adsorption capacity is relatively less. Gas adsorption equilibrium time of Teflon is slower, it is about a few days, and the gas adsorption capacity is relatively more. It is found that Teflon will release part of the gas at higher temperature through experimental research on the influence of Teflon adsorbing gas. Finally it is studied that the distribution of insulation in ionization chamber affects the time response speed of ionization chamber by measuring the signal pulse shape of ionization chamber under the pulse X-ray. Through these experimental research, it is presented that it need to pay attention to select insulation material and to design the internal structure and arrangement of insulating material when we design gas ionization chamber. (authors)

Multi-Layer Mobility Load Balancing in a Heterogeneous LTE Network

DEFF Research Database (Denmark)

Fotiadis, Panagiotis; Polignano, Michele; Laselva, Daniela

2012-01-01

This paper analyzes the behavior of a distributed Mobility Load Balancing (MLB) scheme in a multi-layer 3GPP (3rd Generation Partnership Project) Long Term Evolution (LTE) deployment with different User Equipment (UE) densities in certain network areas covered with pico cells. Target of the study...

Modeling and Simulation of Downlink Subcarrier Allocation Schemes in LTE

DEFF Research Database (Denmark)

Popovska Avramova, Andrijana; Yan, Ying; Dittmann, Lars

2012-01-01

The efficient utilization of the air interface in the LTE standard is achieved through a combination of subcarrier allocation schemes, adaptive modulation and coding, and transmission power allotment. The scheduler in the base station has a major role in achieving the required QoS and the overall...

Investigation of a new handover approach in LTE and WiMAX.

Science.gov (United States)

Hindia, Mohammad Nour; Reza, Ahmed Wasif; Noordin, Kamarul Ariffin

2014-01-01

Nowadays, one of the most important challenges in heterogeneous networks is the connection consistency between the mobile station and the base stations. Furthermore, along the roaming process between the mobile station and the base station, the system performance degrades significantly due to the interferences from neighboring base stations, handovers to inaccurate base station and inappropriate technology selection. In this paper, several algorithms are proposed to improve mobile station performance and seamless mobility across the long-term evolution (LTE) and Worldwide Interoperability for Microwave Access (WiMAX) technologies, along with a minimum number of redundant handovers. Firstly, the enhanced global positioning system (GPS) and the novel received signal strength (RSS) prediction approaches are suggested to predict the target base station accurately. Then, the multiple criteria with two thresholds algorithm is proposed to prioritize the selection between LTE and WiMAX as the target technology. In addition, this study also covers the intercell and cochannel interference reduction by adjusting the frequency reuse ratio 3 (FRR3) to work with LTE and WiMAX. The obtained results demonstrate high next base station prediction efficiency and high accuracy for both horizontal and vertical handovers. Moreover, the received signal strength is kept at levels higher than the threshold, while maintaining low connection cost and delay within acceptable levels. In order to highlight the combination of the proposed algorithms' performance, it is compared with the existing RSS and multiple criteria handover decision algorithms.

Characterization of the pulse plasma source

International Nuclear Information System (INIS)

Milosavljevic, V; Karkari, S K; Ellingboe, A R

2007-01-01

Characterization of the pulse plasma source through the determination of the local thermodynamic equilibrium (LTE) threshold is described. The maximum electron density measured at the peak in discharge current is determined by the width of the He II Paschen alpha spectral line, and the electron temperature is determined from the ratios of the relative intensities of spectral lines emitted from successive ionized stages of atoms. The electron density and temperature maximum values are measured to be 1.3 x 10 17 cm -3 and 19 000 K, respectively. These are typical characteristics for low-pressure, pulsed plasma sources for input energy of 15.8 J at 130 Pa pressure in helium-argon mixture. The use of LTE-based analysis of the emission spectra is justified by measurement of the local plasma electron density at four positions in the discharge tube using a floating hairpin resonance probe. The hairpin resonance probe data are collected during the creation and decay phases of the pulse. From the spatio-temporal profile of the plasma density a 60 μs time-window during which LTE exists throughout the entire plasma source is determined

Cooperation Techniques between LTE in Unlicensed Spectrum and Wi-Fi towards Fair Spectral Efficiency

Directory of Open Access Journals (Sweden)

Vasilis Maglogiannis

2017-08-01

Full Text Available On the road towards 5G, a proliferation of Heterogeneous Networks (HetNets is expected. Sensor networks are of great importance in this new wireless era, as they allow interaction with the environment. Additionally, the establishment of the Internet of Things (IoT has incredibly increased the number of interconnected devices and consequently the already massive wirelessly transmitted traffic. The exponential growth of wireless traffic is pushing the wireless community to investigate solutions that maximally exploit the available spectrum. Recently, 3rd Generation Partnership Project (3GPP announced standards that permit the operation of Long Term Evolution (LTE in the unlicensed spectrum in addition to the exclusive use of the licensed spectrum owned by a mobile operator. Alternatively, leading wireless technology developers examine standalone LTE operation in the unlicensed spectrum without any involvement of a mobile operator. In this article, we present a classification of different techniques that can be applied on co-located LTE and Wi-Fi networks. Up to today, Wi-Fi is the most widely-used wireless technology in the unlicensed spectrum. A review of the current state of the art further reveals the lack of cooperation schemes among co-located networks that can lead to more optimal usage of the available spectrum. This article fills this gap in the literature by conceptually describing different classes of cooperation between LTE and Wi-Fi. For each class, we provide a detailed presentation of possible cooperation techniques that can provide spectral efficiency in a fair manner.

An analytical excitation for an ionizing plasma

NARCIS (Netherlands)

Mullen, van der J.J.A.M.; Sijde, van der B.; Schram, D.C.

1983-01-01

From an analytical model for the population of high-lying excited levels in ionizing plasmas it appears that the distribution is a superposition of the equilibrium (Saha) value and an overpopulation. This overpopulation takes the form of a Maxwell distribution for free electrons. Experiments for He

Body Loss Study of Beamforming Mode in LTE MIMO Mobile Terminals

DEFF Research Database (Denmark)

Zhang, Shuai; Zhao, Kun; Ying, Zhinong

2015-01-01

This paper mainly focuses on the investigation of the body loss of beamforming mode in LTE MIMO mobile terminals with CTIA user effects. The research of the body loss and radiation efficiency is carried out over different phase differences between two ports of each MIMO antenna. During studies......, four kinds of typical LTE MIMO antennas are used, namely, collocated ground free (GF), parallel GF, parallel on ground (OG) and orthogonal OG MIMO antennas, under four mobile terminal lengths at low and high frequencies. Two kinds of CTIA user effects are included in the research. From the studies......, the parallel GF MIMO antenna type exhibits the best beamforming performance in the four MIMO antenna types. In order to verify the simulations, envelope correlation coefficients of two MIMO antenna prototypes are measured. All the measured results agree well with the simulated....

Non-LTE spectral analyses of the lately discovered DB-gap white dwarfs from the SDSS

International Nuclear Information System (INIS)

Huegelmeyer, S D; Dreizler, S

2009-01-01

For a long time, no hydrogen-deficient white dwarfs have been known that have effective temperature between 30 kK and eff < 45 kK (Eisenstein et al. 2006). It has been shown for DO white dwarfs that the relaxation of LTE is necessary to account for non local effects in the atmosphere caused by the intense radiation field. Therefore, we calculated a non-LTE model grid and re-analysed the aforementioned set of SDSS spectra. Our results confirm the existence of DB-gap white dwarfs.

Channelization Issues with Fairness Considerations for MU-MIMO Precoding Based UTRA-LTE/TDD Systems

DEFF Research Database (Denmark)

Rahman, Muhammad Imadur; Wang, Yuanye; Das, Suvra

2008-01-01

resource allocation point of view, choice of any technique will require different fairness conditions among users. In this paper, we have studied these different fairness conditions when combined with basic or joint access schemes mentioned above, while applied in a MU-MIMO based UTRA-LTE system. We have...... evaluated the resource allocation fairness issue when two well-known linear MU-MIMO precoding is used on a UTRA-LTE system. User grouping issue is dealt with when SDMA component is considered in the system. The results in this work provides an indicative analysis of the usability of different channelization...

LTE-advanced a practical systems approach to understanding 3GPP LTE releases 10 and 11 radio access technologies

CERN Document Server

Ahmadi, Sassan

2013-01-01

This book is an in-depth, systematic and structured technical reference on 3GPP's LTE-Advanced (Releases 10 and 11), covering theory, technology and implementation, written by an author who has been involved in the inception and development of these technologies for over 20 years. The book not only describes the operation of individual components, but also shows how they fit into the overall system and operate from a systems perspective. Uniquely, this book gives in-depth information on upper protocol layers, implementation and deployment issues, and services, making it suitable for engine

Evaluation of spectroscopic modeling for iron ions and study on non-equilibrium ionization phenomena for solar and LHD plasmas

International Nuclear Information System (INIS)

Watanabe, Tetsuya; Hara, Hirohisa; Yamamoto, Norimasa; Kato, Daiji; Sakaue, Hiroyuki A.; Murakami, Izumi

2013-01-01

Spectroscopic observations of EUV emission lines in the transition region (TR) and the corona provide unique information on physical conditions in the outer atmosphere of the Sun. The EUV Imaging Spectrometer (EIS) on board the Hinode satellite is capable of observing, for the first time in EUV, spectra and monochromatic images of plasmas in the solar TR and corona; these plasmas could possibly be in non-ionization-equilibrium conditions. EIS observes over two-wavelength bands of 170 - 210 Å and 250 - 290 Å, with typical time-resolutions of 1 - 10 seconds. Iron line emissions emerging from these wavelengths reveal that dynamic plasma accelerations and heating take place in the solar atmosphere. On the other hand, the tracer-encapsulated-pellet (TESPEL) experiments provide spectral information of EUV emission lines from iron ions produced in the Large Helical Device (LHD). Relatively cool plasmas with electron temperatures similar to those of the solar corona can be generated by controlling the neutral beam injector (NBI) system. A time-dependent collisional radiative (CR) model for elemental iron is developed as a common tool to diagnose temperatures and densities of those plasmas in the Sun and in LHD; no systematic model yet exists for iron ions in the L- and M-shell ionization stages, which are very important for coronal plasma diagnostics. Adopting the best available theoretical calculations, as well as generating the experimental data, we improve the atomic parameters of highly charged iron ions, and these results are used to extract more accurate diagnostic information out of the EIS spectra. (author)

Non-LTE equivalent widths for Si II, III and IV

International Nuclear Information System (INIS)

Becker, S.R.; Butler, K.

1990-01-01

Equivalent widths for a set of Si II, III and IV lines reliable for the determination of temperatures in the B star parameter range are given. They are calculated on a fine grid of LTE line blanketed model atmospheres and lie in the wavelength region from 4070 A to 5070 A

Departures from local thermodynamic equilibrium in cutting arc plasmas derived from electron and gas density measurements using a two-wavelength quantitative Schlieren technique

International Nuclear Information System (INIS)

Prevosto, L.; Mancinelli, B.; Artana, G.; Kelly, H.

2011-01-01

A two-wavelength quantitative Schlieren technique that allows inferring the electron and gas densities of axisymmetric arc plasmas without imposing any assumption regarding statistical equilibrium models is reported. This technique was applied to the study of local thermodynamic equilibrium (LTE) departures within the core of a 30 A high-energy density cutting arc. In order to derive the electron and heavy particle temperatures from the inferred density profiles, a generalized two-temperature Saha equation together with the plasma equation of state and the quasineutrality condition were employed. Factors such as arc fluctuations that influence the accuracy of the measurements and the validity of the assumptions used to derive the plasma species temperature were considered. Significant deviations from chemical equilibrium as well as kinetic equilibrium were found at elevated electron temperatures and gas densities toward the arc core edge. An electron temperature profile nearly constant through the arc core with a value of about 14000-15000 K, well decoupled from the heavy particle temperature of about 1500 K at the arc core edge, was inferred.

Perancangan dan Implementasi Duplexer Mikrostrip untuk Frekuensi LTE pada band ke-7

Directory of Open Access Journals (Sweden)

ENCENG SULAEMAN

2017-06-01

Full Text Available ABSTRAK Kebutuhan akan komunikasi bergerak semakin mengalami peningkatan dalam dunia teknologi yang ada saat ini, maka hadirlah teknologi terbaru yaitu Long Term Evolution (LTE. Dengan teknik duplex jenis Frequency Division Duplex (FDD, dirancanglah duplexer yang mampu melakukan proses pengiriman dan penerimaan dalam satu waktu dengan frekuensi yang berbeda antara uplink dan downlink. Pada penelitian ini dirancang dan diimplementasikan sebuah duplekser dengan menggunakan metoda Hybrid Coupler dan Bandstop Filter berbasis Split Ring Resonator untuk band frekuensi ke-7 pada teknologi LTE di sisi Base Transceiver Station (BTS. Duplekser dibuat dengan menggabungkan dua buah hybrid Coupler dan dua buah Bandstop Filter. Hasil pengukuran duplexer saat port Tx mengirimkan sinyal ke antena dengan nilai redaman pada frekuensi tengah downlink sebesar 3.168 dB. Lalu pada saat antena menerima sinyal untuk diteruskan ke Rx terdapat redaman di frekuensi tengah uplink sebesar 6 dB. Sedangkan untuk isolasi dari port Tx-port Rx dihasilkan sebesar 15 dB. Kata kunci: Duplexer, Bandstop Filter, Split Ring Resonator, Hybrid Coupler, dan Long Term Evolution. ABSTRACT The necessary of mobile communication has increased in technology, now it released the new of technology is Long Term Evolution (LTE. Type of duplex is Frequency Division Duplex (FDD, designed a duplexer which it is capable for transmitting and receiving process at the same time with the different of frequency between uplink and downlink. Research of designed and implemented a duplexer using Hybrid Coupler and Bandstop filters based on Split Ring Resonators for the frequency band 7th on LTE technology at Base Transceiver Station (BTS. Duplexer is made by combining two coupler and two bandstop filter. The results of duplexer measurements, when Tx port transmit the signal to antenna port with attenuation at the downlink frequency center at 3.168 dB. Attenuation from antenna port to Rx port about 6 d

Mobility Analysis for Inter-Site Carrier Aggregation in LTE Heterogeneous Networks

DEFF Research Database (Denmark)

Barbera, Simone; Pedersen, Klaus I.; Michaelsen, Per Henrik

2013-01-01

In this paper we analyze the mobility performance for an LTE Heterogeneous Network with macro and pico cells deployed on different carriers. Cases with/without downlink inter-site carrier aggregation are investigated. Extensive system level simulations are exploited to quantify the performance...

Flux Jacobian Matrices For Equilibrium Real Gases

Science.gov (United States)

Vinokur, Marcel

1990-01-01

Improved formulation includes generalized Roe average and extension to three dimensions. Flux Jacobian matrices derived for use in numerical solutions of conservation-law differential equations of inviscid flows of ideal gases extended to real gases. Real-gas formulation of these matrices retains simplifying assumptions of thermodynamic and chemical equilibrium, but adds effects of vibrational excitation, dissociation, and ionization of gas molecules via general equation of state.

Multi-Radio Mobile Device in Role of Hybrid Node Between WiFi and LTE networks

Directory of Open Access Journals (Sweden)

Pavel Masek

2015-05-01

Full Text Available With the ubiquitous wireless network coverage, Machine-Type Communications (MTC is emerging to enable data transfers using devices/sensors without need for human interaction. In this paper we, we introduce a comprehensive simulation scenario for modeling and analysis for heterogeneous MTC. We demonstrate the most expected scenario of MTC communication using the IEEE 802.11 standard for direct communication between sensors and for transmitting data between individual sensor and Machine-Type Communication Gateway (MTCG. The MTCG represents the hybrid node serving as bridge between two heterogeneous networks (WiFi and LTE. Following the idea of hybrid node, two active interfaces must be implemented on this node together with mechanism for handling the incoming traffic (from WiFi network to LTE network. As a simulation tool, the Network Simulator 3 (NS-3 with implemented LTE/EPC Network Simulator (LENA framework was used. The major contribution of this paper therefore lies in the implementation of logic for interconnection of two heterogeneous networks in simulation environment NS-3.

Non-LTE Stellar Population Synthesis of Globular Clusters Using Synthetic Integrated Light Spectra. I. Constructing the IL Spectra

Science.gov (United States)

Young, Mitchell. E.; Short, C. Ian

2017-02-01

We present an investigation of the globular cluster population synthesis method of McWilliam & Bernstein, focusing on the impact of non-LTE (NLTE) modeling effects and color-magnitude diagram (CMD) discretization. Johnson-Cousins-Bessel U - B, B-V, V-I, and J-K colors are produced for 96 synthetic integrated light (IL) spectra with two different discretization prescriptions and three degrees of NLTE treatment. These color values are used to compare NLTE- and LTE-derived population ages. Relative contributions of different spectral types to the IL spectra for different wavebands are measured. IL NLTE spectra are shown to be more luminous in the UV and optical than LTE spectra, but show stronger absorption features in the IR. The main features showing discrepancies between NLTE and LTE IL spectra may be attributed to light metals, primarily Fe I, Ca I, and Ti I, as well as TiO molecular bands. Main-sequence stars are shown to have negligible NLTE effects at IR wavelengths compared to more evolved stars. Photometric color values are shown to vary at the millimagnitude level as a function of CMD discretization. Finer CMD sampling for the upper main sequence and turnoff, base of the red giant branch, and the horizontal branch minimizes this variation. Differences in ages derived from LTE and NLTE IL spectra are found to range from 0.55 to 2.54 Gyr, comparable to the uncertainty in GC ages derived from color indices with observational uncertainties of 0.01 mag, the limiting precision of the Harris catalog.

Optimization and characterization of a Pilot-psi cascaded arc with non-LTE numerical simulation of Ar, H{sub 2} gases

Energy Technology Data Exchange (ETDEWEB)

Ahmad, Zahoor [National Tokamak Fusion Program, PO Box 3329, PAEC Islamabad (Pakistan); Goedheer, W J [FOM Institute for Plasmaphysics ' Rijnhuizen' , Association EURATOM-FOM, POBox 1207, 3430 BE Nieuwegein (Netherlands)

2009-02-01

A numerical simulation code, PLASIMO, is used to model non-LTE plasmas in the cascaded arc for hydrogen and argon. The purpose of these simulations is to optimize the cascaded arc plasma source, which is used to produce a high density plasma column in Pilot-psi, a linear device to study plasma surface interaction processes. Results are compared with the experimental findings to validate the model. The effect of a change in the arc channel geometry on the ionization degree is studied. It is found that for the hydrogen arc an increase in length beyond 30 mm will not increase the ionization degree, in contrast to widening the arc. With an increase in radius from 2 mm to 5 mm for a 30 mm long arc the degree of ionization of hydrogen increases from 5.4 to 38. For the argon arc an increase both in the length and in the width increases the ionization degree. With an increase in length from 30 mm to 40 mm for a 2 mm wide arc the degree of ionization of argon increases from 14.5 to 17.1, whereas with an increase in radius from 2 mm to 5 mm for 30 mm long arc the same increases from 14.5 to 37.5. To simulate the influence of the wall material, the effect of hydrogen wall association on the degree of ionization and dissociation is studied. Wall association in the nozzle section, where heating is absent, significantly reduces the degree of dissociation, in agreement with the experimental data. In Pilot-psi, the arc is operated in a high magnetic field, so the effect of a magnetic field on the yield of Ar{sup +} and H{sup +} ions leaving the arc is also studied. It is found that with a 3 T magnetic field the Ar{sup +} yield increases from 1.6 x 10{sup 20} to 2.1 x 10{sup 20} (25% increase) while the H{sup +} yield increases from 1.4 x 10{sup 20} to 2.9 x 10{sup 20} (100% increase)

Heating of the solar chromosphere by ionization pumping

Science.gov (United States)

Lindsey, C. A.

1981-01-01

A new theory is proposed to explain the heating of the solar chromosphere, and possibly the corona, by the dissipation of hydrodynamic compression waves. The basis of the dissipative mechanism, here referred to as ionization pumping, is hysteresis caused by irreversible relaxation of the chromospheric medium to ionization equilibrium following pressure perturbations. In the middle chromosphere, where hydrogen is partially ionized, it is shown that ionization pumping will cause strong dissipation of waves whose periods are 200s or less. This could cause heating of the chromosphere sufficient to compensate for the radiative losses. The mechanism retains a high efficiency for waves of arbitrarily small amplitude and, thus, can be more efficient than shock dissipation for small perturbations in pressure. The formation of shocks therefore is not required for the dissipation of waves whose periods are several minutes or less.

Heating of the solar chromosphere by ionization pumping

International Nuclear Information System (INIS)

Lindsey, C.A.

1981-01-01

A new theory is proposed to explain the heating of the solar chromosphere, and possibly the corona, by the dissipation of hydrodynamic compression waves. The basis of the disspative mechanism, here referred to as ''ionization pumping,'' is hysteresis caused by irresversible relaxation of the chromospheric medium to ionization equilibrium following pressure perturbations. In the middle chromosphere, where hydrogen is partially ionized, it is shown that ionization pumping will cause strong dissipation of waves whose periods are approx.200 s or less. This could cause heating of the chromosphere sufficient to compensate for the radiative losses. The mechanism retains a high efficiency for waves of arbitrarily small amplitude and, thus, can be more efficient than shock dissipation for small perturbations in pressure. The formation of shocks therefore is not required for the dissipation of waves whose periods are several minutes or less

Base Station Placement Algorithm for Large-Scale LTE Heterogeneous Networks.

Science.gov (United States)

Lee, Seungseob; Lee, SuKyoung; Kim, Kyungsoo; Kim, Yoon Hyuk

2015-01-01

Data traffic demands in cellular networks today are increasing at an exponential rate, giving rise to the development of heterogeneous networks (HetNets), in which small cells complement traditional macro cells by extending coverage to indoor areas. However, the deployment of small cells as parts of HetNets creates a key challenge for operators' careful network planning. In particular, massive and unplanned deployment of base stations can cause high interference, resulting in highly degrading network performance. Although different mathematical modeling and optimization methods have been used to approach various problems related to this issue, most traditional network planning models are ill-equipped to deal with HetNet-specific characteristics due to their focus on classical cellular network designs. Furthermore, increased wireless data demands have driven mobile operators to roll out large-scale networks of small long term evolution (LTE) cells. Therefore, in this paper, we aim to derive an optimum network planning algorithm for large-scale LTE HetNets. Recently, attempts have been made to apply evolutionary algorithms (EAs) to the field of radio network planning, since they are characterized as global optimization methods. Yet, EA performance often deteriorates rapidly with the growth of search space dimensionality. To overcome this limitation when designing optimum network deployments for large-scale LTE HetNets, we attempt to decompose the problem and tackle its subcomponents individually. Particularly noting that some HetNet cells have strong correlations due to inter-cell interference, we propose a correlation grouping approach in which cells are grouped together according to their mutual interference. Both the simulation and analytical results indicate that the proposed solution outperforms the random-grouping based EA as well as an EA that detects interacting variables by monitoring the changes in the objective function algorithm in terms of system

Power efficient dynamic resource scheduling algorithms for LTE

OpenAIRE

Han, C; Beh, KC; Nicolaou, M; Armour, SMD; Doufexi, A

2010-01-01

This paper presents a link level analysis of the rate and energy efficiency performance of the LTE downlink considering the unitary codebook based precoding scheme. In a multi-user environment, appropriate radio resource management strategies can be applied to the system to improve the performance gain by exploiting multi-user diversity in the time, frequency and space domains and the gains can be translated to energy reduction at the base station. Several existing and novel resource scheduli...

To the probe theory in a highly-ionized high-pressure plasma

International Nuclear Information System (INIS)

Baksht, F.G.; Rybakov, A.B.

1997-01-01

The probe theory in highly-ionized high-pressure plasma is presented. The situation typical for high-pressure plasma, when the plasma in the main part of the near-probe layer is in the state of local ionization equilibrium with general temperature for electrons and heavy particles. Possibility is discussed for determining the parameters of non-perturbed plasma through analysis of the probe characteristic at place of ion saturation, transition area and by the probe floating potential. The experiments were carried out by example of highly-ionized xenon plasma under atmospheric pressure

An analytical excitation model for an ionizing plasma

NARCIS (Netherlands)

Mullen, van der J.J.A.M.; Sijde, van der B.; Schram, D.C.

1983-01-01

From an analytical model for the population of high-lying excited levels in ionizing plasmas it appears that the distribution is a superposition of the equilibrium (Saha) value and an overpopulation. This overpopulation takes the form of a Maxwell distribution for free electrons. Experiments for He

LTE delay assessment for real-time management of future smart grids

NARCIS (Netherlands)

Jorguseski, L.; Zhang, H.; Chrysalos, M.; Golinski, M.; Toh, Y.

2017-01-01

This study investigates the feasibility of using Long Term Evolution (LTE), for the real-time state estimation of the smart grids. This enables monitoring and control of future smart grids. The smart grid state estimation requires measurement reports from different nodes in the smart grid and

Development of a Thermo-chemical Non-equilibrium Solver for Hypervelocity Flows

Science.gov (United States)

Balasubramanian, R.; Anandhanarayanan, K.

2015-04-01

In the present study, a three dimensional flowsolver is indigenously developed to numerically simulate hypervelocity thermal and chemical non equilibrium reactive air flow past flight vehicles. The two-temperature, five species, seventeen reactions, thermo-chemical non equilibrium, non-ionizing, air-chemistry model of Park is implemented in a compressible viscous code CERANS and solved in the finite volume framework. The energy relaxation is addressed by a conservation equation for the vibrational energy of the gas mixture resulting in the evaluation of its vibrational temperature. The AUSM-PW+ numerical flux function has been used for modeling the convective fluxes and a central differencing approximation is used for modeling the diffusive fluxes. The flowsolver had been validated for specifically chosen test cases with inherent flow complexities of non-ionizing hypervelocity thermochemical nonequilibrium flows and results obtained are in good agreement with results available in open literature.

The Study of Indoor and Field Trials on 2×8 MIMO Architecture in TD-LTE Network

Directory of Open Access Journals (Sweden)

Xiang Zhang

2013-01-01

the networks are based on frequency division duplexing (FDD. In this paper, measurement methods of four MIMO transmission modes (TMs in time division-LTE (TD-LTE are studied and analyzed. Link level simulation is carried out to evaluate the downlink throughput for different signal-to-noise ratios and parameter settings. Furthermore, indoor and field tests are also presented in the paper to investigate how real-world propagation affects the capacity and the error performance of MIMO transmission scheme. For the indoor test, radio channel emulators are applied to generate realistic wireless fading channel, while in the field trials, a live TD-LTE experiment cellular network is built, which contains several evolved nodeBs (eNBs and a precommercial user equipment (UE. It is shown from both simulation and tests results that MIMO deployment gives a substantial performance improvement compared with the third generation wireless networks.

An Efficient Live TV Scheduling System for 4G LTE Broadcast

KAUST Repository

Lau, Chun Pong

2016-01-01

Traditional live television (TV) broadcasting systems are proven to be spectrum inefficient. Therefore, researchers propose to provide TV services on fourth-generation (4G) long-term evolution (LTE) networks. However, static broadcast, a typical broadcasting method over cellular network, is inefficient in terms of radio resource usage. To solve this problem, the audience-driven live TV scheduling (ADTVS) framework is proposed, to maximize radio resource usage when providing TV broadcasting services over LTE networks. ADTVS, a system-level scheduling framework, considers both available radio resources and audience preferences, in order to dynamically schedule TV channels for broadcasting at various time and locations. By conducting a simulation using real-life data and scenarios, it is shown that ADTVS significantly outperforms the static broadcast method. Numerical results indicate that, on average, ADTVS enables substantial improvement to broadcast efficiency and conserves considerable amount of radio resources, while forgoing less than 5% of user services compared to the benchmark system.

Performance Evaluation of Received Signal Strength Based Hard Handover for UTRAN LTE

DEFF Research Database (Denmark)

Anas, Mohmmad; Calabrese, Francesco Davide; Mogensen, Preben

2007-01-01

This paper evaluates the hard handover performance for UTRAN LTE system. The focus is on the impact that received signal strength based hard handover algorithm have on the system performance measured in terms of number of handovers, time between two consecutive handovers and uplink SINR for a user...... about to experience a handover. A handover algorithm based on received signal strength measurements has been designed and implemented in a dynamic system level simulator and has been studied for different parameter sets in a 3GPP UTRAN LTE recommended simulation scenario. The results suggest...... that a downlink measurement bandwidth of 1.25 MHz and a handover margin of 2 dB to 6 dB are the parameters that will lead to the best compromise between average number of handovers and average uplink SINR for user speeds of 3 kmph to 120 kmph....

Ionization of anisothermal plasmas. Ionisation des plasmas polythermes

Energy Technology Data Exchange (ETDEWEB)

Dennery, F.M.

1994-01-01

During this last mid-century, only the temperature of electrons has been involved in the Saha's mass action law, whatever be the other ionic and neutral ones in any isothermal or anisothermal plasma. In order to set aside this underlying paradox in the case of argon ionization, it is necessary to improve this equation of partial equilibrium after having defined: - the basic Gibbs-Duhem's relations for such a polythermal mixture, - the inhomogeneous equilibrium issued from chemical reactions according to Le Chatelier's principle. (author). 3 refs.

Improving SC-FDMA performance by Turbo Equalization in UTRA LTE Uplink

DEFF Research Database (Denmark)

Berardinelli, Gilberto; Priyanto, Basuki Endah; Sørensen, Troels Bundgaard

2008-01-01

of UTRA Long Term Evolution (LTE) Uplink. The performance is evaluated for 1x2 Single Input Multiple Output (SIMO) antenna configuration in a 6 paths Typical Urban (TU-06) channel profile. For assessment purpose, the results are compared with SC-FDMA MMSE and OFDMA schemes. Simulation results show...

Eight-Element Antenna Array for LTE 3.4-3.8 GHz Mobile Handset Applications

Science.gov (United States)

Yang, Lingsheng; Ji, Ming; Cheng, Biyu; Ni, Bo

2017-05-01

In this letter, an eight-element Multiple-input multiple-output (MIMO) antenna system for LTE mobile handset applications is proposed. The antenna array consists of eight 3D inverted F-shaped antennas (3D-IFA), and the measured -10 dB impedance bandwidth is 3.2-3.9 GHz which can cover the LTE bands 42 and 43 (3.4-3.8 GHz). By controlling the rotation of the antenna elements, no less than 10 dB isolation between antenna elements can be obtained. After using the specially designed meandered slots on the ground as decoupling structures, the measured isolation can be further improved to higher than 13 dB between the antenna elements at the whole operating band.

Anonymous authentication and location privacy preserving schemes for LTE-A networks

Directory of Open Access Journals (Sweden)

Zaher Jabr Haddad

2017-11-01

Full Text Available Long Term Evaluation Advanced (LTE-A is the third generation partnership project for cellular network that allows subscribers to roam into networks (i.e., the Internet and wireless connections using spacial purpose base-stations, such as wireless access points and home node B. In such LTE-A based networks, neither base-stations, nor the Internet and wireless connections are trusted because base-stations are operated by un-trusted subscribers. Attackers may exploit these vulnerabilities to violate the privacy of the LTE-A subscribers. On the other hand, the tradeoff between privacy and authentication is another challenge in such networks. Therefore, in this paper, we propose two anonymous authentication schemes based on one-time pseudonymes and Schnorr Zero Knowledge Protocols. Instead of the international mobile subscriber identity, these schemes enable the user equipment, base-stations and mobility management entity to mutually authenticate each others and update the location of the user equipment without evolving the home subscriber server. The security analysis demonstrate that the proposed schemes thwart security and privacy attacks, such as malicious, international mobile subscriber identity catching, and tracking attacks. Additionally, our proposed schemes preserve the location privacy of user equipment since no entity except the mobility management entity and Gate-Way Mobile Location Center can link between the pseudonymes and the international mobile subscriber identity. Also attackers have no knowledge about international mobile subscriber identity. Hence, the proposed schemes achieve backward/forward secrecy. Furthermore, the performance evaluation shows that the proposed handover schemes impose a small overhead on the mobile nodes and it has smaller computation and communication overheads than those in other schemes.

Throughput Measurement of a Dual-Band MIMO Rectangular Dielectric Resonator Antenna for LTE Applications.

Science.gov (United States)

Nasir, Jamal; Jamaluddin, Mohd Haizal; Ahmad Khan, Aftab; Kamarudin, Muhammad Ramlee; Yen, Bruce Leow Chee; Owais, Owais

2017-01-13

An L-shaped dual-band multiple-input multiple-output (MIMO) rectangular dielectric resonator antenna (RDRA) for long term evolution (LTE) applications is proposed. The presented antenna can transmit and receive information independently using fundamental TE 111 and higher order TE 121 modes of the DRA. TE 111 degenerate mode covers LTE band 2 (1.85-1.99 GHz), 3 (1.71-1.88 GHz), and 9 (1.7499-1.7849 GHz) at f r = 1.8 GHz whereas TE 121 covers LTE band 7 (2.5-2.69 GHz) at f r = 2.6 GHz, respectively. An efficient design method has been used to reduce mutual coupling between ports by changing the effective permittivity values of DRA by introducing a cylindrical air-gap at an optimal position in the dielectric resonator. This air-gap along with matching strips at the corners of the dielectric resonator keeps the isolation at a value more than 17 dB at both the bands. The diversity performance has also been evaluated by calculating the envelope correlation coefficient, diversity gain, and mean effective gain of the proposed design. MIMO performance has been evaluated by measuring the throughput of the proposed MIMO antenna. Experimental results successfully validate the presented design methodology in this work.

Absolute transition probabilities of 5s-5p transitions of Kr I from interferometric measurements in LTE-plasmas

International Nuclear Information System (INIS)

Kaschek, K.; Ernst, G.K.; Boetticher, W.

1984-01-01

Absolute transition probabilities of nine 5s-5p transitions of Kr I have been evaluated by using the hook method. The plasma was produced in a shock tube. The population density of the 5s-levels was calculated, under the assumption of LTE, from the electron density and the ground state number measured by means of a dual wavelength interferometer. An evaluation is given which proves the validity of the LTE assumption. (orig.)

A non-LTE retrieval scheme for sounding the upper atmosphere of Mars in the infrared

Science.gov (United States)

Lopez-Valverde, Miguel Angel; García-Comas, Maya; Funke, Bernd; Jimenez-Monferrer, Sergio; Lopez-Puertas, Manuel

2016-04-01

Several instruments on board Mars Express have been sounding the upper atmosphere of Mars systematically in a limb geometry in the IR part of the spectrum. Two of them in particular, OMEGA and PFS, performed emission measurements during daytime and detected the strongest IR bands of species like CO2 and CO (Piccialli et al, JGRE, submitted). Similarly on Venus, the instrument VIRTIS carried out observations of CO2 and CO bands at 2.7, 4.3 and 4.7 um at high altitudes (Gilli et al, JGRE, 2009). All these daylight atmospheric emissions respond to fluorescent situations, a case of non-local thermodynamic equilibrum conditions (non-LTE), well understood nowadays using comprehensive non-LTE theoretical models and tools (Lopez-Valverde et al., Planet. Space Sci., 2011). However, extensive exploitation of these emissions has only been done in optically thin conditions to date (Gilli et al, Icarus, 2015) or in a broad range of altitudes if in nadir geometry (Peralta et al, Apj, 2015). Within the H2020 project UPWARDS we aim at performing retrievals under non-LTE conditions including optically thick cases, like those of the CO2 and CO strongest bands during daytime in the upper atmosphere of Mars. Similar effort will also be applied eventually to Venus. We will present the non-LTE scheme used for such retrievals, based on similar efforts performed recently in studies of the Earth's upper atmosphere using data from the MIPAS instrument, on board Envisat (Funke et al., Atmos. Chem. Phys., 2009; Jurado-Navarro, PhD Thesis, Univ. Granada, 2015). Acknowledgemnt: This work is supported by the European Union's Horizon 2020 Programme under grant agreement UPWARDS-633127

Sensitivity of the optimal parameter settings for a LTE packet scheduler

NARCIS (Netherlands)

Fernandez-Diaz, I.; Litjens, R.; van den Berg, C.A.; Dimitrova, D.C.; Spaey, K.

Advanced packet scheduling schemes in 3G/3G+ mobile networks provide one or more parameters to optimise the trade-off between QoS and resource efficiency. In this paper we study the sensitivity of the optimal parameter setting for packet scheduling in LTE radio networks with respect to various

Modeling a content-aware LTE MAC downlink scheduler with heterogeneous traffic

DEFF Research Database (Denmark)

Artuso, Matteo; Christiansen, Henrik Lehrmann

2013-01-01

The scheduling policy adopted in the LTE (Long Term Evolution) MAC layer is the most valuable degree of freedom left from the 3GPP (3rd Generation Partnership Project) consortium to the industry and the research community . This paper presents an OPNET model of the downlink scheduling in a one...

Optimized scheduling technique of null subcarriers for peak power control in 3GPP LTE downlink.

Science.gov (United States)

Cho, Soobum; Park, Sang Kyu

2014-01-01

Orthogonal frequency division multiple access (OFDMA) is a key multiple access technique for the long term evolution (LTE) downlink. However, high peak-to-average power ratio (PAPR) can cause the degradation of power efficiency. The well-known PAPR reduction technique, dummy sequence insertion (DSI), can be a realistic solution because of its structural simplicity. However, the large usage of subcarriers for the dummy sequences may decrease the transmitted data rate in the DSI scheme. In this paper, a novel DSI scheme is applied to the LTE system. Firstly, we obtain the null subcarriers in single-input single-output (SISO) and multiple-input multiple-output (MIMO) systems, respectively; then, optimized dummy sequences are inserted into the obtained null subcarrier. Simulation results show that Walsh-Hadamard transform (WHT) sequence is the best for the dummy sequence and the ratio of 16 to 20 for the WHT and randomly generated sequences has the maximum PAPR reduction performance. The number of near optimal iteration is derived to prevent exhausted iterations. It is also shown that there is no bit error rate (BER) degradation with the proposed technique in LTE downlink system.

Wideband LTE power amplifier with integrated novel analog pre-distorter linearizer for mobile wireless communications.

Directory of Open Access Journals (Sweden)

Eswaran Uthirajoo

Full Text Available For the first time, a new circuit to extend the linear operation bandwidth of a LTE (Long Term Evolution power amplifier, while delivering a high efficiency is implemented in less than 1 mm2 chip area. The 950 µm × 900 µm monolithic microwave integrated circuit (MMIC power amplifier (PA is fabricated in a 2 µm InGaP/GaAs process. An on-chip analog pre-distorter (APD is designed to improve the linearity of the PA, up to 20 MHz channel bandwidth. Intended for 1.95 GHz Band 1 LTE application, the PA satisfies adjacent channel leakage ratio (ACLR and error vector magnitude (EVM specifications for a wide LTE channel bandwidth of 20 MHz at a linear output power of 28 dBm with corresponding power added efficiency (PAE of 52.3%. With a respective input and output return loss of 30 dB and 14 dB, the PA's power gain is measured to be 32.5 dB while exhibiting an unconditional stability characteristic from DC up to 5 GHz. The proposed APD technique serves to be a good solution to improve linearity of a PA without sacrificing other critical performance metrics.

Wideband LTE power amplifier with integrated novel analog pre-distorter linearizer for mobile wireless communications.

Science.gov (United States)

Uthirajoo, Eswaran; Ramiah, Harikrishnan; Kanesan, Jeevan; Reza, Ahmed Wasif

2014-01-01

For the first time, a new circuit to extend the linear operation bandwidth of a LTE (Long Term Evolution) power amplifier, while delivering a high efficiency is implemented in less than 1 mm2 chip area. The 950 µm × 900 µm monolithic microwave integrated circuit (MMIC) power amplifier (PA) is fabricated in a 2 µm InGaP/GaAs process. An on-chip analog pre-distorter (APD) is designed to improve the linearity of the PA, up to 20 MHz channel bandwidth. Intended for 1.95 GHz Band 1 LTE application, the PA satisfies adjacent channel leakage ratio (ACLR) and error vector magnitude (EVM) specifications for a wide LTE channel bandwidth of 20 MHz at a linear output power of 28 dBm with corresponding power added efficiency (PAE) of 52.3%. With a respective input and output return loss of 30 dB and 14 dB, the PA's power gain is measured to be 32.5 dB while exhibiting an unconditional stability characteristic from DC up to 5 GHz. The proposed APD technique serves to be a good solution to improve linearity of a PA without sacrificing other critical performance metrics.

Wideband LTE Power Amplifier with Integrated Novel Analog Pre-Distorter Linearizer for Mobile Wireless Communications

Science.gov (United States)

Uthirajoo, Eswaran; Ramiah, Harikrishnan; Kanesan, Jeevan; Reza, Ahmed Wasif

2014-01-01

For the first time, a new circuit to extend the linear operation bandwidth of a LTE (Long Term Evolution) power amplifier, while delivering a high efficiency is implemented in less than 1 mm2 chip area. The 950 µm × 900 µm monolithic microwave integrated circuit (MMIC) power amplifier (PA) is fabricated in a 2 µm InGaP/GaAs process. An on-chip analog pre-distorter (APD) is designed to improve the linearity of the PA, up to 20 MHz channel bandwidth. Intended for 1.95 GHz Band 1 LTE application, the PA satisfies adjacent channel leakage ratio (ACLR) and error vector magnitude (EVM) specifications for a wide LTE channel bandwidth of 20 MHz at a linear output power of 28 dBm with corresponding power added efficiency (PAE) of 52.3%. With a respective input and output return loss of 30 dB and 14 dB, the PA’s power gain is measured to be 32.5 dB while exhibiting an unconditional stability characteristic from DC up to 5 GHz. The proposed APD technique serves to be a good solution to improve linearity of a PA without sacrificing other critical performance metrics. PMID:25033049

A spatiotemporal model for the LTE uplink: Spatially interacting tandem queues approach

KAUST Repository

Gharbieh, Mohammad; Elsawy, Hesham; Bader, Ahmed; Alouini, Mohamed-Slim

2017-01-01

With the proliferation of the Internet-of-things (IoT), there is an undeniable consensus that cellular LTE networks will have to support a dramatically larger number of uplink connections. This is true since most of the devices to be added incur

The reactions of neutral iron clusters with D2O: Deconvolution of equilibrium constants from multiphoton processes

International Nuclear Information System (INIS)

Weiller, B.H.; Bechthold, P.S.; Parks, E.K.; Pobo, L.G.; Riley, S.J.

1989-01-01

The chemical reactions of neutral iron clusters with D 2 O are studied in a continuous flow tube reactor by molecular beam sampling and time-of-flight mass spectrometry with laser photoionization. Product distributions are invariant to a four-fold change in reaction time demonstrating that equilibrium is attained between free and adsorbed D 2 O. The observed negative temperature dependence is consistent with an exothermic, molecular addition reaction at equilibrium. Under our experimental conditions, there is significant photodesorption of D 2 O (Fe/sub n/(D 2 O)/sub m/ + hν → Fe/sub n/ + m D 2 O) along with ionization due to absorption of multiple photons from the ionizing laser. Using a simple model based on a rate equation analysis, we are able to quantitatively deconvolute this desorption process from the equilibrium constants. 8 refs., 1 fig

Access for Internet of Things using Smartphone as a Gateway utilizing LTE and WiFi

DEFF Research Database (Denmark)

Mathur, Prateek; Nielsen, Rasmus Hjorth; Prasad, Neeli R.

2016-01-01

Communicating the Internet of Things (IoT) data relying on Long-Term Evolution (LTE) and WiFi has been been presented in the relevant literature. However, this necessitates devices to have LTE/WiFi capability of their own, that has limitations in the form of power consumption, and radio access...... the data to the Internet. In this paper we present a system model wherein the smartphone functions as a gateway for the IoT devices operating on NFC, ZigBee and Bluetooth. The smartphone functioning as a gateway for transferring IoT data. The system modelled in the form of a Markov Chain based...

Non-LTE radiation in laser-disk target couply

International Nuclear Information System (INIS)

Gu Peijun; Fei Weibing; Feng Tinggui; Wu Changshu

2004-11-01

The coupling of laser-disk target has been studied by Multi-group radiation transfer code RDMGL. The results show that the X-ray spectra are strongly non-LTE and dependent on the atomic model. The plasma states, laser energy absorption and X-ray conversion rates are almost the same as those simulated by three-temperature model code, which fact shows that the three-temperature model is reasonable to describe the exchange of different kinds of energy and the hydrodynamic phenomena of plasmas in laser-target coupling. (authors)

An investigation of interference coordination in heterogeneous network for LTE-Advanced systems

Science.gov (United States)

Hasan, M. K.; Ismail, A. F.; H, Aisha-Hassan A.; Abdullah, Khaizuran; Ramli, H. A. M.

2013-12-01

The novel "femtocell" in Heterogeneous Network (HetNet) for LTE-Advanced (LTE-A) set-up will allow Malaysian wireless telecommunication operators (Maxis, Celcom, Digi, U-Mobile, P1, YTL and etc2.) to extend connectivity coverage where access would otherwise be limited or unavailable, particularly indoors of large building complexes. A femtocell is a small-sized cellular base station that encompasses all the functionality of a typical station. It therefore allows a simpler and self-contained deployment including private residences. For the Malaysian service providers, the main attractions of femtocell usage are the improvements to both coverage and capacity. The operators can provide a better service to end-users in turn reduce much of the agitations and complaints. There will be opportunity for new services at reduced cost. In addition, the operator not only benefits from the improved capacity and coverage but also can reduce both capital expenditure and operating expense i.e. alternative to brand new base station or macrocell installation. Interference is a key issue associated with femtocell development. There are a large number of issues associated with interference all of which need to be investigated, identified, quantified and solved. This is to ensure that the deployment of any femtocells will take place successfully. Among the most critical challenges in femtocell deployment is the interference between femtocell-to-macrocell and femtocell-to-femtocell in HetNets. In this paper, all proposed methods and algorithms will be investigated in the OFDMA femtocell system considering HetNet scenarios for LTE-A.

An investigation of interference coordination in heterogeneous network for LTE-Advanced systems

International Nuclear Information System (INIS)

Hasan, M K; Ismail, A F; Aisha-Hassan A H; Abdullah, Khaizuran; Ramli, H A M

2013-01-01

The novel ''femtocell'' in Heterogeneous Network (HetNet) for LTE-Advanced (LTE-A) set-up will allow Malaysian wireless telecommunication operators (Maxis, Celcom, Digi, U-Mobile, P1, YTL and etc2.) to extend connectivity coverage where access would otherwise be limited or unavailable, particularly indoors of large building complexes. A femtocell is a small-sized cellular base station that encompasses all the functionality of a typical station. It therefore allows a simpler and self-contained deployment including private residences. For the Malaysian service providers, the main attractions of femtocell usage are the improvements to both coverage and capacity. The operators can provide a better service to end-users in turn reduce much of the agitations and complaints. There will be opportunity for new services at reduced cost. In addition, the operator not only benefits from the improved capacity and coverage but also can reduce both capital expenditure and operating expense i.e. alternative to brand new base station or macrocell installation. Interference is a key issue associated with femtocell development. There are a large number of issues associated with interference all of which need to be investigated, identified, quantified and solved. This is to ensure that the deployment of any femtocells will take place successfully. Among the most critical challenges in femtocell deployment is the interference between femtocell-to-macrocell and femtocell-to-femtocell in HetNets. In this paper, all proposed methods and algorithms will be investigated in the OFDMA femtocell system considering HetNet scenarios for LTE-A

Non-local Thermodynamic Equilibrium Stellar Spectroscopy with 1D and Models. I. Methods and Application to Magnesium Abundances in Standard Stars

Science.gov (United States)

Bergemann, Maria; Collet, Remo; Amarsi, Anish M.; Kovalev, Mikhail; Ruchti, Greg; Magic, Zazralt

2017-09-01

We determine Mg abundances in six Gaia benchmark stars using theoretical one-dimensional (1D) hydrostatic model atmospheres, as well as temporally and spatially averaged three-dimensional () model atmospheres. The stars cover a range of Teff from 4700 to 6500 K, log g from 1.6 to 4.4 dex, and [Fe/H] from -3.0 dex to solar. Spectrum synthesis calculations are performed in local thermodynamic equilibrium (LTE) and in non-LTE (NLTE) using the oscillator strengths recently published by Pehlivan Rhodin et al. We find that: (a) Mg abundances determined from the infrared spectra are as accurate as the optical diagnostics, (b) the NLTE effects on Mg I line strengths and abundances in this sample of stars are minor (although for a few Mg I lines the NLTE effects on abundance exceed 0.6 dex in and 0.1 dex in 1D, (c) the solar Mg abundance is 7.56+/- 0.05 dex (total error), in excellent agreement with the Mg abundance measured in CI chondritic meteorites, (d) the 1D NLTE and NLTE approaches can be used with confidence to analyze optical Mg I lines in spectra of dwarfs and sub-giants, but for red giants the Mg I 5711 Å line should be preferred, (e) low-excitation Mg I lines are sensitive to the atmospheric structure; for these lines, LTE calculations with models lead to significant systematic abundance errors. The methods developed in this work will be used to study Mg abundances of a large sample of stars in the next paper in the series.

A Virtual Mixture Approach to the Study of Multistate Equilibrium: Application to Constant pH Simulation in Explicit Water

Science.gov (United States)

Wu, Xiongwu; Brooks, Bernard R.

2015-01-01

Chemical and thermodynamic equilibrium of multiple states is a fundamental phenomenon in biology systems and has been the focus of many experimental and computational studies. This work presents a simulation method to directly study the equilibrium of multiple states. This method constructs a virtual mixture of multiple states (VMMS) to sample the conformational space of all chemical states simultaneously. The VMMS system consists of multiple subsystems, one for each state. The subsystem contains a solute and a solvent environment. The solute molecules in all subsystems share the same conformation but have their own solvent environments. Transition between states is implicated by the change of their molar fractions. Simulation of a VMMS system allows efficient calculation of relative free energies of all states, which in turn determine their equilibrium molar fractions. For systems with a large number of state transition sites, an implicit site approximation is introduced to minimize the cost of simulation. A direct application of the VMMS method is for constant pH simulation to study protonation equilibrium. Applying the VMMS method to a heptapeptide of 3 ionizable residues, we calculated the pKas of those residues both with all explicit states and with implicit sites and obtained consistent results. For mouse epidermal growth factor of 9 ionizable groups, our VMMS simulations with implicit sites produced pKas of all 9 ionizable groups and the results agree qualitatively with NMR measurement. This example demonstrates the VMMS method can be applied to systems of a large number of ionizable groups and the computational cost scales linearly with the number of ionizable groups. For one of the most challenging systems in constant pH calculation, SNase Δ+PHS/V66K, our VMMS simulation shows that it is the state-dependent water penetration that causes the large deviation in lysine66’s pKa. PMID:26506245

A Virtual Mixture Approach to the Study of Multistate Equilibrium: Application to Constant pH Simulation in Explicit Water.

Directory of Open Access Journals (Sweden)

Xiongwu Wu

2015-10-01

Full Text Available Chemical and thermodynamic equilibrium of multiple states is a fundamental phenomenon in biology systems and has been the focus of many experimental and computational studies. This work presents a simulation method to directly study the equilibrium of multiple states. This method constructs a virtual mixture of multiple states (VMMS to sample the conformational space of all chemical states simultaneously. The VMMS system consists of multiple subsystems, one for each state. The subsystem contains a solute and a solvent environment. The solute molecules in all subsystems share the same conformation but have their own solvent environments. Transition between states is implicated by the change of their molar fractions. Simulation of a VMMS system allows efficient calculation of relative free energies of all states, which in turn determine their equilibrium molar fractions. For systems with a large number of state transition sites, an implicit site approximation is introduced to minimize the cost of simulation. A direct application of the VMMS method is for constant pH simulation to study protonation equilibrium. Applying the VMMS method to a heptapeptide of 3 ionizable residues, we calculated the pKas of those residues both with all explicit states and with implicit sites and obtained consistent results. For mouse epidermal growth factor of 9 ionizable groups, our VMMS simulations with implicit sites produced pKas of all 9 ionizable groups and the results agree qualitatively with NMR measurement. This example demonstrates the VMMS method can be applied to systems of a large number of ionizable groups and the computational cost scales linearly with the number of ionizable groups. For one of the most challenging systems in constant pH calculation, SNase Δ+PHS/V66K, our VMMS simulation shows that it is the state-dependent water penetration that causes the large deviation in lysine66's pKa.

A Virtual Mixture Approach to the Study of Multistate Equilibrium: Application to Constant pH Simulation in Explicit Water.

Science.gov (United States)

Wu, Xiongwu; Brooks, Bernard R

2015-10-01

Chemical and thermodynamic equilibrium of multiple states is a fundamental phenomenon in biology systems and has been the focus of many experimental and computational studies. This work presents a simulation method to directly study the equilibrium of multiple states. This method constructs a virtual mixture of multiple states (VMMS) to sample the conformational space of all chemical states simultaneously. The VMMS system consists of multiple subsystems, one for each state. The subsystem contains a solute and a solvent environment. The solute molecules in all subsystems share the same conformation but have their own solvent environments. Transition between states is implicated by the change of their molar fractions. Simulation of a VMMS system allows efficient calculation of relative free energies of all states, which in turn determine their equilibrium molar fractions. For systems with a large number of state transition sites, an implicit site approximation is introduced to minimize the cost of simulation. A direct application of the VMMS method is for constant pH simulation to study protonation equilibrium. Applying the VMMS method to a heptapeptide of 3 ionizable residues, we calculated the pKas of those residues both with all explicit states and with implicit sites and obtained consistent results. For mouse epidermal growth factor of 9 ionizable groups, our VMMS simulations with implicit sites produced pKas of all 9 ionizable groups and the results agree qualitatively with NMR measurement. This example demonstrates the VMMS method can be applied to systems of a large number of ionizable groups and the computational cost scales linearly with the number of ionizable groups. For one of the most challenging systems in constant pH calculation, SNase Δ+PHS/V66K, our VMMS simulation shows that it is the state-dependent water penetration that causes the large deviation in lysine66's pKa.

Influence of relaxation processes on the structure of a thermal boundary layer in partially ionized argon

International Nuclear Information System (INIS)

Dongen, M.E.H. van; Eck, R.B. van P. van; Hagebeuk, H.J.L.; Hirschberg, A.; Hutten-Mansfeld, A.C.B.; Jager, H.J.; Willems, J.F.H.

1981-01-01

A model for the unsteady thermal boundary-layer development at the end wall of a shock tube, in partially ionized atmospheric argon, is proposed. Consideration is given to ionization and thermal relaxation processes. In order to obtain some insight into the influence of the relaxation processes on the structure of the boundary layer, a study of the frozen and equilibrium limits has been carried out. The transition from a near-equilibrium situation in the outer part of the boundary layer towards a frozen situation near the wall is determined numerically. Experimental data on the electron and atom density profiles obtained from laser schlieren and absorption measurements are presented. A quantitative agreement between theory and experiment is found for a moderate degree of ionization (3%). At a higher degree of ionization the structure of the boundary layer is dominated by the influence of radiation cooling, which has been neglected in the model. (author)

Demonstration of digital fronthaul over self-seeded WDM-PON in commercial LTE environment.

Science.gov (United States)

Ma, Yiran; Xu, Zhiguang; Zhang, Chengliang; Lin, Huafeng; Wang, Qing; Zhou, Min; Wang, Heng; Yu, Jingwen; Wang, Xiaomu

2015-05-04

CPRI between BBU and RRU equipment is carried by self-seeded WDM-PON prototype system within commercial LTE end-to-end environment. Delay and jitter meets CPRI requirements while services demonstrated show the same performance as bare fiber.

On the kinetic theory of a fully ionized gas

International Nuclear Information System (INIS)

Bezerra Junior, A.G.; Rodbard, M.G.; Kremer, G.M.

1993-01-01

An alternative method for kinetic theory recently proposed, that combines the features of the Chapman-Enskog and Grad methods, neither using a solution of the integral equation nor the field equations of the moments, is applied to ionized gases. Like in the Grad method, the deviation from equilibrium of the moments are used. Like in the method of Grad, the deviation from equilibrium of the distribution function is written in terms of the moments of the distribution function, but the constitutive equations follow direct from the Boltzmann equation through the Chapman-Enskog method. (author)

QoE Power-Efficient Multimedia Delivery Method for LTE-A

OpenAIRE

Mushtaq, M. Sajid; Mellouk, Abdelhamid; Augustin, Brice; Fowler, Scott

2016-01-01

The fastest growing of multimedia services overfuture wireless communication system demand more networkresources, efficient delivery of multimedia service with highusers satisfaction, and power optimization of User Equipments(UEs). The resources and power optimization are significant infuture mobile computing systems, because emerging multimediaservices consume more resources and power. The 4G standard ofLTE-A wireless system has adopted the Discontinuous Reception(DRX) method to extend and o...

X-ray emission spectroscopy of well-characterised non-LTE plasmas

International Nuclear Information System (INIS)

Bourgaux, A C; Bastiani-Ceccotti, S; Audebert, P; Marquès, J R; Vassura, L; Vinci, T; Jacquemot, S; Dorchies, F; Leguay, P M; Chung, H K; Bowen, C; Dervieux, V; Renaudin, P; Silvert, V

2016-01-01

This paper will present an experimental platform developed on LULI2000 to measure x-ray emission of non-LTE plasmas in well-defined hydrodynamic conditions thanks to implementation of a whole set of diagnostics, including time-resolved electronic and ionic Thomson scattering and self-optical pyrometry. K-, L- and M-shell spectra will be presented and the methodology, that has been developed to analyze them, discussed. (paper)

Traffic Dimensioning and Performance Modeling of 4G LTE Networks

Science.gov (United States)

Ouyang, Ye

2011-01-01

Rapid changes in mobile techniques have always been evolutionary, and the deployment of 4G Long Term Evolution (LTE) networks will be the same. It will be another transition from Third Generation (3G) to Fourth Generation (4G) over a period of several years, as is the case still with the transition from Second Generation (2G) to 3G. As a result,…

Impact of relay station positioning on LTE uplink performance at flow level

NARCIS (Netherlands)

Hennepe, D.H. te; Berg, J.L. van den; Karagiannis, G.

2012-01-01

Long Term Evolution (LTE) is the latest cellular system that is being standardized by the 3rd Generation Partnership Project (3GPP) and is expected to substantially improve end-user throughput and reduce user plane latency, while at the same time significantly improve user experience with full

Impact of Relay Station Positioning on LTE Uplink Performance at Flow Level

NARCIS (Netherlands)

te Hennepe, D.H.; van den Berg, Hans Leo; Karagiannis, Georgios

2012-01-01

Long Term Evolution (LTE) is the latest cellular system that is being standardized by the 3rd Generation Partnership Project (3GPP) and is expected to substantially improve end-user throughput and reduce user plane latency, while at the same time significantly improve user experience with full

Perancangan dan Implementasi Duplexer Mikrostrip untuk Frekuensi LTE pada band ke-7

Directory of Open Access Journals (Sweden)

ENCENG SULAEMAN

2013-07-01

The necessary of mobile communication has increased in technology, now it released the new of technology is Long Term Evolution (LTE. Type of duplex is Frequency Division Duplex (FDD, designed a duplexer which it is capable for transmitting and receiving process at the same time with the different of frequency between uplink and downlink. Research of designed and implemented a duplexer using Hybrid Coupler and Bandstop filters based on Split Ring Resonators for the frequency band 7th on LTE technology at Base Transceiver Station (BTS. Duplexer is made by combining two coupler and two bandstop filter. The results of duplexer measurements, when Tx port transmit the signal to antenna port with attenuation at the downlink frequency center at 3.168 dB. Attenuation from antenna port to Rx port about 6 dB. Isolation between Tx port and Rx port about 15 dB. Keywords: Duplexer, Bandstop Filter, Split Ring Resonator, Hybrid Coupler, and Long Term Evolution.

Optimized LTE cell planning for multiple user density subareas using meta-heuristic algorithms

KAUST Repository

Ghazzai, Hakim; Yaacoub, Elias E.; Alouini, Mohamed-Slim

2014-01-01

Base station deployment in cellular networks is one of the most fundamental problems in network design. This paper proposes a novel method for the cell planning problem for the fourth generation 4G-LTE cellular networks using meta heuristic

TIME DEPENDENT NONEQUILIBRIUM IONIZATION OF TRANSITION REGION LINES OBSERVED WITH IRIS

Energy Technology Data Exchange (ETDEWEB)

Martínez-Sykora, Juan; Pontieu, Bart De; Hansteen, Viggo H. [Lockheed Martin Solar and Astrophysics Laboratory, Palo Alto, CA 94304 (United States); Gudiksen, Boris, E-mail: j.m.sykora@astro.uio.no [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern, NO-0315 Oslo (Norway)

2016-01-20

The properties of nonstatistical equilibrium ionization of silicon and oxygen ions are analyzed in this work. We focus on five solar targets (quiet Sun; coronal hole; plage; quiescent active region, AR; and flaring AR) as observed with the Interface Region Imaging Spectrograph (IRIS). IRIS is best suited for this work owing to the high cadence (up to 0.5 s), high spatial resolution (up to 0.″32), and high signal-to-noise ratios for O iv λ1401 and Si iv λ1402. We find that the observed intensity ratio between lines of three times ionized silicon and oxygen ions depends on their total intensity and that this correlation varies depending on the region observed (quiet Sun, coronal holes, plage, or active regions) and on the specific observational objects present (spicules, dynamic loops, jets, microflares, or umbra). In order to interpret the observations, we compare them with synthetic profiles taken from 2D self-consistent radiative MHD simulations of the solar atmosphere, where the statistical equilibrium or nonequilibrium treatment of silicon and oxygen is applied. These synthetic observations show vaguely similar correlations to those in the observations, i.e., between the intensity ratios and their intensities, but only in the nonequilibrium case do we find that (some of) the observations can be reproduced. We conclude that these lines are formed out of statistical equilibrium. We use our time-dependent nonequilibrium ionization simulations to describe the physical mechanisms behind these observed properties.

Achieving energy efficiency in LTE with joint D2D communications and green networking techniques

KAUST Repository

Yaacoub, Elias E.

2013-07-01

In this paper, the joint operation of cooperative device-to-device (D2D) communications and green cellular communications is investigated. An efficient approach for grouping mobile terminals (MTs) into cooperative clusters is described. In each cluster, MTs cooperate via D2D communications to share content of common interest. Furthermore, an energy-efficient technique for putting BSs in sleep mode in an LTE cellular network is presented. Finally, both methods are combined in order to ensure green communications for both the users\\' MTs and the operator\\'s BSs. The studied methods are investigated in the framework of OFDMA-based state-of-the-art LTE cellular networks, while taking into account intercell interference and resource allocation. © 2013 IEEE.

New solar carbon abundance based on non-LTE CN molecular spectra

International Nuclear Information System (INIS)

Mount, G.H.; Linsky, J.L.

1975-01-01

A detailed non-LTE analysis of solar CN spectra strongly suggests a revised carbon abundance for the Sun. A value of log A/subc/=8.35plus-or-minus0.15 which is significantly lower than the presently accepted value of log A/subc/=8.55 is suggested. This revision may have important consequences in astrophysics

Machine-Learning Identification of Airborne UAV-UEs Based on LTE Radio Measurements

DEFF Research Database (Denmark)

Amorim, Rafhael Medeiros de; Wigard, Jeroen; Nguyen, Huan Cong

2017-01-01

, which use standard LTE measurements from the UE as input, for detecting the presence of airborne users in the network. The algorithms are evaluated based on measurements done with mobile phones attached under a flying drone and on a car. Results are discussed showing the advantages and drawbacks...

英国 EE 的 LTE 运营案例分析及启示

Institute of Scientific and Technical Information of China (English)

钱海峰

2014-01-01

本文通过对英国移动运营商 Everything Ev-erywhere 公司（简称“EE”）的案例研究，从网络、终端、市场策略三个维度进行了问题分析，探寻该企业未能在较长的时间窗口内达到市场预期的原因，并在网络覆盖、终端提供、品牌推广、资费与市场定位、业务等方面总结了对中国移动 LTE 发展的启示。%This article studies the British mobile op-erator, Everything Everywhere's deployment of LTE (referred as "EE" for short), to explore the reason why this company fails to reach the market expectation in a long time from three aspects of the network, terminal and market strategy, and then sums up its experience in network coverage, terminals, brand promotion, tar-iffs and market positioning, business and so on, in or-der to enlighten the development of CMCC's LTE de-velopment.

Novel wideband MIMO antennas that can cover the whole LTE spectrum in handsets and portable computers.

Science.gov (United States)

Sanad, Mohamed; Hassan, Noha

2014-01-01

A dual resonant antenna configuration is developed for multistandard multifunction mobile handsets and portable computers. Only two wideband resonant antennas can cover most of the LTE spectrums in portable communication equipment. The bandwidth that can be covered by each antenna exceeds 70% without using any matching or tuning circuits, with efficiencies that reach 80%. Thus, a dual configuration of them is capable of covering up to 39 LTE (4G) bands besides the existing 2G and 3G bands. 2×2 MIMO configurations have been also developed for the two wideband antennas with a maximum isolation and a minimum correlation coefficient between the primary and the diversity antennas.

Electronic structure and spectroscopy of nucleic acid bases: Ionization energies, ionization-induced structural changes, and photoelectron spectra

Energy Technology Data Exchange (ETDEWEB)

Bravaya, Ksenia B.; Kostko, Oleg; Dolgikh, Stanislav; Landau, Arie; Ahmed, Musahid; Krylov, Anna I.

2010-08-02

We report high-level ab initio calculations and single-photon ionization mass spectrometry study of ionization of adenine (A), thymine (T), cytosine (C) and guanine (G). For thymine and adenine, only the lowest-energy tautomers were considered, whereas for cytosine and guanine we characterized five lowest-energy tautomeric forms. The first adiabatic and several vertical ionization energies were computed using equation-of-motion coupled-cluster method for ionization potentials with single and double substitutions. Equilibrium structures of the cationic ground states were characterized by DFT with the {omega}B97X-D functional. The ionization-induced geometry changes of the bases are consistent with the shapes of the corresponding molecular orbitals. For the lowest-energy tautomers, the magnitude of the structural relaxation decreases in the following series G > C > A > T, the respective relaxation energies being 0.41, 0.32, 0.25 and 0.20 eV. The computed adiabatic ionization energies (8.13, 8.89, 8.51-8.67 and 7.75-7.87 eV for A,T,C and G, respectively) agree well with the onsets of the photoionization efficiency (PIE) curves (8.20 {+-} 0.05, 8.95 {+-} 0.05, 8.60 {+-} 0.05 and 7.75 {+-} 0.05 eV). Vibrational progressions for the S{sub 0}-D{sub 0} vibronic bands computed within double-harmonic approximation with Duschinsky rotations are compared with previously reported experimental photoelectron spectra.

The effect of SNR structure on non-equilibrium X-ray spectra

International Nuclear Information System (INIS)

Hamilton, A.J.S.; Sarazin, C.L.

1983-01-01

A technique is presented for characterizing the ionization structure and consequent thermal X-ray emission of a SNR when non-equilibrium ionization effects are important. The technique allows different theoretical SNR models to be compared and contrasted rapidly in advance of detailed numerical computations. In particular it is shown that the spectrum of a Sedov remnant can probably be applied satisfactorily in a variety of SNR structures, including the reverse shock model advocated by Chevalier (1982) for Type I SN, the isothermal similarity solution of Solinger, Rappaport and Buff (1975), and various inhomogenous or 'messy' structures. (Auth.)

On the Conductive Loss of High-Q Frequency Reconfigurable Antennas for LTE Frequencies

DEFF Research Database (Denmark)

Barrio, Samantha Caporal Del

2018-01-01

Intrinsically narrowband and highly tunable systems are a promising way to address the bandwidth challenge of LTE. However, narrowband antennas exhibit low efficiencies. This paper details the loss mechanism of narrowband antennas by investigating the contribution of the resistance of the tuner...

Applying SDN/OpenFlow in Virtualized LTE to support Distributed Mobility Management (DMM)

NARCIS (Netherlands)

Karimzadeh Motallebi Azar, Morteza; Valtulina, Luca; Karagiannis, Georgios

2014-01-01

Distributed Mobility Management (DMM) is a mobility management solution, where the mobility anchors are distributed instead of being centralized. The use of DMM can be applied in cloud-based (virtualized) Long Term Evolution (LTE) mobile network environments to (1) provide session continuity to

A multi-mode multi-band RF receiver front-end for a TD-SCDMA/LTE/LTE-advanced in 0.18-μm CMOS process

International Nuclear Information System (INIS)

Guo Rui; Zhang Haiying

2012-01-01

A fully integrated multi-mode multi-band directed-conversion radio frequency (RF) receiver front-end for a TD-SCDMA/LTE/LTE-advanced is presented. The front-end employs direct-conversion design, and consists of two differential tunable low noise amplifiers (LNA), a quadrature mixer, and two intermediate frequency (IF) amplifiers. The two independent tunable LNAs are used to cover all the four frequency bands, achieving sufficient low noise and high gain performance with low power consumption. Switched capacitor arrays perform a resonant frequency point calibration for the LNAs. The two LNAs are combined at the driver stage of the mixer, which employs a folded double balanced Gilbert structure, and utilizes PMOS transistors as local oscillator (LO) switches to reduce flicker noise. The front-end has three gain modes to obtain a higher dynamic range. Frequency band selection and mode of configuration is realized by an on-chip serial peripheral interface (SPI) module. The front-end is fabricated in a TSMC 0.18-μm RF CMOS process and occupies an area of 1.3 mm 2 . The measured double-sideband (DSB) noise figure is below 3.5 dB and the conversion gain is over 43 dB at all of the frequency bands. The total current consumption is 31 mA from a 1.8-V supply. (semiconductor integrated circuits)

Composition and partition functions of partially ionized hydrogen plasma in Non-Local Thermal Equilibrium (Non-LThE) and Non-Local Chemical Equilibrium (Non-LChE)

International Nuclear Information System (INIS)

Chen Kuan; Eddy, T.L.

1993-01-01

A GTME (Generalized MultiThermodynamic Equilibrium) plasma model is developed for plasmas in both Non-LThE (Non-Local Thermal Equilibrium) and Non-LChE (Non-Local Chemical Equilibrium). The model uses multitemperatures for thermal nonequilibrium and non-zero chemical affinities as a measure of the deviation from chemical equilibrium. The plasma is treated as an ideal gas with the Debye-Hueckel approximation employed for pressure correction. The proration method is used when the cutoff energy level is between two discrete levels. The composition and internal partition functions of a hydrogen plasma are presented for electron temperatures ranging from 5000 to 35000 K and pressures from 0.1 to 1000 kPa. Number densities of 7 different species of hydrogen plasma and internal partition functions of different energy modes (rotational, vibrational, and electronic excitation) are computed for three affinity values. The results differ from other plasma properties in that they 1) are not based on equilibrium properties; and 2) are expressed as a function of different energy distribution parameters (temperatures) within each energy mode of each species as appropriate. The computed number densities and partition functions are applicable to calculating the thermodynamic, transport, and radiation properties of a hydrogen plasma not in thermal and chemical equilibria. The nonequilibrium plasma model and plasma compositions presented in this paper are very useful to the diagnosis of high-speed and/or low-pressure plasma flows in which the assumptions of local thermal and chemical equilibrium are invalid. (orig.)

Charge correlation effects on ionization of weak polyelectrolytes

International Nuclear Information System (INIS)

Panagiotopoulos, A Z

2009-01-01

Ionization curves of weak polyelectrolytes were obtained as a function of the charge coupling strength from Monte Carlo simulations. In contrast to many earlier studies, the present work treats counterions explicitly, thus allowing the investigation of charge correlation effects at strong couplings. For conditions representing typical weak polyelectrolytes in water near room temperature, ionization is suppressed because of interactions between nearby dissociated groups, as also seen in prior work. A novel finding here is that, for stronger couplings, relevant for non-aqueous environments in the absence of added salt, the opposite behavior is observed-ionization is enhanced relative to the behavior of the isolated groups due to ion-counterion correlation effects. The fraction of dissociated groups as a function of position along the chain also behaves non-monotonically. Dissociation is highest near the ends of the chains for aqueous polyelectrolytes and highest at the chain middle segments for non-aqueous environments. At intermediate coupling strengths, dissociable groups appear to behave in a nearly ideal fashion, even though chain dimensions still show strong expansion effects due to ionization. These findings provide physical insights on the impact of competition between acid/base chemical equilibrium and electrostatic attractions in ionizable systems.

Multiscale Modeling of Multiphase Fluid Flow

Science.gov (United States)

2016-08-01

was compared to the original equilibrium volume of the neat solvent as a measure of the solubility of carbon dioxide and ammonia in pure water and...temperature and two-temperature models has been used, in which either local thermal equilibrium ( LTE ) between PCM and foams was assumed, or the...solved in the simulations. 6.2.2 Direct Numerical Simulation of PCM in Foam Without the need for extra ad hoc assumptions such as LTE , direct

Evaluating TCMS Train-to-Ground communication performances based on the LTE technology and discreet event simulations

DEFF Research Database (Denmark)

Bouaziz, Maha; Yan, Ying; Kassab, Mohamed

2018-01-01

is shared between the train and different passengers. The simulation is based on the discrete-events network simulator Riverbed Modeler. Next, second step focusses on a co-simulation testbed, to evaluate performances with real traffic based on Hardware-In-The-Loop and OpenAirInterface modules. Preliminary...... (Long Term Evolution) network as an alternative communication technology, instead of GSM-R (Global System for Mobile communications-Railway) because of some capacity and capability limits. First step, a pure simulation is used to evaluate the network load for a high-speed scenario, when the LTE network...... simulation and co-simulation results show that LTE provides good performance for the TCMS traffic exchange in terms of packet delay and data integrity...

Novel Wideband MIMO Antennas That Can Cover the Whole LTE Spectrum in Handsets and Portable Computers

Directory of Open Access Journals (Sweden)

Mohamed Sanad

2014-01-01

Full Text Available A dual resonant antenna configuration is developed for multistandard multifunction mobile handsets and portable computers. Only two wideband resonant antennas can cover most of the LTE spectrums in portable communication equipment. The bandwidth that can be covered by each antenna exceeds 70% without using any matching or tuning circuits, with efficiencies that reach 80%. Thus, a dual configuration of them is capable of covering up to 39 LTE (4G bands besides the existing 2G and 3G bands. 2×2 MIMO configurations have been also developed for the two wideband antennas with a maximum isolation and a minimum correlation coefficient between the primary and the diversity antennas.

Electron temperature measurement of tungsten inert gas arcs

International Nuclear Information System (INIS)

Tanaka, Manabu; Tashiro, Shinichi

2008-01-01

In order to make clear the physical grounds of deviations from LTE (Local Thermodynamic Equilibrium) in the atmospheric helium TIG arcs electron temperature and LTE temperature obtained from electron number density were measured by using of line-profile analysis of the laser scattering method without an assumption of LTE. The experimental results showed that in comparison with the argon TIG arcs, the region where a deviation from LTE occurs tends to expand in higher arc current because the plasma reaches the similar state to LTE within shorter distance from the cathode due to the slower cathode jet velocity

Performance evaluation of ICN/CCN based service migration approach in virtualized LTE systems

NARCIS (Netherlands)

Satria, Triadimas; Karimzadeh Motallebi Azar, Morteza; Karagiannis, Georgios

2014-01-01

The continuous growth in using mobile devices (e.g. smart phones, tablets, etc.) has increased the complexity in provisioning cellular network resources. Applying the cloud computing model in LTE (Long Term Evolution) systems could be a good solution to increase LTE’s performance by building a

A NON-LOCAL THERMODYNAMIC EQUILIBRIUM ANALYSIS OF BORON ABUNDANCES IN METAL-POOR STARS

International Nuclear Information System (INIS)

Tan Kefeng; Shi Jianrong; Zhao Gang

2010-01-01

The non-local thermodynamic equilibrium (NLTE) line formation of neutral boron in the atmospheres of cool stars are investigated. Our results confirm that NLTE effects for the B I resonance lines, which are due to a combination of overionization and optical pumping effects, are most important for hot, metal-poor, and low-gravity stars; however, the amplitude of departures from local thermodynamic equilibrium (LTE) found by this work is smaller than that of previous studies. In addition, our calculation shows that the line formation of B I will get closer to LTE if the strength of collisions with neutral hydrogen increases, which is contrary to the result of previous studies. The NLTE line formation results are applied to the determination of boron abundances for a sample of 16 metal-poor stars with the method of spectrum synthesis of the B I 2497 A resonance lines using the archived HST/GHRS spectra. Beryllium and oxygen abundances are also determined for these stars with the published equivalent widths of the Be II 3131 A resonance and O I 7774 A triplet lines, respectively. The abundances of the nine stars which are not depleted in Be or B show that, no matter what the strength of collisions with neutral hydrogen may be, both Be and B increase with O quasilinearly in the logarithmic plane, which confirms the conclusions that Be and B are mainly produced by the primary process in the early Galaxy. The most noteworthy result of this work is that B increases with Fe or O at a very similar speed as, or a bit faster than, Be does, which is in accord with the theoretical models. The B/Be ratios remain almost constant over the metallicity range investigated here. Our average B/Be ratio falls in the interval [13 ± 4, 17 ± 4], which is consistent with the predictions of the spallation process. The contribution of B from the ν-process may be required if the 11 B/ 10 B isotopic ratios in metal-poor stars are the same as the meteoric value. An accurate measurement of the

Perancangan Dan Analisis Antena Mikrostrip Mimo Circular Pada Frekuensi 2.35 GHz Untuk Aplikasi LTE

Directory of Open Access Journals (Sweden)

Imam M.P Budi

2017-02-01

Full Text Available LTE (long Term Evolution merupakan teknologi komunikasi wireless generasi keempat yang saat ini sedang mengalami perkembangan. Salah satu perangkat yang sangat dibutuhkan pada teknologi tersebut adalah antenna. Teknik yang digunakan adalah teknik MIMO. Teknik MIMO menggunakan multiantena baik di sisi transmitter maupun di sisi receiver dengan koefisien korelasi di bawah 0.2. Untuk menghasilkan nilai koefisien korelasi di bawah 0.2, antena menggunakan ?/2 untuk jarak antar dua antena. Perancangan dan realisasi antena pada skripsi ini dipergunakan untuk aplikasi LTE yang bekerja pada frekuensi 2.3 GHz sampai 2.4 GHz. Simulasi antena menunjukkan frekuensi kerja yang direncanakan yaitu antara 2.3 GHz – 2.4 GHz, memiliki Return Loss -38.582 dB dan VSWR 1.0238 pada frekuensi tengah 2.350 MHz, gain sebesar 4.332 dBi. Hasil pengukuran antena satu terdapat pergeseran frekuensi dari 2.300 MHz - 2.400 MHz menjadi 2.310 - 2.384 MHz, antena  ini memiliki  Return  Loss -35.476 dB dan VSWR 1.034. Bandwidth 74 Mhz. Untuk antena dua terdapat pergeseran frekuensi menjadi 2.310 - 2.382 MHz, dengan Return  Loss -33.637 dB  dan VSWR  1.042. Bandwidth 72 MHz. Pada frekuensi 2.35 GHz gain sebesar 8 dBi dengan pola radiasi unidirectional dan polarisasi elips. Dari perancangan dan analisis tersebut, maka antena ini dapat digunakan sebagai antena teknologi LTE

The Origin of B-type Runaway Stars: Non-LTE Abundances as a Diagnostic

Energy Technology Data Exchange (ETDEWEB)

McEvoy, Catherine M.; Dufton, Philip L.; Smoker, Jonathan V.; Keenan, Francis P. [Astrophysics Research Centre, School of Mathematics and Physics, Queen’s University Belfast, Belfast BT7 1NN (United Kingdom); Lambert, David L. [The University of Texas at Austin, Department of Astronomy, RLM 16.316, Austin, TX 78712 (United States); Schneider, Fabian R. N. [Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH (United Kingdom); De Wit, Willem-Jan [European Southern Observatory, Alonso de Cordova 3107, Casilla 19001, Vitacura, Santiago 19 (Chile)

2017-06-10

There are two accepted mechanisms to explain the origin of runaway OB-type stars: the binary supernova (SN) scenario and the cluster ejection scenario. In the former, an SN explosion within a close binary ejects the secondary star, while in the latter close multibody interactions in a dense cluster cause one or more of the stars to be ejected from the region at high velocity. Both mechanisms have the potential to affect the surface composition of the runaway star. tlusty non-LTE model atmosphere calculations have been used to determine the atmospheric parameters and the C, N, Mg, and Si abundances for a sample of B-type runaways. These same analytical tools were used by Hunter et al. for their analysis of 50 B-type open-cluster Galactic stars (i.e., nonrunaways). Effective temperatures were deduced using the Si-ionization balance technique, surface gravities from Balmer line profiles, and microturbulent velocities derived using the Si spectrum. The runaways show no obvious abundance anomalies when compared with stars in the open clusters. The runaways do show a spread in composition that almost certainly reflects the Galactic abundance gradient and a range in the birthplaces of the runaways in the Galactic disk. Since the observed Galactic abundance gradients of C, N, Mg, and Si are of a similar magnitude, the abundance ratios (e.g., N/Mg) are as obtained essentially uniform across the sample.

Structure of non-equilibrium seeded plasma excited with microwave; Micro ha reiki hiheiko seed plasma no kozo

Energy Technology Data Exchange (ETDEWEB)

Miyakawa, M.; Murakami, T.; Suekane, T.; Okuno, Y.; Kabashima, S. [Tokyo Institute of Technology, Tokyo (Japan)

1996-10-20

Structure of non-equilibrium cesium seeded argon plasma excited with microwave power is simulated numerically. The plasmas produced at suitable microwave powers are found to consist of three regimes, that is, the region limited by charged particle loss toward the wall, the full seed ionization and the diffusion limited regions. The fully ionized seed plasma is produced within the skin-depth determined by the electrical conductivity of the plasma, and the thickness of the fully ionized seed plasma depends on the seed fractions gas pressure and microwave power. 15 refs., 6 figs.

Energy balance in the solar transition region. I - Hydrostatic thermal models with ambipolar diffusion

Science.gov (United States)

Fontenla, J. M.; Avrett, E. H.; Loeser, R.

1990-01-01

The energy balance in the lower transition region is analyzed by constructing theoretical models which satisfy the energy balance constraint. The energy balance is achieved by balancing the radiative losses and the energy flowing downward from the corona. This energy flow is mainly in two forms: conductive heat flow and hydrogen ionization energy flow due to ambipolar diffusion. Hydrostatic equilibrium is assumed, and, in a first calculation, local mechanical heating and Joule heating are ignored. In a second model, some mechanical heating compatible with chromospheric energy-balance calculations is introduced. The models are computed for a partial non-LTE approach in which radiation departs strongly from LTE but particles depart from Maxwellian distributions only to first order. The results, which apply to cases where the magnetic field is either absent, or uniform and vertical, are compared with the observed Lyman lines and continuum from the average quiet sun. The approximate agreement suggests that this type of model can roughly explain the observed intensities in a physically meaningful way, assuming only a few free parameters specified as chromospheric boundary conditions.

BADGER v1.0: A Fortran equation of state library

Science.gov (United States)

Heltemes, T. A.; Moses, G. A.

2012-12-01

The BADGER equation of state library was developed to enable inertial confinement fusion plasma codes to more accurately model plasmas in the high-density, low-temperature regime. The code had the capability to calculate 1- and 2-T plasmas using the Thomas-Fermi model and an individual electron accounting model. Ion equation of state data can be calculated using an ideal gas model or via a quotidian equation of state with scaled binding energies. Electron equation of state data can be calculated via the ideal gas model or with an adaptation of the screened hydrogenic model with ℓ-splitting. The ionization and equation of state calculations can be done in local thermodynamic equilibrium or in a non-LTE mode using a variant of the Busquet equivalent temperature method. The code was written as a stand-alone Fortran library for ease of implementation by external codes. EOS results for aluminum are presented that show good agreement with the SESAME library and ionization calculations show good agreement with the FLYCHK code. Program summaryProgram title: BADGERLIB v1.0 Catalogue identifier: AEND_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEND_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 41 480 No. of bytes in distributed program, including test data, etc.: 2 904 451 Distribution format: tar.gz Programming language: Fortran 90. Computer: 32- or 64-bit PC, or Mac. Operating system: Windows, Linux, MacOS X. RAM: 249.496 kB plus 195.630 kB per isotope record in memory Classification: 19.1, 19.7. Nature of problem: Equation of State (EOS) calculations are necessary for the accurate simulation of high energy density plasmas. Historically, most EOS codes used in these simulations have relied on an ideal gas model. This model is inadequate for low

A MU-MIMO CQI estimation method for MU-MIMO UEs in LTE systems

DEFF Research Database (Denmark)

Nguyen, Hung Tuan; Kovacs, Istvan

2012-01-01

Abstract—This paper addresses a method to estimate the multi user channel quality indicator (CQI) from the reported rank 1 single user CQI in LTE systems. We investigate the relationship between the multi user CQI and the channel condition. Based on that, we propose an updating mechanism where th...

Elemental composition and ionization state of the solar atmosphere and solar wind

International Nuclear Information System (INIS)

Joselyn, J.A.C.

1978-01-01

Abundance measurements have always proved useful in generating and refining astrophysical theories. Some of the classical problems of astrophysics involve determining the relative abundances of elements in the atmosphere of a star from observations of its line spectrum, and then synthesizing the physical processes which would produce such abundances. Theories of the formation of the solar system are critically tested by their ability to explain observed abundances, and, elemental abundances can serve as tracers, helping to determine the origin and transport of ions. Since the solar wind originates at the sun, it can act as a diagnostic probe of solar conditions. In particular, measurements of the composition of the solar wind should be related to the solar composition. And, assuming ionization equilibrium, measurements of the relative abundances of the ionization states in the solar wind should infer coronal temperatures and temperature gradients. However, most spherically symmetric models of the solar wind are unable to explain the relationship between the composition estimated from solar observations and as measured at 1 AU; and, recent observations of significant flow speeds in the transition region raise doubts about the validity of the assumption of ionization equilibrium

Numerical simulation of hypersonic inlet flows with equilibrium or finite rate chemistry

Science.gov (United States)

Yu, Sheng-Tao; Hsieh, Kwang-Chung; Shuen, Jian-Shun; Mcbride, Bonnie J.

1988-01-01

An efficient numerical program incorporated with comprehensive high temperature gas property models has been developed to simulate hypersonic inlet flows. The computer program employs an implicit lower-upper time marching scheme to solve the two-dimensional Navier-Stokes equations with variable thermodynamic and transport properties. Both finite-rate and local-equilibrium approaches are adopted in the chemical reaction model for dissociation and ionization of the inlet air. In the finite rate approach, eleven species equations coupled with fluid dynamic equations are solved simultaneously. In the local-equilibrium approach, instead of solving species equations, an efficient chemical equilibrium package has been developed and incorporated into the flow code to obtain chemical compositions directly. Gas properties for the reaction products species are calculated by methods of statistical mechanics and fit to a polynomial form for C(p). In the present study, since the chemical reaction time is comparable to the flow residence time, the local-equilibrium model underpredicts the temperature in the shock layer. Significant differences of predicted chemical compositions in shock layer between finite rate and local-equilibrium approaches have been observed.

Dual connectivity for LTE-advanced heterogeneous networks

DEFF Research Database (Denmark)

Wang, Hua; Rosa, Claudio; Pedersen, Klaus I.

2016-01-01

Dual connectivity (DC) allows user equipments (UEs) to receive data simultaneously from different eNodeBs (eNBs) in order to boost the performance in a heterogeneous network with dedicated carrier deployment. Yet, how to efficiently operate with DC opens a number of research questions. In this pa......Dual connectivity (DC) allows user equipments (UEs) to receive data simultaneously from different eNodeBs (eNBs) in order to boost the performance in a heterogeneous network with dedicated carrier deployment. Yet, how to efficiently operate with DC opens a number of research questions...... aggregation (CA) and virtually zerolatency fronthaul connections, and in any case it is significantly higher compared to the case without DC. Keywords: Dual connectivity Heterogeneous network LTE-advanced Radio resource management Performance evaluation...

Experimental Characterization of LTE Wireless Links in High-Speed Trains

Directory of Open Access Journals (Sweden)

Tomás Domínguez-Bolaño

2017-01-01

Full Text Available Multimedia and data-based services experienced a nonstopping growth over the last few years. People are continuously on the move using devices to access multimedia contents or other data-based services. Due to this, railway companies are showing a great interest in deploying broadband mobile wireless networks in high-speed-trains with the aim of supporting both passenger services provisioning as well as automatic train control and signaling. Nowadays, the most widely used technology for communications between trains and the railway infrastructure is GSM for Railways (GSM-R; however, it has limited capabilities to support such advanced services. Due to its success in the mass market, Long Term Evolution (LTE seems to be the best candidate to substitute GSM-R. In this paper, we experimentally characterize the downlink between an LTE Evolved NodeB (eNodeB and a high-speed train in a commercial high-speed line. We consider two links: the one between the eNodeB and the antennas placed outdoors on the train roof, and the direct link between the eNodeB and a receiver inside the train. Such a characterization consists in assessing the path loss, the Signal to Noise Ratio, the K-Factor, the Power Delay Profile, the delay spread, and the Doppler Power Spectral Density.

Dual Band Metamaterial Antenna For LTE/Bluetooth/WiMAX System.

Science.gov (United States)

Hasan, Md Mehedi; Faruque, Mohammad Rashed Iqbal; Islam, Mohammad Tariqul

2018-01-19

A compact metamaterial inspired antenna operate at LTE, Bluetooth and WiMAX frequency band is introduced in this paper. For the lower band, the design utilizes an outer square metallic strip forcing the patch to radiate as an equivalent magnetic-current loop. For the upper band, another magnetic current loop is created by adding metamaterial structure near the feed line on the patch. The metamaterial inspired antenna dimension of 42 × 32 mm 2 compatible to wireless devices. Finite integration technique based CST Microwave Studio simulator has been used to design and numerical investigation as well as lumped circuit model of the metamaterial antenna is explained with proper mathematical derivation. The achieved measured dual band operation of the conventional antenna are sequentially, 0.561~0.578 GHz, 2.346~2.906 GHz, and 2.91~3.49 GHz, whereas the metamaterial inspired antenna shows dual-band operation from 0.60~0.64 GHz, 2.67~3.40 GHz and 3.61~3.67 GHz, respectively. Therefore, the metamaterial antenna is applicable for LTE and WiMAX applications. Besides, the measured metamaterial antenna gains of 0.15~3.81 dBi and 3.47~3.75 dBi, respectively for the frequency band of 2.67~3.40 GHz and 3.61~3.67 GHz.

Tofacitinib, an oral Janus kinase inhibitor, in patients from Mexico with rheumatoid arthritis: Pooled efficacy and safety analyses from Phase 3 and LTE studies.

Science.gov (United States)

Burgos-Vargas, Ruben; Cardiel, Mario; Xibillé, Daniel; Pacheco-Tena, César; Pascual-Ramos, Virginia; Abud-Mendoza, Carlos; Mahgoub, Ehab; Rahman, Mahboob; Fan, Haiyun; Rojo, Ricardo; García, Erika; Santana, Karina

2017-05-25

Tofacitinib is an oral Janus kinase inhibitor for the treatment of rheumatoid arthritis (RA). We characterized efficacy and safety of tofacitinib in Mexican patients from RA Phase 3 and long-term extension (LTE) studies. Data from Mexican patients with RA and an inadequate response to disease-modifying antirheumatic drugs (DMARDs) were taken from four Phase 3 studies (pooled across studies) and one open-label LTE study of tofacitinib. Patients received tofacitinib 5 or 10mg twice daily, adalimumab (one Phase 3 study) or placebo (four Phase 3 studies) as monotherapy or in combination with conventional synthetic DMARDs. Efficacy up to Month 12 (Phase 3) and Month 36 (LTE) was assessed by American College of Rheumatology 20/50/70 response rates, Disease Activity Score (erythrocyte sedimentation rate), and Health Assessment Questionnaire-Disability Index. Safety, including incidence rates (IRs; patients with events/100 patient-years) for adverse events (AEs) of special interest, was assessed throughout the studies. 119 and 212 Mexican patients were included in the Phase 3 and LTE analyses, respectively. Tofacitinib-treated patients in Phase 3 had numerically greater improvements in efficacy responses versus placebo at Month 3. Efficacy was sustained in Phase 3 and LTE studies. IRs for AEs of special interest were similar to those with tofacitinib in the global and Latin American RA populations. In Mexican patients from the tofacitinib global RA program, tofacitinib efficacy was demonstrated up to Month 12 in Phase 3 studies and Month 36 in the LTE study, with a safety profile consistent with tofacitinib global population. Copyright © 2017 Elsevier España, S.L.U. and Sociedad Española de Reumatología y Colegio Mexicano de Reumatología. All rights reserved.

Ionizing and non-ionizing radiations

International Nuclear Information System (INIS)

1994-01-01

The monograph is a small manual to get a knowledge of ionizing and non-ionizing radiations. The main chapters are: - Electromagnetic radiations - Ionizing and non-ionizing radiations - Non-ionizing electromagnetic radiations - Ionizing electromagnetic radiation - Other ionizing radiations - Ionizing radiation effects - The Nuclear Safety Conseil

Errors in Sounding of the Atmosphere Using Broadband Emission Radiometry (SABER) Kinetic Temperature Caused by Non-Local Thermodynamic Equilibrium Model Parameters

Science.gov (United States)

Garcia-Comas, Maya; Lopez-Puertas, M.; Funke, B.; Bermejo-Pantaleon, D.; Marshall, Benjamin T.; Mertens, Christopher J.; Remsberg, Ellis E.; Mlynczak, Martin G.; Gordley, L. L.; Russell, James M.

2008-01-01

The vast set of near global and continuous atmospheric measurements made by the SABER instrument since 2002, including daytime and nighttime kinetic temperature (T(sub k)) from 20 to 105 km, is available to the scientific community. The temperature is retrieved from SABER measurements of the atmospheric 15 micron CO2 limb emission. This emission separates from local thermodynamic equilibrium (LTE) conditions in the rarefied mesosphere and thermosphere, making it necessary to consider the CO2 vibrational state non-LTE populations in the retrieval algorithm above 70 km. Those populations depend on kinetic parameters describing the rate at which energy exchange between atmospheric molecules take place, but some of these collisional rates are not well known. We consider current uncertainties in the rates of quenching of CO2 (v2 ) by N2 , O2 and O, and the CO2 (v2 ) vibrational-vibrational exchange to estimate their impact on SABER T(sub k) for different atmospheric conditions. The T(sub k) is more sensitive to the uncertainty in the latter two and their effects depend on altitude. The T(sub k) combined systematic error due to non-LTE kinetic parameters does not exceed +/- 1.5 K below 95 km and +/- 4-5 K at 100 km for most latitudes and seasons (except for polar summer) if the Tk profile does not have pronounced vertical structure. The error is +/- 3 K at 80 km, +/- 6 K at 84 km and +/- 18 K at 100 km under the less favourable polar summer conditions. For strong temperature inversion layers, the errors reach +/- 3 K at 82 km and +/- 8 K at 90 km. This particularly affects tide amplitude estimates, with errors of up to +/- 3 K.

Effect of AQM-Based RLC Buffer Management on the eNB Scheduling Algorithm in LTE Network

Directory of Open Access Journals (Sweden)

Anup Kumar Paul

2017-09-01

Full Text Available With the advancement of the Long-Term Evolution (LTE network and smart-phones, most of today’s internet content is delivered via cellular links. Due to the nature of wireless signal propagation, the capacity of the last hop link can vary within a short period of time. Unfortunately, Transmission Control Protocol (TCP does not perform well in such scenarios, potentially leading to poor Quality of Service (QoS (e.g., end-to-end throughput and delay for the end user. In this work, we have studied the effect of Active Queue Management (AQM based congestion control and intra LTE handover on the performance of different Medium Access Control (MAC schedulers with TCP traffic by ns3 simulation. A proper AQM design in the Radio Link Control (RLC buffer of eNB in the LTE network leads to the avoidance of forced drops and link under-utilization along with robustness to a variety of network traffic-loads. We first demonstrate that the original Random Early Detection (RED linear dropping function cannot cope well with different traffic-load scenarios. Then, we establish a heuristic approach in which different non-linear functions are proposed with one parameter free to define. In our simulations, we demonstrate that the performance of different schedulers can be enhanced via proper dropping function.

Efficient Priority Access to the Shared Commercial Radio with Offloading for Public Safety in LTE Heterogeneous Networks

Directory of Open Access Journals (Sweden)

Chafika Tata

2014-01-01

Full Text Available This paper presents the algorithm Courteous Priority Access to the shared commercial radio with offloading (CPAwO, for public safety network (PSN over LTE heterogeneous networks (HetNets. We propose a solution for prioritization of PSN users with access to the commercial radio network resources. Our model offers additional radio resources to the PSN. Furthermore, it ensures a certain priority for commercial users by assigning quantities of additional radio resources through the courteous scheme. This allows delaying preemption and blocking bearers when the radio resources are limited. The other part of CPAwO model is to apply the principle of offloading in order to reduce the impact of the macrocell congestion. This technique is to switch the new bearers arriving at the LTE macrocells to small cells, in order to decrease the number of the blocked and interrupted bearers in the network. The results of the simulation showed that the allocation of radio resources via the courteous mechanism with offloading of new bearers to small cells reduces the rate of blocking bearers and delays the preemption of active bearers present in the LTE HetNets. It also reduces the cost of the end-to-end communications, thanks to the reallocation of free frequencies.

Approximate thermodynamic state relations in partially ionized gas mixtures

International Nuclear Information System (INIS)

Ramshaw, John D.

2004-01-01

Thermodynamic state relations for mixtures of partially ionized nonideal gases are often approximated by artificially partitioning the mixture into compartments or subvolumes occupied by the pure partially ionized constituent gases, and requiring these subvolumes to be in temperature and pressure equilibrium. This intuitively reasonable procedure is easily shown to reproduce the correct thermal and caloric state equations for a mixture of neutral (nonionized) ideal gases. The purpose of this paper is to point out that (a) this procedure leads to incorrect state equations for a mixture of partially ionized ideal gases, whereas (b) the alternative procedure of requiring that the subvolumes all have the same temperature and free electron density reproduces the correct thermal and caloric state equations for such a mixture. These results readily generalize to the case of partially degenerate and/or relativistic electrons, to a common approximation used to represent pressure ionization effects, and to two-temperature plasmas. This suggests that equating the subvolume electron number densities or chemical potentials instead of pressures is likely to provide a more accurate approximation in nonideal plasma mixtures

A 1.2-V CMOS front-end for LTE direct conversion SAW-less receiver

International Nuclear Information System (INIS)

Wang Riyan; Li Zhengping; Zhang Weifeng; Zeng Longyue; Huang Jiwei

2012-01-01

A CMOS RF front-end for the long-term evolution (LTE) direct conversion receiver is presented. With a low noise transconductance amplifier (LNA), current commutating passive mixer and transimpedance operational amplifier (TIA), the RF front-end structure enables high-integration, high linearity and simple frequency planning for LTE multi-band applications. Large variable gain is achieved using current-steering transconductance stages. A current commutating passive mixer with 25% duty-cycle LO improves gain, noise and linearity. A direct coupled current-input filter (DCF) is employed to suppress the out-of-band interferer. Fabricated in a 0.13-μm CMOS process, the RF front-end achieves a 45 dB conversion voltage gain, 2.7 dB NF, −7 dBm IIP3, and +60 dBm IIP2 with calibration from 2.3 to 2.7 GHz. The total RF front end with divider draws 40 mA from a single 1.2-V supply. (semiconductor integrated circuits)

Energy-efficient two-hop LTE resource allocation in high speed trains with moving relays

KAUST Repository

Alsharoa, Ahmad M.

2014-05-01

High-speed railway system equipped with moving relay stations placed on the middle of the ceiling of each train wagon is investigated. The users inside the train are served in two hops via the 3GPP Long Term Evolution (LTE) technology. The objective of this work is to maximize the number of served users by respecting a specific quality-of-service constraint while minimizing the total power consumption of the eNodeB and the moving relays. We propose an efficient algorithm based on the Hungarian method to find the optimal resource allocation over the LTE resource blocks in order to serve the maximum number of users with the minimum power consumption. Moreover, we derive a closed-form expression for the power allocation problem. Our simulation results illustrate the performance of the proposed scheme and compare it with various previously developed algorithms as well as with the direct transmission scenario. © 2014 IFIP.

An Improved Mathematical Scheme for LTE-Advanced Coexistence with FM Broadcasting Service.

Science.gov (United States)

Shamsan, Zaid Ahmed; Al-Hetar, Abdulaziz M

2016-01-01

Power spectral density (PSD) overlapping analysis is considered the surest approach to evaluate feasibility of compatibility between wireless communication systems. In this paper, a new closed-form for the Interference Signal Power Attenuation (ISPA) is mathematically derived to evaluate interference caused from Orthogonal Frequency Division Multiplexing (OFDM)-based Long Term Evolution (LTE)-Advanced into Frequency Modulation (FM) broadcasting service. In this scheme, ISPA loss due to PSD overlapping of both OFDM-based LTE-Advanced and FM broadcasting service is computed. The proposed model can estimate power attenuation loss more precisely than the Advanced Minimum Coupling Loss (A-MCL) and approximate-ISPA methods. Numerical results demonstrate that the interference power is less than that obtained using the A-MCL and approximate ISPA methods by 2.8 and 1.5 dB at the co-channel and by 5.2 and 2.2 dB at the adjacent channel with null guard band, respectively. The outperformance of this scheme over the other methods leads to more diminishing in the required physical distance between the two systems which ultimately supports efficient use of the radio frequency spectrum.

A spatiotemporal model for the LTE uplink: Spatially interacting tandem queues approach

KAUST Repository

Gharbieh, Mohammad

2017-07-31

With the proliferation of the Internet-of-things (IoT), there is an undeniable consensus that cellular LTE networks will have to support a dramatically larger number of uplink connections. This is true since most of the devices to be added incur machine-type communications which is dominantly upstream. Can current LTE network withstand this challenge? To answer this question, the joint performance of random access process and the uplink data transmission should be investigated. These two problems have been classically treated in the literature in a disjoint fashion. In this paper, they are jointly analyzed as an inseparable couple. To do that, a tandem queuing model is adopted whereby devices are represented as spatially interacting queues. The interaction between queues is governed by the mutual inter-cell and intra-cell interference. To that end, a joint stochastic geometry and queueing theory model is exploited to study this problem and a spatiotemporal analytical model is developed accordingly. Network stability and scalability are two prime performance criteria for performance assessment. In light of these two criteria, the developed model is poised to offer valuable insights into efficient access and resource allocation strategies.

New Configuration of Handset MIMO Antenna for LTE 700 Band Applications

Directory of Open Access Journals (Sweden)

Byeonggwi Mun

2013-01-01

Full Text Available A compact handset multiple-input multiple-output (MIMO antenna for long-term evolution (LTE 700 band (746~787 MHz applications is proposed. The proposed antenna consists of two symmetrical PIFAs. Without the usage of any additional coupling elements between closely mounted antennas, a high isolation (>15 dB and a low enveloped correlation coefficient (ECC<0.35 are achieved by the optimum location and arrangement of MIMO antenna elements.

Delay efficient cooperation in public safety vehicular networks using LTE and IEEE 802.11p

KAUST Repository

Atat, Rachad; Yaacoub, Elias E.; Alouini, Mohamed-Slim; Filali, Fethi

2012-01-01

(LTE) is used for long range communications with the base station (BS) and 802.11p is considered for inter-vehicle collaboration on the short range. A high mobility environment with correlated shadowing is adopted. Both schemes are shown to outperform

Meandered Monopoles for 700 MHz LTE Handsets and Improved MIMO Channel Capacity Performance

Directory of Open Access Journals (Sweden)

I. Dioum

2011-12-01

Full Text Available In this paper, we present the design and the measurement of MIMO meandered monopole antennas and the computation of their channel capacity performance. The initial proposed handset-system is composed of a meandered monopole operating in the LTE 700 MHz band, connected to a parasitic radiating element for the upper 2.5 GHz LTE band. Two antennas of the same kind are then closely positioned on the same 120x50 mm2 Printed Circuit Board (PCB. A neutralization line connects the two antennas to enhance their port-to-port isolation in the 700 MHz band. The computation of the channel capacity performance in this band is based on propagation simulations performed with the GRIMM model from the CREMANT. Two system-prototypes are evaluated: one with the neutralization line for enhanced port-to-port isolation and a second without the neutralization exhibiting poor antenna-to-antenna isolation. It is demonstrated that the neutralization technique helps in giving a minimum improvement of 12% of the capacity performance of the handset-system, and a maximum improvement 46%, in the chosen environment.

Advanced Kr Atomic Structure and Ionization Kinetics for Pinches on ZR

Science.gov (United States)

Dasgupta, Arati; Clark, Robert; Giuliani, John; Ouart, Nick; Davis, Jack; Jones, Brent; Ampleford, Dave; Hansen, Stephanie

2011-10-01

High fluence photon sources above 10 keV are a challenge for HED plasmas. This motivates Kr atomic modeling as its K-shell radiation starts at 13 keV. We have developed atomic structure and collisional-radiatve data for the full K-and L-shell and much of the M-shell using the the state-of-the-art Flexible Atomic Code. All relevant atomic collisional and radiative processes that affect ionization balance and are necessary to accurately model the pinch dynamics and the spectroscopic details of the emitted radiation are included in constructing the model. This non-LTE CRE model will be used to generate synthetic spectra for fixed densities and temperatures relevant for Kr gas-puff simulations in ZR. Work supported by DOE/NNSA. Sandia is a multi-program laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

III. Penning ionization, associative ionization and chemi-ionization processes

International Nuclear Information System (INIS)

Cermak, V.

1975-01-01

Physical mechanisms of three important ionization processes in a cold plasma and the methods of their experimental study are discussed. An apparatus for the investigation of the Penning ionization using ionization processes of long lived metastable rare gas atoms is described. Methods of determining interaction energies and ionization rates from the measured energy spectra of the originating electrons are described and illustrated by several examples. Typical associative ionization processes are listed and the ionization rates are compared with those of the Penning ionization. Interactions with short-lived excited particles and the transfer of excitation without ionization are discussed. (J.U.)

Measurements of the structure of an ionizing shock wave in a hydrogen-helium mixture.

Science.gov (United States)

Leibowitz, L. P.

1973-01-01

Shock structure during ionization of a hydrogen-helium mixture has been followed using hydrogen line and continuum emission measurements. A reaction scheme is proposed which includes hydrogen dissociation and a two-step excitation-ionization mechanism for hydrogen ionization by atom-atom and atom-electron collisions. Agreement has been achieved between numerical calculations and measurements of emission intensity as a function of time for shock velocities from 13 to 20 km/sec in a 0.208 H2-0.792 He mixture. The electron temperature was found to be significantly different from the heavy particle temperature during much of the ionization process. Similar time histories for H beta and continuum emission indicate upper level populations of hydrogen in equilibrium with the electron concentration during the relaxation process.

Kinetics of swelling of polyelectrolyte gels: Fixed degree of ionization

Science.gov (United States)

Sen, Swati; Kundagrami, Arindam

2015-12-01

The swelling kinetics of uncharged and charged polymer (polyelectrolyte) gels in salt-free conditions is studied in one dimension by solving the constitutive equation of motion (Newton's law for the elementary gel volume) of the displacement variable by two theoretical methods: one in which the classical definition of stress is used with the bulk modulus taken as a parameter, and the other in which a phenomenological expression of the osmotic stress as a function of polymer density and degree of ionization is taken as an input to the dynamics. The time-evolution profiles for spatially varying polymer density and stress, along with the location of the gel-solvent interface, are obtained from the two methods. We show that both the polymer density (volume fraction) and stress inside the gel follow expected behaviours of being maximum for the uniformly shrunken gel, and relaxing slowly to the lowest values as the gel approaches equilibrium. We further show that, by comparing the temporal profiles of the gel-solvent interface and other variables between the two methods, one may attempt to assign an effective bulk modulus to the polyelectrolyte gel as a function of the degree of ionization and other parameters of the gel such as hydrophobicity, cross-link density, and the temperature. The major result we get is that the effective bulk modulus of a polyelectrolyte gel increases monotonically with its degree of ionization. In the process of identifying the parameters for a monotonic swelling, we calculated using a well-known expression of the free energy the equilibrium results of two-phase co-existence and the critical point of a polyelectrolyte gel with a fixed degree of ionization.

On the thermal raleigh problem in partially ionized argon

International Nuclear Information System (INIS)

Hutten Mansfeld, A.C.B.

1976-01-01

A partially ionized gas is created by the reflection of a shock wave with incident Mach numbers in the range 7 to 10 and an initial pressure of 5 Torr against the cold end wall of a shock tube. Heat exchange between the plasma and this cold wall induces several relaxation processes in the thermal boundary layer. Of these, relaxation of i) the electron and heavy particles temperature and ii) the degree of ionization towards a local thermodynamic equilibrium state are considered. In the model, transport and relaxation processes are treated simultaneously. A classification on the basis of relaxation phenomena is performed, i.e., simplified sets of equations are obtained in a systematic way from the frozen or equilibrium limits of the relaxation processes. A finite difference numerical solution for the different models is obtained. Because the boundary conditions are of mixed type and the relaxation processes show aspects of stiffness, the application of a backward implicit discretization scheme is necessary. As a diagnostic tool, a two wavelength version of the laser schlieren method is used. The measurements provide time histories of both the electron and atom number density gradients

Numerical study of laser-induced blast wave coupled with unsteady ionization processes

International Nuclear Information System (INIS)

Ogino, Y; Ohnishi, N; Sawada, K

2008-01-01

We present the results of the numerical simulation of laser-induced blast wave coupled with rate equations to clarify the unsteady property of ionization processes during pulse heating. From comparison with quasi-steady computations, the plasma region expands more widely, which is sustained by the inverse-bremsstrahlung since an ionization equilibrium does not establish at the front of the plasma region. The delayed relaxation leads to the rapid expansion of the driving plasma and enhances the energy conversion efficiency from a pulse heating laser to the blast wave

C.I.T. alpha particle extraction and measurement: Low-Z ablation cloud profile simulation for alpha-particle diagnostics: Progress report, September 1988 to April 1989

International Nuclear Information System (INIS)

Gerdin, G.; Vahala, L.; El Cashlan, A.G.

1989-05-01

A steady state flow model including non-LTE effects has been developed to simulate plasma-pellet interactions for both hydrogen and lithium pellets. For hydrogen pellets, where the LTE assumption breaks down in the ionization region, singularities in the flow predicted by the LTE model were removed by the addition of radiative recombination. For lithium pellets good agreement of the model with experiment is found when compared with the results from Alcator C. 10 refs., 3 figs

Investigation of Diagonal Antenna-Chassis Mode in Mobile Terminal LTE MIMO Antennas for Bandwidth Enhancement

DEFF Research Database (Denmark)

Zhang, Shuai; Zhao, Kun; Ying, Zhinong

2015-01-01

mechanism of the mismatch of these three bandwidth ranges is also explained. Furthermore, the diagonal antenna-chassis mode is also studied for MIMO elements in the adjacent and diagonal corner locations. As a practical example, a wideband collocated LTE MIMO antenna is proposed and measured. It covers......A diagonal antenna-chassis mode is investigated in long-term evolution multiple-input-multiple-output (LTE MIMO) antennas. The MIMO bandwidth is defined in this paper as the overlap range of the low-envelope correlation coefficient, high total efficiency, and -6-dB impedance matching bandwidths...... the bands of 740960 and 1700-2700 MHz, where the total efficiencies are better than -3.4 and -1.8 dB, with lower than 0.5 and 0.1, respectively. The measurements agree well with the simulations. Since the proposed method only needs to modify the excitation locations of the MIMO elements on the chassis...

Assessment of LTE Wireless Access for Monitoring of Energy Distribution in the Smart Grid

DEFF Research Database (Denmark)

Madueño, Germán Corrales; Nielsen, Jimmy Jessen; Min Kim, Dong

2016-01-01

While LTE is becoming widely rolled out for human-type services, it is also a promising solution for cost-efficient connectivity of the smart grid monitoring equipment. This is a type of machine-to-machine (M2M) traffic that consists mainly of sporadic uplink transmissions. In such a setting...

IMPLEMENTATION OF TRANSMITTER AND RECEIVER ARCHITECTURE FOR PHYSICAL HYBRID INDICATOR CHANNEL OF LTE-ADVANCED USING PARTIAL RECONFIGURATION IN ML605 VIRTEX-6 DEVICE

Directory of Open Access Journals (Sweden)

S. Syed Ameer Abbas

2014-09-01

Full Text Available LTE-A (Long Term Evolution-Advanced is the fourth generation technology to increase the speed of wireless data network. The LTE-A Physical layer provides both data and control information between an enhanced base station and mobile user equipment which is quite complex and consists of a mixture of technologies. Since there is requirement for more resources to accommodate all the channels in a single FPGA, Partial Reconfiguration (PR technique is introduced to configure the total hardware into sub modules that configure and operate in different instants of time. PR enables a part of FPGA to be reconfigured, while the rest continues to function without any interruptions and reduces the hardware resource power and fabric area. This work proposes the realization of transmitter and receiver architecture of Physical Hybrid Indicator Channel (PHICH channel for LTE-A using partial reconfiguration on xc6vlx240tff1156-1 FPGA. The receiver architecture for PHICH is to report the correct reception of uplink user data to the User Equipment (UE in the form of Acknowledgment (ACK, or Negative ACK (NACK in a 1 millisecond duration sub-frame of Long Term Evolution (LTE System. The modules for the different diversities are reconfigured based on the control signals from the transmitter.

An orthogonal wavelet division multiple-access processor architecture for LTE-advanced wireless/radio-over-fiber systems over heterogeneous networks

Science.gov (United States)

Mahapatra, Chinmaya; Leung, Victor CM; Stouraitis, Thanos

2014-12-01

The increase in internet traffic, number of users, and availability of mobile devices poses a challenge to wireless technologies. In long-term evolution (LTE) advanced system, heterogeneous networks (HetNet) using centralized coordinated multipoint (CoMP) transmitting radio over optical fibers (LTE A-ROF) have provided a feasible way of satisfying user demands. In this paper, an orthogonal wavelet division multiple-access (OWDMA) processor architecture is proposed, which is shown to be better suited to LTE advanced systems as compared to orthogonal frequency division multiple access (OFDMA) as in LTE systems 3GPP rel.8 (3GPP, http://www.3gpp.org/DynaReport/36300.htm). ROF systems are a viable alternative to satisfy large data demands; hence, the performance in ROF systems is also evaluated. To validate the architecture, the circuit is designed and synthesized on a Xilinx vertex-6 field-programmable gate array (FPGA). The synthesis results show that the circuit performs with a clock period as short as 7.036 ns (i.e., a maximum clock frequency of 142.13 MHz) for transform size of 512. A pipelined version of the architecture reduces the power consumption by approximately 89%. We compare our architecture with similar available architectures for resource utilization and timing and provide performance comparison with OFDMA systems for various quality metrics of communication systems. The OWDMA architecture is found to perform better than OFDMA for bit error rate (BER) performance versus signal-to-noise ratio (SNR) in wireless channel as well as ROF media. It also gives higher throughput and mitigates the bad effect of peak-to-average-power ratio (PAPR).

Evaluation of a Cross Layer Scheduling Algorithm for LTE Downlink

Directory of Open Access Journals (Sweden)

A. Popovska Avramova

2013-06-01

Full Text Available The LTE standard is a leading standard in the wireless broadband market. The Radio Resource Management at the base station plays a major role in satisfying users demand for high data rates and quality of service. This paper evaluates a cross layer scheduling algorithm that aims at minimizing the resource utilization. The algorithm makes decisions based on channel conditions, the size of transmission buffers and different quality of service demands. Simulation results show that the new algorithm improves the resource utilization and provides better guarantees for service quality.

Reply to 'Photon emission from sputtered atoms - the observation of apparent local thermodynamic equilibrium in the excitation' by R.J. MacDonald, R.F. Garrett and P.J. Martin

International Nuclear Information System (INIS)

Tsong, I.S.T.

1978-01-01

MacDonald, Garrett and Martin have measured the intensities of spectral lines of Fe and Ni in alloy samples to study the problem of local thermodynamic equilibrium (LTE) in sputtering by plotting log(Ilambda 3 /gf) versus E. The measurements were made using a spectrometer with good resolution, 0.4 A, and great care was exercised in selecting only the lines free from interference or overlap. While the author agrees that their experimental approach is superior to the one attempted earlier and their experimental data are therefore more accurate, he does not agree with their data analysis. (Auth.)

Tuning Range Optimization of a Planar Inverted F Antenna for LTE Low Frequency Bands

DEFF Research Database (Denmark)

Barrio, Samantha Caporal Del; Pelosi, Mauro; Franek, Ondrej

2011-01-01

This paper presents a Planar Inverted F Antenna (PIFA) tuned with a fixed capacitor to the low frequency bands supported by the Long Term Evolution (LTE) technology. The tuning range is investigated and optimized with respect to the bandwidth and the efficiency of the resulting antenna. Simulatio...... and mock-ups are presented....

Statistical equilibrium of copper in the solar atmosphere

International Nuclear Information System (INIS)

Shi, J. R.; Mashonkina, L.; Zhao, G.; Gehren, T.; Zeng, J. L.

2014-01-01

Non-local thermodynamic equilibrium (NLTE) line formation for neutral copper in the one-dimensional solar atmospheres is presented for the atomic model, including 96 terms of Cu I and the ground state of Cu II. The accurate oscillator strengths for all the line transitions in model atom and photoionization cross sections were calculated using the R-matrix method in the Russell-Saunders coupling scheme. The main NLTE mechanism for Cu I is the ultraviolet overionization. We find that NLTE leads to systematically depleted total absorption in the Cu I lines and, accordingly, positive abundance corrections. Inelastic collisions with neutral hydrogen atoms produce minor effects on the statistical equilibrium of Cu I in the solar atmosphere. For the solar Cu I lines, the departures from LTE are found to be small, the mean NLTE abundance correction of ∼0.01 dex. It was found that the six low-excitation lines, with excitation energy of the lower level E exc ≤ 1.64 eV, give a 0.14 dex lower mean solar abundance compared to that from the six E exc > 3.7 eV lines, when applying experimental gf-values of Kock and Richter. Without the two strong resonance transitions, the solar mean NLTE abundance from 10 lines of Cu I is log ε ☉ (Cu) = 4.19 ± 0.10, which is consistent within the error bars with the meteoritic value 4.25 ± 0.05 of Lodders et al. The discrepancy between E exc = 1.39-1.64 eV and E exc > 3.7 eV lines can be removed when the calculated gf-values are adopted and a mean solar abundance of log ε ☉ (Cu) = 4.24 ± 0.08 is derived.

Approaches for clarifying excitation mechanisms in spectrochemical excitation sources

NARCIS (Netherlands)

Schram, D.C.; Raaymakers, I.J.M.M.; Sijde, van der B.; Schenkelaars, H.J.W.; Boumans, P.W.J.M.

1983-01-01

It is shown that the state of an ICP plasma can be adequately described by a measured electron density distribution. Even though the plasma is not in full local thermal equilibrium (LTE), the electron temperature can be deduced from the density with the LTE relation with more accuracy than direct

Line Emission and X-ray Line Polarization of Multiply Ionized Mo Ions

Science.gov (United States)

Petkov, E. E.; Safronova, A. S.; Kantsyrev, V. L.; Shlyaptseva, V. V.; Stafford, A.; Safronova, U. I.; Shrestha, I. K.; Schultz, K. A.; Childers, R.; Cooper, M. C.; Beiersdorfer, P.; Hell, N.; Brown, G. V.

2016-10-01

We present a comprehensive experimental and theoretical study of the line emission from multiply ionized Mo ions produced by two different sets of experiments: at LLNL EBIT and the pulsed power generator Zebra at UNR. Mo line emission and polarization measurements were accomplished at EBIT for the first time. In particular, benchmarking experiments at the LLNL EBIT with Mo ions produced at electron beam energies from 2.75 keV up to 15 keV allowed us to break down these very complicated spectra into spectra with only few ionization stages and to select processes that influence them as well as to measure line polarization. The EBIT data were recorded using the EBIT Calorimeter Spectrometer and a crystal spectrometer with a Ge crystal. X-ray Mo spectra and pinhole images were collected from Z-pinch plasmas produced from various wire loads. Non-LTE modeling, high-precision relativistic atomic and polarization data were used to analyze L-shell Mo spectra. The influence of different plasma processes including electron beams on Mo line radiation is summarized. This work was supported by NNSA under DOE Grant DE-NA0002954. Experiments at the NTF/UNR were funded in part by DE-NA0002075. Work at LLNL was performed under the auspices of the U.S. DOE under contract DE-AC52-07NA27344.

Designs of precoding for LTE TDD using cell specific reference signals

DEFF Research Database (Denmark)

Sun, Fan; Lu, Lu; Sørensen, Troels Bundgaard

2010-01-01

We design non-codebook-based Multiple-Input Multiple-Output (MIMO) precoding schemes using multiple cell-specific reference signals patterns for the time division duplex (TDD) mode of LTE, where channel reciprocity can be exploited. Previously proposed non-codebookbased precoding schemes typically...... use UE specific reference signals for demodulation. Cell specific reference signals are however always allocated for the transmission of common control signalling, mobility measurements and downlink channel quality measurements. In order to save the resources occupied by UE specific reference signals...

Comments on equilibrium, transient equilibrium, and secular equilibrium in serial radioactive decay

International Nuclear Information System (INIS)

Prince, J.R.

1979-01-01

Equations describing serial radioactive decay are reviewed along with published descriptions or transient and secular equilibrium. It is shown that terms describing equilibrium are not used in the same way by various authors. Specific definitions are proposed; they suggest that secular equilibrium is a subset of transient equilibrium

Investigation on the role of air in the dynamical evolution and thermodynamic state of a laser-induced aluminium plasma by spatial- and time-resolved spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Cristoforetti, G., E-mail: gabriele.cristoforetti@cnr.i [National Institute of Optics, Research Area of National Research Council, Via G.Moruzzi, 1 - 56124 Pisa (Italy); Lorenzetti, G.; Legnaioli, S.; Palleschi, V. [Institute of Chemistry of Organometallic Compounds, Research Area of National Research Council, Via G.Moruzzi, 1 - 56124 Pisa (Italy)

2010-09-15

The amount and the spatial distribution of air atoms and ions in a laser-induced plasma in ambient air provide important information about the formation of the plasma and its successive evolution history. For this reason, in the present work, the air mixing in a laser-induced plasma in air at atmospheric pressure and its influence on its thermodynamic evolution were studied. Information about spatial distributions of atoms and ions from Al, N and O were achieved by Abel-inverted spectra in the plume. The occurrence of LTE in the plume was also assessed by the utilization of theoretical criteria, and by the analysis of experimental spectra. Aluminium atoms and ions were found to be in LTE, while nitrogen and oxygen were not because of their longer times of relaxation toward equilibrium. Nitrogen was found to be over-ionized with respect to Saha-Eggert equilibrium, indicating that the plasma is recombining. Experimental observations suggest that the concentration of air species in the plasma is larger than that of aluminium, even in the region closer to the target, where the aluminium lines are stronger. In the front part of the plume only emission lines from air species were observed. The results suggest that a Laser-Supported Detonation (LSD) regime occurs during the trailing part of the laser pulse, resulting in the strong inclusion into the plasma of air elements. In this scenario, also the thermodynamic history of the plume is affected by the predominance of air species.

A non-local thermodynamic equilibrium, line-blanketed synthetic spectrum of Iota Herculis - C, Al, and Si lines

Science.gov (United States)

Grigsby, James A.

1991-01-01

A non-LTE line-blanketed model stellar atmosphere is used to compute a model of I Herculis (B3 IV) with a Teff of 17,500 K and a log g of 3.75, following the conclusions of Peters and Polidan (1985). Detailed profiles of a number of lines of C, Al, and Si in the 1200-2000-A region are computed, including the resonance lines of C II, Al II, and Al III. These profiles are compared to observations obtained from the coaddition of eight IUE SWP images, using a technique developed by Leckrone and Adelman (1989). Comparison of carbon lines with a model that is underabundant in carbon by a factor of 2 relative to the sun indicates that the C abundance of Iota Her is at most one-half solar. Non-LTE effects are examined by comparing an LTE model possessing identical atmospheric parameters with the non-LTE model. Substantial differences in the populations of the model atomic states are found, but differences in the temperature structure of the two models often mask the non-LTE effects in the synthetic spectra.

Simulation of convection-stabilized low-current glow and arc discharges in atmospheric-pressure air

International Nuclear Information System (INIS)

Naidis, G V

2007-01-01

A two-dimensional model of stationary convection-stabilized low-current glow and arc discharge columns in atmospheric-pressure air is developed which accounts for deviation of the plasma state from the local thermodynamic equilibrium (LTE). In addition to equations of energy, continuity and momentum (analogous to those used in LTE arc models), the non-LTE model includes balance equations for plasma species and for the vibrational energy of nitrogen molecules. The kinetic scheme is used which was developed recently for the simulation of low-current wall-stabilized discharges in air. Results of calculation of discharge parameters over a wide current range are presented. It is shown that the non-equilibrium effects are substantial at currents lower than ∼ 100 mA. The calculated plasma parameters agree with available experimental data

Investigation on IMCP based clustering in LTE-M communication for smart metering applications

Directory of Open Access Journals (Sweden)

Kartik Vishal Deshpande

2017-06-01

Full Text Available Machine to Machine (M2M is foreseen as an emerging technology for smart metering applications where devices communicate seamlessly for information transfer. The M2M communication makes use of long term evolution (LTE as its backbone network and it results in long-term evolution for machine type communication (LTE-M network. As huge number of M2M devices is to be handled by single eNB (evolved Node B, clustering is exploited for efficient processing of the network. This paper investigates the proposed Improved M2M Clustering Process (IMCP based clustering technique and it is compared with two well-known clustering algorithms, namely, Low Energy Adaptive Clustering Hierarchical (LEACH and Energy Aware Multihop Multipath Hierarchical (EAMMH techniques. Further, the IMCP algorithm is analyzed with two-tier and three-tier M2M systems for various mobility conditions. The proposed IMCP algorithm improves the last node death by 63.15% and 51.61% as compared to LEACH and EAMMH, respectively. Further, the average energy of each node in IMCP is increased by 89.85% and 81.15%, as compared to LEACH and EAMMH, respectively.

Characterization of RFX-mod passive conducting structures to optimize plasma start up and equilibrium control

International Nuclear Information System (INIS)

Marchiori, G.; Grando, L.; Cavinato, M.

2007-01-01

The load assembly of RFX-mod consists of three toroidal conducting structures whose eddy currents affect the plasma equilibrium magnetic configuration. The high number of electromagnetic probes mounted on the components of the load assembly allowed to analyse the response of each structure to a variation of the magnetic field vertical component. The capability of evaluating the axisymmetric toroidal currents in the passive structures and therefore their contribution to the equilibrium configuration by a 2D FE MHD equilibrium code was validated. The design and implementation of a feedback control system of the magnetic field vertical component before the gas ionization allowed meeting the requirement of an accurate control of this quantity in view of operation at higher plasma current and independently of the magnetizing winding programming

Test Setup for Anechoic Room based MIMO OTA Testing of LTE Terminals

DEFF Research Database (Denmark)

Carreño, Xavier; Fan, Wei; Nielsen, Jesper Ødum

2013-01-01

introduced into, for example, LTE andWiMAX systems. The main purpose of this testing is to validate that the user equipment will have a good performance in real use. CTIA, 3GPP and COST are spending a big effort in standardizing the OTA testing procedure which is much more complex than similar SISO OTA...... the activities related to the MIMO OTA lab being built at Aalborg University (AAU), Denmark and the testing being performed....

Heterogeneous LTE/802.11a mobile relays for data rate enhancement and energy-efficiency in high speed trains

KAUST Repository

Atat, Rachad

2012-12-01

Performance enhancements of cellular networks for passengers in high speed railway systems are investigated. Relays placed on top of each train car are proposed. These relays communicate with the cellular base station (BS) over Long Term Evolution (LTE) long range links and with the mobile terminals (MTs) inside the train cars using IEEE 802.11a short range links. Scenarios with unicasting and multicasting from the BS are studied, both in the presence and absence of the relays. In addition, LTE resource allocation is taken into account. The presence of the relays is shown to lead to significant enhancements in the effective data rates of the MTs, in addition to leading to huge savings in the energy consumption from the batteries of the MTs. © 2012 IEEE.

A genetic algorithm solution for the operation of green LTE networks with energy and environment considerations

KAUST Repository

Ghazzai, Hakim; Yaacoub, Elias E.; Alouini, Mohamed-Slim; Abu-Dayya, Adnan A.

2012-01-01

, as additional power sources in smart grids, becomes a real challenge to network operators to reduce power costs. In this paper, we propose a method based on genetic algorithms that decreases the energy consumption of a Long-Term Evolution (LTE) cellular network

Non-LTE Analysis of Interstellar Line Spectra of SiO

Science.gov (United States)

Zhang, Ziwei; Stancil, Phillip C.

2016-01-01

SiO emission lines are important probes of chemical processes in diverse astrophysical environments. In circumstellar outflows of AGB stars, the production of silicate grains is preceded by SiO formation, making SiO a useful measure of Si depletion. SiO is also commonly observed in shocks associated with the outflows of young stellar objects, both low- and high-mass. To model SiO emission for non-LTE conditions requires collisional rate coefficients due to H2 impact which are currently unavailable. Unknown collisional rate coefficients are often estimated from known systems. For the case of SiO-H2, rate coefficients have previously been adapted from a different collider, He (Dayau & Balanca 2006), based on a reduced-mass scaling approach. Recently it has been suggested that scaling via the interaction potential well depth and the reduced masses of the collisional systems may be more reliable (Walker et al. 2014). Using the non-LTE spectral modeling package Radex (van der Tak et al. 2007), we construct diagnostic plots of SiO line ratios using SiO-H2 collisional rate coefficients based on (i) reduced-mass scaling from the LAMDA database, (ii) potential well-depth scaling, and (iii) a more comprehensive input with multiple colliders (H2, He and H). Our goal is to give a more rigorous approach to SiO line emission simulations to better understand Si chemistry, dust formation/destruction, and other astrophysical processes.This work was supported by NASA ATP grant NNX15AI61G.

Evaluation of Potential Relay Locations in a Urban Macro-Cell Scenario with Applicability to LTE-A

DEFF Research Database (Denmark)

Rodriguez, Ignacio; Coletti, Claudio; Sørensen, Troels Bundgaard

2012-01-01

. This paper presents a measurement-based study focusing on the performance evaluation of the relay backhaul link for different potential relay locations and antenna configurations in a real urban macro-cell scenario. Based on the assumption that a similar network deployment would apply for LTE-A, a fully......Relay base stations are expected to play an important role in extending coverage for beyond 3G networks, such as LTE-A. However, the signal quality experienced on the backhaul link between the macro-cell and the relay node has a major impact on the performance of the multi-hop transmission...... operational 3G network has been used for measuring both received signal strength and Signal-to-Interference-Ratio (SIR). Furthermore, the results have been used to estimate the performance of the multi-hop transmission under simplifying assumptions. The experimental results show that by increasing the relay...

A New Test of Copper and Zinc Abundances in Late-type Stars Using Ultraviolet Cu II and Zn II Lines

Science.gov (United States)

Roederer, Ian U.; Barklem, Paul S.

2018-04-01

We present new abundances derived from Cu I, Cu II, Zn I, and Zn II lines in six warm (5766 ≤ {T}eff} ≤ 6427 K), metal-poor (‑2.50 ≤ [Fe/H] ≤ ‑0.95) dwarf and subgiant (3.64 ≤ log g ≤ 4.44) stars. These abundances are derived from archival high-resolution ultraviolet spectra from the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope and ground-based optical spectra from several observatories. Ionized Cu and Zn are the majority species, and abundances derived from Cu II and Zn II lines should be largely insensitive to departures from local thermodynamic equilibrium (LTE). We find good agreement between the [Zn/H] ratios derived separately from Zn I and Zn II lines, suggesting that departures from LTE are, at most, minimal (≲0.1 dex). We find that the [Cu/H] ratios derived from Cu II lines are 0.36 ± 0.06 dex larger than those derived from Cu I lines in the most metal-poor stars ([Fe/H] McDonald Observatory of the University of Texas at Austin.

Integrated Power Saving for Multiple Relays and UEs in LTE-TDD

OpenAIRE

Chun-Chuan Yang; Jeng-Yueng Chen; Yi-Ting Mai; Chen-Ming Yang

2017-01-01

In this paper, the design of integrated sleep scheduling for relay nodes and user equipments under a Donor eNB (DeNB) in the mode of Time Division Duplex (TDD) in LTE-A is presented. The idea of virtual time is proposed to deal with the discontinuous pattern of the available radio resource in TDD, and based on the estimation of the traffic load, three power saving schemes in the top-down strategy are presented. Associated mechanisms in each scheme including calculation of the virtual subframe...

Análisis de las estrategias de gestión del espectro radioeléctrico en un sistema LTE con la herramienta Atoll

OpenAIRE

López Diaz, Eduardo José

2012-01-01

Estudiar el impacto de usar una estrategia ICIC y los posibles esquemas de reuso frecuencial en un sistema LTE. English: the Mobile Communications Research Group as part of the Signal Theory and Communications Department of the Polytechnic University of Catalonia, in order to keep up with the latest technological trends in the mobile networks field, saw the need to study and analyze the new emerging mobile standards such as LTE (Long Term Evolution), and through Atoll, a mobile network rad...

Multiuser Scheduling on the Downlink of an LTE Cellular System

Directory of Open Access Journals (Sweden)

Raymond Kwan

2008-01-01

Full Text Available The challenge of scheduling user transmissions on the downlink of a long-term evolution (LTE cellular communication system is addressed. In particular, a novel optimalmultiuser scheduler is proposed. Numerical results show that the system performance improves with increasing correlation among OFDMA subcarriers. It is found that only a limited amount of feedback information is needed to achieve relatively good performance. A suboptimal reduced-complexity scheduler is also proposed and shown to provide good performance. The suboptimal scheme is especially attractive when the number of users is large, in which case the complexity of the optimal scheme is high.

Downlink Radio Resource Management for LTE-Advanced System with Combined MU-MIMO and Carrier Aggregation Features

DEFF Research Database (Denmark)

Nguyen, Hung Tuan; Kovacs, Istvan

2012-01-01

In this paper we study the performance enhancement of a downlink LTE-Advanced system with a combination of the multi-user MIMO and carrier aggregation transmission techniques. Radio resource management for the systems with the combined features are proposed, and the system performance is evaluate...

Application of approximations for joint cumulative k-distributions for mixtures to FSK radiation heat transfer in multi-component high temperature non-LTE plasmas

International Nuclear Information System (INIS)

Maurente, André; França, Francis H.R.; Miki, Kenji; Howell, John R.

2012-01-01

Approximations for joint cumulative k-distribution for mixtures are efficient for full spectrum k-distribution (FSK) computations. These approximations provide reduction of the database that is necessary to perform FSK computation when compared to the direct approach, which uses cumulative k-distributions computed from the spectrum of the mixture, and also less computational expensive when compared to techniques in which RTE's are required to be solved for each component of the mixture. The aim of the present paper is to extend the approximations for joint cumulative k-distributions for non-LTE media. For doing that, a FSK to non-LTE media formulation well-suited to be applied along with approximations for joint cumulative k-distributions is presented. The application of the proposed methodology is demonstrated by solving the radiation heat transfer in non-LTE high temperature plasmas composed of N, O, N 2 , NO, N 2 + and mixtures of these species. The two more efficient approximations, that is, the superposition and multiplication are employed and analyzed.

Performance Evaluation of Multicast Video Distribution using LTE-A in Vehicular Environments

OpenAIRE

Thota, Jayashree; Bulut, Berna; Doufexi, Angela; Armour, Simon; Nix, Andrew

2017-01-01

Application Layer Forward Error Correction (AL-FEC) based on Raptor codes has been employed in Multimedia Broadcast/Multicast Services (MBMS) to improve reliability. This paper considers a cross-layer system based on the latest Raptor Q codes for transmitting high data rate video. Multiple Input Multiple Output (MIMO) channels in a realistic outdoor environment for a user moving at 50kmph in an LTE-A system is considered. A link adaptation model with optimized cross-layer parameters is propos...

Voice-Centric LTE Femtocells and Improper Graph Colorings

DEFF Research Database (Denmark)

Garcia, Luis Guilherme Uzeda; Pedersen, Klaus; Mogensen, Preben

2012-01-01

. The investigation revolves around the sensible definition of the underlying graph, i.e. the network model, rather than focusing on the coloring algorithms and their properties. Ultimately, we posit that improper online graph-coloring suffices and is actually preferable. In short, settling for less......This paper addresses carrier-based inter-cell interference coordination (CB-ICIC) among LTE femtocells operating on a single carrier. CB-ICIC is in many ways linked to the widely investigated dynamic channel assignment problem, which is often studied in the context of graph coloring......-than-optimal configurations avoids uncontrolled service interruptions. Such disruptions tend to raise understandable concerns when it comes to fully autonomous selection of operational CCs. Our results dispel such concerns by showing that conservative methods can achieve most of the benefits of unrestricted off-line coloring...

Multicell Cooperation for LTE-Advanced Heterogeneous Network Scenarios

DEFF Research Database (Denmark)

Soret, Beatriz; Wang, Hua; Rosa, Claudio

2013-01-01

In this article we present two promising practical use cases for simple multicell cooperation for LTE-Advanced heterogeneous network (HetNet) scenarios with macro and small cells. For co-channel deployment cases, we recommend the use of enhanced inter-cell interference coordination (e......ICIC) to mitigate cross-tier interference and ensure sufficient offload of users from macro to small cells. It is shown how the eICIC benefit is maximized by using a distributed inter-base station control framework for dynamic adjustment of essential parameters. Secondly, for scenarios where macro and small cells...... are deployed at different carriers an efficient use of the fragmented spectrum can be achieved by using collaborative inter-site carrier aggregation. In addition to distributed coordination/collaboration between base station nodes, the importance of explicit terminal assistance is highlighted. Comprehensive...

Model uncertainties of local-thermodynamic-equilibrium K-shell spectroscopy

Science.gov (United States)

Nagayama, T.; Bailey, J. E.; Mancini, R. C.; Iglesias, C. A.; Hansen, S. B.; Blancard, C.; Chung, H. K.; Colgan, J.; Cosse, Ph.; Faussurier, G.; Florido, R.; Fontes, C. J.; Gilleron, F.; Golovkin, I. E.; Kilcrease, D. P.; Loisel, G.; MacFarlane, J. J.; Pain, J.-C.; Rochau, G. A.; Sherrill, M. E.; Lee, R. W.

2016-09-01

Local-thermodynamic-equilibrium (LTE) K-shell spectroscopy is a common tool to diagnose electron density, ne, and electron temperature, Te, of high-energy-density (HED) plasmas. Knowing the accuracy of such diagnostics is important to provide quantitative conclusions of many HED-plasma research efforts. For example, Fe opacities were recently measured at multiple conditions at the Sandia National Laboratories Z machine (Bailey et al., 2015), showing significant disagreement with modeled opacities. Since the plasma conditions were measured using K-shell spectroscopy of tracer Mg (Nagayama et al., 2014), one concern is the accuracy of the inferred Fe conditions. In this article, we investigate the K-shell spectroscopy model uncertainties by analyzing the Mg spectra computed with 11 different models at the same conditions. We find that the inferred conditions differ by ±20-30% in ne and ±2-4% in Te depending on the choice of spectral model. Also, we find that half of the Te uncertainty comes from ne uncertainty. To refine the accuracy of the K-shell spectroscopy, it is important to scrutinize and experimentally validate line-shape theory. We investigate the impact of the inferred ne and Te model uncertainty on the Fe opacity measurements. Its impact is small and does not explain the reported discrepancies.

LTE modeling of inhomogeneous chromospheric structure using high-resolution limb observations

Science.gov (United States)

Lindsey, C.

1987-01-01

The paper discusses considerations relevant to LTE modeling of rough atmospheres. Particular attention is given to the application of recent high-resolution observations of the solar limb in the far-infrared and radio continuum to the modeling of chromospheric spicules. It is explained how the continuum limb observations can be combined with morphological knowledge of spicule structure to model the physical conditions in chromospheric spicules. This discussion forms the basis for a chromospheric model presented in a parallel publication based on observations ranging from 100 microns to 2.6 mm.

Comparison of the Marcus and Pekar partitions in the context of non-equilibrium, polarizable-continuum solvation models

International Nuclear Information System (INIS)

You, Zhi-Qiang; Herbert, John M.; Mewes, Jan-Michael; Dreuw, Andreas

2015-01-01

The Marcus and Pekar partitions are common, alternative models to describe the non-equilibrium dielectric polarization response that accompanies instantaneous perturbation of a solute embedded in a dielectric continuum. Examples of such a perturbation include vertical electronic excitation and vertical ionization of a solution-phase molecule. Here, we provide a general derivation of the accompanying polarization response, for a quantum-mechanical solute described within the framework of a polarizable continuum model (PCM) of electrostatic solvation. Although the non-equilibrium free energy is formally equivalent within the two partitions, albeit partitioned differently into “fast” versus “slow” polarization contributions, discretization of the PCM integral equations fails to preserve certain symmetries contained in these equations (except in the case of the conductor-like models or when the solute cavity is spherical), leading to alternative, non-equivalent matrix equations. Unlike the total equilibrium solvation energy, however, which can differ dramatically between different formulations, we demonstrate that the equivalence of the Marcus and Pekar partitions for the non-equilibrium solvation correction is preserved to high accuracy. Differences in vertical excitation and ionization energies are <0.2 eV (and often <0.01 eV), even for systems specifically selected to afford a large polarization response. Numerical results therefore support the interchangeability of the Marcus and Pekar partitions, but also caution against relying too much on the fast PCM charges for interpretive value, as these charges differ greatly between the two partitions, especially in polar solvents

Comparison of the Marcus and Pekar partitions in the context of non-equilibrium, polarizable-continuum solvation models

Energy Technology Data Exchange (ETDEWEB)

You, Zhi-Qiang; Herbert, John M., E-mail: herbert@chemistry.ohio-state.edu [Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210 (United States); Mewes, Jan-Michael; Dreuw, Andreas [Interdisciplinary Center for Scientific Computing, Ruprechts-Karls University, Im Neuenheimer Feld 368, 69120 Heidelberg (Germany)

2015-11-28

The Marcus and Pekar partitions are common, alternative models to describe the non-equilibrium dielectric polarization response that accompanies instantaneous perturbation of a solute embedded in a dielectric continuum. Examples of such a perturbation include vertical electronic excitation and vertical ionization of a solution-phase molecule. Here, we provide a general derivation of the accompanying polarization response, for a quantum-mechanical solute described within the framework of a polarizable continuum model (PCM) of electrostatic solvation. Although the non-equilibrium free energy is formally equivalent within the two partitions, albeit partitioned differently into “fast” versus “slow” polarization contributions, discretization of the PCM integral equations fails to preserve certain symmetries contained in these equations (except in the case of the conductor-like models or when the solute cavity is spherical), leading to alternative, non-equivalent matrix equations. Unlike the total equilibrium solvation energy, however, which can differ dramatically between different formulations, we demonstrate that the equivalence of the Marcus and Pekar partitions for the non-equilibrium solvation correction is preserved to high accuracy. Differences in vertical excitation and ionization energies are <0.2 eV (and often <0.01 eV), even for systems specifically selected to afford a large polarization response. Numerical results therefore support the interchangeability of the Marcus and Pekar partitions, but also caution against relying too much on the fast PCM charges for interpretive value, as these charges differ greatly between the two partitions, especially in polar solvents.

Effects of radiation transport on mass ablation rate and conversion efficiency in numerical simulations of inertial confinement fusion

International Nuclear Information System (INIS)

Gupta, N.K.

2002-01-01

The effects of radiation transport on hydrodynamic parameters of laser produced plasmas are studied. LTE and non-LTE atomic models are used to calculate multi group opacities and emissivities. Screened hydrogenic atom model is used to calculate the energy levels. The population densities of neutral to fully ionized ions are obtained by solving the steady state rate equations. Radiation transport is treated in multi-group diffusion or Sn method. A comparison is made between 1 and 100 group radiation transport and LTE and non-LTE models. For aluminium, multi group radiation transport leads to much higher mass ablation as compared to the 1 group and no radiation transport cases. This in turn leads to higher ablation pressures. However, for gold gray approximation gives higher mass ablation as compared to multi group simulations. LTE conversion efficiency of laser light into x-rays is more than the non-LTE estimates. For LTE as well as non-LTE cases, the one group approximation over-predicts the conversion efficiency Multi group non-LTE simulations predict that the conversion efficiency increases with laser intensity up to a maximum and then it decreases. (author)

An interpretation of hydrogen and helium line spectra of the loop prominence observed on November 3, 1973

International Nuclear Information System (INIS)

Kureizumi, Takeshi; Kubota, Jun; Kawaguchi, Ichiro; Tamenaga, Tatsuo; Maeda, Koichiro.

1977-01-01

The H sub(I), He sub(I), and He sub(II) emission lines of the loop prominence observed on November 3, 1973 in the rapidly developing phase are analyzed. The difference in widths of these lines suggests they do not originate in the same volume. The estimated T sub(e) (8000-9000 K) and n sub(e) (-- 2 x 10 12 cm -3 ) in the loop from the Balmer lines do not change appreciably with time everywhere in the loop during our observation (00 sup(h)40 sup(m)-01 sup(h)10 sup(m)UT). The degree of ionization of hydrogen is estimated to be in the range of 0.8 to 1.0. The ionizing mechanisms may be attributed to the UV radiation (lambda<=912A) from the underlying flare region. Local thermodynamic equilibrium (LTE) is approximately established in the excited levels of He sub(I), but the singlet levels are somewhat overpopulated. The UV radiation field (lambda<=504A) from the surrounding coronal condensation is estimated from microwave and X-ray flux measurements of S sub(OLRAD)9. The ionization of He sub(I) (ionization degree 0.1-0.2) is mainly controlled by UV radiation from the coronal condensation. An adequate thread structure model of the loop prominence is suggested. (auth.)

Testing common classical LTE and NLTE model atmosphere and line-formation codes for quantitative spectroscopy of early-type stars

International Nuclear Information System (INIS)

Przybilla, Norbert; Nieva, Maria-Fernanda; Butler, Keith

2011-01-01

It is generally accepted that the atmospheres of cool/lukewarm stars of spectral types A and later are described well by LTE model atmospheres, while the O-type stars require a detailed treatment of NLTE effects. Here model atmosphere structures, spectral energy distributions and synthetic spectra computed with ATLAS9/SYNTHE and TLUSTY/SYNSPEC, and results from a hybrid method combining LTE atmospheres and NLTE line-formation with DETAIL/SURFACE are compared. Their ability to reproduce observations for effective temperatures between 15 000 and 35 000 K are verified. Strengths and weaknesses of the different approaches are identified. Recommendations are made as to how to improve the models in order to derive unbiased stellar parameters and chemical abundances in future applications, with special emphasis on Gaia science.

User Acceptance of Long-Term Evolution (LTE) Services: An Application of Extended Technology Acceptance Model

Science.gov (United States)

Park, Eunil; Kim, Ki Joon

2013-01-01

Purpose: The aim of this paper is to propose an integrated path model in order to explore user acceptance of long-term evolution (LTE) services by examining potential causal relationships between key psychological factors and user intention to use the services. Design/methodology/approach: Online survey data collected from 1,344 users are analysed…

Numerical simulation of the ionization effects of low- and high-altitude nuclear explosions

International Nuclear Information System (INIS)

Zhao Zhengyu; Wang Xiang

2007-01-01

Low-altitude and high-altitude nuclear explosions are sources of intensive additional ionization in ionosphere. In this paper, in terms of the ionization equilibrium equation system and the equation of energy deposition of radiation in atmosphere, and considering the influence of atmosphere, the temporal and spatial distribution of ionization effects caused by atmospheric nuclear detonation are investigated. The calculated results show that the maximum of additional free electron density produced by low-altitude nuclear explosion is greater than that by the high-altitude nuclear burst. As to the influence of instant nuclear radiation, there is obvious difference between the low-altitude and the high-altitude explosions. The influence range and the continuance time caused by delayed nuclear radiation is less for the low-altitude nuclear detonation than that for the high-altitude one. (authors)

Multiband LTE-A and 4-PAM signals over large-core plastic fibers for in-home networks

NARCIS (Netherlands)

Forni, F.; Shi, Y.; van den Boom, H.P.A.; Tangdiongga, E.; Koonen, A.M.J.

2016-01-01

This letter presents the transmission of eight standard compliant 64-QAM long term evolution advanced (LTE-A) bands and 1.4 Gb/s 4-pulse amplitude modulation (PAM) signals over 20 m of 1 mm core diameter graded-index polymethyl methacrylate plastic optical fiber. The optical transceiver consists of

SISTEMAS MULTIMEDIA BASADOS EN PROTOCOLO IP IMS APLICADOS A SERVICIOS LTE DE 4G

Directory of Open Access Journals (Sweden)

Edgar Alfonso Cipagauta Pedraza

2013-01-01

Full Text Available Este artículo presenta de una manera sencilla, el sistema creado para soportar los servicios de multimedia dentro de red de nueva generación (NGN llamada IP Multimedia Subsystem (IMS a la vez que se explica su relación con la tecnología Long Term Evolution (LTE definida por el 3GPP en su release 8. IMS se trata de una arquitectura integrada en el núcleo de red para ofrecer servicios multimediales de audio y video sobre una infraestructura. Entonces ahora, los servicios prestados pasarán a ser ofrecidos a través de IP IMS y será la piedra angular en donde estos servicios se generarán y se ofrecerán. LTE es sin duda un impulsor de IMS, pero hay otros factores que empiezan a favorecer y a plantear un modelo de negocio favorable para la arquitectura multimedia. IMS está orientado a habilitar la convergencia de servicios, combinando el crecimiento de la Internet con el de las comunicaciones móviles, desde cualquier ubicación y método de forma continua y permanente.

Kinetics of a plasma streamer ionization front

Science.gov (United States)

Taccogna, Francesco; Pellegrini, Fabrizio

2018-02-01

A streamer is a non-linear and non-local gas breakdown mode. Its large-scale coherent structures, such as the ionization front, are the final results of a hierarchical cascade starting from the single particle dynamics. Therefore, this phenomenon covers, by definition, different space and time scales. In this study, we have reproduced the ionization front formation and development by means of a particle-based numerical methodology. The physical system investigated concerns of a high-voltage ns-pulsed surface dielectric barrier discharge. Different reduced electric field regimes ranging from 50 to 500 Td have been considered for two gases: pure atomic Ar and molecular N2. Results have shown the detailed structure of the negative streamer: the leading edge, the head, the interior and the tail. Its dynamical evolution and the front propagation velocity have been calculated for the different cases. Finally, the deviation of the electron energy distribution function from equilibrium behavior has been pointed out as a result of a fast and very localized phenomenon.

Implementation of LTE SC-FDMA on the USRP2 Software Defined Radio Platform

DEFF Research Database (Denmark)

Jørgensen, Peter Bjørn; Hansen, Thomas Lundgaard; Sørensen, Troels Bundgaard

2011-01-01

In this paper we discuss the implementation of a Single Carrier Frequency Division Multiple Access (SC-FDMA) transceiver running over the Universal Software Radio Peripheral 2 (USRP2). SC-FDMA is the air interface which has been selected for the uplink in the latest Long Term Evolution (LTE....../s. Experimental results on the Bit Error Rate (BER) versus Signal-to-Noise Ratio (SNR) are presented and compared to theoretical and simulated performance....

MCS and sub-band selection for downlink interference coordination in LTE-A Femtocells

OpenAIRE

Muñoz Medina, Olga; Agustín de Dios, Adrián; Vidal Manzano, José

2012-01-01

This paper proposes a decentralized algorithm for interference coordination in LTE-A networks, based on the exchange of information (pricing) at control plane level. In our approach, every user equipment (UE) report the maximum modulation and coding scheme (MCS) that can be used within several sets (sub-bands) of available resource blocks, along with a parameter (cost) that measures the MCS degradation due to the transmission from an interfering neighbor. Through the e...

Measurement of the non-thermal properties in a low-pressure spraying plasma

International Nuclear Information System (INIS)

Jung, Yong Ho; Chung, Kyu Sun

2002-01-01

The non-thermal properties of a low-pressure spraying plasma have been characterized by using optical emission spectroscopy and single probes installed in a fast scanning probe system. A two-temperature model of the electrons is introduced to explain their non-isothermal properties, which are measured using single probes. The excitation temperatures of the atomic and the ionic lines are calculated from measurements of the emission intensities of Ar (I) and Ar (II), and those temperatures can be explained by using a local thermodynamic equilibrium (LTE) or a non-local thermodynamic equilibrium (non-LTE) model. In order to deduce more reasonable values (excitation temperatures), we introduce a multi-thermodynamic equilibrium (MTE) model, which gives different temperatures, depending upon the atomic excitation states

A fundamental analysis of the validity of thermodynamic models of ionized and excited particle production during sputtering

International Nuclear Information System (INIS)

Snowdon, K.J.

1979-01-01

The concept of LTE and its existence criteria are applied to the sputtering problem. After presenting arguments against the existence of LTE within the solid, expressions are derived which allow a calculation of the minimum secondary electron yields and sputtering conditions required for the establishment of partial and complete LTE within the hemisphere or hemispherical shell immediately above the point of impact of an incident, heavy projectile. It is found by application of the theory of 50 keV Ar + bombardment of zinc that secondary electron yields per incident projectile of greater than 10 5 are required before either complete, or partial, LTE can be established during sputtering. Further refinements of the model are not expected to reduce this figure the four or more orders of magnitude required for agreement with experimental yields. (author)

On the impact of D2D traffic offloading on energy efficiency in green LTE-A HetNets

KAUST Repository

Yaacoub, Elias E.; Ghazzai, Hakim; Alouini, Mohamed-Slim; Abu-Dayya, Adnan A.

2014-01-01

multiple access-based state-of-the-art LTE cellular networks, while taking resource allocation and intercell interference into account. Results show that the proposed approach leads to energy savings for both the operator and the MTs, while leading

Simulation of non LTE opacity with incoming radiation

Science.gov (United States)

Klapisch, Marcel; Busquet, Michel

2009-11-01

Simulation of radiative properties of hot plasmas is important for ICF, other laboratory plasmas, and astrophysics. When mid-Z or high-Z elements are involved, the spectra are so complex that one commonly uses LTE approximation. This was recently done in interpreting a carefully calibrated experiment on Fe at 160 eV [1]. However some disagreement remains concerning the ion charge distribution. The newest version of HULLAC [2] has the capability to take into account an incoming radiation field in solving the rate equations of the coronal radiative model (CRM). We will show results with different representation of the radiation field.[4pt] [1] J.E. Bailey, G.A. Rochau, C.A. Iglesias, et al., Phys. Rev. Lett. 99, (2007) 265002-4.[0pt] [2] M. Klapisch and M. Busquet, High Ener. Dens. Phys. 5, (2009) 105-9.

5 Watt GaN HEMT Power Amplifier for LTE

Directory of Open Access Journals (Sweden)

K. Niotaki

2014-04-01

Full Text Available This work presents the design and implementation of a stand-alone linear power amplifier at 2.4 GHz with high output power. A GaN HEMT transistor is selected for the design and implementation of the power amplifier. The device exhibits a gain of 11.7 dB and a drain efficiency of 39% for an output power of 36.7 dBm at 2.4 GHz for an input power of 25dBm. The carrier to intermodulation ratio is better than 25 dB for a two tone input signal of 25 dBm of total power and a spacing of 5 MHz. The fabricated device is also tested with LTE input signals of different bandwidths (5MHz to 20MHz.

Treatment of Electronic Energy Level Transition and Ionization Following the Particle-Based Chemistry Model

Science.gov (United States)

Liechty, Derek S.; Lewis, Mark

2010-01-01

A new method of treating electronic energy level transitions as well as linking ionization to electronic energy levels is proposed following the particle-based chemistry model of Bird. Although the use of electronic energy levels and ionization reactions in DSMC are not new ideas, the current method of selecting what level to transition to, how to reproduce transition rates, and the linking of the electronic energy levels to ionization are, to the author s knowledge, novel concepts. The resulting equilibrium temperatures are shown to remain constant, and the electronic energy level distributions are shown to reproduce the Boltzmann distribution. The electronic energy level transition rates and ionization rates due to electron impacts are shown to reproduce theoretical and measured rates. The rates due to heavy particle impacts, while not as favorable as the electron impact rates, compare favorably to values from the literature. Thus, these new extensions to the particle-based chemistry model of Bird provide an accurate method for predicting electronic energy level transition and ionization rates in gases.

Frame Allocation and Scheduling for Relay Networks in the LTE Advanced Standard

OpenAIRE

Roth, Stefan

2010-01-01

The use of relays is seen as a promising way to extend cell coverage and increase rates in LTE Advanced networks. Instead of increasing the number of base stations (BS), relays with lower cost could provide similar gains. A relay will have a wireless link to the closest BS as only connection to the core network and will cover areas close to the cell edge or other areas with limited rates. Performing transmissions in several hops (BS-relay & relay-user) requires more radio resources than u...

Next Phase of Mobile Communications – LTE: The End of Fixed Broadband?

OpenAIRE

Eylert, Bernd; Eras, Martin; Zeh, Thomas

2008-01-01

With the introduction of the Internet in the early 90th years of the last century, broadband demand has increased tremendously. As ISDN was the modern technology at that time, which has had its correspondence in the mobile world in the GSM technology, DSL and its evolution has its correspondence in UMTS/3G and its evolution into HSPA (High Speed Packet Access) and soon in LTE (Long Term Evolution). With the globalisation of our industries business has changed during the last 15 years. Employe...

Equilibrium Droplets on Deformable Substrates: Equilibrium Conditions.

Science.gov (United States)

Koursari, Nektaria; Ahmed, Gulraiz; Starov, Victor M

2018-05-15

Equilibrium conditions of droplets on deformable substrates are investigated, and it is proven using Jacobi's sufficient condition that the obtained solutions really provide equilibrium profiles of both the droplet and the deformed support. At the equilibrium, the excess free energy of the system should have a minimum value, which means that both necessary and sufficient conditions of the minimum should be fulfilled. Only in this case, the obtained profiles provide the minimum of the excess free energy. The necessary condition of the equilibrium means that the first variation of the excess free energy should vanish, and the second variation should be positive. Unfortunately, the mentioned two conditions are not the proof that the obtained profiles correspond to the minimum of the excess free energy and they could not be. It is necessary to check whether the sufficient condition of the equilibrium (Jacobi's condition) is satisfied. To the best of our knowledge Jacobi's condition has never been verified for any already published equilibrium profiles of both the droplet and the deformable substrate. A simple model of the equilibrium droplet on the deformable substrate is considered, and it is shown that the deduced profiles of the equilibrium droplet and deformable substrate satisfy the Jacobi's condition, that is, really provide the minimum to the excess free energy of the system. To simplify calculations, a simplified linear disjoining/conjoining pressure isotherm is adopted for the calculations. It is shown that both necessary and sufficient conditions for equilibrium are satisfied. For the first time, validity of the Jacobi's condition is verified. The latter proves that the developed model really provides (i) the minimum of the excess free energy of the system droplet/deformable substrate and (ii) equilibrium profiles of both the droplet and the deformable substrate.

Life adversity in depressed and non-depressed older adults: A cross-sectional comparison of the brief LTE-Q questionnaire and life events and difficulties interview as part of the CASPER study.

Science.gov (United States)

Donoghue, Hjördis M; Traviss-Turner, Gemma D; House, Allan O; Lewis, Helen; Gilbody, Simon

2016-03-15

There is a paucity of research on the nature of life adversity in depressed and non-depressed older adults. Early life events work used in-depth interviews; however, larger epidemiological trials investigate life adversity using brief questionnaires. This study investigates the type of life adversity experienced in later life and its association with depression and compares adversity captured using a brief (LTE-Q) and in-depth (LEDS) measure. 960 participants over 65 years were recruited in UK primary care to complete the PHQ-9 and LTE-Q. A sub-sample (n=19) completed the LEDS and a question exploring the subjective experience of the LTE-Q and LEDS. Important life adversity was reported on the LTE-Q in 48% of the sample. In the LTE-Q sample the prevalence of depression (PHQ-9≥10) was 12%. Exposure to recent adversity was associated with doubling of the odds of depression. The LTE-Q only captured a proportion of adversity measured by the LEDS (42% vs 84%). Both measures showed health, bereavement and relationship events were most common. The cross-sectional design limits the extent to which inferences can be drawn around the direction of causality between adversity and depression. Recall in older adults is questionable. UK older adults face adversity in areas of health, bereavement and relationships which are associated with depression. This has clinical relevance for psychological interventions for older adults to consider social context and social support. It helps identify the strengths and weaknesses of a brief adversity measure in large scale research. Further research is needed to explore the mechanisms of onset and direction of causality. Copyright © 2016 Elsevier B.V. All rights reserved.