WorldWideScience

Sample records for previous lte models

  1. LTE UE Power Consumption Model

    DEFF Research Database (Denmark)

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

    2012-01-01

    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...... 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...

  2. Hydrogenic ionization model for mixtures in non-LTE plasmas

    International Nuclear Information System (INIS)

    Djaoui, A.

    1999-01-01

    The Hydrogenic Ionization Model for Mixtures (HIMM) is a non-Local Thermodynamic Equilibrium (non-LTE), time-dependent ionization model for laser-produced plasmas containing mixtures of elements (species). In this version, both collisional and radiative rates are taken into account. An ionization distribution for each species which is consistent with the ambient electron density is obtained by use of an iterative procedure in a single calculation for all species. Energy levels for each shell having a given principal quantum number and for each ion stage of each species in the mixture are calculated using screening constants. Steady-state non-LTE as well as LTE solutions are also provided. The non-LTE rate equations converge to the LTE solution at sufficiently high densities or as the radiation temperature approaches the electron temperature. The model is particularly useful at low temperatures where convergence problems are usually encountered in our previous models. We apply our model to typical situation in x-ray laser research, laser-produced plasmas and inertial confinement fusion. Our results compare well with previously published results for a selenium plasma. (author)

  3. LTE RF subsystem power consumption modeling

    DEFF Research Database (Denmark)

    Musiige, Deogratius; Vincent, Laulagnet; Anton, François

    2012-01-01

    This paper presents a new power consumption emulation model, for all possible scenarios of the RF subsystem, when transmitting a LTE signal. The model takes the logical interface parameters, Tx power, carrier frequency and bandwidth between the baseband and RF subsystem as inputs to compute...

  4. 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.

  5. An elemental diffusion description for LTE plasma models

    Energy Technology Data Exchange (ETDEWEB)

    Hartgers, A; Heijden, H W P van der; Beks, M L; Dijk, J van; Mullen, J A M van der [Department of Physics, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven (Netherlands)

    2005-09-21

    A novel method to describe diffusive processes in plasmas in local thermodynamic equilibrium (LTE) was developed, based on the transport of elements instead of individual species. This method combines the elegance of the LTE description of a chemical composition with the flexibility of explicit transport for each element. A simple model of a metal halide lamp containing Hg dosed with NaI is used to illustrate the method.

  6. 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.

  7. Plasma LTE4/PGF2α Ratio and Blood Eosinophil Count Are Increased in Elderly Asthmatics With Previous Asthma Exacerbation.

    Science.gov (United States)

    Ban, Ga Young; Ye, Young Min; Kim, Sang Ha; Hur, Gyu Young; Kim, Joo Hee; Shim, Jae Jung; Cho, Kumsun; Cho, Joo Youn; Park, Hae Sim

    2017-07-01

    The tools for asthma control assessment recommended by the current guideline are cognitive function- and effort-dependent, which is substantially impaired in the elderly. The aim of this study is to investigate objective assessment tools of asthma control status and previous asthma exacerbation (AE) in elderly subjects. Asthmatics aged >60 years who were treated with step 2 or 3 by the Global Initiative for Asthma (GINA) guideline were enrolled. During the 12-week study period, the subjects used either 400 μg of budesonide plus 10 mg of montelukast or 800 μg of inhaled budesonide. The occurrence of AE during the 4-week run-in and 12-week treatment period was monitored. After 12-week of treatment, sputum eosinophil count, peripheral eosinophil count, the plasma leukotriene E4 (LTE4), and prostaglandin F2α (PGF2α) metabolite levels were measured using the UHPLC/Q-ToF MS system. The study subjects were divided into group 1 (asthmatics who experienced AE during the study period) and group 2 (those who did not). A total of 101 patients aged 60-85 years were enrolled. Twenty-three patients (22.8%) had experienced AE. The plasma LTE4 level, LTE4/PGF2α ratio, and peripheral eosinophil count were significantly higher in group 1 than in group 2 (P=0.023, P=0.010, P=0.033, respectively). The plasma LTE4/PGF2α ratio and peripheral eosinophil count at week 12 were significantly associated with previous AE (odds ratio [OR]=1.748, P=0.013; OR=1.256, P=0.027). Receiver operating characteristic (ROC) curves to discriminate the subjects with previous AE, including these 2 parameters, showed that the area under the curve was 0.700 (P=0.004), with 73.9% sensitivity and 47.9% specificity. In conclusion, a combination of plasma LTE4/PGF2α ratio and peripheral eosinophil count can be an objective assessment tool which is significantly associated with asthma control status in elderly asthmatics. Copyright © 2017 The Korean Academy of Asthma, Allergy and Clinical Immunology · The

  8. 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.

  9. An improved LTE model of a high pressure sulfur discharge

    Energy Technology Data Exchange (ETDEWEB)

    Johnston, C W; Heijden, H W P van der; Hartgers, A; Garloff, K; Dijk, J van; Mullen, J J A M van der [Department of Applied Physics, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven (Netherlands)

    2004-01-21

    An existing LTE model (Johnston C W et al 2002 J. Phys. D: Appl. Phys. 35 342) of a high pressure sulfur discharge is improved upon by more accurate and complete treatment of each term in the energy balance. The simulation program PLASIMO (Janssen G M et al 1999 Plasma Sources Sci. Technol. 8 1, van Dijk J 2001 Modelling of plasma light sources: an object-oriented approach PhD Thesis Eindhoven University of Technology, The Netherlands, ISBN 90-386-1819-0), which is an integrated environment for construction and execution of plasma models, has been used to define and solve all aspects of the model. The electric field is treated as being dc, and the temperature dependent nature of species interactions is incorporated in determination of transport coefficients. In addition to the main radiative transition, B3{sup {sigma}}{sub g}{sup -}, several others in S{sub 2} are included. These are B''3{sup {pi}}{sub u} {yields} X3{sup {sigma}}{sub g}{sup -}, B'3{sup {pi}}{sub g} {yields} {l_brace}A3{sup {sigma}}{sub u}{sup +}, A'3{sup {delta}}{sub u}{r_brace} and e1{sup {pi}}{sub g} {yields} c1{sup {sigma}}{sub u}{sup -}. The S{sub 3} molecule is also included in the composition as an absorbing particle. Furthermore, radiation production is treated quantum mechanically. The principle improvement over the previous work is that both the position of the spectral maximum and the pressure shift are quantitatively described by the current model. Both are chiefly due to the presence of S{sub 3}.

  10. Time dependent modeling of non-LTE plasmas: Final report

    International Nuclear Information System (INIS)

    1988-06-01

    During the period of performance of this contract Science Applications International Corporation (SAIC) has aided Lawrence Livermore National Laboratory (LLNL) in the development of an unclassified modeling tool for studying time evolution of high temperature ionizing and recombining plasmas. This report covers the numerical code developed, (D)ynamic (D)etailed (C)onfiguration (A)ccounting (DDCA), which was written to run on the National Magnetic Fusion Energy Computing Center (NMFECC) network as well as the classified Livermore Computer Center (OCTOPUS) network. DDCA is a One-Dimensional (1D) time dependent hydrodynamic model which makes use of the non-LTE detailed atomic physics ionization model DCA. 5 refs

  11. 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...

  12. 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.

  13. Recent advances in non-LTE stellar atmosphere models

    Science.gov (United States)

    Sander, Andreas A. C.

    2017-11-01

    In the last decades, stellar atmosphere models have become a key tool in understanding massive stars. Applied for spectroscopic analysis, these models provide quantitative information on stellar wind properties as well as fundamental stellar parameters. The intricate non-LTE conditions in stellar winds dictate the development of adequate sophisticated model atmosphere codes. The increase in both, the computational power and our understanding of physical processes in stellar atmospheres, led to an increasing complexity in the models. As a result, codes emerged that can tackle a wide range of stellar and wind parameters. After a brief address of the fundamentals of stellar atmosphere modeling, the current stage of clumped and line-blanketed model atmospheres will be discussed. Finally, the path for the next generation of stellar atmosphere models will be outlined. Apart from discussing multi-dimensional approaches, I will emphasize on the coupling of hydrodynamics with a sophisticated treatment of the radiative transfer. This next generation of models will be able to predict wind parameters from first principles, which could open new doors for our understanding of the various facets of massive star physics, evolution, and death.

  14. Augmented twin-nonlinear two-box behavioral models for multicarrier LTE power amplifiers.

    Science.gov (United States)

    Hammi, Oualid

    2014-01-01

    A novel class of behavioral models is proposed for LTE-driven Doherty power amplifiers with strong memory effects. The proposed models, labeled augmented twin-nonlinear two-box models, are built by cascading a highly nonlinear memoryless function with a mildly nonlinear memory polynomial with cross terms. Experimental validation on gallium nitride based Doherty power amplifiers illustrates the accuracy enhancement and complexity reduction achieved by the proposed models. When strong memory effects are observed, the augmented twin-nonlinear two-box models can improve the normalized mean square error by up to 3 dB for the same number of coefficients when compared to state-of-the-art twin-nonlinear two-box models. Furthermore, the augmented twin-nonlinear two-box models lead to the same performance as previously reported twin-nonlinear two-box models while requiring up to 80% less coefficients.

  15. 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...... reservation protocol. Specifically, the limited number of contention preambles and the limited amount of uplink grants per random access response are crucial to consider when dimensioning LTE networks for MTC. We propose a low-complexity model that encompasses these two limitations and allows us to evaluate...... on the preamble collisions. A comparison with the simulated LTE access reservation procedure that follows the 3GPP specifications, confirms that our model provides an accurate estimation of the system outage event and the number of supported MTC devices....

  16. 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).

  17. 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...

  18. 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,…

  19. 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…

  20. 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...

  1. Non-LTE modeling with non-thermal electrons

    Science.gov (United States)

    Le, Hai; Scott, Howard

    2017-10-01

    We present a computational tool to simulate self-consistently the time evolution of the non-LTE kinetics and the electron energy distribution function (EEDF). The standard collisional-radiative rate equations for the atomic states are solved together with a Boltzmann-Fokker-Planck (BFP) equation for the EEDF. Both elastic and inelastic processes as well as radiative transitions are included. The EEDF is discretized on a non-uniform grid in energy space, and the numerical solution of the BFP equation is based on a set of recently developed algorithms. Several numerical examples are presented to demonstrate the capability of the code. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344.

  2. Non-LTE model calculations for SN 1987A and the extragalactic distance scale

    Science.gov (United States)

    Schmutz, W.; Abbott, D. C.; Russell, R. S.; Hamann, W.-R.; Wessolowski, U.

    1990-01-01

    This paper presents model atmospheres for the first week of SN 1987A, based on the luminosity and density/velocity structure from hydrodynamic models of Woosley (1988). The models account for line blanketing, expansion, sphericity, and departures from LTE in hydrogen and helium and differ from previously published efforts because they represent ab initio calculations, i.e., they contain essentially no free parameters. The formation of the UV spectrum is dominated by the effects of line blanketing. In the absorption troughs, the Balmer line profiles were fit well by these models, but the observed emissions are significantly stronger than predicted, perhaps due to clumping. The generally good agreement between the present synthetic spectra and observations provides independent support for the overall accuracy of the hydrodynamic models of Woosley. The question of the accuracy of the Baade-Wesselink method is addressed in a detailed discussion of its approximations. While the application of the standard method produces a distance within an uncertainty of 20 percent in the case of SN 1987A, systematic errors up to a factor of 2 are possible, particularly if the precursor was a red supergiant.

  3. 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

    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...... manufacturers to identify main power consumers when taking actual operating characteristics into account. The smartphone power consumption model includes the main power consumers in the cellular subsystem as a function of receive and transmit power and data rate, and is fitted to empirical power consumption...... 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...

  4. Non-LTE CO, revisited

    Science.gov (United States)

    Ayres, Thomas R.; Wiedemann, Gunter R.

    1989-01-01

    A more extensive and detailed non-LTE simulation of the Delta v = 1 bands of CO than attempted previously is reported. The equations of statistical equilibrium are formulated for a model molecule containing 10 bound vibrational levels, each split into 121 rotational substates and connected by more than 1000 radiative transitions. Solutions are obtained for self-consistent populations and radiation fields by iterative application of the 'Lambda-operator' to an initial LTE distribution. The formalism is used to illustrate models of the sun and Arcturus. For the sun, negligible departures from LTE are found in either a theoretical radiative-equilibrium photosphere with outwardly falling temperatures in its highest layers or in a semiempirical hot chromosphere that reproduces the spatially averaged emission cores of Ca II H and K. The simulations demonstrate that the puzzling 'cool cores' of the CO Delta V = 1 bands observed in limb spectra of the sun and in flux spectra of Arcturus cannot be explained simply by non-LTE scattering effects.

  5. 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.

  6. 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.

  7. Quantitative spectroscopy of extreme helium stars Model atmospheres and a non-LTE abundance analysis of BD+10°2179

    Science.gov (United States)

    Kupfer, T.; Przybilla, N.; Heber, U.; Jeffery, C. S.; Behara, N. T.; Butler, K.

    2017-10-01

    Extreme helium stars (EHe stars) are hydrogen-deficient supergiants of spectral type A and B. They are believed to result from mergers in double degenerate systems. In this paper, we present a detailed quantitative non-LTE spectral analysis for BD+10°2179, a prototype of this rare class of stars, using UV-Visual Echelle Spectrograph and Fiber-fed Extended Range Optical Spectrograph spectra covering the range from ˜3100 to 10 000 Å. Atmosphere model computations were improved in two ways. First, since the UV metal line blanketing has a strong impact on the temperature-density stratification, we used the atlas12 code. Additionally, We tested atlas12 against the benchmark code sterne3, and found only small differences in the temperature and density stratifications, and good agreement with the spectral energy distributions. Secondly, 12 chemical species were treated in non-LTE. Pronounced non-LTE effects occur in individual spectral lines but, for the majority, the effects are moderate to small. The spectroscopic parameters give Teff =17 300±300 K and log g = 2.80±0.10, and an evolutionary mass of 0.55±0.05 M⊙. The star is thus slightly hotter, more compact and less massive than found in previous studies. The kinematic properties imply a thick-disc membership, which is consistent with the metallicity [Fe/H] ≈ -1 and α-enhancement. The refined light-element abundances are consistent with the white dwarf merger scenario. We further discuss the observed helium spectrum in an appendix, detecting dipole-allowed transitions from about 150 multiplets plus the most comprehensive set of known/predicted isolated forbidden components to date. Moreover, a so far unreported series of pronounced forbidden He I components is detected in the optical-UV.

  8. Non-LTE Models for the Thermal Structure of Hot Jupiters

    Science.gov (United States)

    Yelle, Roger V.; Koskinen, Tommi; Lavvas, Panayiotis

    2017-10-01

    Numerous models exist for the thermal structure of the lower and upper atmospheres of hot Jupitersbut the middle atmosphere has yet to be investigated in detail. We present the first calculations forthe thermal structure of hot Jupiter atmospheres from 1 mbar to 1 nbar, a region that is critical to theformation of observable spectral features, especially the strong resonance lines of alkali metals. Themodels connect the LTE region at the high pressure with the thermosphere at the low pressure. Animportant goal of this research is the description of the sharp temperature gradient that leads to thehigh thermospheric temperatures and is a critical factor in establishing atmospheric escape rates. Thecalculations include thermal conduction, UV heating, and radiative transfer in the molecular bands androtational lines of H2O. The radiative transfer calculations treat departures from LTE, that becomeimportant at pressures less than ~1 microbar. We will discuss the interplay between radiative transferin vibrational bands, that experience non-LTE effects, and rotational lines, which do not. The implicationsfor interpretation of Na I transit depths on HD189733B will be discussed and well as the connectionwith atmospheric escape rates.

  9. 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.

  10. A fully blanketed early B star LTE model atmosphere using an opacity sampling technique

    International Nuclear Information System (INIS)

    Phillips, A.P.; Wright, S.L.

    1980-01-01

    A fully blanketed LTE model of a stellar atmosphere with Tsub(e) = 21914 K (thetasub(e) = 0.23), log g = 4 is presented. The model includes an explicit representation of the opacity due to the strongest lines, and uses a statistical opacity sampling technique to represent the weaker line opacity. The sampling technique is subjected to several tests and the model is compared with an atmosphere calculated using the line-distribution function method. The limitations of the distribution function method and the particular opacity sampling method used here are discussed in the light of the results obtained. (author)

  11. 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

  12. 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...

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. IUE observations of Si and C lines and comparison with non-LTE models

    Science.gov (United States)

    Kamp, L. W.

    1982-01-01

    Classical model atmosphere techniques are applied to analyze IUE spectra, and to determine abundances, effective temperatures and gravities. Measurements of the equivalent widths and other properties of the line profiles of 24 photospheric lines of Si II, Si III, Si IV, C II, C III and C IV are presented in the range of 1175-1725 A for seven B and two O stars. Observed line profiles are compared with theoretical profiles computed using non-LTE theory and models, and using line-blanketed model atmospheres. Agreement is reasonably good, although strong lines are calculated to be systematically stronger than those observed, while the reverse occurs for weak lines, and empirical profiles have smaller wings than theoretical profiles. It is concluded that the present theory of line formation when used with solar abundances, represents fairly well observed UV photospheric lines of silicon and carbon ions in the atmospheres of main sequence stars of types B5-O9.

  18. Basis expansion model for channel estimation in LTE-R communication system

    Directory of Open Access Journals (Sweden)

    Ling Deng

    2016-05-01

    Full Text Available This paper investigates fast time-varying channel estimation in LTE-R communication systems. The Basis Expansion Model (BEM is adopted to fit the fast time-varying channel in a high-speed railway communication scenario. The channel impulse response is modeled as the sum of basis functions multiplied by different coefficients. The optimal coefficients are obtained by theoretical analysis. Simulation results show that a Generalized Complex-Exponential BEM (GCE-BEM outperforms a Complex-Exponential BEM (CE-BEM and a polynomial BEM in terms of Mean Squared Error (MSE. Besides, the MSE of the CE-BEM decreases gradually as the number of basis functions increases. The GCE-BEM has a satisfactory performance with the serious fading channel.

  19. A self-consistent LTE model of a microwave-driven, high-pressure sulfur lamp

    Energy Technology Data Exchange (ETDEWEB)

    Johnston, C.W.; Mullen, J.J.A.M. van der [Department of Applied Physics, Eindhoven University of Technology (Netherlands)]. E-mails: C.W.Johnston@tue.nl; J.J.A.M.v.d.Mullen@tue.nl; Heijden, H.W.P. van der; Janssen, G.M.; Dijk, J. van [Department of Applied Physics, Eindhoven University of Technology (Netherlands)

    2002-02-21

    A one-dimensional LTE model of a microwave-driven sulfur lamp is presented to aid our understanding of the discharge. The energy balance of the lamp is determined by Ohmic input on one hand and transport due to conductive heat transfer and molecular radiation on the other. We discuss the origin of operational trends in the spectrum, present the model and discuss how the material properties of the plasma are determined. Not only are temperature profiles and electric field strengths simulated but also the spectrum of the lamp from 300 to 900 nm under various conditions of input power and lamp filling pressure. We show that simulated spectra demonstrate observed trends and that radiated power increases linearly with input power as is also found from experiment. (author)

  20. 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

  1. 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.

  2. Tractable Stochastic Geometry Model for IoT Access in LTE Networks

    KAUST Repository

    Gharbieh, Mohammad

    2017-02-07

    The Internet of Things (IoT) is large-scale by nature. This is not only manifested by the large number of connected devices, but also by the high volumes of traffic that must be accommodated. Cellular networks are indeed a natural candidate for the data tsunami the IoT is expected to generate in conjunction with legacy human-type traffic. However, the random access process for scheduling request represents a major bottleneck to support IoT via LTE cellular networks. Accordingly, this paper develops a mathematical framework to model and study the random access channel (RACH) scalability to accommodate IoT traffic. The developed model is based on stochastic geometry and discrete time Markov chains (DTMC) to account for different access strategies and possible sources of inter-cell and intra-cell interferences. To this end, the developed model is utilized to assess and compare three different access strategies, which incorporate a combination of transmission persistency, back-off, and power ramping. The analysis and the results showcased herewith clearly illustrate the vulnerability of the random access procedure as the IoT intensity grows. Finally, the paper offers insights into effective scenarios for each transmission strategy in terms of IoT intensity and RACH detection thresholds.

  3. Partial redistribution in 3D non-LTE radiative transfer in solar-atmosphere models

    Science.gov (United States)

    Sukhorukov, Andrii V.; Leenaarts, Jorrit

    2017-01-01

    Context. Resonance spectral lines such as H I Ly α, Mg II H&K, and Ca II H&K that form in the solar chromosphere, are influenced by the effects of 3D radiative transfer as well as partial redistribution (PRD). So far no one has modeled these lines including both effects simultaneously owing to the high computing demands of existing algorithms. Such modeling is, however, indispensable for accurate diagnostics of the chromosphere. Aims: We present a computationally tractable method to treat PRD scattering in 3D model atmospheres using a 3D non-local thermodynamic equilibrium (non-LTE) radiative transfer code. Methods: To make the method memory-friendly, we use the hybrid approximation for the redistribution integral. To make the method fast, we use linear interpolation on equidistant frequency grids. We verify our algorithm against computations with the RH code and analyze it for stability, convergence, and usefulness of acceleration using model atoms of Mg II with the H&K lines and H I with the Ly α line treated in PRD. Results: A typical 3D PRD solution can be obtained in a model atmosphere with 252 × 252 × 496 coordinate points in 50 000-200 000 CPU hours, which is a factor ten slower than computations assuming complete redistribution. We illustrate the importance of the joint action of PRD and 3D effects for the Mg II H&K lines for disk-center intensities, as well as the center-to-limb variation. Conclusions: The proposed method allows for the simulation of PRD lines in a time series of radiation-magnetohydrodynamic models, in order to interpret observations of chromospheric lines at high spatial resolution.

  4. Modeling and Event-Driven Simulation of Coordinated Multi-Point in LTE-Advanced with Constrained Backhaul

    DEFF Research Database (Denmark)

    Artuso, Matteo; Christiansen, Henrik Lehrmann

    2014-01-01

    Inter-cell interference (ICI) is considered as the most critical bottleneck to ubiquitous 4th generation cellular access in the mobile long term evolution (LTE). To address the problem, several solutions are under evaluation as part of LTE-Advanced (LTE-A), the most promising one being coordinated...

  5. 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

  6. 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.

  7. Performance of LTE in High Speed Railway Scenarios

    DEFF Research Database (Denmark)

    Sniady, Aleksander; Soler, José

    2013-01-01

    , alternative technologies, such as LTE, have to be considered as a future railway communication technology. This paper presents an analysis of transfer delay and data integrity of European Train Control System (ETCS) messages transmitted over LTE network. The analysis is made using OPNET models of a high speed...... railway line and LTE systems....

  8. 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...

  9. 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.

  10. Multidimensional Big Spatial Data Modeling Through A Case Study: Lte Rf Subsystem Power Consumption Modeling

    DEFF Research Database (Denmark)

    Antón Castro, Francesc/François; Musiige, Deogratius; Mioc, Darka

    2016-01-01

    This paper presents a case study for comparing different multidimensional mathematical modeling methodologies used in multidimensional spatial big data modeling and proposing a new technique. An analysis of multidimensional modeling approaches (neural networks, polynomial interpolation and homoto...

  11. 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

  12. 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.

  13. 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.

  14. Previous Experience a Model of Practice UNAE

    OpenAIRE

    Ruiz, Ormary Barberi; Pesántez Palacios, María Dolores

    2017-01-01

    The statements presented in this article represents a preliminary version of the proposed model of pre-professional practices (PPP) of the National University of Education (UNAE) of Ecuador, an urgent institutional necessity is revealed in the descriptive analyzes conducted from technical support - administrative (reports, interviews, testimonials), pedagogical foundations of UNAE (curricular directionality, transverse axes in practice, career plan, approach and diagnostic examination as subj...

  15. 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

  16. 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.

  17. Self-consistent Non-LTE Model of Infrared Molecular Emissions and Oxygen Dayglows in the Mesosphere and Lower Thermosphere

    Science.gov (United States)

    Feofilov, Artem G.; Yankovsky, Valentine A.; Pesnell, William D.; Kutepov, Alexander A.; Goldberg, Richard A.; Mauilova, Rada O.

    2007-01-01

    We present the new version of the ALI-ARMS (for Accelerated Lambda Iterations for Atmospheric Radiation and Molecular Spectra) model. The model allows simultaneous self-consistent calculating the non-LTE populations of the electronic-vibrational levels of the O3 and O2 photolysis products and vibrational level populations of CO2, N2,O2, O3, H2O, CO and other molecules with detailed accounting for the variety of the electronic-vibrational, vibrational-vibrational and vibrational-translational energy exchange processes. The model was used as the reference one for modeling the O2 dayglows and infrared molecular emissions for self-consistent diagnostics of the multi-channel space observations of MLT in the SABER experiment It also allows reevaluating the thermalization efficiency of the absorbed solar ultraviolet energy and infrared radiative cooling/heating of MLT by detailed accounting of the electronic-vibrational relaxation of excited photolysis products via the complex chain of collisional energy conversion processes down to the vibrational energy of optically active trace gas molecules.

  18. 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.

  19. Non-LTE, line-blanketed model atmospheres for late O- and early B-type stars

    Science.gov (United States)

    Grigsby, James A.; Morrison, Nancy D.; Anderson, Lawrence S.

    1992-01-01

    The use of non-LTE line-blanketed model atmospheres to analyze the spectra of hot stars is reported. The stars analyzed are members of clusters and associations, have spectral types in the range O9-B2 and luminosity classes in the range III-IV, have slow to moderate rotation, and are photometrically constant. Sampled line opacities of iron-group elements were incorporated in the radiative transfer solution; solar abundances were assumed. Good to excellent agreement is obtained between the computed profiles and essentially all the line profiles used to fix the model, and reliable stellar parameters are derived. The synthetic M II 5581 equivalent widths agree well with the observed ones at the low end of the temperature range studied, but, above 25,000 K, the synthetic line is generally stronger than the observed line. The behavior of the observed equivalent widths of N II, N III, C II and C III lines as a function of Teff is studied. Most of the lines show much scatter, with no consistent trend that could indicate abundance differences from star to star.

  20. 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.

  1. 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.

  2. Massive Multispecies, Multilevel Non-LTE Model Atmospheres for Novae in Outburst

    International Nuclear Information System (INIS)

    Short, C. Ian; Hauschildt, Peter H.; Baron, E.

    1999-01-01

    We have used our PHOENIX multipurpose model atmosphere code to calculate atmospheric models that represent novae in the optically thick wind phases of their outburst. We have improved the treatment of non-local thermodynamic equilibrium (NLTE) effects by expanding the number of elements that are included in the calculations from 15 to 19 and the number of ionization stages from 36 to 87. The code can now treat a total of 10,713 levels and 102,646 lines in NLTE. Al, P, K, and Ni are included for the first time in the NLTE treatment, and most elements now have at least the lowest six ionization stages included in the NLTE calculation. We have investigated the effects of expanded NLTE treatment on the chemical concentration of astrophysically significant species in the atmosphere, the equilibrium structure of the atmosphere, and the emergent flux distribution. Although we have found general qualitative agreement with previous, more limited NLTE models, the expanded NLTE treatment leads to significantly different values for the size of many of the NLTE deviations. In particular, for the hottest model presented here (T eff =35,000 K), for which NLTE effects are largest, we find that the expanded NLTE treatment reduces the NLTE effects for these important variables: H i concentration, pressure structure, and emergent far-UV flux. Moreover, we find that the addition of new NLTE species may greatly affect the concentration of species that were already treated in NLTE, so that, generally, all species that contribute significantly to the e - reservoir or to the total opacity, or whose line spectrum overlaps or interlocks with that of a species of interest, must be treated in NLTE to ensure an accurate result for any particular species. (c) (c) 1999. The American Astronomical Society

  3. 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...

  4. 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

  5. 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.

  6. Cloud computing models and their application in LTE based cellular systems

    NARCIS (Netherlands)

    Staring, A.J.; Karagiannis, Georgios

    2013-01-01

    As cloud computing emerges as the next novel concept in computer science, it becomes clear that the model applied in large data storage systems used to resolve issues coming forth from an increasing demand, could also be used to resolve the very high bandwidth requirements on access network, core

  7. 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

  8. 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

  9. 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.

  10. 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.

  11. 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.

  12. 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...

  13. Electron temperature determination in LTE and non-LTE plasmas

    International Nuclear Information System (INIS)

    Eddy, T.L.

    1983-01-01

    This article discusses how most experimental investigations assume a type of ''thermal equilibrium'' in which the excited levels are assumed to be populated according to the electron kinetic temperature, in the determination of electron temperature in LTE and non-LTE plasmas. This is justified on the basis that electron collisions dominate the equilibration of adjacent excited levels as shown by Byron, Stabler and Boartz. The comparison of temperature values calculated by various common methods as a check for local thermodynamic equilibrium (LTDE) or local thermal equilibrium (LTE) of the upper excited levels and the free electrons has been shown to indicate the excitation temperature in all cases utilized. Thomas shows that the source function of the first excited level may be dominated by non-local radiation, which would usually result in a different population than local collisional excitation would provide. Ionization from upper levels is by collisional means. The result may yield different valued excitation and electron temperatures

  14. 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

  15. Modeling of Wi-Fi IEEE 802.11ac Offloading Performance For 1000x Capacity Expansion of LTE-Advanced

    DEFF Research Database (Denmark)

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

    2013-01-01

    This paper studies indoor Wi-Fi IEEE 802.11ac deployment as a capacity expansion solution of LTE-A (Long Term Evolution-Advanced) network to achieve 1000 times higher capacity. Besides increasing the traffic volume by a factor of x1000, we also increase the minimum target user data rate to 10Mbit....../s. The objective is to understand the performance and offloading capability of Wi-Fi 802.11ac at 5GHz. For the performance evaluation of Wi-Fi, we propose a novel analytical throughput model that captures both key 802.11ac enhancements and multi-cell interference. We provide a quantitative evaluation of large......-scale indoor Wi-Fi 802.11ac deployment in a real urban scenario by extensive simulations. We conclude that deploying indoor Wi-Fi access points in almost every building is essential to carry the x1000 traffic volume and ensure a minimum user data rate of 10Mbit/s....

  16. VoLTE performance in railway scenarios

    DEFF Research Database (Denmark)

    Sniady, Aleksander; Sønderskov, Morten; Soler, José

    2015-01-01

    communication is still a crucial service for railways. Regardless of its advantages, LTE can only become a railway communication technology if it provides voice communication fulfilling railway requirements. This paper presents how Voice over LTE (VoLTE) can be used to build railway communication services...

  17. 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...

  18. 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

  19. Non-LTE analysis of copper abundances for the two distinct halo populations in the solar neighborhood

    Science.gov (United States)

    Yan, H. L.; Shi, J. R.; Nissen, P. E.; Zhao, G.

    2016-01-01

    Context. Two distinct halo populations were found in the solar neighborhood by a series of works. They can be clearly separated by [α/Fe] and several other elemental abundance ratios including [Cu/Fe]. Very recently, a non-local thermodynamic equilibrium (non-LTE) study revealed that relatively large departures exist between LTE and non-LTE results in copper abundance analysis. The study also showed that non-LTE effects of neutral copper vary with stellar parameters and thus affect the [Cu/Fe] trend. Aims: We aim to derive the copper abundances for the stars from the sample of Nissen & Schuster (2010) with both LTE and non-LTE calculations. Based on our results, we study the non-LTE effects of copper and investigate whether the high-α population can still be distinguished from the low-α population in the non-LTE [Cu/Fe] results. Methods: Our differential abundance ratios are derived from the high-resolution spectra collected from VLT/UVES and NOT/FIES spectrographs. Applying the MAFAGS opacity sampling atmospheric models and spectrum synthesis method, we derive the non-LTE copper abundances based on the new atomic model with current atomic data obtained from both laboratory and theoretical calculations. Results: The copper abundances determined from non-LTE calculations are increased by 0.01 to 0.2 dex depending on the stellar parameters compared with the LTE results. The non-LTE [Cu/Fe] trend is much flatter than the LTE one in the metallicity range -1.6 FIES) at the Nordic Optical Telescope (NOT) on La Palma, and on data from the European Southern Observatory ESO/ST-ECF Science Archive Facility (programs 65.L-0507, 67.D-0086, 67.D-0439, 68.D-0094, 68.B-0475, 69.D-0679, 70.D-0474, 71.B-0529, 72.B-0585, 76.B-0133 and 77.B-0507).

  20. 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.

  1. 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.

  2. LTE-Enhanced Cognitive Radio Network Testbed (LTE-CORNET)

    Science.gov (United States)

    2016-11-01

    is a French non-profit organisation that provides a standard-compliant implementation of a subset of Release 10 LTE for Linux-based general purpose...Disconnection Occasionally, the UE behaviour was erratic and it would refuse to latch onto the network. On other occasions, it would randomly...attempted, but there was not much luck. Finally, the only reliable option to shake the UE out of its random behaviour was to do a full factory reset

  3. Fast Control Channel Decoding for LTE UE Power Saving

    DEFF Research Database (Denmark)

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

    2012-01-01

    % it is concluded that the FCCD method is a valuable aid to prolong LTE phones' battery lifetime. The results are generated using a two state Markov chain model to simulate traffic and scheduling, and verified mathematically. The work also includes an examination of various data traffic types' on/off relation...

  4. 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.

  5. 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.

  6. 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

  7. Analysis Cost 231 MultiWall Model on 4G LTE FDD 1800 and 900 Mhz Femtocell Network Planning

    Directory of Open Access Journals (Sweden)

    Alfin Hikmaturokhman

    2016-10-01

    Full Text Available Indoor cellular network system is one solution to overcome weak signals transmited by eNodeB. Building with high cellular communication traffic levels , requiring indoor network system to maintain continuity of communication by all users. Therefore, it is necessary to plan an indoor network using Femtocell Access Point (FAP. This research is based on network design indoor propagation COST 231-Multiwall Model using the software Radiowave Propagation Simulator (RPS and conducted at Telkom Office. The collection of data obtained is used to perform calculations on research variables include the calculation of capacity and coverage. The research showed the number of FAP for capacity and coverage is 3 FAP. The Coverage Results for scenario 2 is the best result compared with the other scenarios, with the following results, the frequency of 1800 MHz at Building 1 of -19.86 dBm, Building 2 at -21.34 dBm, and Building 3 at -28, 07 dBm. While the scenario 2 for the 900 MHz frequency in Building 1 at -13.38 dBm, Building 2 at -14.52 dBm, and building 3 of -20.39 dBm.

  8. 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

  9. 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

  10. Cross layer scheduling algorithm for LTE Downlink

    DEFF Research Database (Denmark)

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

    2012-01-01

    The LTE standards is leading standard in the wireless broadband market. In order to accommodate the increased demand for mobile data services the radio interface in the LTE standard is enhanced with advanced technologies such as OFDMA (Orthogonal Frequency Division Multiple Access) and MIMO...

  11. 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...... communication is still a crucial service for railways. Regardless of its advantages, LTE can only become a railway communication technology if it provides voice communication fulfilling railway requirements. This paper presents how Voice over LTE (VoLTE) can be used to build railway communication services...

  12. 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.

  13. MU-MIMO in LTE Systems

    DEFF Research Database (Denmark)

    Duplicy, Jonathan; Badic, Biljana; Balraj, Rajarajan

    2011-01-01

    focus is on making Multi-User Multiple-Input Multiple-Output (MUMIMO) practically realizable. This article presents an overview of the different MU-MIMO schemes included / being studied in 3GPP standardization; from LTE (Long Term Evolution) to LTE-Advanced. MU-MIMO system concepts and implementation...... for LTE Release 8 are provided. Interestingly, it is shown that MU-MIMO only offers marginal performance gains with respect to singleuser MIMO. This arises from the limited MU-MIMO features included in Release 8 and calls for improved schemes for the upcoming releases....

  14. LTE-advanced air interface technology

    CERN Document Server

    Zhang, Xincheng

    2012-01-01

    Opportunities are at hand for professionals eager to learn and apply the latest theories and practices in air interface technologies. Written by experienced researchers and professionals, LTE-Advanced Air Interface Technology thoroughly covers the performance targets and technology components studied by 3GPP for LTE-Advanced. Besides being an explanatory text about LTE-Advanced air interface technology, this book exploits the technical details in the 3GPP specification, and explains the motivation and implication behind the specifications.After a general description of wireless cellular techno

  15. Power-Consumption Measurements for LTE User Equipment

    DEFF Research Database (Denmark)

    Lauridsen, Mads

    If you are designing smartphone chipsets or operating a mobile network, you need to determine how certain parameters affect a speciic smartphone’s power consumption and igure out how to adjust the parameters to improve battery life. In this application note we show how to use the Agilent E6621A PXT......, 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]....... 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...

  16. 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....

  17. 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.

  18. LTE OFFLOADING THROUGH WiFi NETWORKS

    Directory of Open Access Journals (Sweden)

    A. N. Steputin

    2015-11-01

    Full Text Available The subject of the article is Wi-Fi offloading of LTE networks as one of the methods for solving a problem of the lack of availability of network resources in the future. Comparison of mobile networks offloading technologies, such as femtocells, Small Cells and Wi-Fi, is given. Architecture of cooperative LTE+Wi-Fi network including both new network components and new functions for standard LTE network components is presented as well as interaction between components. Special attention is paid to the usage of mobile IP protocols providing connection to the LTE Core both by trusted and untrusted Wi-Fi access. Evaluation of implementation effectiveness and prospective of the technology is given. The relation between amounts of users reconnected to Wi-Fi, data rate of LTE network and amount of access points are submitted as a part of the simulation of user’s equipment transition process from LTE to Wi-Fi network. A conclusion based on the research is made that stepwise phase-in of this technology enables to solve the problem of mobile network resources shortage in metropolises due to permanent traffic growth. It is presented that access points addition and transference of the customers to Wi-Fi network significantly reduce the overload on the base station herewith it increases some data rate with preservation of quality of provided services.

  19. Echo State Learning for Wireless Virtual Reality Resource Allocation in UAV-enabled LTE-U Networks

    OpenAIRE

    Chen, Mingzhe; Saad, Walid; Yin, Changchuan

    2017-01-01

    In this paper, the problem of resource management is studied for a network of wireless virtual reality (VR) users communicating using an unmanned aerial vehicle (UAV)-enabled LTE-U network. In the studied model, the UAVs act as VR control centers that collect tracking information from the VR users over the wireless uplink and, then, send the constructed VR images to the VR users over an LTE-U downlink. Therefore, resource allocation in such a UAV-enabled LTE-U network must jointly consider th...

  20. 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.

  1. 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)

  2. A Multi-Carrier Scheduling Algorithm for LTE-Advanced

    DEFF Research Database (Denmark)

    Vulpe, Alexander; Mihovska, Albena D.; Prasad, Ramjee

    2013-01-01

    LTE-Advanced aims to provide a transmission bandwidth of 100 MHz by using Carrier Aggregation to aggregate LTE Rel. 8 carriers. In order to increase the system capacity, resource allocation becomes a very good tool, and, in the context of the existence of multiple Component Carriers in LTE-Advanc...

  3. 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 ma...

  4. User Multiplexing in Relay Enhanced LTE-Advanced Networks

    DEFF Research Database (Denmark)

    Teyeb, Oumer Mohammed; Frederiksen, Frank; Redana, Simone

    2010-01-01

    The 3rd Generation Partnership Project has recently started the standardization process for LTE-Advanced, as a major evolution step of UTRAN LTE Release 8. One of the key enhancing technologies being studied that may help to fulfill the challenging performance targets of LTE-Advanced networks is ...

  5. Systematic investigation of NLTE phenomena in the limit of small departures from LTE

    International Nuclear Information System (INIS)

    Libby, S.B.; Graziani, F.R.; More, R.M.; Kato, T.

    1997-01-01

    In this paper, we begin a systematic study of Non-Local Thermal Equilibrium (NLTE) phenomena in near equilibrium (LTE) high energy density, highly radiative plasmas. It is shown that the principle of minimum entropy production rate characterizes NLTE steady states for average atom rate equations in the case of small departures form LTE. With the aid of a novel hohlraum-reaction box thought experiment, we use the principles of minimum entropy production and detailed balance to derive Onsager reciprocity relations for the NLTE responses of a near equilibrium sample to non-Planckian perturbations in different frequency groups. This result is a significant symmetry constraint on the linear corrections to Kirchoff close-quote s law. We envisage applying our strategy to a number of test problems which include: the NLTE corrections to the ionization state of an ion located near the edge of an otherwise LTE medium; the effect of a monochromatic radiation field perturbation on an LTE medium; the deviation of Rydberg state populations from LTE in recombining or ionizing plasmas; multi-electron temperature models such as that of Busquet; and finally, the effect of NLTE population shifts on opacity models. copyright 1997 American Institute of Physics

  6. 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.

  7. 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....

  8. 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)

  9. 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.

  10. 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)

  11. 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

    any trends with equivalent width to within modelling uncertainties of 0.05 dex, all without having to invoke any microturbulent broadening; for HD122563 we predict that the current best parallax-based surface gravity is overestimated by 0.5 dex. Using a 3D non-LTE analysis, we infer iron abundances...

  12. 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...

  13. Evaluation of ETCS performance with LTE as alternative railway communication network using OPNET

    DEFF Research Database (Denmark)

    Sniady, Aleksander; Soler, José

    2013-01-01

    GSM-Railways (GSM-R) is a communication mobile network designed to fulfill specific communication needs of railways. GSM-R is being widely deployed across Europe and other countries around the world for providing railway voice and train control services (ETCS). Despite that, GSM-R already shows...... various shortcomings in terms of capacity and support for additional data services. This triggers the issue whether railways could greatly benefit from an alternative communication technology. One of the possible alternatives is LTE. In our work we analyze delivery of railway services over an LTE network....... This work is done using OPNET as simulator for modeling real life railway scenarios and communication infrastructure. These scenarios take advantage of OPNET features allowing modeling an end-to-end LTE network, as well as trains movement over an exemplary real life railway line....

  14. 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...

  15. 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.)

  16. 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

  17. 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...... for the LTE-700 band in small terminals is raised....

  18. '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

  19. 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.

  20. Non-LTE line formation of Fe in late-type stars - IV. Modelling of the solar centre-to-limb variation in 3D

    Science.gov (United States)

    Lind, K.; Amarsi, A. M.; Asplund, M.; Barklem, P. S.; Bautista, M.; Bergemann, M.; Collet, R.; Kiselman, D.; Leenaarts, J.; Pereira, T. M. D.

    2017-07-01

    Our ability to model the shapes and strengths of iron lines in the solar spectrum is a critical test of the accuracy of the solar iron abundance, which sets the absolute zero-point of all stellar metallicities. We use an extensive 463-level Fe atom with new photoionization cross-sections for Fe I and quantum mechanical calculations of collisional excitation and charge transfer with neutral hydrogen; the latter effectively remove a free parameter that has hampered all previous line formation studies of Fe in non-local thermodynamic equilibrium (NLTE). For the first time, we use realistic 3D NLTE calculations of Fe for a quantitative comparison to solar observations. We confront our theoretical line profiles with observations taken at different viewing angles across the solar disc with the Swedish 1-m Solar Telescope. We find that 3D modelling well reproduces the observed centre-to-limb behaviour of spectral lines overall, but highlight aspects that may require further work, especially cross-sections for inelastic collisions with electrons. Our inferred solar iron abundance is log (ɛFe) = 7.48 ± 0.04 dex.

  1. 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.

  2. The non-LTE formation of Li I lines in cool stars

    NARCIS (Netherlands)

    Carlsson, M.; Rutten, R.J.; Bruls, J.H.M.J.; Shchukina, N. G.

    1994-01-01

    We study the non-LTE (non local thermodynamic equilibrium) formation of Li I lines in the spectra of cool stars for a grid of radiative-equilibrium model atmospheres with variation in effective temperature, gravity, metallicity and lithium abundance. We analyze the mechanisms by which departures

  3. 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

  4. 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.

  5. 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”.

  6. Validation of SWAT+ at field level and comparison with previous SWAT models in simulating hydrologic quantity

    Science.gov (United States)

    GAO, J.; White, M. J.; Bieger, K.; Yen, H.; Arnold, J. G.

    2017-12-01

    Over the past 20 years, the Soil and Water Assessment Tool (SWAT) has been adopted by many researches to assess water quantity and quality in watersheds around the world. As the demand increases in facilitating model support, maintenance, and future development, the SWAT source code and data have undergone major modifications over the past few years. To make the model more flexible in terms of interactions of spatial units and processes occurring in watersheds, a completely revised version of SWAT (SWAT+) was developed to improve SWAT's ability in water resource modelling and management. There are only several applications of SWAT+ in large watersheds, however, no study pays attention to validate the new model at field level and assess its performance. To test the basic hydrologic function of SWAT+, it was implemented in five field cases across five states in the U.S. and compared the SWAT+ created results with that from the previous models at the same fields. Additionally, an automatic calibration tool was used to test which model is easier to be calibrated well in a limited number of parameter adjustments. The goal of the study was to evaluate the performance of SWAT+ in simulating stream flow on field level at different geographical locations. The results demonstrate that SWAT+ demonstrated similar performance with previous SWAT model, but the flexibility offered by SWAT+ via the connection of different spatial objects can result in a more accurate simulation of hydrological processes in spatial, especially for watershed with artificial facilities. Autocalibration shows that SWAT+ is much easier to obtain a satisfied result compared with the previous SWAT. Although many capabilities have already been enhanced in SWAT+, there exist inaccuracies in simulation. This insufficiency will be improved with advancements in scientific knowledge on hydrologic process in specific watersheds. Currently, SWAT+ is prerelease, and any errors are being addressed.

  7. 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....

  8. 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.

  9. LTE advanced 3GPP solution for IMT-advanced

    CERN Document Server

    Holma, Harri

    2012-01-01

    From the editors of the highly successful LTE for UMTS: Evolution to LTE-Advanced, this new book examines the main technical enhancements brought by LTE-Advanced, thoroughly covering 3GPP Release 10 specifications and the main items in Release 11. Using illustrations, graphs and real-life scenarios, the authors systematically lead readers through this cutting-edge topic to provide an outlook on existing technologies as well as possible future developments. The book is structured to follow the main technical areas that will be enhanced by the LTE-Advanced specifications. The mai

  10. 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.

  11. 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

  12. Non-LTE aluminium abundances in late-type stars

    Science.gov (United States)

    Nordlander, T.; Lind, K.

    2017-11-01

    Aims: Aluminium plays a key role in studies of the chemical enrichment of the Galaxy and of globular clusters. However, strong deviations from LTE (non-LTE) are known to significantly affect the inferred abundances in giant and metal-poor stars. Methods: We present non-local thermodynamic equilibrium (NLTE) modeling of aluminium using recent and accurate atomic data, in particular utilizing new transition rates for collisions with hydrogen atoms, without the need for any astrophysically calibrated parameters. For the first time, we perform 3D NLTE modeling of aluminium lines in the solar spectrum. We also compute and make available extensive grids of abundance corrections for lines in the optical and near-infrared using one-dimensional model atmospheres, and apply grids of precomputed departure coefficients to direct line synthesis for a set of benchmark stars with accurately known stellar parameters. Results: Our 3D NLTE modeling of the solar spectrum reproduces observed center-to-limb variations in the solar spectrum of the 7835 Å line as well as the mid-infrared photospheric emission line at 12.33 μm. We infer a 3D NLTE solar photospheric abundance of A(Al) = 6.43 ± 0.03, in exact agreement with the meteoritic abundance. We find that abundance corrections vary rapidly with stellar parameters; for the 3961 Å resonance line, corrections are positive and may be as large as +1 dex, while corrections for subordinate lines generally have positive sign for warm stars but negative for cool stars. Our modeling reproduces the observed line profiles of benchmark K-giants, and we find abundance corrections as large as -0.3 dex for Arcturus. Our analyses of four metal-poor benchmark stars yield consistent abundances between the 3961 Å resonance line and lines in the UV, optical and near-infrared regions. Finally, we discuss implications for the galactic chemical evolution of aluminium.

  13. The Importance of Business Model Factors for Cloud Computing Adoption: Role of Previous Experiences

    Directory of Open Access Journals (Sweden)

    Bogataj Habjan Kristina

    2017-08-01

    Full Text Available Background and Purpose: Bringing several opportunities for more effective and efficient IT governance and service exploitation, cloud computing is expected to impact the European and global economies significantly. Market data show that despite many advantages and promised benefits the adoption of cloud computing is not as fast and widespread as foreseen. This situation shows the need for further exploration of the potentials of cloud computing and its implementation on the market. The purpose of this research was to identify individual business model factors with the highest impact on cloud computing adoption. In addition, the aim was to identify the differences in opinion regarding the importance of business model factors on cloud computing adoption according to companies’ previous experiences with cloud computing services.

  14. 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

  15. 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...

  16. 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

  17. 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...

  18. 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

  19. 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

  20. 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)

  1. From LTE to 5G for Connected Mobility

    DEFF Research Database (Denmark)

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

    2017-01-01

    Long Term Evolution, the fourth generation of mobile communication technology, has been commercially deployed for about five years. Even though it is continuously updated through new releases, and with LTE Advanced Pro Release 13 being the latest one, the development of the fifth generation has...... 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...

  2. 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.

  3. Non-LTE line formation of Fe in late-type stars - IV. Modelling of the solar centre-to-limb variation in 3D

    DEFF Research Database (Denmark)

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

    2017-01-01

    Our ability to model the shapes and strengths of iron lines in the solar spectrum is a critical test of the accuracy of the solar iron abundance, which sets the absolute zero-point of all stellar metallicities. We use an extensive 463-level Fe atom with new photoionization cross-sections for Fe I...

  4. Multi Level Integrity Management in LTE/LTE-A Networks

    Directory of Open Access Journals (Sweden)

    Ouafae Kasmi

    2017-06-01

    Full Text Available The sector of telecommunications is experiencing a large growth and rapid change in developing applications due to the variety of technologies, to increase the number of users and to arrival services varied from the high demand of the service quality such as streaming, web navigation. In this regard, the 3rd Generation Partnership Project (3GPP organization has greatly motivated to develop Next Generation Network (NGN. Indeed, telecom operators are forced to make a portfolio of available services more efficient to ensure customer loyalty. This article aims to propose an incorporation a layer above the quality of service (QoS controller based on Fuzzy Logic to determine the guaranteed levels of QoS and levels of criticality. It describes a new approach of multi criticality in order to ensure the integrity in IP Multimedia Subsystem (IMS networks. This approach is based on the recent model of integrity Totel. The proposed approach is tested and evaluated using Fuzzy Inference System to simulate levels of criticality for determining an adequate QoS level that ensures the customer’s needs. The simulation results describe the comparison between three membership function Triangle, Trapezoidal, Gaussian also describes the comparison between the methods of defuzzification to find whose gives better results and has more efficient in the aspect of chance value for levels of QoS and levels of criticality.

  5. 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.

  6. Discovery of previously unrecognised local faults in London, UK, using detailed 3D geological modelling

    Science.gov (United States)

    Aldiss, Don; Haslam, Richard

    2013-04-01

    In parts of London, faulting introduces lateral heterogeneity to the local ground conditions, especially where construction works intercept the Palaeogene Lambeth Group. This brings difficulties to the compilation of a ground model that is fully consistent with the ground investigation data, and so to the design and construction of engineering works. However, because bedrock in the London area is rather uniform at outcrop, and is widely covered by Quaternary deposits, few faults are shown on the geological maps of the area. This paper discusses a successful resolution of this problem at a site in east central London, where tunnels for a new underground railway station are planned. A 3D geological model was used to provide an understanding of the local geological structure, in faulted Lambeth Group strata, that had not been possible by other commonly-used methods. This model includes seven previously unrecognised faults, with downthrows ranging from about 1 m to about 12 m. The model was constructed in the GSI3D geological modelling software using about 145 borehole records, including many legacy records, in an area of 850 m by 500 m. The basis of a GSI3D 3D geological model is a network of 2D cross-sections drawn by a geologist, generally connecting borehole positions (where the borehole records define the level of the geological units that are present), and outcrop and subcrop lines for those units (where shown by a geological map). When the lines tracing the base of each geological unit within the intersecting cross-sections are complete and mutually consistent, the software is used to generate TIN surfaces between those lines, so creating a 3D geological model. Even where a geological model is constructed as if no faults were present, changes in apparent dip between two data points within a single cross-section can indicate that a fault is present in that segment of the cross-section. If displacements of similar size with the same polarity are found in a series

  7. 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

  8. 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.

  9. Game Theory-based Channel Selection for LTE-U

    OpenAIRE

    Ciccarelli, Enrico

    2016-01-01

    The Project intends to analyse the performance of a game theory-based channel selection in LTE-U. The main topic of this thesis project is the study of a channel selection strategy for LTE-U based on the game theory. The method consists on a repeated game where each small cell is a player with the purpose of finding the best channel where to set up the LTE-U carrier and it uses the ITEL-BA algorithm in order to make the system to converge to a Nash Equilibrium state. The aim is to evaluate...

  10. LTE for Railways: Impact on Performance of ETCS Railway Signaling

    DEFF Research Database (Denmark)

    Sniady, Aleksander; Soler, José

    2014-01-01

    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...

  11. 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......, the amount of traffic that can be served in a cell is not constrained by the data capacity, but rather by the signaling constraints in the PRACH, PDCCH, and PUSCH channels. In this paper we explore these limitations using a detailed simulation of the LTE access reservation protocol (ARP). We find that 1...... method, with reduced number of signaling messages, needs to be considered in standardization for M2M applications. Additionally we propose a tractable analytical model that accurately evaluates the outage for a given scenario at click-speed. The model accounts for the features of the PRACH, PDCCH, PDSCH...

  12. 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.

  13. 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)

  14. Correlation Coefficient Control For A Frequency Reconfigurable Dual-Band Compact MIMO Antenna Destined For LTE

    OpenAIRE

    Tatomirescu, Alexandru; Buskgaard, Emil Feldborg; Pedersen, Gert Frølund

    2014-01-01

    In this contribution, we are proposing a compact design for an implementation of a two element MIMO antenna destined for LTE smart phones. The antennas are collocated at one end of the PCB to minimize antenna volume. Each element is dual-band and frequency reconfigurable using tunable capacitors.The MIMO performance is investigated in two different channel models through efficiency, branch power imbalance and envelope correlation. The proposed antennas have acceptable levels of isolation betw...

  15. 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.

  16. 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...

  17. 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...

  18. Fine-grained LTE Radio Link Estimation for Mobile Phones

    OpenAIRE

    Bui, Nicola; Michelinakis, Foivos; Widmer, Joerg

    2017-01-01

    Recently, spectrum optimization solutions require mobile phones to obtain precise, accurate and fine-grained estimates of the radio link data rate. In particular, the effectiveness of anticipatory schemes depends on the granularity of these measurements. In this paper we use a reliable LTE control channel sniffer (OWL) to extensively compare mobile phone measurements against exact LTE radio link data rates. We also provide a detailed study of latencies measured on mobile phones, the sniffer, ...

  19. 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...

  20. 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.

  1. 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...

  2. 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

  3. Quantitative Comparison of the Efficiency and Scalability of the Current and Future LTE Network Architectures

    Directory of Open Access Journals (Sweden)

    Morteza Karimzadeh

    2017-01-01

    Full Text Available The core architecture of current mobile networks does not scale well to cope with future traffic demands owing to its highly centralized composition. Typically, it is believed that decentralization of the network architecture would be a sustainable approach to deal with ever growing amount of mobile data traffic. Nevertheless, the decentralization strategy of network architecture has not been properly examined through quantitative performance studies. Given that LTE will be the leading mobile networking technology in the coming 5–10 years, we conduct a hybrid study model to compare performance of current and future (decentralized LTE network architectures. Particularly, our analysis presents numerical results quantifying impact of the number of attached nodes on the load at network routers and links, on the latency, and on the processing cost of the user’s data and control planes. Analytical results demonstrate that decentralization of the LTE network architecture achieves higher performance compared to the current architecture and improves the latency and cost of data packet delivery more than 10 and 6 times, respectively. Furthermore, it is also observed that GTP outperforms PMIP for all studied performance metrics in the decentralized architecture and provides about twofold better latency and cost for data packet delivery and roughly 6 times lower data traffic load on the network routers.

  4. 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.

  5. Third metacarpal condylar fatigue fractures in equine athletes occur within previously modelled subchondral bone.

    Science.gov (United States)

    Whitton, R Christopher; Trope, Gareth D; Ghasem-Zadeh, Ali; Anderson, Garry A; Parkin, Timothy D H; Mackie, Eleanor J; Seeman, Ego

    2010-10-01

    Bone modelling and remodelling reduce the risk of fatigue fractures; the former by adapting bone to its loading circumstances, the latter by replacing fatigued bone. Remodelling transiently increases porosity because of the normal delay in onset of the formation phase of the remodelling sequence. Protracted intense loading suppresses remodelling leaving modelling as the only means of maintaining bone strength. We therefore hypothesized that race horses with fatigue fractures of the distal third metacarpal bone (MC3) will have reduced porosity associated with suppressed remodelling while continued adaptive modelling will result in higher volume fraction (BV/TV) at this site. Using high resolution peripheral quantitative computed tomography (HR-pQCT), we measured the distal aspect of the MC3 obtained at postmortem from 13 thoroughbred race horses with condylar fractures of the MC3 (cases), 8 horses without fractures (training controls), 14 horses with a fracture at another site (fractured controls) and 9 horses resting from training (resting controls). Porosity of the subchondral bone of MC3 was lower in cases than resting controls (12±1.4% vs. 18±1.6%, P=0.017) although areas of focal porosity were observed adjacent to fractures in 6/13 horses. BV/TV of the distal metacarpal epiphysis tended to be higher in horses with condylar fractures (0.79±0.015) than training controls (0.74±0.019, P=0.070), but also higher in controls with a fracture elsewhere (0.79±0.014) than the training controls (0.74±0.019, P=0.040). BV/TV was higher in horses over three years of age than those aged two or three years (0.79±0.01 vs. 0.74±0.01, P=0.016). All metacarpal condylar fractures occurred within focal areas of high BV/TV. We infer that intense training in equine athletes suppresses remodelling of third metacarpal subchondral bone limiting damage repair while modelling increases regional bone volume in an attempt to minimise local stresses but may fail to offset bone

  6. 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 ...

  7. 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

  8. Effects of previous severe exercise on two and three parameter critical power modeling

    Directory of Open Access Journals (Sweden)

    Eduardo Kokubun

    2007-09-01

    Full Text Available The purpose of this study was to apply the two and three-parameter critical power model equations after depletion of a fi xed amount of anaerobic work capacity (AWC, followed by a short rest period. Sixteen subjects underwent: (1 two practice trials for ergometer familiarization to severe exercise; (2 4-5 exercise bouts on different days for the estimation of critical power (CP and AWC using the two and three parameter models; (3 the same procedures as described in stage 2 were repeated after 30 s recovery from 180 s of exercise completed at an intensity that would have elicited exhaustion in around 300 s. The CP2parameter (130-174 W versus 131-170 W and CP3parameter (108 versus 100 W estimated after prior severe exercise followed by a short rest period remained stable compared to the fatigue-free tests. The AWC2parameter was reduced in response to prior severe exercise. The AWC3parameter was not significantly reduced. The correlations between CP2parameter derived from the same equation with and without prior AWC2parameter reduction were strong (r = 0.97-0.99, P ABSTRACT O propósito do presente estudo foi aplicar as equações do modelo de potência crítica de dois e três parâmetros após a depleção de uma quantia fi xa de capacidade de trabalho anaeróbio (AWC, seguido de um período curto de repouso. Dezesseis sujeitos realizaram: (1 duas familiarizações ao exercício severo no cicloergômetro; (2 4-5 exercícios máximos em dias diferentes para a estimativa da CP e AWC por meio dos modelos de dois e três parâmetros; (3 os mesmos procedimentos descritos no #2 foram realizados após 30 s de repouso e de um exercício de 180 s a uma intensidade em que a exaustão provavelmente ocorreria em ~300 s. A CP2parameter (130-174 W versus 131-170 W e CP3parameter (108 versus 100 W estimadas após o exercício prévio severo e seguido por um curto período de repouso permaneceu estável quando comparado às estimativas sem o exercício pr

  9. Liver growth factor treatment reverses emphysema previously established in a cigarette smoke exposure mouse model.

    Science.gov (United States)

    Pérez-Rial, Sandra; Del Puerto-Nevado, Laura; Girón-Martínez, Alvaro; Terrón-Expósito, Raúl; Díaz-Gil, Juan J; González-Mangado, Nicolás; Peces-Barba, Germán

    2014-11-01

    Chronic obstructive pulmonary disease (COPD) is an inflammatory lung disease largely associated with cigarette smoke exposure (CSE) and characterized by pulmonary and extrapulmonary manifestations, including systemic inflammation. Liver growth factor (LGF) is an albumin-bilirubin complex with demonstrated antifibrotic, antioxidant, and antihypertensive actions even at extrahepatic sites. We aimed to determine whether short LGF treatment (1.7 μg/mouse ip; 2 times, 2 wk), once the lung damage was established through the chronic CSE, contributes to improvement of the regeneration of damaged lung tissue, reducing systemic inflammation. We studied AKR/J mice, divided into three groups: control (air-exposed), CSE (chronic CSE), and CSE + LGF (LGF-treated CSE mice). We assessed pulmonary function, morphometric data, and levels of various systemic inflammatory markers to test the LGF regenerative capacity in this system. Our results revealed that the lungs of the CSE animals showed pulmonary emphysema and inflammation, characterized by increased lung compliance, enlargement of alveolar airspaces, systemic inflammation (circulating leukocytes and serum TNF-α level), and in vivo lung matrix metalloproteinase activity. LGF treatment was able to reverse all these parameters, decreasing total cell count in bronchoalveolar lavage fluid and T-lymphocyte infiltration in peripheral blood observed in emphysematous mice and reversing the decrease in monocytes observed in chronic CSE mice, and tends to reduce the neutrophil population and serum TNF-α level. In conclusion, LGF treatment normalizes the physiological and morphological parameters and levels of various systemic inflammatory biomarkers in a chronic CSE AKR/J model, which may have important pathophysiological and therapeutic implications for subjects with stable COPD. Copyright © 2014 the American Physiological Society.

  10. 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.

  11. Perancangan Cakupan Area Long Term Evolution (LTE Di Daerah Banyumas

    Directory of Open Access Journals (Sweden)

    Alfin Hikmaturokhman

    2012-11-01

    Full Text Available Along with the rapid technological developments in all fields of technology, it’s including telecommunications technology. Many facilities are offered, for example, is the development of telecommunications services for voice, data and video. This offer must be supported by great technology,which  is  ability transfer data with high speed transfer data rate. The technology that able to grant this needs is LTE technology. LTE technology was developed from  Global System for Mobile (GSM and Universal Mobile Telecommunication System (UMTS and this technology  has transfer data rate  up to 100 Mbps for the downlink and 50 Mbps for the uplink direction. Because the distribution of technological progress in various areas including Banyumas, it would require an application of LTE technology in that area. These applications will not run without  proper planning of an LTE network to cover all areas of Banyumas. In order to  apply the optimal LTE network in Banyumas it is necessary to design LTE coverage area, they consist of link budget and number of eNode B that required to cover whole area Banyumas. By using QPSK modulation and coding rate ½ it has value traffic capacity about 3.344,096 kbps/km2. ENode B number that can cover  whole area is as much as 59  eNode B. Impact of coding rate to MAPLvalue is when  value of the coding rate is greater it’s produces a smaller value of MAPL and the number of eNode B is increase.

  12. Abstract Radio Resource Management Framework for System Level Simulations in LTE-A Systems

    DEFF Research Database (Denmark)

    Fotiadis, Panagiotis; Viering, Ingo; Zanier, Paolo

    2014-01-01

    This paper provides a simple mathematical model of different packet scheduling policies in Long Term Evolution- Advanced (LTE-A) systems, by investigating the performance of Proportional Fair (PF) and the generalized cross-Component Carrier scheduler from a theoretical perspective. For that purpose......, an abstract Radio Resource Management (RRM) framework has been developed and tested for different ratios of users with Carrier Aggregation (CA) capabilities. The conducted system level simulations confirm that the proposed model can satisfactorily capture the main properties of the aforementioned scheduling...

  13. 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...... multimedia services. Fast handover among these networks is paramount for mission critical applications. Therefore this paper explores the possibilities and advantages of using the Media Independent Handover, an IEEE standard, in improving the handover performance in a TETRA-LTE heterogeneous environment...

  14. Synchronized RACH-less Handover Solution for LTE Heterogeneous Networks

    DEFF Research Database (Denmark)

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

    2015-01-01

    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...... 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...

  15. 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...

  16. Voice-Centric LTE Femtocells and Improper Graph Colorings

    DEFF Research Database (Denmark)

    Garcia, Luis Guilherme Uzeda; Pedersen, Klaus; Mogensen, Preben

    2012-01-01

    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. The investig......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...

  17. 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 (eICIC) to mit......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...... system level simulation results illustrate the performance benefits of the presented techniques....

  18. Heterogeneous LTE-Advanced Network Expansion for 1000x Capacity

    DEFF Research Database (Denmark)

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

    2013-01-01

    rate. We conclude that the 1000 times network capacity increase simultaneously with a 10 times increase of minimum user data rate can be reached by LTE-Advanced deploying approximately 10 times outdoor micro sites and 100 times more indoor femto cells, relative to the number of reference macro sites......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...

  19. Uplink Scheduling and Adjacent-Channel Coupling Loss Analysis for TD-LTE Deployment

    Directory of Open Access Journals (Sweden)

    Woon-Young Yeo

    2014-01-01

    Full Text Available 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.

  20. 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.

  1. 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...

  2. 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

    2017-01-01

    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

  3. 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

  4. Evaluation of a Cross Layer Scheduling Algorithm for LTE Downlink

    DEFF Research Database (Denmark)

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

    2013-01-01

    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...

  5. 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.

  6. 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...

  7. Cloudified mobility and bandwidth prediction in virtualized LTE networks

    NARCIS (Netherlands)

    Zhao, Z.; Karimzadeh, M.; Braun, T.; Pras, A.; Berg, J.L. van den

    2017-01-01

    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

  8. Online Calibration for LTE-Based Antenna Array System

    Directory of Open Access Journals (Sweden)

    Kyunghoon Kim

    2016-01-01

    Full Text Available This paper presents a novel calibration method that equalizes the impulse responses of all the Radio Frequency (RF modules of an antenna array system operating in Long-Term Evolution (LTE evolved NodeB (eNB. The proposed technique utilizes the Zadoff-Chu (Z-C sequence of the Primary Synchronization Signal (PSS and Sounding Reference Signal (SRS that are available in every LTE data frame for downlink and uplink, respectively, for estimating and compensating the differences in the impulse responses among the RF modules. The proposed calibration method is suitable for wide bandwidth signal environments of LTE because it equalizes the impulse response of each RF module, which is ultimately equivalent to compensate the phase and amplitude differences among RF modules for the entire frequency band. In addition, the proposed method is applicable while the target eNB is transmitting or receiving a data stream. From various experimental tests obtained from a test-bed implemented with 2 RF modules, it has been verified that the proposed method provides a reliable calibration for Release 10 Time Division Duplex (TDD LTE signals. Phase errors after the calibration in our test-bed have been found to be about 2.418° and 2.983° for downlink and uplink, respectively.

  9. 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

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

    Directory of Open Access Journals (Sweden)

    Seungseob Lee

    Full Text Available 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

  11. 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.

  12. Previously published midazolam-alfentanil response surface model cannot predict patient response well in gastrointestinal endoscopy sedation.

    Science.gov (United States)

    Liou, Jing-Yang; Ting, Chien-Kun; Huang, Yu-Ying; Tsou, Mei-Yung

    2016-03-01

    A response surface model is a mathematical model used to predict multiple-drug pharmacodynamic interactions. With the use of a previously published volunteer model, we tested the accuracy of the midazolam-alfentanil response surface model during gastrointestinal endoscopy. We enrolled 35 adult patients scheduled for combined endoscopic procedures. Patients were sedated with intravenous midazolam and alfentanil, and monitored with real-time auditory evoked potential. Sedation Observer's Assessment of Alertness/Sedation (OAA/S) scores were recorded by an independent observer every 2 minutes. Patients with OAA/S scores of ≥ 4 were designated as "awake". Pharmacokinetic profiles were calculated using the TIVA trainer. The published response surface model was modified to make estimations more reasonable. Patient response (OAA/S score ≥ 4 or response during gastrointestinal endoscopic procedure sedation. Accuracy in predicting an OAA/S score of response ranged from 0.04% to 2.94% at the time of arousal (OAA/S score ≥ 4) and from 0.24% to 15.55% when the patient was asleep (OAA/S score response of patients undergoing sedated gastrointestinal endoscopic procedures. Future model parameter adjustments are required. Copyright © 2016. Published by Elsevier Taiwan LLC.

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

    NARCIS (Netherlands)

    Ahmad, Z.; W. J. Goedheer,

    2009-01-01

    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

  14. Validation of a Previously Developed Geospatial Model That Predicts the Prevalence of Listeria monocytogenes in New York State Produce Fields.

    Science.gov (United States)

    Weller, Daniel; Shiwakoti, Suvash; Bergholz, Peter; Grohn, Yrjo; Wiedmann, Martin; Strawn, Laura K

    2016-02-01

    Technological advancements, particularly in the field of geographic information systems (GIS), have made it possible to predict the likelihood of foodborne pathogen contamination in produce production environments using geospatial models. Yet, few studies have examined the validity and robustness of such models. This study was performed to test and refine the rules associated with a previously developed geospatial model that predicts the prevalence of Listeria monocytogenes in produce farms in New York State (NYS). Produce fields for each of four enrolled produce farms were categorized into areas of high or low predicted L. monocytogenes prevalence using rules based on a field's available water storage (AWS) and its proximity to water, impervious cover, and pastures. Drag swabs (n = 1,056) were collected from plots assigned to each risk category. Logistic regression, which tested the ability of each rule to accurately predict the prevalence of L. monocytogenes, validated the rules based on water and pasture. Samples collected near water (odds ratio [OR], 3.0) and pasture (OR, 2.9) showed a significantly increased likelihood of L. monocytogenes isolation compared to that for samples collected far from water and pasture. Generalized linear mixed models identified additional land cover factors associated with an increased likelihood of L. monocytogenes isolation, such as proximity to wetlands. These findings validated a subset of previously developed rules that predict L. monocytogenes prevalence in produce production environments. This suggests that GIS and geospatial models can be used to accurately predict L. monocytogenes prevalence on farms and can be used prospectively to minimize the risk of preharvest contamination of produce. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  15. 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.

  16. Ignition and Growth Modeling of Detonating LX-04 (85% HMX / 15% VITON) Using New and Previously Obtained Experimental Data

    Science.gov (United States)

    Tarver, Craig

    2017-06-01

    An Ignition and Growth reactive flow model for detonating LX-04 (85% HMX / 15% Viton) was developed using new and previously obtained experimental data on: cylinder test expansion; wave curvature; failure diameter; and laser interferometric copper and tantalum foil free surface velocities and LiF interface particle velocity histories. A reaction product JWL EOS generated by the CHEETAH code compared favorably with the existing, well normalized LX-04 product JWL when both were used with the Ignition and Growth model. Good agreement with all existing experimental data was obtained. Keywords: LX-04, HMX, detonation, Ignition and Growth PACS:82.33.Vx, 82.40.Fp This work was performed under the auspices of the U. S. Department of Energy by the Lawrence Livermore National Laboratory under Contract No. DE-AC52-07NA27344.

  17. 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...

  18. 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.

  19. Performance of LTE ADVANCED Uplink in a Flat Rayleigh Channel

    Directory of Open Access Journals (Sweden)

    Edward Kasem

    2013-01-01

    Full Text Available This paper describes the performance of LTE advanced uplink transmission in a flat Rayleigh channel. The uplink is simulated using a modified version of the Vienna uplink link level matlab code simulator. This modified version supports two transmission antennas instead of one. Moreover, it includes two extra processes; layer mapping and precoding. In addition, the demodulation reference signal is presented and employed to allow channel estimation. In this paper, the structure of the LTE advanced system is described. Furthermore, we present generation of the demodulation reference signal. Four combinations of two distinct channel estimation and two signal detection methods are used to provide the simulation results of performance evaluation in term of the BER and throughput curves for selected scenarios.

  20. Design and Optimization of LTE 1800 MIMO Antenna

    Science.gov (United States)

    Wong, Huey Shin; Islam, Mohammad Tariqul

    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. PMID:24967440

  1. 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...

  2. 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...

  3. LTE-based Satellite Communications in LEO Mega-Constellations

    OpenAIRE

    Guidotti, A.; Vanelli-Coralli, A.; Foggi, T.; Colavolpe, G.; Caus, M.; Bas, J.; Cioni, S.; Modenini, A.

    2017-01-01

    The integration of satellite and terrestrial networks is a promising solution for extending broadband coverage to areas not connected to a terrestrial infrastructure, as also demonstrated by recent commercial and standardisation endeavours. However, the large delays and Doppler shifts over the satellite channel pose severe technical challenges to traditional terrestrial systems, as LTE or 5G. In this paper, two architectures are proposed for a LEO mega-constellation realising a satellite-enab...

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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...... performance, ruling out the LTE devices unknown MIMO 2x2 antenna performance....

  9. Centralized and Distributed Solutions for Fast Muting Adaptation in LTE-Advanced HetNets

    DEFF Research Database (Denmark)

    Soret, Beatriz; Pedersen, Klaus I.

    2015-01-01

    Enhanced Intercell Interference Coordination (eICIC) is known to provide promising performance benefits for LTE-Advanced Heterogeneous Networks. The use of eICIC facilitates more flexible inter-layer load balancing by means of small cell Range Extension (RE) and Almost Blank Subframes (ABS). Even...... though the eICIC configuration (RE and ABS) ideally should be instantaneously adapted to follow the fluctuations of the traffic and the channel conditions over time, previous studies have focused on slow intercell coordination. In this paper, we investigate fast dynamic eICIC solutions for centralized....... Two different fast muting adaptation algorithms are derived, and it is shown how those can be appplied to both the centralized and the distributed architecture. Performance results with bursty traffic show that the fast dynamic adaptation provides significant gains, both in 5%-ile and 50%-ile user...

  10. Transcriptomic analysis in a Drosophila model identifies previously implicated and novel pathways in the therapeutic mechanism in neuropsychiatric disorders

    Directory of Open Access Journals (Sweden)

    Priyanka eSingh

    2011-03-01

    Full Text Available We have taken advantage of a newly described Drosophila model to gain insights into the potential mechanism of antiepileptic drugs (AEDs, a group of drugs that are widely used in the treatment of several neurological and psychiatric conditions besides epilepsy. In the recently described Drosophila model that is inspired by pentylenetetrazole (PTZ induced kindling epileptogenesis in rodents, chronic PTZ treatment for seven days causes a decreased climbing speed and an altered CNS transcriptome, with the latter mimicking gene expression alterations reported in epileptogenesis. In the model, an increased climbing speed is further observed seven days after withdrawal from chronic PTZ. We used this post-PTZ withdrawal regime to identify potential AED mechanism. In this regime, treatment with each of the five AEDs tested, namely, ethosuximide (ETH, gabapentin (GBP, vigabatrin (VGB, sodium valproate (NaVP and levetiracetam (LEV, resulted in rescuing of the altered climbing behavior. The AEDs also normalized PTZ withdrawal induced transcriptomic perturbation in fly heads; whereas AED untreated flies showed a large number of up- and down-regulated genes which were enriched in several processes including gene expression and cell communication, the AED treated flies showed differential expression of only a small number of genes that did not enrich gene expression and cell communication processes. Gene expression and cell communication related upregulated genes in AED untreated flies overrepresented several pathways - spliceosome, RNA degradation, and ribosome in the former category, and inositol phosphate metabolism, phosphatidylinositol signaling, endocytosis and hedgehog signaling in the latter. Transcriptome remodeling effect of AEDs was overall confirmed by microarray clustering that clearly separated the profiles of AED treated and untreated flies. Besides being consistent with previously implicated pathways, our results provide evidence for a role of

  11. 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...

  12. 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

  13. 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

  14. 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%.

  15. 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.

  16. 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

    interference coordination schemes. In addition, ideal Interference Cancellation (IC) scheme with ability to remove completely the dominant interferer shows less effective for UAVs than for users on the ground. On the other hand, macro network diversity has very good potential for drones, as not only......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...

  17. 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.

  18. RRM Strategies in LTE&WiMAX Interworking System

    DEFF Research Database (Denmark)

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

    high quality streaming video. In order to provide those demanding real-time multimedia and very high data rates, scarce radio resources must be used effectively to maximize the channel utilization. The presentation will focus on scheduling techniques possibly adaptable to dynamically changing network......, 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...

  19. Modelling the response of stable water isotopes in Greenland precipitation to orbital configurations of the previous interglacial

    Directory of Open Access Journals (Sweden)

    Jesper Sjolte

    2014-09-01

    Full Text Available The relation between δ 18O of precipitation and temperature has been used in numerous studies to reconstruct past temperatures at ice core sites in Greenland and Antarctica. During the past two decades, it has become clear that the slope between δ 18O and temperature varies in both space and time. Here, we use a general circulation model driven by changes in orbital parameters to investigate the Greenland δ 18O–temperature relation for the previous interglacial, the Eemian. In our analysis, we focus on changes in the moisture source regions, and the results underline the importance of taking the seasonality of climate change into account. The orbitally driven experiments show that continental evaporation over North America increases during summer in the warm parts of the Eemian, while marine evaporation decreases. This likely flattens the Greenland δ 18O response to temperature during summer. Since the main climate change in the experiments occurs during summer this adds to a limited response of δ 18O, which is more strongly tied to temperature during winter than during summer. A south–west to north–east gradient in the δ 18O–temperature slope is also evident for Greenland, with low slopes in the south–west and steeper slopes in the north–east. This probably reflects the proportion of continental moisture and Arctic moisture arriving in Greenland, with more continental moisture in the south–west and less in the north–east, and vice versa for the Arctic moisture.

  20. Previous exercise training has a beneficial effect on renal and cardiovascular function in a model of diabetes.

    Directory of Open Access Journals (Sweden)

    Kleiton Augusto dos Santos Silva

    Full Text Available Exercise training (ET is an important intervention for chronic diseases such as diabetes mellitus (DM. However, it is not known whether previous exercise training intervention alters the physiological and medical complications of these diseases. We investigated the effects of previous ET on the progression of renal disease and cardiovascular autonomic control in rats with streptozotocin (STZ-induced DM. Male Wistar rats were divided into five groups. All groups were followed for 15 weeks. Trained control and trained diabetic rats underwent 10 weeks of exercise training, whereas previously trained diabetic rats underwent 14 weeks of exercise training. Renal function, proteinuria, renal sympathetic nerve activity (RSNA and the echocardiographic parameters autonomic modulation and baroreflex sensitivity (BRS were evaluated. In the previously trained group, the urinary albumin/creatinine ratio was reduced compared with the sedentary diabetic and trained diabetic groups (p<0.05. Additionally, RSNA was normalized in the trained diabetic and previously trained diabetic animals (p<0.05. The ejection fraction was increased in the previously trained diabetic animals compared with the diabetic and trained diabetic groups (p<0.05, and the myocardial performance index was improved in the previously trained diabetic group compared with the diabetic and trained diabetic groups (p<0.05. In addition, the previously trained rats had improved heart rate variability and BRS in the tachycardic response and bradycardic response in relation to the diabetic group (p<0.05. This study demonstrates that previous ET improves the functional damage that affects DM. Additionally, our findings suggest that the development of renal and cardiac dysfunction can be minimized by 4 weeks of ET before the induction of DM by STZ.

  1. An LTE effective temperature scale for red supergiants in the Magellanic clouds

    Science.gov (United States)

    Tabernero, H. M.; Dorda, R.; Negueruela, I.; González-Fernández, C.

    2018-02-01

    We present a self-consistent study of cool supergiants (CSGs) belonging to the Magellanic clouds. We calculated stellar atmospheric parameters using LTE KURUCZ and MARCS atmospheric models for more than 400 individual targets by fitting a careful selection of weak metallic lines. We explore the existence of a Teff scale and its implications in two different metallicity environments (each Magellanic cloud). Critical and in-depth tests have been performed to assess the reliability of our stellar parameters (i.e. internal error budget, NLTE systematics). In addition, several Montercarlo tests have been carried out to infer the significance of the Teff scale found. Our findings point towards a unique Teff scale that seems to be independent of the environment.

  2. Correlation Coefficient Control For A Frequency Reconfigurable Dual-Band Compact MIMO Antenna Destined For LTE

    DEFF Research Database (Denmark)

    Tatomirescu, Alexandru; Buskgaard, Emil Feldborg; Pedersen, Gert Frølund

    2014-01-01

    In this contribution, we are proposing a compact design for an implementation of a two element MIMO antenna destined for LTE smart phones. The antennas are collocated at one end of the PCB to minimize antenna volume. Each element is dual-band and frequency reconfigurable using tunable capacitors....... The MIMO performance is investigated in two different channel models through efficiency, branch power imbalance and envelope correlation. The proposed antennas have acceptable levels of isolation between them, even in the low-bands, while having a good efficiency. Furthermore, the correlation coefficient...... is controlled by manipulating the ground currents between the antennas using a tunable capacitor. Nonetheless, using this mechanism to control the coupling between the antennas, the total efficiency is affected....

  3. Previous exercise training has a beneficial effect on renal and cardiovascular function in a model of diabetes.

    Science.gov (United States)

    Silva, Kleiton Augusto dos Santos; Luiz, Rafael da Silva; Rampaso, Rodolfo Rosseto; de Abreu, Nayda Parísio; Moreira, Édson Dias; Mostarda, Cristiano Teixeira; De Angelis, Kátia; de Paulo Castro Teixeira, Vicente; Irigoyen, Maria Cláudia; Schor, Nestor

    2012-01-01

    Exercise training (ET) is an important intervention for chronic diseases such as diabetes mellitus (DM). However, it is not known whether previous exercise training intervention alters the physiological and medical complications of these diseases. We investigated the effects of previous ET on the progression of renal disease and cardiovascular autonomic control in rats with streptozotocin (STZ)-induced DM. Male Wistar rats were divided into five groups. All groups were followed for 15 weeks. Trained control and trained diabetic rats underwent 10 weeks of exercise training, whereas previously trained diabetic rats underwent 14 weeks of exercise training. Renal function, proteinuria, renal sympathetic nerve activity (RSNA) and the echocardiographic parameters autonomic modulation and baroreflex sensitivity (BRS) were evaluated. In the previously trained group, the urinary albumin/creatinine ratio was reduced compared with the sedentary diabetic and trained diabetic groups (ptrained diabetic and previously trained diabetic animals (ptrained diabetic animals compared with the diabetic and trained diabetic groups (ptrained diabetic group compared with the diabetic and trained diabetic groups (ptrained rats had improved heart rate variability and BRS in the tachycardic response and bradycardic response in relation to the diabetic group (p<0.05). This study demonstrates that previous ET improves the functional damage that affects DM. Additionally, our findings suggest that the development of renal and cardiac dysfunction can be minimized by 4 weeks of ET before the induction of DM by STZ.

  4. 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

  5. Jammer Type Estimation in LTE with a Smart Jammer Repeated Game

    KAUST Repository

    Aziz, Farhan

    2017-02-22

    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-zero-sum) Bayesian game with asymmetric information, with the network being the uninformed player. Although significant work has been done on optimal strategy computation and control of information revelation of the informed player in repeated asymmetric information games, it has been limited to zero-sum games with perfect monitoring. Recent progress on the strategy computation of the uninformed player is also limited to zero-sum games with perfect monitoring and is focused on expected payoff formulations. Since the proposed formulation is a general-sum game with imperfect monitoring, existing formulations cannot be leveraged for estimating true state of nature (the jammer type). Hence, a threat-based mechanism is proposed for the uninformed player (the network) to estimate the informed player’s type (jammer type). The proposed mechanism helps the network resolve uncertainty about the state of nature (jammer type) so that it can compute a repeated-game strategy conditioned on its estimate. The proposed algorithm does not rely on the commonly assumed “full monitoring” premise, and uses a combination of threat-based mechanism and non-parametric estimation to estimate the jammer type. In addition, it does not require any explicit feedback from the network users nor does it rely on a specific distribution (e.g., Gaussian) of test statistic. It is shown that the proposed algorithm’s estimation performance is quite robust under realistic modeling and observational constraints despite all the aforementioned challenges.

  6. 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....... Examples of Railway Emergency Call and One-to-One Call are provided. Service performance, in terms of call setup times and voice transmission quality, is analyzed in simulation scenarios modelling two railway scenarios in Denmark....

  7. 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.

  8. 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.

  9. 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

  10. 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......-cell radio deployments reach overload, especially in high-density areas, such as major train stations. In this paper, an LTE micro-cell deployment is investigated in high-density railway areas. Copenhagen Main Station is considered as a realistic deployment study case, with a set of relevant railway...

  11. Planar Printed Shorted Monopole Antenna with Coupled Feed for LTE/WWAN Mobile Handset Applications

    Directory of Open Access Journals (Sweden)

    Do-Gu Kang

    2013-01-01

    Full Text Available A shorted monopole antenna with coupled feed for LTE/WWAN mobile handset applications is described. The basic resonance of the shorted monopole combines with the resonance formed by the coupling between the coupling strip and the feeding pad to cover the LTE700, GSM850, and GSM900 bands. Both the feeding pad and the coupling strip operate with the shorting strip as a loop antenna. The resonance of the loop antenna and the harmonics of the shorted monopole combine to cover the GSM1800, GSM1900, UMTS, and LTE2300 bands. A stable and omnidirectional radiation pattern with reasonable gain has been observed over the operating bandwidth.

  12. Multiband Printed Asymmetric Dipole Antenna for LTE/WLAN Applications

    Directory of Open Access Journals (Sweden)

    Chia-Mei Peng

    2013-01-01

    Full Text Available The ability of a single layer strip fed printed asymmetric dipole antenna, which is composed of top-loading, asymmetric coplanar waveguide (ACPW and stepped-feeding structure, to operate at three wide frequency bands (698~960 MHz, 1710~2620 MHz, and 5150~5850 MHz to cover WLAN and LTE operation has been demonstrated. A prototype of the proposed antenna with 57.5 mm in length, 0.4 mm in thickness, and 5 mm in width is fabricated and experimentally investigated. The experimental results indicate that the VSWR 2.5 : 1 bandwidths achieved were 74.3%, 40.8%, and 18.2% at 700 MHz, 2450 MHz, and 5500 MHz, respectively. Experimental results are shown to verify the validity of theoretical work.

  13. 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...

  14. Miniaturized Balanced Antenna with Integrated Balun for Practical LTE Applications

    Directory of Open Access Journals (Sweden)

    I. T. E. Elfergani

    2017-06-01

    Full Text Available A design of dual-band balanced antenna structure operating in the 700 and 2600MHz LTE bands is studied and investigated. The overall dimensions of the radiator are 50 × 18 × 7 mm^3 allowing it to be easily concealed within mobile handsets. A broad-band balun is designed and integrated with the antenna handset in order to provide the feeding network and perform the measurements of the antenna radiation performance. Prototypes of proposed antenna with and without balun are fabricated and verified. The simulated and practical results with and without the handheld effects in terms of reflection coefficient, power gain and radiation pattern, are studied and shown reasonable agreement.

  15. 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.

  16. General expressions for downlink signal to interference and noise ratio in homogeneous and heterogeneous LTE-Advanced networks

    Directory of Open Access Journals (Sweden)

    Nora A. Ali

    2016-11-01

    Full Text Available The interference is the most important problem in LTE or LTE-Advanced networks. In this paper, the interference was investigated in terms of the downlink signal to interference and noise ratio (SINR. In order to compare the different frequency reuse methods that were developed to enhance the SINR, it would be helpful to have a generalized expression to study the performance of the different methods. Therefore, this paper introduces general expressions for the SINR in homogeneous and in heterogeneous networks. In homogeneous networks, the expression was applied for the most common types of frequency reuse techniques: soft frequency reuse (SFR and fractional frequency reuse (FFR. The expression was examined by comparing it with previously developed ones in the literature and the comparison showed that the expression is valid for any type of frequency reuse scheme and any network topology. Furthermore, the expression was extended to include the heterogeneous network; the expression includes the problem of co-tier and cross-tier interference in heterogeneous networks (HetNet and it was examined by the same method of the homogeneous one.

  17. General expressions for downlink signal to interference and noise ratio in homogeneous and heterogeneous LTE-Advanced networks.

    Science.gov (United States)

    Ali, Nora A; Mourad, Hebat-Allah M; ElSayed, Hany M; El-Soudani, Magdy; Amer, Hassanein H; Daoud, Ramez M

    2016-11-01

    The interference is the most important problem in LTE or LTE-Advanced networks. In this paper, the interference was investigated in terms of the downlink signal to interference and noise ratio (SINR). In order to compare the different frequency reuse methods that were developed to enhance the SINR, it would be helpful to have a generalized expression to study the performance of the different methods. Therefore, this paper introduces general expressions for the SINR in homogeneous and in heterogeneous networks. In homogeneous networks, the expression was applied for the most common types of frequency reuse techniques: soft frequency reuse (SFR) and fractional frequency reuse (FFR). The expression was examined by comparing it with previously developed ones in the literature and the comparison showed that the expression is valid for any type of frequency reuse scheme and any network topology. Furthermore, the expression was extended to include the heterogeneous network; the expression includes the problem of co-tier and cross-tier interference in heterogeneous networks (HetNet) and it was examined by the same method of the homogeneous one.

  18. GPM Ground Validation NASA EPFL-LTE Parsivel DSD Data Lausanne, Switzerland V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The GPM Ground Validation NASA EPFL-LTE Parsivel DSD Data Lausanne, Switzerland dataset consists of a network of 16 Parsivel disdrometers deployed on the Ecole...

  19. A cognitive gateway-based spectrum sharing method in downlink round robin scheduling of LTE system

    Science.gov (United States)

    Deng, Hongyu; Wu, Cheng; Wang, Yiming

    2017-07-01

    A key technique of LTE is how to allocate efficiently the resource of radio spectrum. Traditional Round Robin (RR) scheduling scheme may lead to too many resource residues when allocating resources. When the number of users in the current transmission time interval (TTI) is not the greatest common divisor of resource block groups (RBGs), and such a phenomenon lasts for a long time, the spectrum utilization would be greatly decreased. In this paper, a novel spectrum allocation scheme of cognitive gateway (CG) was proposed, in which the LTE spectrum utilization and CG’s throughput were greatly increased by allocating idle resource blocks in the shared TTI in LTE system to CG. Our simulation results show that the spectrum resource sharing method can improve LTE spectral utilization and increase the CG’s throughput as well as network use time.

  20. 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)

  1. 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

    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...... 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......) signaling, which is one of the essential railway communication services. Results of the simulations demonstrate that LTE can solve the urgent capacity problem faced by railways currently deploying GSM-R....

  2. 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...... on the following assumptions: (1) there are sufficient resources in the data phase for all detected contention tokens, and (2) the base station is able to detect collisions, i.e., tokens activated by multiple users. These assumptions are not always applicable to LTE - specifically, (1) due to the variable amount...... of the two-phase LTE reservation protocol and asses its performance, when assumptions (1) and (2) do not hold....

  3. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-05-01

    As early as 2014, mobile network operators’ spectral capacity will be overwhelmed by the demand brought on by new devices and applications. To augment capacity and meet this demand, operators may choose to deploy a Dynamic Spectrum Access (DSA) overlay. The signaling and functionality required by such an overlay have not yet been fully considered in the architecture of the planned Long Term Evolution Advanced (LTE+) networks. This paper presents a Spectrum Accountability framework to be integrated into LTE+ architectures, defining specific element functionality, protocol interfaces, and signaling flow diagrams required to enforce the rights and responsibilities of primary and secondary users. We also quantify, through integer programs, the benefits of using DSA channels to augment capacity under a scenario in which LTE+ network can opportunistically use TV and GSM spectrum. The framework proposed here may serve as a guide in the development of future LTE+ network standards that account for DSA.

  5. Per-Oral Endoscopic Myotomy (POEM) After Previous Laparoscopic Heller Myotomy Is Feasible and Safe in a Porcine Model.

    Science.gov (United States)

    Miles, Luke F; Frelich, Matthew J; Gould, Jon C; Dua, Kulwinder S; Jensen, Eric S; Kastenmeier, Andrew S

    2015-10-01

    We sought to evaluate the feasibility, safety, and difficulty of performing the per-oral endoscopic myotomy (POEM) procedure in the setting of a prior Heller myotomy using a survival porcine model. Four pigs underwent laparoscopic Heller myotomy with Dor partial anterior fundoplication followed by the POEM performed 4 weeks later. Two additional pigs served as controls, undergoing only the POEM. All procedures were completed without complications. The revisional POEM was not significantly more difficult than POEM controls based on procedure time, POEM procedure components, or procedure difficulty scores. Revisional POEM had a longer mean operative time when compared with Heller myotomy (126.0 vs. 83.8 min; Pmyotomy is safe and feasible in the porcine model and has potential as an option for patients suffering from recurrent or persistent symptoms after failed surgical myotomy.

  6. Use of a PBPK model with dose-dependent elimination rates predicts higher peak dioxin exposures than previously estimated

    Energy Technology Data Exchange (ETDEWEB)

    Emond, C. [NRC, NAS, WA, DC (United States); Michalek, J.E. [Air Force Research Lab., Brooks City-Base, TX (United States); Birnbaum, L.S.; DeVito, M.J. [PKB, ETD, ORD, NHEERL U.S. EPA, RTP, NC (United States)

    2004-09-15

    Exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is associated with increased risk for cancer, diabetes and reproductive toxicities in numerous epidemiological studies. Several of these studies base exposure estimates on measurements of blood levels years after the accidental or occupational exposures. Peak exposures have been estimated in these studies assuming a mono or biphasic elimination rate for TCDD, with estimates of half-life ranging from 5 to 12 years. Recent clinical studies suggest that the elimination rate of TCDD is dose dependent. To address this question a physiologically based pharmacokinetic (PBPK) model can be used to predict the concentration of TCDD with a dose-dependent elimination rate. The aims of this study were to validate a dose-dependent elimination rate by using a PBPK model and to adequately predict the concentration of TCDD shortly after the exposure.

  7. Combined Admission Control and Scheduling for QoS Differentiation in LTE Uplink

    DEFF Research Database (Denmark)

    Anas, Mohmmad; Rosa, Claudio; Calabrese, Francesco Davide

    2008-01-01

    Long term evolution (LTE) architecture shall support end-to-end quality of service (QoS). For the QoS support and service differentiation it is important that the admission control and packet scheduling functionalities are QoS-aware. In this paper a combined admission control and a decoupled time......-frequency domain scheduling framework for LTE uplink is presented. The proposed framework is shown to effectively differentiate QoS user classes in a mixed traffic scenario....

  8. 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.

  9. 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.

  10. UPPGHA: Uniform Privacy Preservation Group Handover Authentication Mechanism for mMTC in LTE-A Networks

    Directory of Open Access Journals (Sweden)

    Jin Cao

    2018-01-01

    Full Text Available Machine Type Communication (MTC, as one of the most important wireless communication technologies in the future wireless communication, has become the new business growth point of mobile communication network. It is a key point to achieve seamless handovers within Evolved-Universal Terrestrial Radio Access Network (E-UTRAN for massive MTC (mMTC devices in order to support mobility in the Long Term Evolution-Advanced (LTE-A networks. When mMTC devices simultaneously roam from a base station to a new base station, the current handover mechanisms suggested by the Third-Generation Partnership Project (3GPP require several handover signaling interactions, which could cause the signaling load over the access network and the core network. Besides, several distinct handover procedures are proposed for different mobility scenarios, which will increase the system complexity. In this paper, we propose a simple and secure uniform group-based handover authentication scheme for mMTC devices based on the multisignature and aggregate message authentication code (AMAC techniques, which is to fit in with all of the mobility scenarios in the LTE-A networks. Compared with the current 3GPP standards, our scheme can achieve a simple authentication process with robust security protection including privacy preservation and thus avoid signaling congestion. The correctness of the proposed group handover authentication protocol is formally proved in the Canetti-Krawczyk (CK model and verified based on the AVISPA and SPAN.

  11. Modeling and Evaluation of LTE in Intelligent Transportation Systems

    NARCIS (Netherlands)

    Trichias, K.; van den Berg, Hans Leo; de Jongh, J.; Litjens, R.; Dimitrova, D.C.; Brogle, M.; Braun, T.; Heijenk, Gerhard J.; Meratnia, Nirvana

    The term Intelligent Transportation Systems (ITS) refers to adding information and communications technology to transport infrastructure and ve- hicles. The IEEE 802.11p standard is considered the main candidate for com- munication within the context of ITS and it performs well for active safety use

  12. Optimized smart grid energy procurement for LTE networks using evolutionary algorithms

    KAUST Repository

    Ghazzai, Hakim

    2014-11-01

    Energy efficiency aspects in cellular networks can contribute significantly to reducing worldwide greenhouse gas emissions. The base station (BS) sleeping strategy has become a well-known technique to achieve energy savings by switching off redundant BSs mainly for lightly loaded networks. Moreover, introducing renewable energy as an alternative power source has become a real challenge among network operators. In this paper, we formulate an optimization problem that aims to maximize the profit of Long-Term Evolution (LTE) cellular operators and to simultaneously minimize the CO2 emissions in green wireless cellular networks without affecting the desired quality of service (QoS). The BS sleeping strategy lends itself to an interesting implementation using several heuristic approaches, such as the genetic (GA) and particle swarm optimization (PSO) algorithms. In this paper, we propose GA-based and PSO-based methods that reduce the energy consumption of BSs by not only shutting down underutilized BSs but by optimizing the amounts of energy procured from different retailers (renewable energy and electricity retailers), as well. A comparison with another previously proposed algorithm is also carried out to evaluate the performance and the computational complexity of the employed methods.

  13. 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)

  14. A high linearity downconverter for SAW-less LTE receivers

    International Nuclear Information System (INIS)

    Jiang Peichen; Guan Rui; Wang Wufeng; Chen Dongpo; Zhou Jianjun

    2012-01-01

    This paper presents a high linearity downconverter implemented in a 0.18 μm CMOS process for long term evolution (LTE) receivers without a surface acoustic wave (SAW) filter. The proposed downconverter is composed of a transconductance (G m ) stage, a passive mixer, a current buffer, a transimpedance (TIA) stage, and a DC-offset cancellation (DCOC) loop. The current buffer is utilized to provide very low load impedance for the passive mixer at high frequencies and reduce the output voltage swing induced by out-of-band blockers. This technique improves the input referred third-order intercept point (IIP3) and second-order intercept point (IIP2) of the down-converter by 4.5 dB and 11 dB, respectively. The measured results show that the proposed downconverter achieves a voltage conversion gain of 29.5 dB, double sideband noise figure of 12.7 dB, out-of-band IIP3 of 13 dBm and IIP2 of more than 62 dBm.

  15. Performance analysis of IMS based LTE and WIMAX integration architectures

    Directory of Open Access Journals (Sweden)

    A. Bagubali

    2016-12-01

    Full Text Available In the current networking field many research works are going on regarding the integration of different wireless technologies, with the aim of providing uninterrupted connectivity to the user anywhere, with high data rates due to increased demand. However, the number of objects like smart devices, industrial machines, smart homes, connected by wireless interface is dramatically increasing due to the evolution of cloud computing and internet of things technology. This Paper begins with the challenges involved in such integrations and then explains the role of different couplings and different architectures. This paper also gives further improvement in the LTE and Wimax integration architectures to provide seamless vertical handover and flexible quality of service for supporting voice, video, multimedia services over IP network and mobility management with the help of IMS networks. Evaluation of various parameters like handover delay, cost of signalling, packet loss,, is done and the performance of the interworking architecture is analysed from the simulation results. Finally, it concludes that the cross layer scenario is better than the non cross layer scenario.

  16. Highly Compact MIMO Antenna System for LTE/ISM Applications

    Directory of Open Access Journals (Sweden)

    Lingsheng Yang

    2015-01-01

    Full Text Available Planar monopole antenna is proposed as the antenna element to form a compact dual-element multiple-input-multiple-output (MIMO antenna system for LTE2300 (used in Asia and Africa and ISM band operation. The system can cover a 310 MHz (2.20–2.51 GHz operating bandwidth, with the total size of 15.5 mm × 18 mm × 1.6 mm. Measured isolation higher than 16 dB is obtained without any specially designed decoupling structures, while the edge-to-edge element spacing is only 7.8 mm (0.08λ at 2.20 GHz. Radiation characteristics, correlation coefficient, and the performance of the whole system with a metal sheet and a plastic housing show this system is competitive for practical MIMO applications. The antenna element is further used to build an eight-element MIMO antenna system; also good results are achieved.

  17. On the Impact of Explicit Uplink Information on Autonomous Component Carrier Selection for LTE-A Femtocells

    DEFF Research Database (Denmark)

    Sanchez-Moya, Fernando; Villalba-Espinosa, Juan; Garcia, Luis Guilherme Uzeda

    2011-01-01

    argumentation by including uplink information into the component carrier selection process. We assess and discuss the uplink performance of two proposed variants of ACCS via extensive system level simulations. The striking conclusion based on the results is that the mere addition of uplink information, which......The increasing popularity of the femtocell concept has revamped the interest in dynamic interference coordination techniques for dense and uncoordinated deployments of low- power home base stations. One of the proposed schemes for 4G OFDMA femtocells is known as Autonomous Component Carrier...... Selection (ACCS). ACCS capitalizes on the carrier aggregation framework of LTE-Advanced to curb inter-cell interference levels. Albeit being exclusively based on downlink information, previous contributions attested the effectiveness of the scheme in the uplink as well. This paper extends the initial...

  18. Non-LTE analysis of the Ofpe/WN9 star HDE 269227 (R84)

    Science.gov (United States)

    Schmutz, Werner; Leitherer, Claus; Hubeny, Ivan; Vogel, Manfred; Hamann, Wolf-Rainer

    1991-01-01

    The paper presents the results of a spectral analysis of the Ofpe/WN9 star HD 269227 (R84), which assumes a spherically expanding atmosphere to find solutions for equations of radiative transfer. The spectra of hydrogen and helium were predicted with a non-LTE model. Six stellar parameters were determined for R84. The shape of the velocity law is empirically found, since it can be probed from the terminal velocity of the wind. The six stellar parameters are further employed in a hydrodynamic model where stellar wind is assumed to be directed by radiation pressure, duplicating the mass-loss rate and the terminal wind velocity. The velocity laws found by computation and analysis are found to agree, supporting the theory of radiation-driven stellar wind. R84 is surmised to be a post-red supergiant which lost half of its initial mass, possibly during the red-supergiant phase. This mass loss is also suggested by its spectroscopic similarity to S Doradus.

  19. NON-LTE INVERSIONS OF THE Mg ii h and k AND UV TRIPLET LINES

    Energy Technology Data Exchange (ETDEWEB)

    De la Cruz Rodríguez, Jaime; Leenaarts, Jorrit [Institute for Solar Physics, Dept. of Astronomy, Stockholm University, AlbaNova University Centre, SE-106 91 Stockholm Sweden (Sweden); Ramos, Andrés Asensio [Instituto de Astrofísica de Canarias, E-38205, La Laguna, Tenerife (Spain)

    2016-10-20

    The Mg ii h and k lines are powerful diagnostics for studying the solar chromosphere. They have become particularly popular with the launch of the Interface Region Imaging Spectrograph ( IRIS ) satellite, and a number of studies that include these lines have lead to great progress in understanding chromospheric heating, in many cases thanks to the support from 3D MHD simulations. In this study, we utilize another approach to analyze observations: non-LTE inversions of the Mg ii h and k and UV triplet lines including the effects of partial redistribution. Our inversion code attempts to construct a model atmosphere that is compatible with the observed spectra. We have assessed the capabilities and limitations of the inversions using the FALC atmosphere and a snapshot from a 3D radiation-MHD simulation. We find that Mg ii h and k allow reconstructing a model atmosphere from the middle photosphere to the transition region. We have also explored the capabilities of a multi-line/multi-atom setup, including the Mg ii h and k, the Ca ii 854.2 nm, and the Fe i 630.25 lines to recover the full stratification of physical parameters, including the magnetic field vector, from the photosphere to the chromosphere. Finally, we present the first inversions of observed IRIS spectra from quiet-Sun, plage, and sunspot, with very promising results.

  20. Diagnostic Utility of Urinary LTE4 in Asthma, Allergic Rhinitis, Chronic Rhinosinusitis, Nasal Polyps, and Aspirin Sensitivity.

    Science.gov (United States)

    Divekar, Rohit; Hagan, John; Rank, Matthew; Park, Miguel; Volcheck, Gerald; O'Brien, Erin; Meeusen, Jeffrey; Kita, Hirohito; Butterfield, Joseph

    2016-01-01

    Urinary leukotriene E4 (LTE4) is a well-validated marker of the cysteinyl leukotriene pathway, and LTE4 elevation has been described in conditions such as asthma, aspirin sensitivity, and chronic rhinosinusitis (CRS). There have been a number of reports investigating the role of spot urine LTE4 to predict aspirin sensitivity; however, variability in urinary LTE4 may affect the accuracy of this approach. Here, we explored the utility of 24-hour urinary LTE4 in 5 clinical diagnoses of allergic rhinitis, asthma, chronic rhinosinusitis with nasal polyps (CRSwNP), CRS without nasal polyps, and aspirin sensitivity. This was a retrospective review of patients who had 24-hour quantification of urinary LTE4 by a clinically validated liquid chromatography tandem mass spectrometry method and their assigned diagnoses after assessment and clinical care. Twenty-four-hour urinary LTE4 elevations were seen in those with asthma and those with CRSwNP but influenced by underlying aspirin sensitivity. Elevation in LTE4 was significant in those with CRSwNP after adjusting for aspirin sensitivity. Allergic rhinitis was not associated with elevated LTE4 excretion. Receiver operator characteristic analysis of 24-hour urinary LTE4 showed that a cutoff value of 166 pg/mg Cr suggested the presence of history of aspirin sensitivity with 89% specificity, whereas a cutoff value of 241 pg/mg Cr discriminated "challenge-confirmed" aspirin-sensitive subjects with 92% specificity. Elevated 24-hour excretion of urinary LTE4 is a reliable and simple test to identify aspirin sensitivity in patients with respiratory diagnoses. Copyright © 2016 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

  1. 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.

  2. 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.

  3. 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

  4. 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.

  5. Random access with adaptive packet aggregation in LTE/LTE-A.

    Science.gov (United States)

    Zhou, Kaijie; Nikaein, Navid

    While random access presents a promising solution for efficient uplink channel access, the preamble collision rate can significantly increase when massive number of devices simultaneously access the channel. To address this issue and improve the reliability of the random access, an adaptive packet aggregation method is proposed. With the proposed method, a device does not trigger a random access for every single packet. Instead, it starts a random access when the number of aggregated packets reaches a given threshold. This method reduces the packet collision rate at the expense of an extra latency, which is used to accumulate multiple packets into a single transmission unit. Therefore, the tradeoff between packet loss rate and channel access latency has to be carefully selected. We use semi-Markov model to derive the packet loss rate and channel access latency as functions of packet aggregation number. Hence, the optimal amount of aggregated packets can be found, which keeps the loss rate below the desired value while minimizing the access latency. We also apply for the idea of packet aggregation for power saving, where a device aggregates as many packets as possible until the latency constraint is reached. Simulations are carried out to evaluate our methods. We find that the packet loss rate and/or power consumption are significantly reduced with the proposed method.

  6. 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.

  7. 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

    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...... Internet of Things, but with different trade-offs....

  8. Preliminary results on 3D channel modeling: From theory to standardization

    KAUST Repository

    Kammoun, Abla

    2014-06-01

    Three dimensional (3D) beamforming (also elevation beamforming) is now gaining interest among researchers in wireless communication. The reason can be attributed to its potential for enabling a variety of strategies such as sector or user specific elevation beamforming and cell-splitting. Since these techniques cannot be directly supported by current LTE releases, the 3GPP is now working on defining the required technical specifications. In particular, a large effort is currently being made to get accurate 3D channel models that support the elevation dimension. This step is necessary as it will evaluate the potential of 3D and full dimensional (FD) beamforming techniques to benefit from the richness of real channels. This work aims at presenting the on-going 3GPP study item \\'study on 3D-channel model for elevation beamforming and FD-MIMO studies for LTE\\' and positioning it with respect to previous standardization works. © 2014 IEEE.

  9. 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.

  10. Radio Resource Management for Uplink Carrier Aggregation in LTE-Advanced

    DEFF Research Database (Denmark)

    Wang, Hua; Rosa, Claudio; Pedersen, Klaus I.

    2015-01-01

    transmission for LTE-Advanced UEs has to be careful. A pathloss-threshold based component carrier (CC) and cluster configuration algorithm is proposed to determine whether an LTE-Advanced UE should be configured with multiple CCs and/or dual cluster scheduling. An extended bandwidth-expansion based packet......This paper investigates the uplink resource allocation problem in the context of LTE-Advanced systems with carrier aggregation (CA) and dual-cluster scheduling. On one hand these Rel’10 functionalities can increase the available transmission bandwidth and scheduling flexibility in uplink....... On the other hand they will introduce additional power back-off for the power amplifier in the user equipment (UE) with non-contiguous resource allocation. Taking into account that the uplink is inherently limited by the maximum transmission power of the UE, the assignment of uplink CA and/or dual cluster...

  11. PREVIOUS SECOND TRIMESTER ABORTION

    African Journals Online (AJOL)

    PNLC

    PREVIOUS SECOND TRIMESTER ABORTION: A risk factor for third trimester uterine rupture in three ... for accurate diagnosis of uterine rupture. KEY WORDS: Induced second trimester abortion - Previous uterine surgery - Uterine rupture. ..... scarred uterus during second trimester misoprostol- induced labour for a missed ...

  12. 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...

  13. Coupling element antenna with slot tuning for handheld devices at LTE frequencies

    DEFF Research Database (Denmark)

    Barrio, Samantha Caporal Del; Pelosi, Mauro; Franek, Ondrej

    2012-01-01

    . A reconfigurable slot is inserted in the ground plane in order to lower its resonance frequency. The tuning is done by a capacitor across the slot. It is shown that covering all frequencies between the 900-GSM band and the 700-LTE band can be achieved. The radiating structure also presents a resonance in the high...... LTE band which is unaffected by the tuning mechanism of the lower band. Moreover, the efficiency can be optimized by an analysis of the currents across the slot. The study also shows that holding the device does not lead to additional mismatch losses which will further improve the overall efficiency....

  14. Observed departures from LTE ionization equilibrium in late-type giants

    International Nuclear Information System (INIS)

    Ramsey, L.W.

    1977-01-01

    Photoelectric scans of the Ca I line at 6572 A and the forbidden Ca II transition at 7323 A are studied in the K giant α Tau, the M supergiant α Ori, and the M giants β And, α Cet, μ Gem, and β Peg. The relative strengths of these lines are shown to be indicative of the ratio of the relative number densities of the neutral and ionized species in the photosphere. The analysis indicates an overionization relative to LTE in qualitative agreement with the theoretical calculations of Auman and Woodrow for the K and M giants. The M supergiant α Ori exhibits a large over-ionization relative to LTE

  15. 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.

  16. 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...

  17. 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...

  18. 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.

  19. 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

    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....... 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...

  20. 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

    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...... 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...

  1. 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.

  2. MHAV: Multitier Heterogeneous Adaptive Vehicular Network with LTE and DSRC

    Directory of Open Access Journals (Sweden)

    S. Ansari

    2017-12-01

    Full Text Available Enabling cooperation between vehicles form vehicular networks, which provide safety, traffic efficiency and infotainment. The most vital of these applications require reliability and low latency. Considering these requirements, this paper presents a multitier heterogeneous adaptive vehicular (MHAV network. Comprising of transport operator or authority owned vehicles in high tier and all the other privately owned vehicles in low tier, integrating cellular network with dedicated short range communications. The proposed framework is implemented and evaluated in Glasgow city center model. Simulation results demonstrate that the proposed architecture outperforms previous multitier architectures in terms of latency while offloading traffic from cellular networks.

  3. 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

  4. Spatial Frequency Scheduling for Uplink SC-FDMA based Linearly Precoded LTE Multiuser MIMO Systems

    DEFF Research Database (Denmark)

    Lin, Zihuai; Xiao, Pei; Sørensen, Troels Bundgaard

    2010-01-01

    This paper investigates the performance of the 3GPP Long Term Evolution (LTE) uplink Single Carrier (SC) Frequency Division Multiple Access (FDMA) based linearly precoded multiuserMultiple InputMultiple Output (MIMO) systems with frequency domain packet scheduling. A mathematical expression...

  5. 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...

  6. Performance Analysis of Handover Measurements and Layer 3 Filtering for UTRAN LTE

    DEFF Research Database (Denmark)

    Anas, Mohmmad; Calabrese, Francesco Davide; Östling, Per-Erik

    2007-01-01

    B domain L3 filtering has been studied by using a dynamic system level simulator for a 3GPP UTRAN LTE recommended scenario. The results suggest that RSS measurement with linear or dB domain L3 filtering is a better criterion for handover in terms of reduced number of handovers for a small penalty...

  7. A Novel Energy-Saving Resource Allocation Scheme in LTE-A Relay Networks

    Directory of Open Access Journals (Sweden)

    Jen-Jee Chen

    2016-01-01

    Full Text Available The relay node (RN in Long-Term Evolution-Advanced (LTE-A networks is used to enhance the coverage of high data rate and solve the coverage hole problem. Considering the limited energy nature of User Equipment (UE, connecting to the RN instead of Evolved Node B (eNB is a better choice for cell-edge UE items. In this paper, on the premise of compatibility to the LTE-A resource allocation specification, we discuss an uplink radio resource, uplink path, modulation and coding scheme (MCS, and transmit power allocation problem for energy conservation in LTE-A relay networks. The objective is to minimize the total energy consumption of UE items while guaranteeing the constraints of UE items’ quality of service (QoS, bit-error-rate (BER, total system resource, and maximum transmit power. Since the problem is NP-complete and the scheduling period in LTE-A is short (the subframe length is only 1 ms, we propose an efficient method to solve the problem. The complexity analysis shows the time complexity of the proposed heuristics is O(n2. Simulation results demonstrate that our algorithm can effectively reduce the energy consumption of UE items and guarantee users’ service quality.

  8. 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.

  9. Heterogeneous Deployment to Meet Traffic Demand in a Realistic LTE Urban Scenario

    DEFF Research Database (Denmark)

    Coletti, Claudio; Hu, Liang; Nguyen, Huan Cong

    2012-01-01

    The main objective of the paper is to investigate and compare the downlink performance of different LTE heterogene-ous network (HetNet) deployment solutions. By adding small cells to the existing macro overlay, network coverage and capacity can be significantly enhanced to accommodate the fast...

  10. 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...

  11. 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

  12. 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...

  13. 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

  14. 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.

  15. 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

  16. 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.

  17. 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.

  18. 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

  19. 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

  20. 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...

  1. Improved Mobility Performance in LTE Co-Channel HetNets Through Speed Differentiated Enhancements

    DEFF Research Database (Denmark)

    Barbera, Simone; Michaelsen, Per Henrik; Säily, Mikko

    2012-01-01

    This paper analyzes the mobility performance of LTE (Long Term Evolution) co-channel heterogeneous networks (HetNet) with macro and pico cells. Improved methods for differentiating offload and mobility robustness as a function of the UE (User Equipment) mobility are proposed. The suggested solution...

  2. 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

  3. 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...

  4. 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...

  5. 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...

  6. Non-LTE effects on the strength of the Lyman edge in quasar accretion disks

    Science.gov (United States)

    Stoerzer, H.; Hauschildt, P. H.; Allard, F.

    1994-01-01

    We have calculated UV/EUV (300 A which is less than or equal to lambda which is less than or equal to 1500 A) continuous energy distributions of accretion disks in the centers of active galactic nuclei (AGNs) for disk luminosities in the range 0.1 L(sub Edd) less than or equal to L(sub acc) less than 1.0 L(sub Edd) and central masses ranging from 10(exp 8) solar mass to 10(exp 9) solar mass. The vertical gas pressure structure of the disk and the disk height are obtained analytically; the temperature stratification and the resulting continuum radiation fields are calculated numerically. We have included non-Local Thermodynamic Equilibrium (LTE) effects of both the ionization equilibrium and the level populations of hydrogen and helium. We show that these non-LTE effects reduce the strength of the Lyman edge when comapred to the LTE case. In non-LTE we find that the edge can be weakly in emission or absorption for disks seen face-on, depending on the disk parameters.

  7. 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...

  8. 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

    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...

  9. 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....

  10. 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

    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...

  11. 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.

  12. 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...

  13. 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...

  14. Interpreting "Personality" Taxonomies: Why Previous Models Cannot Capture Individual-Specific Experiencing, Behaviour, Functioning and Development. Major Taxonomic Tasks Still Lay Ahead.

    Science.gov (United States)

    Uher, Jana

    2015-12-01

    As science seeks to make generalisations, a science of individual peculiarities encounters intricate challenges. This article explores these challenges by applying the Transdisciplinary Philosophy-of-Science Paradigm for Research on Individuals (TPS-Paradigm) and by exploring taxonomic "personality" research as an example. Analyses of researchers' interpretations of the taxonomic "personality" models, constructs and data that have been generated in the field reveal widespread erroneous assumptions about the abilities of previous methodologies to appropriately represent individual-specificity in the targeted phenomena. These assumptions, rooted in everyday thinking, fail to consider that individual-specificity and others' minds cannot be directly perceived, that abstract descriptions cannot serve as causal explanations, that between-individual structures cannot be isomorphic to within-individual structures, and that knowledge of compositional structures cannot explain the process structures of their functioning and development. These erroneous assumptions and serious methodological deficiencies in widely used standardised questionnaires have effectively prevented psychologists from establishing taxonomies that can comprehensively model individual-specificity in most of the kinds of phenomena explored as "personality", especially in experiencing and behaviour and in individuals' functioning and development. Contrary to previous assumptions, it is not universal models but rather different kinds of taxonomic models that are required for each of the different kinds of phenomena, variations and structures that are commonly conceived of as "personality". Consequently, to comprehensively explore individual-specificity, researchers have to apply a portfolio of complementary methodologies and develop different kinds of taxonomies, most of which have yet to be developed. Closing, the article derives some meta-desiderata for future research on individuals' "personality".

  15. Laparoscopy After Previous Laparotomy

    Directory of Open Access Journals (Sweden)

    Zulfo Godinjak

    2006-11-01

    Full Text Available Following the abdominal surgery, extensive adhesions often occur and they can cause difficulties during laparoscopic operations. However, previous laparotomy is not considered to be a contraindication for laparoscopy. The aim of this study is to present that an insertion of Veres needle in the region of umbilicus is a safe method for creating a pneumoperitoneum for laparoscopic operations after previous laparotomy. In the last three years, we have performed 144 laparoscopic operations in patients that previously underwent one or two laparotomies. Pathology of digestive system, genital organs, Cesarean Section or abdominal war injuries were the most common causes of previouslaparotomy. During those operations or during entering into abdominal cavity we have not experienced any complications, while in 7 patients we performed conversion to laparotomy following the diagnostic laparoscopy. In all patients an insertion of Veres needle and trocar insertion in the umbilical region was performed, namely a technique of closed laparoscopy. Not even in one patient adhesions in the region of umbilicus were found, and no abdominal organs were injured.

  16. 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)

  17. 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

  18. Wi-Fi Influence on LTE-U Downlink Data and Control Channel Performance in Shared Frequency Bands

    Directory of Open Access Journals (Sweden)

    J. Milos

    2017-04-01

    Full Text Available Nowadays, providers of wireless services try to find appropriate ways to increase user data throughput mainly for future 5G cellular networks. Utilizing the unlicensed spectrum (ISM bands for such purpose is a promising solution: unlicensed frequency bands can be used as a complementary data pipeline for UMTS LTE (Universal Mobile Telecommunication System - Long Term Evolution and its advanced version LTE-Advanced, especially in pico- or femtocells. However, coexisting LTE and WLAN services in shared ISM bands at the same time can suffer unwanted performance degradation. This paper focuses predominantly on co-channel coexistence issues (worst case between LTE and WLAN (IEEE 802.11n services in the ISM band. From the viewpoint of novelty, the main outcomes of this article are follows. Firstly, an appropriate signal processing approach for coexisting signals with different features in the baseband is proposed. It is applied in advanced link-layer simulators and its correctness is verified by various simulations. Secondly, the influence of IEEE 802.11n on LTE data and control channel performance is explored. Performance evaluation is based on error rate curves, depending on Signal-to-Interference ratio (SIR. Presented results allow for better understanding the influence of IEEE 802.11n on the LTE downlink physical control channels (PCCH and are valuable for mobile infrastructure vendors and operators to optimize system parameters.

  19. 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...

  20. Molecular and mathematical modeling analyses of inter-island transmission of rabies into a previously rabies-free island in the Philippines.

    Science.gov (United States)

    Tohma, Kentaro; Saito, Mariko; Demetria, Catalino S; Manalo, Daria L; Quiambao, Beatriz P; Kamigaki, Taro; Oshitani, Hitoshi

    2016-03-01

    Rabies is endemic in the Philippines and dog bites are a major cause of rabies cases in humans. The rabies control program has not been successful in eliminating rabies because of low vaccination coverage among dogs. Therefore, more effective and feasible strategies for rabies control are urgently required in the country. To control rabies, it is very important to know if inter-island transmission can occur because rabies can become endemic once the virus is introduced in areas that previously had no reported cases. Our molecular epidemiological study suggests that inter-island transmission events can occur; therefore, we further investigated these inter-island transmission using phylogenetic and modeling approaches. We investigate inter-island transmission between Luzon and Tablas Islands in the Philippines. Phylogenetic analysis and mathematical modeling demonstrate that there was a time lag of several months to a year from rabies introduction to initial case detection, indicating the difficulties in recognizing the initial rabies introductory event. There had been no rabies cases reported in Tablas Island; however, transmission chain was sustained on this island after the introduction of rabies virus because of low vaccination coverage among dogs. Across the islands, a rabies control program should include control of inter-island dog transportation and rabies vaccination to avoid viral introduction from the outside and to break transmission chains after viral introduction. However, this program has not yet been completely implemented and transmission chains following inter-island virus transmission are still observed. Local government units try to control dog transport; however, it should be more strictly controlled, and a continuous rabies control program should be implemented to prevent rabies spread even in rabies-free areas. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

  1. 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.

  2. 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.

  3. Design aspects of LTE desalination plant utilizing waste heat from nuclear research reactor

    International Nuclear Information System (INIS)

    Rao, I.S.; Srivastava, V.K.; Tewari, P.K.

    2004-01-01

    Nuclear research reactors produce significant amount of low quality waste heat which can be utilized for producing high quality water from seawater by coupling a Low Temperature Evaporation (LTE) desalination unit. Salient features and design considerations of the desalination plant coupled to the nuclear research reactor and the performance of the desalination plant under varying operational conditions applicable to waste heat utilization from the reactor are discussed. Chemical and radioactive analysis of the product water is given to indicate the usefulness of the water to meet the demineralized water makeup requirements of the reactor. The general scheme of integrating desalination plant with the nuclear research reactor is also presented. This LTE desalination plant utilizing waste heat from a nuclear research reactor is the first of its kind and is a demonstration of safety and economics of nuclear desalination technology as a viable alternative to produce demineralised water from seawater. (author)

  4. Feedback Compression Schemes for Downlink Carrier Aggregation in LTE-Advanced

    DEFF Research Database (Denmark)

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

    2011-01-01

    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......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...

  5. [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.

  6. Joint time-frequency domain proportional fair scheduler with HARQ for 3GPP LTE systems

    OpenAIRE

    Beh, KC; Doufexi, A; Armour, SMD

    2008-01-01

    This paper explores the potential gain of joint diversity in both frequency domain and time domain which can be exploited to achieve spectral efficiency gains whilst simultaneously facilitating QoS/ fairness in an OFDMA system particularly in 3GPP Long Term Evolution (LTE)). The performance of several joint time-frequency schedulers is investigated. Simulation results show that joint time frequency schedulers achieve significantly superior performance compared to a more conventional time doma...

  7. Data Aggregation and Packet Bundling of Uplink Small Packets for Monitoring Applications in LTE

    DEFF Research Database (Denmark)

    Kim, Dong Min; Sørensen, René Brandborg; Mahmood, Kashif

    2017-01-01

    topic. In this article we analyze the deployment scenarios in which aggregators can perform cellular access on behalf of multiple MTC devices. We study the effect of packet bundling at the aggregator, which alleviates overhead and resource waste when sending small packets. The aggregators give rise...... of aggregators and packet bundle size. Our results show that, in general, data aggregation can benefit the uplink massive MTC in LTE by reducing the signaling overhead....

  8. 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.

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

    Science.gov (United States)

    Naudts, Dries; Shahid, Adnan; Giannoulis, Spilios; Laermans, Eric

    2017-01-01

    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. PMID:28858243

  10. Optimized Scheduling Technique of Null Subcarriers for Peak Power Control in 3GPP LTE Downlink

    Science.gov (United States)

    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. PMID:24883376

  11. Numerical non-LTE 3D radiative transfer using a multigrid method

    Science.gov (United States)

    Bjørgen, Johan P.; Leenaarts, Jorrit

    2017-03-01

    Context. 3D non-LTE radiative transfer problems are computationally demanding, and this sets limits on the size of the problems that can be solved. So far, multilevel accelerated lambda iteration (MALI) has been the method of choice to perform high-resolution computations in multidimensional problems. The disadvantage of MALI is that its computing time scales as O(n2), with n the number of grid points. When the grid becomes finer, the computational cost increases quadratically. Aims: We aim to develop a 3D non-LTE radiative transfer code that is more efficient than MALI. Methods: We implement a non-linear multigrid, fast approximation storage scheme, into the existing Multi3D radiative transfer code. We verify our multigrid implementation by comparing with MALI computations. We show that multigrid can be employed in realistic problems with snapshots from 3D radiative magnetohydrodynamics (MHD) simulations as input atmospheres. Results: With multigrid, we obtain a factor 3.3-4.5 speed-up compared to MALI. With full-multigrid, the speed-up increases to a factor 6. The speed-up is expected to increase for input atmospheres with more grid points and finer grid spacing. Conclusions: Solving 3D non-LTE radiative transfer problems using non-linear multigrid methods can be applied to realistic atmospheres with a substantial increase in speed.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. Combined Resource Allocation System for Device-to-Device Communication towards LTE Networks

    Directory of Open Access Journals (Sweden)

    Abbas Fakhar

    2016-01-01

    Full Text Available The LTE networks are being developed to grant mobile broadband services in the fourth generation (4G systems and allow operators to use spectrum more efficiently.D2D communication is a promising technique to provide wireless services and enhance spectrum exploitation in the LTE Heterogeneous Networks (HetNets.D2D communication in HetNets allows users to communicate with each other directly by reusing the resources when communicating via the base stations. But during the downlink period, both the D2D receiver and the Heterogeneous Users equipment’s (HUE experience interference caused by resource allocation. In this article, we identify and analyze the interference problem of HetNets caused by D2D transmitter during download. We propose a combined resource allocation and resource reuse method for LTE HetNets, where resource allocation to HUEs is employed on the basis of comparative fair algorithm and resource reuse to D2D users is employed on acquisitive empirical algorithm. This approach evaluates whether D2D mode is suitable or not by path loss evaluation, after that decreases the interference to HUE by selection of the minimum channel gain between HUE and D2D transmitter each time to mitigate interference. Our simulation results show that the efficiency and throughput of HetNets is improved by using the proposed method.

  17. 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.

  18. Disks Surrounding Massive Stars: When Computational Models are Confronted by Observations

    Science.gov (United States)

    2010-01-01

    distribución espectral de enerǵıa y la polarización del continuo . Los modelos con es- tructura térmica precisa y campos de radiación son esenciales...circumstellar disks for Be stars, using a non-LTE radiative transfer code which incorporates a number of improvements over previous treatments of the disk...the other predicted observables. The code has a number of improvements over previous disk models available in the literature. For example, the disk

  19. Observations and Modeling of Atmospheric Radiance Structure

    National Research Council Canada - National Science Library

    Wintersteiner, Peter

    2001-01-01

    The overall purpose of the work that we have undertaken is to provide new capabilities for observing and modeling structured radiance in the atmosphere, particularly the non-LTE regions of the atmosphere...

  20. 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.

  1. 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.

  2. Models for the computation of opacity of mixtures

    International Nuclear Information System (INIS)

    Klapisch, Marcel; Busquet, Michel

    2013-01-01

    We compare four models for the partial densities of the components of mixtures. These models yield different opacities as shown on polystyrene, acrylic and polyimide in local thermodynamical equilibrium (LTE). Two of these models, the ‘whole volume partial pressure’ model (M1) and its modification (M2) are not thermodynamically consistent (TC). The other two models are TC and minimize free energy. M3, the ‘partial volume equal pressure’ model, uses equality of chemical potential. M4 uses commonality of free electron density. The latter two give essentially identical results in LTE, but M4’s convergence is slower. M4 is easily generalized to non-LTE conditions. Non-LTE effects are shown by the variation of the Planck mean opacity of the mixtures with temperature and density. (paper)

  3. 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.

  4. Effects of Film Modeling on the Reduction of Anxiety-Related Behaviors in Individuals Varying in Level of Previous Experience in the Stress Situation.

    Science.gov (United States)

    Melamed, Barbara G.; And Others

    1978-01-01

    Evaluated influence of film preparation on children undergoing dental sessions with respect to peer modeling v demonstration of procedures and amount of information. Children exposed to peer-model videotaped presentations immediately preceding their restorative treatment exhibited fewer disruptive behaviors and less apprehension than those…

  5. 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.

  6. 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

  7. A genetic algorithm solution for the operation of green LTE networks with energy and environment considerations

    KAUST Repository

    Ghazzai, Hakim

    2012-01-01

    The Base Station (BS) sleeping strategy has become a well-known technique to achieve energy savings in cellular networks by switching off redundant BSs mainly for lightly loaded networks. Besides, the exploitation of renewable energies, 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 by not only shutting down underutilized BSs but also by optimizing the amounts of energy procured from the smart grid without affecting the desired Quality of Service. © 2012 Springer-Verlag.

  8. 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

  9. Performance Analysis of enhanced Inter-cell Interference Coordination in LTE-Advanced Heterogeneous Networks

    DEFF Research Database (Denmark)

    Wang, Yuanye; Pedersen, Klaus I.

    2012-01-01

    The performance of enhanced Inter-Cell Interference Coordination (eICIC) for Long Term Evolution (LTE)- Advanced with co-channel deployment of both macro and pico is analyzed. The use of pico-cell Range Extension (RE) and time domain eICIC (TDM muting) is combined. The performance is evaluated...... in different scenarios are identified. The presented performance results and findings can serve as input to guidelines for co-channel deployment of macro and pico-eNBs with eICIC....

  10. 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...

  11. Using LTE Networks for UAV Command and Control Link: A Rural-Area Coverage Analysis

    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...... interference coordination schemes. In addition, ideal Interference Cancellation (IC) scheme with ability to remove completely the dominant interferer shows less effective for UAVs than for users on the ground. On the other hand, macro network diversity has very good potential for drones, as not only...

  12. Non-LTE Abundances of Magnesium, Aluminum and Sulfur in OB Stars Near the Solar Circle

    OpenAIRE

    Daflon, S.; Cunha, K.; Smith, V. V.; Butler, K.

    2002-01-01

    Non-LTE abundances of magnesium, aluminum and sulfur are derived for a sample of 23 low-v \\sin i stars belonging to six northern OB associations of the Galactic disk within 1 kpc of the Sun. The abundances are obtained from the fitting of synthetic line profiles to high resolution spectra. A comparison of our results with HII region abundances indicates good agreement for sulfur while the cepheid abundances are higher. The derived abundances of Mg show good overlap with the cepheid results. T...

  13. Indoor Radio Planning A Practical Guide for GSM, DCS, UMTS, HSPA and LTE

    CERN Document Server

    Tolstrup, Morten

    2011-01-01

    Why is indoor coverage needed, and how it is best implemented? As the challenge of providing higher data speeds and quality for mobile applications intensifies, ensuring adequate in-building and tunnel coverage and capacity is increasingly important. A unique, single-source reference on the theoretical and practical knowledge behind indoor and tunnel radio planning, Indoor Radio Planning, Second Edition provides an overview of mobile networks systems and coverage solutions with GSM, UMTS, HSPA and LTE cellular systems technologies as a backdrop. All of the available solutions, from basic passi

  14. Modelling of near-field radionuclide transport phenomena in a KBS-3V type of repository for nuclear waste with Goldsim Code - and verification against previous methods

    International Nuclear Information System (INIS)

    Pulkkanen, V.-M.; Nordman, H.

    2010-03-01

    Traditional radionuclide transport models overestimate significantly some phenomena, or completely ignore them. This motivates the development of new more precise models. As a result, this work is a description of commissioning of a new KBS-3V near-field radionuclide transport model, which has been done with a commercial software called GoldSim. According to earlier models, GoldSim model uses rz coordinates, but the solubilities of radionuclides have been treated more precisely. To begin with, the physical phenomena concerning near-field transport have been introduced according to GoldSim way of thinking. Also, the computational methods of GoldSim have been introduced and compared to methods used earlier. The actual verification of GoldSim model has been carried out by comparing the GoldSim results from simple cases to the corresponding results obtained with REPCOM, a software developed by VTT and used in several safety assessments. The results agree well. Finally, a few complicated cases were studied. In these cases, the REPCOM's limitations in handling of some phenomena become evident. The differences in the results are caused especially by the extension of the solubility limit to the whole computational domain, and the element-wise treatment of the solubilities which was used instead of nuclide-wise treatment. This work has been carried out as a special assignment to the former laboratory of Advanced Energy Systems in Helsinki University of Technology. The work was done at VTT. (orig.)

  15. Modelling of near-field radionuclide transport phenomena in a KBS-3V type of repository for nuclear waste with Goldsim Code - and verification against previous methods

    Energy Technology Data Exchange (ETDEWEB)

    Pulkkanen, V.-M.; Nordman, H. (VTT Technical Research Centre, Espoo (Finland))

    2010-03-15

    Traditional radionuclide transport models overestimate significantly some phenomena, or completely ignore them. This motivates the development of new more precise models. As a result, this work is a description of commissioning of a new KBS-3V near-field radionuclide transport model, which has been done with a commercial software called GoldSim. According to earlier models, GoldSim model uses rz coordinates, but the solubilities of radionuclides have been treated more precisely. To begin with, the physical phenomena concerning near-field transport have been introduced according to GoldSim way of thinking. Also, the computational methods of GoldSim have been introduced and compared to methods used earlier. The actual verification of GoldSim model has been carried out by comparing the GoldSim results from simple cases to the corresponding results obtained with REPCOM, a software developed by VTT and used in several safety assessments. The results agree well. Finally, a few complicated cases were studied. In these cases, the REPCOM's limitations in handling of some phenomena become evident. The differences in the results are caused especially by the extension of the solubility limit to the whole computational domain, and the element-wise treatment of the solubilities which was used instead of nuclide-wise treatment. This work has been carried out as a special assignment to the former laboratory of Advanced Energy Systems in Helsinki University of Technology. The work was done at VTT. (orig.)

  16. Integrated astrophysical modeling

    Energy Technology Data Exchange (ETDEWEB)

    Weaver, T. A.; Eastman, R. G.; Dubois, P.; Eltgroth, P. G.; Gentile, N.; Jedamzik, K.; Wilson, J. R.

    1997-06-03

    In this project, we have developed prototype techniques for defining and extending a variety of astrophysical modeling capabilities, including those involving multidimensional hydrodynamics, complex transport, and flexibly-coupled equation-of state and nuclear reaction networks. As expected, this project is having both near-term payoffs in understanding complex astrophysical phenomena, as well as significant spin-offs in terms of people and ideas to related ASCI code efforts. Most of our work in the first part of this project was focused on the modularization, extension, and initial integration of 4 previously separate and incommensurate codes: the stellar evolution/explosion code KEPLER; the non-LTE spectral line transport code, EDDINGTON, used for modeling supernovae spectra; the 3-D smooth particle hydro code, PIP; and the discontinuous-finite-element, 3D hydro module from the lCF3D code.

  17. Non-LTE profiles of strong solar lines

    Science.gov (United States)

    Schneeberger, T. J.; Beebe, H. A.

    1976-01-01

    The complete linearization method is applied to the formation of strong lines in the solar atmosphere. Transitions in Na(I), Mg(I), Ca(I), Mg(II), and Ca(II) are computed with a standard atmosphere and microturbulent velocity model. The computed profiles are compared to observations at disk center.

  18. A collisional-radiative average atom model for hot plasmas

    International Nuclear Information System (INIS)

    Rozsnyai, B.F.

    1996-01-01

    A collisional-radiative 'average atom' (AA) model is presented for the calculation of opacities of hot plasmas not in the condition of local thermodynamic equilibrium (LTE). The electron impact and radiative rate constants are calculated using the dipole oscillator strengths of the average atom. A key element of the model is the photon escape probability which at present is calculated for a semi infinite slab. The Fermi statistics renders the rate equation for the AA level occupancies nonlinear, which requires iterations until the steady state. AA level occupancies are found. Detailed electronic configurations are built into the model after the self-consistent non-LTE AA state is found. The model shows a continuous transition from the non-LTE to the LTE state depending on the optical thickness of the plasma. 22 refs., 13 figs., 1 tab

  19. LTE-advanced random access mechanism for M2M communication: A review

    Science.gov (United States)

    Mustafa, Rashid; Sarowa, Sandeep; Jaglan, Reena Rathee; Khan, Mohammad Junaid; Agrawal, Sunil

    2016-03-01

    Machine Type Communications (MTC) enables one or more self-sufficient machines to communicate directly with one another without human interference. MTC applications include smart grid, security, e-Health and intelligent automation system. To support huge numbers of MTC devices, one of the challenging issues is to provide a competent way for numerous access in the network and to minimize network overload. In this article, the different control mechanisms for overload random access are reviewed to avoid congestion caused by random access channel (RACH) of MTC devices. However, past and present wireless technologies have been engineered for Human-to-Human (H2H) communications, in particular, for transmission of voice. Consequently the Long Term Evolution (LTE) -Advanced is expected to play a central role in communicating Machine to Machine (M2M) and are very optimistic about H2H communications. Distinct and unique characteristics of M2M communications create new challenges from those in H2H communications. In this article, we investigate the impact of massive M2M terminals attempting random access to LTE-Advanced all at once. We discuss and review the solutions to alleviate the overload problem by Third Generation Partnership Project (3GPP). As a result, we evaluate and compare these solutions that can effectively eliminate the congestion on the random access channel for M2M communications without affecting H2H communications.

  20. 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.

  1. 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.

  2. The Effective Radiation Pattern Concept for Realistic Performance Estimation of LTE Wireless Systems

    Directory of Open Access Journals (Sweden)

    Dimitra Zarbouti

    2013-01-01

    Full Text Available Radio channels induce distortions to the radiation pattern of beamforming systems such as beam broadening as well as sidelobe level and null rising. If these effects are ignored, the system performance is overestimated. This paper proposes the simple concept of an effective radiation pattern (ERP calculated by optimally fitting the “real-world” radiation pattern to the ERP. The proposed ERP method is incorporated into a multicell bad urban 4G LTE operational scenario which employs beamforming for both the BSs and the RNs. The performed simulations provide evidence that the ideal instead of the real radiation pattern overestimates the SIR and capacity by almost 3 dB and 13 Mbps, respectively, for the reference scenario without RNs. It also proves that the ERP method produces almost identical performance results with the real radiation pattern, and hence it is a simple and viable option for realistic performance analysis. Finally, the network performance is studied as a function of the number of RNs with the help of the ERP method. Results show that a beamforming LTE network with RNs that also employ beamforming provides 3 dB SIR gain with the addition of 1 RN per cell and 15 dB gain with 4 RNs per cell.

  3. 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.

  4. Cross-Layer Scheduling and Resource Allocation for Heterogeneous Traffic in 3G LTE

    Directory of Open Access Journals (Sweden)

    Richard Musabe

    2014-01-01

    Full Text Available 3G long term evolution (LTE introduces stringent needs in order to provide different kinds of traffic with Quality of Service (QoS characteristics. The major problem with this nature of LTE is that it does not have any paradigm scheduling algorithm that will ideally control the assignment of resources which in turn will improve the user satisfaction. This has become an open subject and different scheduling algorithms have been proposed which are quite challenging and complex. To address this issue, in this paper, we investigate how our proposed algorithm improves the user satisfaction for heterogeneous traffic, that is, best-effort traffic such as file transfer protocol (FTP and real-time traffic such as voice over internet protocol (VoIP. Our proposed algorithm is formulated using the cross-layer technique. The goal of our proposed algorithm is to maximize the expected total user satisfaction (total-utility under different constraints. We compared our proposed algorithm with proportional fair (PF, exponential proportional fair (EXP-PF, and U-delay. Using simulations, our proposed algorithm improved the performance of real-time traffic based on throughput, VoIP delay, and VoIP packet loss ratio metrics while PF improved the performance of best-effort traffic based on FTP traffic received, FTP packet loss ratio, and FTP throughput metrics.

  5. A proposed algorithm for scheduling and resource allocation For the downlink of LTE networks

    Directory of Open Access Journals (Sweden)

    Kareem Dhahir Rahi

    2017-07-01

    Full Text Available Long Term Evaluation (LTE networks can be categorized as a member of the third generation of mobile communication system, and it is capable of supporting real time multimedia and a variety of broadband technologies. In order to satisfy customers, these technologies must be transmitted with a good level of Quality of Service (QoS. This can be achieved by fulfilling a number of requirements such as lowest possible packet loss rate and delay. While from a provider’s perspective, improving the systems performance by efficient and fair spectrum allocation is challenging issue. As known, these requirements are mainly managed by the scheduler at the transmitter side. In this research, a novel algorithm of scheduling is proposed and implemented for real time applications in the downlink of LTE networks. The proposed algorithm reduces the number of packets that has been dropped due to congestion as well as the number of lost packets due to bad channel quality, and thus enhancing the system performance. It also prioritizes the user with the highest packet loss rate by taking into account the packet loss rate of each user and maintaining the metric of fairness within normal levels as the number of users increases. Also the system capacity, throughput and modulation order were increased by taking advantage of the Adaptive Modulation and Coding Scheme (AMC. The proposed algorithm has proven to be more efficient in terms of system performance than similar algorithms

  6. Rituximab, Cyclophosphamide, Dexamethasone (RCD) regimen induces cure in WSU-WM xenograft model and a partial remission in previously treated Waldenstrom's macroglobulinemia patient.

    Science.gov (United States)

    Mohammad, Ramzi M; Aboukameel, Amro; Nabha, Sanaa; Ibrahim, Dina; Al-Katib, Ayad

    2002-08-01

    Waldenstrom's macroglobulinemia (WM) is an uncommon lymphoproliferative disease which remains incurable with current treatment protocols. We have previously established a permanent WM cell line, WSU-WM, which grows as a xenograft in severe combined immune deficient (SCID) mice. In this study, we investigated the antitumor effects of Rituximab (RTX), Cyclophosphamide (CTX), Dexamethasone (DEX) [RCD]-Regimen in vivo WSU-WM SCID xenograft and in a patient with WM. For the pre-clinical efficacy study, WSU-WM-bearing SCID mice were randomly assigned to receive RTX (150 mg/kg/inj, i.v., QDX5), CTX (90 mg/kg/inj, s.c. QDX5) as single agents or diluent. The combination group received RTX at 150 mg/kg/inj, QDX5; CTX at 150 mg/kg/inj, QODX3 and DEX at 1.0 mg/kg/inj, i.v., QDX5. Tumor growth inhibition (T/C), tumor growth delay (T - C), and log10 kill (net) for RTX and CTX were 24.5%, 37 days, 5.52 and 88%, 0.0 days, 0.0log10 kill, respectively. No cures were observed with either agent; however, all mice (6/6, with bilateral tumors) were cured when treated with RCD-regimen. A 57-year-old patient with relapsed WM was treated with the RCD-regimen and showed an excellent partial remission for seven months. The patient tolerated the treatment very well, the hemoglobin improved dramatically, platelets remained stable, the IgM level normalized and there was only minimal involvement of bone marrow. Based on these results, the RCD regimen is effective against WM and its activity should be further evaluated in clinical trials.

  7. Comment on "Assessing Discrepancies Between Previous Plate Kinematic Models of Mesozoic Iberia and Their Constraints" by Barnett-Moore Et Al.

    Science.gov (United States)

    van Hinsbergen, Douwe J. J.; Spakman, Wim; Vissers, Reinoud L. M.; van der Meer, Douwe G.

    2017-12-01

    In their recent paper, Barnett-Moore et al. (2016) reflect on current models of Iberian plate motion in the Jurassic and Cretaceous as well as ongoing debates on the reliability of the various types of kinematic data that form independent constraints on Iberia's motion relative to Eurasia. They question the validity of various marine geophysical, seismic, tomographic, geological, and paleomagnetic data sets from the Bay of Biscay, Central Atlantic Ocean, and Iberia for kinematic reconstruction of Iberia and conclude that neither models invoking Aptian-Albian transtension, nor compression, are consistent with currently available data. An important element in their analysis is that they discard the large paleomagnetic data set from the Jurassic and Cretaceous from Iberia based on perceived limitations of that data set. In addition, they argue that seismic tomographic images exclude a scenario of subduction in the Aptian-Albian in the Pyrenees, and based on this "question the validity of current plate reconstructions, their constraints, and geodynamic scenarios, which are in support of this scenario [e.g., Vissers et al., 2016]." We welcome the discussion raised by Barnett-Moore et al. (2016) on the reliability and usefulness of paleomagnetic data as independent constraint for Iberia's plate motion in the Mesozoic. Taking these paleomagnetic data at face value, Vissers et al. (2016) recently showed that these are consistent with an 40° counterclockwise rotation of Iberia in the Aptian, requiring up to 500 km of Aptian convergence across the Pyrenees, that is, through subduction. In this comment, we aim to critically assess whether and how the concerns on the quality of paleomagnetic data raised by Barnett-Moore et al. (2016) may allow for an alternative explanation, particularly one with a Mesozoic rotation of Iberia that is small enough so as to not requiring subduction. We also reassess whether seismic tomographic images indeed refute subduction scenarios, using 8

  8. Global history of the ancient monocot family Araceae inferred with models accounting for past continental positions and previous ranges based on fossils.

    Science.gov (United States)

    Nauheimer, Lars; Metzler, Dirk; Renner, Susanne S

    2012-09-01

    The family Araceae (3790 species, 117 genera) has one of the oldest fossil records among angiosperms. Ecologically, members of this family range from free-floating aquatics (Pistia and Lemna) to tropical epiphytes. Here, we infer some of the macroevolutionary processes that have led to the worldwide range of this family and test how the inclusion of fossil (formerly occupied) geographical ranges affects biogeographical reconstructions. Using a complete genus-level phylogeny from plastid sequences and outgroups representing the 13 other Alismatales families, we estimate divergence times by applying different clock models and reconstruct range shifts under different models of past continental connectivity, with or without the incorporation of fossil locations. Araceae began to diversify in the Early Cretaceous (when the breakup of Pangea was in its final stages), and all eight subfamilies existed before the K/T boundary. Early lineages persist in Laurasia, with several relatively recent entries into Africa, South America, South-East Asia and Australia. Water-associated habitats appear to be ancestral in the family, and DNA substitution rates are especially high in free-floating Araceae. Past distributions inferred when fossils are included differ in nontrivial ways from those without fossils. Our complete genus-level time-scale for the Araceae may prove to be useful for ecological and physiological studies. © 2012 The Authors. New Phytologist © 2012 New Phytologist Trust.

  9. Relay Architectures for 3GPP LTE-Advanced

    Directory of Open Access Journals (Sweden)

    Peters StevenW

    2009-01-01

    Full Text Available The Third Generation Partnership Project's Long Term Evolution-Advanced is considering relaying for cost-effective throughput enhancement and coverage extension. While analog repeaters have been used to enhance coverage in commercial cellular networks, the use of more sophisticated fixed relays is relatively new. The main challenge faced by relay deployments in cellular systems is overcoming the extra interference added by the presence of relays. Most prior work on relaying does not consider interference, however. This paper analyzes the performance of several emerging half-duplex relay strategies in interference-limited cellular systems: one-way, two-way, and shared relays. The performance of each strategy as a function of location, sectoring, and frequency reuse are compared with localized base station coordination. One-way relaying is shown to provide modest gains over single-hop cellular networks in some regimes. Shared relaying is shown to approach the gains of local base station coordination at reduced complexity, while two-way relaying further reduces complexity but only works well when the relay is close to the handset. Frequency reuse of one, where each sector uses the same spectrum, is shown to have the highest network throughput. Simulations with realistic channel models provide performance comparisons that reveal the importance of interference mitigation in multihop cellular networks.

  10. ANALISA PERENCANAAN JARINGAN 4G LTE PADA GEDUNG A FAKULTAS TEKNIK UNIVERSITAS JEMBER MENGGUNAKAN RADIOWAVE PROPAGATION SIMULATOR 5.4

    Directory of Open Access Journals (Sweden)

    Farah Oktauliah

    2017-02-01

    Full Text Available Kondisi gedung yang memiliki banyak ruangan juga terdapat banyak redaman yang mengakibatkan pelemahan sinyal sehingga diperlukan adanya perencanaan jaringan nirkabel. Tulisan ini membahas perencanaan jaringan 4G LTE pada Gedung A Fakultas Teknik Universitas Jember yang kemudian disimulasikan oleh perangkat lunak Radiowave Propagation Simulator (RPS 5.4 dengan variasi pengambilan data berupa jenis antena dan letak ketinggian Femtocell Access Point (FAP. Perencanaan jaringan 4G LTE menggunakan metode propagasi indoor COST 231 Multi Wall diperoleh jumlah FAP yang dibutuhkan pada Lantai 1 sebesar 2 FAP, Lantai 2 sebesar 4 FAP, dan Lantai 3 sebesar 4 FAP. Analisa cakupan yang efektif pada perencanaan jaringan 4G LTE indoor diperoleh saat FAP menggunakan jenis isotropic antenna dan letak ketinggian FAP 2 meter dari permukaan lantai seperti pada Lantai 1 saat ketinggian FAP 2 meter dan menggunakan dipole antenna diperoleh mean level daya sebesar -88,04 dBm dan isotropic antenna diperoleh mean level daya sebesar -87,89 dBm, sedangkan saat FAP 3,5 meter menggunakan dipole antenna diperoleh mean level daya sebesar -88,89 dBm dan isotropic antenna diperoleh mean level daya sebesar -88,33 dBm. Perencanaan jaringan 4G LTE menggunakan RPS 5.4 dan metode COST 231 Multi Wall dapat diterapkan pada Gedung A Fakultas Teknik Universitas Jember.

  11. Realistic Indoor Wi-Fi and Femto deployment Study as the Offloading Solutions to LTE Macro Network

    DEFF Research Database (Denmark)

    Hu, Liang; Coletti, Claudio; Nguyen, Huan Cong

    2012-01-01

    -carrier macro network will suffer high network outage which is defined as proportion of outage users. A user is considered to be in outage if they have a user throughput less than 1 Mbps. We evaluate the performance of indoor Wi-Fi and Femto cell deployment to offload the congested LTE macro network. We show...

  12. 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.

  13. Experimenting with 4G LTE for area coverage and the envisioned C2 deployments over 5G

    CSIR Research Space (South Africa)

    Malinga, Linda

    2017-11-01

    Full Text Available Force (SANDF). Multimedia services (voice, video, and data) and distance were used as performance measure metrics. Using a 400 MHz portable LTE system, a 10 km and 11 km radii coverage area was achieved in Line of Sight (LOS) for bushveld and maritime...

  14. 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.

  15. Nonequilibrium thermodynamic models and applications to hydrogen plasma

    International Nuclear Information System (INIS)

    Cho, K.Y.

    1988-01-01

    A generalized multithermal equilibrium (GMTE) thermodynamic model is developed and presented with applications to hydrogen. A new chemical equilibrium equation for GMTE is obtained without the ensemble temperature concept, used by a previous MTE model. The effects of the GMTE model on the derivation and calculation of the thermodynamic, transport, and radiative properties are presented and significant differences from local thermal equilibrium (LTE) and two temperature model are discussed. When the electron translational temperature (T e ) is higher than the translational temperature of the heavy particles, the effects of hydrogen molecular species to the properties are significant at high T e compared with LTE results. The density variations of minor species are orders of magnitude with kinetic nonequilibrium at a constant electron temperature. A collisional-radiative model is also developed with the GMTE chemical equilibrium equation to study the effects of radiative transfer and the ambipolar diffusion on the population distribution of the excited atoms. The nonlocal radiative transfer effect is parameterized by an absorption factor, which is defined as a ratio of the absorbed intensity to the spontaneous emission coefficient

  16. Mobility enhancements for LTE-Advanced Multilayer Networks with Inter-Site Carrier Aggregation

    DEFF Research Database (Denmark)

    Pedersen, Klaus I.; Michaelsen, Per Henrik; Rosa, Claudio

    2013-01-01

    In this article we first summarize some of the most recent HetNet mobility studies for LTE-Advanced, and use these to highlight the challenges that should be further addressed in theresearch community. A state-of-the-art HetNet scenario with macros and small cells deployed on different carriers......, while using inter-site carrier aggregation, is hereafter studied. Hybrid Het- Net mobility solutions for such cases are derived, where macrocell mobility is network controlled, while small-cell mobility is made UEautonomous. The proposed scheme is characterized by having the UE devices autonomously...... decide small cell addition, removal, and change without any explicit signaling of Measurement events to the network or any signaling of hand-over commands from the network. Hence, the proposed solution effectively offloads the network from having to perform frequent small cell handoff decisions...

  17. Delay efficient cooperation in public safety vehicular networks using LTE and IEEE 802.11p

    KAUST Repository

    Atat, Rachad

    2012-01-01

    Cooperative schemes for critical content distribution over vehicular networks are presented and analyzed. The first scheme is based on unicasting from the base station, whereas the second is based on threshold based multicasting. Long Term Evolution (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 non-cooperative unicasting and multicasting, respectively, when the appropriate 802.11p power class is used. The first scheme achieves the best performance among the compared methods, and a practical approximation of that scheme is shown to be close to optimal performance. © 2012 IEEE.

  18. Feasibility of LTE 700 MHz Digital Dividend for Broadband Development Acceleration in Rural Areas

    Directory of Open Access Journals (Sweden)

    Denny Setiawan

    2012-04-01

    Full Text Available The need of broadband services to reduce digital divide in rural areas had increased in the recent years. The government of the Republic Indonesia shared similar intention and had set guidance of ICT development in its "economic master plan" and "medium term development plan". This paper addressed feasibility and suitability of its implementation in Indonesia, by conducting assessment of possible solutions. Using mixed method, the study was started with qualitative approach to identify possible options, conducted benchmarking and case study analysis to narrow down the options and finally conducted quantitative calculation for the two remaining options and measure performance of the solutions. The results of analysis concluded that early implementation of LTE in 700 MHz Digital Dividend would be feasible in certain geographical areas to fasten the broadband plan development in Indonesia.

  19. Efficient Resource Allocation and Sectorization for Fractional Frequency Reuse (FFR in LTE Femtocell Systems

    Directory of Open Access Journals (Sweden)

    M. T. Kawser

    2015-12-01

    Full Text Available The Fractional Frequency Reuse (FFR is a resource allocation technique that can effectively mitigate inter-cell interference (ICI in LTE based HetNets and it is a promising solution. Various FFR schemes have been suggested to address the challenge of interference in femtocell systems. In this paper, we study the scopes of interference mitigation and capacity improvement. We propose a resource allocation scheme that gradually varies frequency resource share with distance from the eNodeB for both macrocells and femtocells in order to attain better utilization of the resources. This is performed effectively using three layers in the cell. The proposal also employs high number sectors in a cell, low interference and good frequency reuse. Monte-Carlo simulations are performed, which show that the proposed scheme achieves significantly better throughput compared to the existing FFR schemes.

  20. Dual Band Parasitic Element Patch Antenna for LTE/WLAN Applications

    Directory of Open Access Journals (Sweden)

    BAG Biplab

    2017-05-01

    Full Text Available In this paper, a single layer coaxial fed dual band slotted microstrip antenna is proposed. The proposed antenna consists of two direct couple parasitic elements and L-shape slots on the main resonating element. Two resonant modes are excited and it covers 4G LTE and WLAN middle band. The -10dB impedance bandwidth for resonant frequency of 2.35GHz and 5.28GHz are 140MHz (2.25-2.39GHz and 570MHz (5.18-5.75GHz, respectively. The measured VSWR at 2.35GHz is 1.27 and at 5.28GHz is 1.41. The proposed antenna is simple in design and compact in size. The simulated and measured results are in good agreement.

  1. Hierarchical Modulation with Vector Rotation for E-MBMS Transmission in LTE Systems

    Directory of Open Access Journals (Sweden)

    Hui Zhao

    2010-01-01

    Full Text Available Enhanced Multimedia Broadcast and Multicast Service (E-MBMS is considered of key importance for the proliferation of Long-Term Evolution (LTE network in mobile market. Hierarchical modulation (HM, which involves a “base-layer” (BL and an “enhancement-layer” (EL bit streams, is a simple technique for achieving tradeoff between service quality and radio coverage. Therefore, it is appealing for MBMS. Generally, HM suffers from the severe performance degradation of the less protected EL stream. In this paper, HM with vector rotation operation introduced to EL stream is proposed, in order to improve EL's performance. With the proper interleaving in frequency domain, this operation can exploit the inherent diversity gain from the multipath channel. In this way, HM with vector rotation can effectively enhance multimedia broadcasting on quality video and coverage. The simulation results with scalable video coding (SVC as source show the significant benefits in comparison with the conventional HM and alternative schemes.

  2. Optimized green operation of LTE networks in the presence of multiple electricity providers

    KAUST Repository

    Ghazzai, Hakim

    2012-12-01

    Energy efficiency aspects in cellular networks can significantly contribute to the reduction of greenhouse gas emissions and help to save the environment. The base station (BS) sleeping strategy has become a well-known technique to achieve energy savings by switching off redundant BSs mainly for lightly loaded networks. Besides, introducing renewable energies as alternative power sources becomes a real challenge to network operators. In this paper, we propose a method that reduces the energy consumption of BSs by not only shutting down underutilized BSs but also by optimizing the amounts of energy procured from different retailers (Renewable energy and electricity retailers). We formulate an optimization problem that leads to the maximization of the profit of a Long-Term Evolution (LTE) cellular operator, and at the same time to the minimization of CO2 emissions in green wireless cellular networks without affecting the desired Quality of Service. © 2012 IEEE.

  3. Conceptual aspects: analyses law, ethical, human, technical, social factors of development ICT, e-learning and intercultural development in different countries setting out the previous new theoretical model and preliminary findings

    NARCIS (Netherlands)

    Kommers, Petrus A.M.; Smyrnova-Trybulska, Eugenia; Morze, Natalia; Issa, Tomayess; Issa, Theodora

    2015-01-01

    This paper, prepared by an international team of authors focuses on the conceptual aspects: analyses law, ethical, human, technical, social factors of ICT development, e-learning and intercultural development in different countries, setting out the previous and new theoretical model and preliminary

  4. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Kefeng; Shi, Jianrong; Zhao, Gang [Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Takada-Hidai, Masahide [Liberal Arts Education Center, Tokai University, 4-1-1 Kitakaname, Hiratsuka, Kanagawa 259-1292 (Japan); Takeda, Yoichi, E-mail: tan@nao.cas.cn [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)

    2016-05-20

    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.

  6. 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...

  7. 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...

  8. 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.

  9. Pengaruh Iklan Secara Online Terhadap Keputusan Pembelian (Survey Pada Mahasiswa Pengguna Produk Telkomsel Internet 4g Lte)

    OpenAIRE

    Prasetyo, Deni Dwi; Yulianto, Edy; Sunarti, Sunarti

    2016-01-01

    Consumers' buying decision was influenced by promotional approach from the company, such as through online medias. Consumers were getting smarter and knowledgeable due to the development of technology that allowed them getting various information easily. This research aimed to analyze the factors of consumers' buying decision to ward the product of Telkomsel Internet 4G LTE. The result of partial analysiss howed that message content, message structure, message format and message source were p...

  10. Risk-Informed Interference Assessment for Shared Spectrum Bands: A Wi-Fi/LTE Coexistence Case Study

    OpenAIRE

    Voicu, Andra M.; Simić, Ljiljana; de Vries, J. Pierre; Petrova, Marina; Mähönen, Petri

    2017-01-01

    Interference evaluation is crucial when deciding whether and how wireless technologies should operate. In this paper we demonstrate the benefit of risk-informed interference assessment to aid spectrum regulators in making decisions, and to readily convey engineering insight. Our contributions are: we apply, for the first time, risk assessment to a problem of inter-technology spectrum sharing, i.e. Wi-Fi/LTE in the 5 GHz unlicensed band, and we demonstrate that this method comprehensively quan...

  11. A Cost-Based Adaptive Handover Hysteresis Scheme to Minimize the Handover Failure Rate in 3GPP LTE System

    OpenAIRE

    Gil Gye-Tae; Lee Doo-Won; Kim Dong-Hoi

    2010-01-01

    We deal with a cost-based adaptive handover hysteresis scheme for the horizontal handover decision strategies, as one of the self-optimization techniques that can minimize the handover failure rate (HFR) in the 3rd generation partnership project (3GPP) long-term evolution (LTE) system based on the network-controlled hard handover. Especially, for real-time operation, we propose an adaptive hysteresis scheme with a simplified cost function considering some dominant factors closely related to ...

  12. 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.

  13. EXTRAPOLATION TECHNIQUES EVALUATING 24 HOURS OF AVERAGE ELECTROMAGNETIC FIELD EMITTED BY RADIO BASE STATION INSTALLATIONS: SPECTRUM ANALYZER MEASUREMENTS OF LTE AND UMTS SIGNALS.

    Science.gov (United States)

    Mossetti, Stefano; de Bartolo, Daniela; Veronese, Ivan; Cantone, Marie Claire; Cosenza, Cristina; Nava, Elisa

    2017-04-01

    International and national organizations have formulated guidelines establishing limits for occupational and residential electromagnetic field (EMF) exposure at high-frequency fields. Italian legislation fixed 20 V/m as a limit for public protection from exposure to EMFs in the frequency range 0.1 MHz-3 GHz and 6 V/m as a reference level. Recently, the law was changed and the reference level must now be evaluated as the 24-hour average value, instead of the previous highest 6 minutes in a day. The law refers to a technical guide (CEI 211-7/E published in 2013) for the extrapolation techniques that public authorities have to use when assessing exposure for compliance with limits. In this work, we present measurements carried out with a vectorial spectrum analyzer to identify technical critical aspects in these extrapolation techniques, when applied to UMTS and LTE signals. We focused also on finding a good balance between statistically significant values and logistic managements in control activity, as the signal trend in situ is not known. Measurements were repeated several times over several months and for different mobile companies. The outcome presented in this article allowed us to evaluate the reliability of the extrapolation results obtained and to have a starting point for defining operating procedures. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  14. Simulations of an Argon Z-pinch Implosion with time-dependent non-LTE kinetics

    Science.gov (United States)

    Ouart, N.; Dasgupta, A.; Giuliani, J.; Jones, B.; Ampleford, D.; Harvey-Thompson, A.; Jennings, C.; Tangri, V.; Clark, R.

    2017-10-01

    Three argon gas-puff implosions were performed on the Z-machine at SNL. These three loads had the same density profile from an 8cm dia. nozzle, a 1mg/cm mass, and a 2.5cm length. The experiments produced similar radiative powers and yields. Simulations with the 2D MHD code Mach2-TCRE reproduced the experimental K-shell powers, yields, and emission region. It was also shown that the ratio of the Ly α to He α + IC lines from the simulation had good agreement to measurements after peak K-power; however, the simulation's line ratio was higher prior to the peak power. The authors attribute the difference to 3D effects or on the implicit assumption of steady-state population kinetics. This presentation will illustrate the effect of time-dependent level populations on the radiation from simulations using the NRL DZAPP code. DZAPP is a coupled 1D MHD, detailed non-LTE atomic physics with radiation transport, incorporating a transmission line circuit. The line ratios and K-powers from the steady-state and time-dependent populations will be presented and compared with experiment. This work supported by DOE/NNSA. SNL is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International, Inc., for the US DOE/NNSA under contract DE-NA-0003525.

  15. A High Isolation MIMO Antenna without Decoupling Structure for LTE 700 MHz

    Directory of Open Access Journals (Sweden)

    Yanjie Wu

    2015-01-01

    Full Text Available This paper presents a long-term evolution (LTE 700 MHz band multiple-input-multiple-output (MIMO antenna, and high isolation between the two symmetrical antenna elements is obtained without introducing extra decoupling structure. Each antenna element is a combination antenna of PIFA and a meander monopole antenna. The end of the PIFA and the meander monopole antenna are, respectively, overlapped with the 50 Ω microstrip feed line, the two overlapping areas produce additional capacitance which can be considered decoupling structures to enhance the isolation for the MIMO antenna, as well as the impedance matching of the antenna elements. The MIMO antenna is etched on FR4 PCB board with dimensions of 71 × 40 × 1.6 mm3; the edge-to-edge separation of the two antenna elements is only nearly 0.037 λ at 700 MHz. Both simulation and measurement results are used to confirm the MIMO antenna performance; the operating bandwidth is 698–750 MHz with S11≤−6 dB and S21≤−23 dB.

  16. A Novel LTE Scheduling Algorithm for Green Technology in Smart Grid

    Science.gov (United States)

    Hindia, Mohammad Nour; Reza, Ahmed Wasif; Noordin, Kamarul Ariffin; Chayon, Muhammad Hasibur Rashid

    2015-01-01

    Smart grid (SG) application is being used nowadays to meet the demand of increasing power consumption. SG application is considered as a perfect solution for combining renewable energy resources and electrical grid by means of creating a bidirectional communication channel between the two systems. In this paper, three SG applications applicable to renewable energy system, namely, distribution automation (DA), distributed energy system-storage (DER) and electrical vehicle (EV), are investigated in order to study their suitability in Long Term Evolution (LTE) network. To compensate the weakness in the existing scheduling algorithms, a novel bandwidth estimation and allocation technique and a new scheduling algorithm are proposed. The technique allocates available network resources based on application’s priority, whereas the algorithm makes scheduling decision based on dynamic weighting factors of multi-criteria to satisfy the demands (delay, past average throughput and instantaneous transmission rate) of quality of service. Finally, the simulation results demonstrate that the proposed mechanism achieves higher throughput, lower delay and lower packet loss rate for DA and DER as well as provide a degree of service for EV. In terms of fairness, the proposed algorithm shows 3%, 7 % and 9% better performance compared to exponential rule (EXP-Rule), modified-largest weighted delay first (M-LWDF) and exponential/PF (EXP/PF), respectively. PMID:25830703

  17. Digital Implementation of an Improved LTE Stream Cipher Snow-3G Based on Hyperchaotic PRNG

    Directory of Open Access Journals (Sweden)

    Mahdi Madani

    2017-01-01

    Full Text Available SNOW-3G is a stream cipher used by the 3GPP standards as the core part of the confidentiality and integrity algorithms for UMTS and LTE networks. This paper proposes an enhancement of the regular SNOW-3G ciphering algorithm based on HC-PRNG. The proposed cipher scheme is based on hyperchaotic generator which is used as an additional layer to the SNOW-3G architecture to improve the randomness of its output keystream. The objective of this work is to achieve a high security strength of the regular SNOW-3G algorithm while maintaining its standardized properties. The originality of this new scheme is that it provides a good trade-off between good randomness properties, performance, and hardware resources. Numerical simulations, hardware digital implementation, and experimental results using Xilinx FPGA Virtex technology have demonstrated the feasibility and the efficiency of our secure solution while promising technique can be applied to secure the new generation mobile standards. Thorough analysis of statistical randomness is carried out demonstrating the improved statistical randomness properties of the new scheme compared to the standard SNOW-3G, while preserving its resistance against cryptanalytic attacks.

  18. Energy Savings through Site Renewal in an HSPA/LTE Network Evolution Scenario

    DEFF Research Database (Denmark)

    Micallef, Gilbert; Mogensen, Preben

    Mobile network operators are committing themselves to reduce the energy consumption of their networks. However, the expected growth in traffic and the upgrades required to sustain this growth pose a serious question on whether these targets are achievable. Through a case study, this paper looks a...... to just 12%. In some cases, when a less aggressive traffic growth is assumed, the energy savings are enough to balance any increase in energy. In a best case scenario, where all sites are replaced when new equipment is available, energy savings close to 40% are achievable....... at how the energy consumption of a mobile network is likely to develop over a period of nine years, considering the evolution of an existing HSPA layer into a multi-layered (HSPA+LTE) network. Besides, this study also considers four different equipment versions released throughout the years, which...... are introduced in the network based on a replacement strategy. In addition, the two most modern sites are assumed to be configured with remote radio head. In comparison to the reference case which leads to an increase in energy consumption of almost 200%, considering these site upgrades can limit the increase...

  19. Enabling Remote Health-Caring Utilizing IoT Concept over LTE-Femtocell Networks.

    Science.gov (United States)

    Hindia, M N; Rahman, T A; Ojukwu, H; Hanafi, E B; Fattouh, A

    2016-01-01

    As the enterprise of the "Internet of Things" is rapidly gaining widespread acceptance, sensors are being deployed in an unrestrained manner around the world to make efficient use of this new technological evolution. A recent survey has shown that sensor deployments over the past decade have increased significantly and has predicted an upsurge in the future growth rate. In health-care services, for instance, sensors are used as a key technology to enable Internet of Things oriented health-care monitoring systems. In this paper, we have proposed a two-stage fundamental approach to facilitate the implementation of such a system. In the first stage, sensors promptly gather together the particle measurements of an android application. Then, in the second stage, the collected data are sent over a Femto-LTE network following a new scheduling technique. The proposed scheduling strategy is used to send the data according to the application's priority. The efficiency of the proposed technique is demonstrated by comparing it with that of well-known algorithms, namely, proportional fairness and exponential proportional fairness.

  20. A novel LTE scheduling algorithm for green technology in smart grid.

    Directory of Open Access Journals (Sweden)

    Mohammad Nour Hindia

    Full Text Available Smart grid (SG application is being used nowadays to meet the demand of increasing power consumption. SG application is considered as a perfect solution for combining renewable energy resources and electrical grid by means of creating a bidirectional communication channel between the two systems. In this paper, three SG applications applicable to renewable energy system, namely, distribution automation (DA, distributed energy system-storage (DER and electrical vehicle (EV, are investigated in order to study their suitability in Long Term Evolution (LTE network. To compensate the weakness in the existing scheduling algorithms, a novel bandwidth estimation and allocation technique and a new scheduling algorithm are proposed. The technique allocates available network resources based on application's priority, whereas the algorithm makes scheduling decision based on dynamic weighting factors of multi-criteria to satisfy the demands (delay, past average throughput and instantaneous transmission rate of quality of service. Finally, the simulation results demonstrate that the proposed mechanism achieves higher throughput, lower delay and lower packet loss rate for DA and DER as well as provide a degree of service for EV. In terms of fairness, the proposed algorithm shows 3%, 7 % and 9% better performance compared to exponential rule (EXP-Rule, modified-largest weighted delay first (M-LWDF and exponential/PF (EXP/PF, respectively.

  1. Biomedical sensing analyzer (BSA) for mobile-health (mHealth)-LTE.

    Science.gov (United States)

    Adibi, Sasan

    2014-01-01

    The rapid expansion of mobile-based systems, the capabilities of smartphone devices, as well as the radio access and cellular network technologies are the wind beneath the wing of mobile health (mHealth). In this paper, the concept of biomedical sensing analyzer (BSA) is presented, which is a novel framework, devised for sensor-based mHealth applications. The BSA is capable of formulating the Quality of Service (QoS) measurements in an end-to-end sense, covering the entire communication path (wearable sensors, link-technology, smartphone, cell-towers, mobile-cloud, and the end-users). The characterization and formulation of BSA depend on a number of factors, including the deployment of application-specific biomedical sensors, generic link-technologies, collection, aggregation, and prioritization of mHealth data, cellular network based on the Long-Term Evolution (LTE) access technology, and extensive multidimensional delay analyses. The results are studied and analyzed in a LabView 8.5 programming environment.

  2. Analysis on Target Detection and Classification in LTE Based Passive Forward Scattering Radar.

    Science.gov (United States)

    Raja Abdullah, Raja Syamsul Azmir; Abdul Aziz, Noor Hafizah; Abdul Rashid, Nur Emileen; Ahmad Salah, Asem; Hashim, Fazirulhisyam

    2016-09-29

    The passive bistatic radar (PBR) system can utilize the illuminator of opportunity to enhance radar capability. By utilizing the forward scattering technique and procedure into the specific mode of PBR can provide an improvement in target detection and classification. The system is known as passive Forward Scattering Radar (FSR). The passive FSR system can exploit the peculiar advantage of the enhancement in forward scatter radar cross section (FSRCS) for target detection. Thus, the aim of this paper is to show the feasibility of passive FSR for moving target detection and classification by experimental analysis and results. The signal source is coming from the latest technology of 4G Long-Term Evolution (LTE) base station. A detailed explanation on the passive FSR receiver circuit, the detection scheme and the classification algorithm are given. In addition, the proposed passive FSR circuit employs the self-mixing technique at the receiver; hence the synchronization signal from the transmitter is not required. The experimental results confirm the passive FSR system's capability for ground target detection and classification. Furthermore, this paper illustrates the first classification result in the passive FSR system. The great potential in the passive FSR system provides a new research area in passive radar that can be used for diverse remote monitoring applications.

  3. A novel LTE scheduling algorithm for green technology in smart grid.

    Science.gov (United States)

    Hindia, Mohammad Nour; Reza, Ahmed Wasif; Noordin, Kamarul Ariffin; Chayon, Muhammad Hasibur Rashid

    2015-01-01

    Smart grid (SG) application is being used nowadays to meet the demand of increasing power consumption. SG application is considered as a perfect solution for combining renewable energy resources and electrical grid by means of creating a bidirectional communication channel between the two systems. In this paper, three SG applications applicable to renewable energy system, namely, distribution automation (DA), distributed energy system-storage (DER) and electrical vehicle (EV), are investigated in order to study their suitability in Long Term Evolution (LTE) network. To compensate the weakness in the existing scheduling algorithms, a novel bandwidth estimation and allocation technique and a new scheduling algorithm are proposed. The technique allocates available network resources based on application's priority, whereas the algorithm makes scheduling decision based on dynamic weighting factors of multi-criteria to satisfy the demands (delay, past average throughput and instantaneous transmission rate) of quality of service. Finally, the simulation results demonstrate that the proposed mechanism achieves higher throughput, lower delay and lower packet loss rate for DA and DER as well as provide a degree of service for EV. In terms of fairness, the proposed algorithm shows 3%, 7 % and 9% better performance compared to exponential rule (EXP-Rule), modified-largest weighted delay first (M-LWDF) and exponential/PF (EXP/PF), respectively.

  4. Dual-Polarized Cross Bowtie Dipole for 3G and LTE Applications

    Directory of Open Access Journals (Sweden)

    Zhi-Ya Zhang

    2013-01-01

    Full Text Available A dual-polarized cross bowtie dipole element with parasitical circular patch and vertical metal cylinders for base station antennas is presented. A pair of orthogonal cross bowtie dipoles, with a reflector ground plane, is used to obtain the two linear polarizations. Besides two inverted L-shaped feed strips and two shorted feed baluns, parasitical circular patch is introduced to improve the impendence bandwidth and vertical metal cylinders are employed to decrease the lateral dimensions of the antenna. A wideband impedance characteristic of about 45.6% for VSWR ≤ 1.5 (+45° polarization and VSWR ≤ 1.5 (−45° polarization ranging from 1.76 to 2.80 GHz is obtained. Moreover, the stable peak gain, unidirectional radiation patterns, high isolation between the two orthogonal polarizations, and low cross-polarization over the whole operating band are also achieved. The proposed antenna is very suitable for potential base station applications in mobile communication such as TD-SCDMA, WCDMA, and CDMA2000 and LTE applications.

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

    KAUST Repository

    Ghazzai, Hakim

    2014-09-01

    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 algorithms. In this approach, we aim to satisfy both coverage and cell capacity constraints simultaneously by formulating a practical optimization problem. We start by performing a typical coverage and capacity dimensioning to identify the initial required number of base stations. Afterwards, we implement a Particle Swarm Optimization algorithm or a recently-proposed Grey Wolf Optimizer to find the optimal base station locations that satisfy both problem constraints in the area of interest which can be divided into several subareas with different user densities. Subsequently, an iterative approach is executed to eliminate eventual redundant base stations. We have also performed Monte Carlo simulations to study the performance of the proposed scheme and computed the average number of users in outage. Results show that our proposed approach respects in all cases the desired network quality of services even for large-scale dimension problems.

  6. A Compact Frequency Reconfigurable Hybrid DRA for LTE/Wimax Applications

    Directory of Open Access Journals (Sweden)

    Sajid Aqeel

    2017-01-01

    Full Text Available A compact hybrid antenna structure with frequency reconfiguration capabilities is presented in this article. The proposed design employs a combination of a rectangular DR element and a coupling slot on the structure’s ground plane (GP. The slot shifts the fundamental DRA mode by introducing a slow wave effect and its resonant behavior helps to achieve an omnidirectional pattern at low frequencies. The slot is loaded with a series of PIN diode switches whose ON/OFF combinations alter the effective slot length. Slot loading with PIN diodes results in frequency reconfiguration of the proposed structure with a large tuning range of 76.2% (between 1.73 and 3.86 GHz. A parametric analysis was performed to investigate the effects of slot length, width, and position on the reflection coefficients of the proposed structure. A prototype of the proposed design was fabricated and results were measured. The measured results show a close agreement with the simulated ones. The proposed design is suitable for DCS 1800 MHz, PCS 1900 MHZ, UMTS, LTE 2500–2700 MHz, and Wimax 3.5 GHz.

  7. Enabling Remote Health-Caring Utilizing IoT Concept over LTE-Femtocell Networks.

    Directory of Open Access Journals (Sweden)

    M N Hindia

    Full Text Available As the enterprise of the "Internet of Things" is rapidly gaining widespread acceptance, sensors are being deployed in an unrestrained manner around the world to make efficient use of this new technological evolution. A recent survey has shown that sensor deployments over the past decade have increased significantly and has predicted an upsurge in the future growth rate. In health-care services, for instance, sensors are used as a key technology to enable Internet of Things oriented health-care monitoring systems. In this paper, we have proposed a two-stage fundamental approach to facilitate the implementation of such a system. In the first stage, sensors promptly gather together the particle measurements of an android application. Then, in the second stage, the collected data are sent over a Femto-LTE network following a new scheduling technique. The proposed scheduling strategy is used to send the data according to the application's priority. The efficiency of the proposed technique is demonstrated by comparing it with that of well-known algorithms, namely, proportional fairness and exponential proportional fairness.

  8. 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.

  9. Development of a Buried Layer Platform at the OMEGA Laser to Study Open L-Shell Spectra from Coronal (non-LTE) Plasmas

    Science.gov (United States)

    Marley, Edward; Jarrot, Charlie; Schneider, Marilyn; Kemp, Elijah; Foord, Mark; Heeter, Robert; Liedahl, Duane; Widmann, Klause; Mauche, Christopher; Brown, Greg; Emig, James

    2017-10-01

    A buried layer platform is being developed at the OMEGA laser to study the open L-shell spectra of coronal (non LTE) plasmas (ne few 1021/cm3, Te 0.8-1.2 keV) of mid Z materials. Studies have been done using a 250 μm diameter dot composed of a layer of 1200 Å thick Zn between two 600 Å thick layers of Ti, in the center of a 1000 μm diameter, 13 μm thick beryllium tamper. Lasers heat the target from both sides for up to 3 ns. The size of the microdot vs time was measured with x-ray imaging (face-on and side-on). The radiant x-ray power was measured with a low-resolution absolutely calibrated x-ray spectrometer (DANTE). The temperature was measured from the Ti helium-beta complex. The use of this platform for the verification of atomic models is discussed. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  10. Calculation of emission and absorption spectra of LTE plasma by the STA [Super Transition Array] method

    International Nuclear Information System (INIS)

    Bar-Shalon, A.; Oreg, J.

    1991-01-01

    Recent improvements in the Super Transition Array (STA) method for calculating Bound-Bound (BB) and Bound-Free (BF) emission and absorption spectra for LTE plasma are described and illustrated. The method accounts for all possible BB and BF radiative transitions in the plasma. Full detailed first order quantum relativistic treatment is used for calculating transition energies and probabilities. The enormous number of configurations are divided into sets of superconfigurations comprised of a collection of energetically grouped configurations. The contribution of the transition array between two superconfigurations to a specific one-electron transition is then represented by a Gaussian whose moments are calculated accurately using a technique that bypasses the necessity of direct summation over all the levels involved. The calculation of these moments involves the populations of the configurations given by their statistical weights and the Boltzmann factor. For each configuration within the super configuration we use zeroeth order energies in the Boltzmann factor corrected by a super configuration averaged first order term. The structure of the spectrum is increasingly revealed by splitting each STA into a number of smaller STAs. When the spectrum converges it describes the detailed 'UTA' structure, where each configuration-to-configuration array is represented by a separate Gaussian with first order energy in the Boltzmann factor. Convergence is reached with only a few thousand STAs, at most, which makes the calculations practical. It should be pointed out that in this treatment the STA moments are obtained by summing over all level-to-level transitions, rather than configuration-to-configuration average transitions. 4 refs., 9 figs

  11. Calculation of emission and absorption spectra of LTE plasma by the STA method

    International Nuclear Information System (INIS)

    Oreg, A.B.J.; Goldstein, W.H.

    1991-01-01

    Recent improvements in the Super Transition Array (STA) method for calculating Bound-Bound (BB) and Bound-Free (BF) emission and absorption spectra for LTE plasma are described and illustrated. The method accounts for all possible BB and BF radiative transitions in the plasma. Full detailed first order quantum relativistic treatment is used for calculating transition energies and probabilities. The enormous number of configurations are divided into sets of superconfigurations comprised of a collection of energetically grouped configurations to a specific one-electron transition is then represented by a Gaussian whose moments (total intensity, average energy and variance) are calculated accurately using a technique that bypasses the necessity of direct summation over all the levels involved. The calculation of these moments involves the populations of the configurations given by their statistical weights and the Boltzmann factor. For each configuration within the superconfiguration the authors use zeroeth order energies in the Boltzmann factor corrected by a superconfiguration averaged first order term. The structure of the spectrum is increasingly revealed by splitting each STA into a number of smaller STAs. When the spectrum converges it describes the detailed UTA structure, where each configuration-to-configuration array is represented by a separate Gaussian with first order energy in the Boltzmann factor. Convergence is reached with only a few thousand STAs, at most, which makes the calculations practical. It should be pointed out that in this treatment the STA moments are obtained by summing over all level-to-level transitions, rather than configuration-to-configuration average transitions. The authors also take into account orbital relaxation by calculating orbitals and energies for each superconfiguration in its own, optimized potential

  12. Calculation of emission and absorption spectra of LTE plasma by the STA (Super Transition Array) method

    Science.gov (United States)

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

    1991-01-01

    Recent improvements in the Super Transition Array (STA) method for calculating Bound-Bound (BB) and Bound-Free (BF) emission and absorption spectra for Laser Thermal Equilibrium (LTE) plasma are described and illustrated. The method accounts for all possible BB and BF radiative transitions in the plasma. Full detailed first order quantum relativistic treatment is used for calculating transition energies and probabilities. The enormous number of configurations are divided into sets of superconfigurations comprised of a collection of energetically grouped configurations. The contribution of the transition array between two superconfigurations to a specific one-electron transition is then represented by a Gaussian whose moments are calculated accurately using a technique that bypasses the necessity of direct summation over all the levels involved. The calculation of these moments involves the populations of the configurations given by their statistical weights and the Boltzmann factor. For each configuration within the super configuration zeroeth order energies are used in the Boltzmann factor corrected by a super configuration averaged first order term. The structure of the spectrum is increasingly revealed by splitting each STA into a number of smaller STAs. When the spectrum converges it describes the detailed UTA structure, where each configuration-to-configuration array is represented by a separate Gaussian with first order energy in the Boltzmann factor. Convergence is reached with only a few thousand STAs, at most, which makes the calculations practical. It should be pointed out that in this treatment the STA moments are obtained by summing over all level-to-level transitions, rather than configuration-to-configuration average transitions.

  13. A novel downlink scheduling strategy for traffic communication system based on TD-LTE technology.

    Science.gov (United States)

    Chen, Ting; Zhao, Xiangmo; Gao, Tao; Zhang, Licheng

    2016-01-01

    There are many existing classical scheduling algorithms which can obtain better system throughput and user equality, however, they are not designed for traffic transportation environment, which cannot consider whether the transmission performance of various information flows could meet comprehensive requirements of traffic safety and delay tolerance. This paper proposes a novel downlink scheduling strategy for traffic communication system based on TD-LTE technology, which can perform two classification mappings for various information flows in the eNodeB: firstly, associate every information flow packet with traffic safety importance weight according to its relevance to the traffic safety; secondly, associate every traffic information flow with service type importance weight according to its quality of service (QoS) requirements. Once the connection is established, at every scheduling moment, scheduler would decide the scheduling order of all buffers' head of line packets periodically according to the instant value of scheduling importance weight function, which calculated by the proposed algorithm. From different scenario simulations, it can be verified that the proposed algorithm can provide superior differentiated transmission service and reliable QoS guarantee to information flows with different traffic safety levels and service types, which is more suitable for traffic transportation environment compared with the existing popularity PF algorithm. With the limited wireless resource, information flow closed related to traffic safety will always obtain priority scheduling right timely, which can help the passengers' journey more safe. Moreover, the proposed algorithm cannot only obtain good flow throughput and user fairness which are almost equal to those of the PF algorithm without significant differences, but also provide better realtime transmission guarantee to realtime information flow.

  14. New hybrid frequency reuse method for packet loss minimization in LTE network.

    Science.gov (United States)

    Ali, Nora A; El-Dakroury, Mohamed A; El-Soudani, Magdi; ElSayed, Hany M; Daoud, Ramez M; Amer, Hassanein H

    2015-11-01

    This paper investigates the problem of inter-cell interference (ICI) in Long Term Evolution (LTE) mobile systems, which is one of the main problems that causes loss of packets between the base station and the mobile station. Recently, different frequency reuse methods, such as soft and fractional frequency reuse, have been introduced in order to mitigate this type of interference. In this paper, minimizing the packet loss between the base station and the mobile station is the main concern. Soft Frequency Reuse (SFR), which is the most popular frequency reuse method, is examined and the amount of packet loss is measured. In order to reduce packet loss, a new hybrid frequency reuse method is implemented. In this method, each cell occupies the same bandwidth of the SFR, but the total system bandwidth is greater than in SFR. This will provide the new method with a lot of new sub-carriers from the neighboring cells to reduce the ICI which represents a big problem in many applications and causes a lot of packets loss. It is found that the new hybrid frequency reuse method has noticeable improvement in the amount of packet loss compared to SFR method in the different frequency bands. Traffic congestion management in Intelligent Transportation system (ITS) is one of the important applications that is affected by the packet loss due to the large amount of traffic that is exchanged between the base station and the mobile node. Therefore, it is used as a studied application for the proposed frequency reuse method and the improvement in the amount of packet loss reached 49.4% in some frequency bands using the new hybrid frequency reuse method.

  15. 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)

  16. 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.

  17. On magnetohydrodynamic thermal instabilities in magnetic flux tubes. [in plane parallel stellar atmosphere in LTE and hydrostatic equilibrium

    Science.gov (United States)

    Massaglia, S.; Ferrari, A.; Bodo, G.; Kalkofen, W.; Rosner, R.

    1985-01-01

    The stability of current-driven filamentary modes in magnetic flux tubes embedded in a plane-parallel atmosphere in LTE and in hydrostatic equilibrium is discussed. Within the tube, energy transport by radiation only is considered. The dominant contribution to the opacity is due to H- ions and H atoms (in the Paschen continuum). A region in the parameter space of the equilibrium configuration in which the instability is effective is delimited, and the relevance of this process for the formation of structured coronae in late-type stars and accretion disks is discussed.

  18. Deploying IPv6 in 3GPP networks evolving mobile broadband from 2G to LTE and beyond

    CERN Document Server

    Korhonen, Jouni; Soininen, Jonne

    2013-01-01

    Deploying IPv6 in 3GPP Networks - Evolving Mobile Broadband from 2G to LTE and Beyond  A practical guide enabling mobile operators to deploy IPv6 with confidence The most widely used cellular mobile broadband network technology is based on the 3GPP standards. The history and background of the 3GPP technology is in the Global Mobile Service (GSM) technology and the work done in European Telecommunications Standards Institute (ETSI). This primary voice service network has evolved to be the dominant mobile Internet access technology. Deploying IPv6 in

  19. Self-Organizing Networks (SON) Self-Planning, Self-Optimization and Self-Healing for GSM, UMTS and LTE

    CERN Document Server

    Ramiro, Juan

    2011-01-01

    With the current explosion in network traffic, and mounting pressure on operators' business case, Self-Organizing Networks (SON) play a crucial role. They are conceived to minimize human intervention in engineering processes and at the same time improve system performance to maximize Return-on-Investment (ROI) and secure customer loyalty. Written by leading experts in the planning and optimization of Multi-Technology and Multi-Vendor wireless networks, this book describes the architecture of Multi-Technology SON for GSM, UMTS and LTE, along with the enabling technologies for SON planning, opti

  20. Non-LTE modelling of prominence fine structures using hydrogen Lyman-line profiles

    Czech Academy of Sciences Publication Activity Database

    Schwartz, Pavol; Gunár, S.; Curdt, W.

    2015-01-01

    Roč. 577, May (2015), A92/1-A92/10 ISSN 0004-6361 R&D Projects: GA ČR GAP209/12/0906 Grant - others:SAV(SK) VEGA 2/0108/12 Institutional support: RVO:67985815 Keywords : Sun * filaments * prominences Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.378, year: 2014

  1. X-ray emission from hydrodynamical simulations in non-LTE wind models

    Czech Academy of Sciences Publication Activity Database

    Krtička, J.; Feldmeier, A.; Oskinova, L.M.; Kubát, Jiří; Hamann, W.-R.

    2009-01-01

    Roč. 508, č. 2 (2009), s. 841-848 ISSN 0004-6361 R&D Projects: GA ČR GA205/08/0003 Institutional research plan: CEZ:AV0Z10030501 Keywords : stars * winds * outflows Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.179, year: 2009

  2. Testing the reliability of non-LTE spectroscopic models for complexions

    Czech Academy of Sciences Publication Activity Database

    Hansen, s.; Armstrong, G.S.J.; Bastiani-Ceccotti, S.; Bowen, C.; Chung, H.-K.; Colgan, J.P.; de Gaufridy de Dortan, Francois; Fontes, C.J.; Gilleron, F.; Marquès, J.-R.; Piron, R.; Peyrusse, O.; Poirier, M.; Ralchenko, Yu.; Sasaki, A.; Stambulchik, E.; Thais, F.

    2013-01-01

    Roč. 9, č. 3 (2013), 523-527 ISSN 1574-1818 R&D Projects: GA MŠk ED1.1.00/02.0061; GA MŠk EE.2.3.20.0087 Grant - others:ELI Beamlines(XE) CZ.1.05/1.1.00/02.0061; OP VK 2 LaserGen(XE) CZ.1.07/2.3.00/20.0087 Institutional support: RVO:68378271 Keywords : X-ray spectroscopy * atomic kinetics * plasma diagnostics Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 1.519, year: 2013

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

    Czech Academy of Sciences Publication Activity Database

    Labrosse, N.; Heinzel, Petr; Vial, J. C.; Kucera, T.; Parenti, S.; Gunár, Stanislav; Schmieder, B.; Kilper, G.

    2010-01-01

    Roč. 151, č. 4 (2010), s. 243-332 ISSN 0038-6308 R&D Projects: GA ČR GA205/07/1100 Grant - others:ESA(XE) ESA-PECS project No. 98030 Institutional research plan: CEZ:AV0Z10030501 Keywords : solar prominences * spectroscopy * radiative transfer Subject RIV: BB - Applied Statistics, Operational Research Impact factor: 4.433, year: 2010

  4. 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)

  5. DIANA: A Machine Learning Mechanism for Adjusting the TDD Uplink-Downlink Configuration in XG-PON-LTE Systems

    Directory of Open Access Journals (Sweden)

    Panagiotis Sarigiannidis

    2017-01-01

    Full Text Available Modern broadband hybrid optical-wireless access networks have gained the attention of academia and industry due to their strategic advantages (cost-efficiency, huge bandwidth, flexibility, and mobility. At the same time, the proliferation of Software Defined Networking (SDN enables the efficient reconfiguration of the underlying network components dynamically using SDN controllers. Hence, effective traffic-aware schemes are feasible in dynamically determining suitable configuration parameters for advancing the network performance. To this end, a novel machine learning mechanism is proposed for an SDN-enabled hybrid optical-wireless network. The proposed architecture consists of a 10-gigabit-capable passive optical network (XG-PON in the network backhaul and multiple Long Term Evolution (LTE radio access networks in the fronthaul. The proposed mechanism receives traffic-aware knowledge from the SDN controllers and applies an adjustment on the uplink-downlink configuration in the LTE radio communication. This traffic-aware mechanism is capable of determining the most suitable configuration based on the traffic dynamics in the whole hybrid network. The introduced scheme is evaluated in a realistic environment using real traffic traces such as Voice over IP (VoIP, real-time video, and streaming video. According to the obtained numerical results, the proposed mechanism offers significant improvements in the network performance in terms of latency and jitter.

  6. A Differentially Driven Dual-Polarized Dual-Wideband Complementary Antenna for 2G/3G/LTE Applications

    Directory of Open Access Journals (Sweden)

    Botao Feng

    2014-01-01

    Full Text Available A novel differentially driven dual-polarized dual-wideband complementary patch antenna with high isolation is proposed for 2G/3G/LTE applications. In order to generate dual-polarization and dual-wideband properties, a pair of biorthogonal dual-layer η-shaped tapered line feeding structures is utilized to feed two pairs of dual-layer U-shaped patches, respectively. The upper-layer U-shaped patches mainly serve the upper frequency band, while the lower-layer ones chiefly work for the lower frequency band. Besides, a horned reflector is introduced to improve radiation patterns and provide stable gain. The prototype antenna can achieve a bandwidth of 25.7% (0.78 GHz–1.01 GHz with a stable gain of 7.8±0.7 dBi for the lower band, and a bandwidth of 45.7% (1.69 GHz–2.69 GHz with a gain of 9.5±1.1 dBi for the upper band. Input isolation exceeding 30 dB has been obtained in the wide bandwidth. Thus, it can be potentially used as a base station antenna for 2G/3G/LTE networks.

  7. Joint Dynamic Radio Resource Allocation and Mobility Load Balancing in 3GPP LTE Multi-Cell Network

    Directory of Open Access Journals (Sweden)

    F. Li

    2015-04-01

    Full Text Available Load imbalance, together with inefficient utilization of system resource, constitute major factors responsible for poor overall performance in Long Term Evolution (LTE network. In this paper, a novel scheme of joint dynamic resource allocation and load balancing is proposed to achieve a balanced performance improvement in 3rd Generation Partnership Project (3GPP LTE Self-Organizing Networks (SON. The new method which aims at maximizing network resource efficiency subject to inter-cell interference and intra-cell resource constraints is implemented in two steps. In the first step, an efficient resource allocation, including user scheduling and power assignment, is conducted in a distributed manner to serve as many users in the whole network as possible. In the second step, based on the resource allocation scheme, the optimization objective namely network resource efficiency can be calculated and load balancing is implemented by switching the user that can maximize the objective function. Lagrange Multipliers method and heuristic algorithm are used to resolve the formulated optimization problem. Simulation results show that our algorithm achieves better performance in terms of user throughput, fairness, load balancing index and unsatisfied user number compared with the traditional approach which takes resource allocation and load balancing into account, respectively.

  8. On the definition of adapted audio/video profiles for high-quality video calling services over LTE/4G

    Science.gov (United States)

    Ndiaye, Maty; Quinquis, Catherine; Larabi, Mohamed Chaker; Le Lay, Gwenael; Saadane, Hakim; Perrine, Clency

    2014-01-01

    During the last decade, the important advances and widespread availability of mobile technology (operating systems, GPUs, terminal resolution and so on) have encouraged a fast development of voice and video services like video-calling. While multimedia services have largely grown on mobile devices, the generated increase of data consumption is leading to the saturation of mobile networks. In order to provide data with high bit-rates and maintain performance as close as possible to traditional networks, the 3GPP (The 3rd Generation Partnership Project) worked on a high performance standard for mobile called Long Term Evolution (LTE). In this paper, we aim at expressing recommendations related to audio and video media profiles (selection of audio and video codecs, bit-rates, frame-rates, audio and video formats) for a typical video-calling services held over LTE/4G mobile networks. These profiles are defined according to targeted devices (smartphones, tablets), so as to ensure the best possible quality of experience (QoE). Obtained results indicate that for a CIF format (352 x 288 pixels) which is usually used for smartphones, the VP8 codec provides a better image quality than the H.264 codec for low bitrates (from 128 to 384 kbps). However sequences with high motion, H.264 in slow mode is preferred. Regarding audio, better results are globally achieved using wideband codecs offering good quality except for opus codec (at 12.2 kbps).

  9. Effect of threatening life experiences and adverse family relations in ulcerative colitis: analysis using structural equation modeling and comparison with Crohn's disease.

    Science.gov (United States)

    Slonim-Nevo, Vered; Sarid, Orly; Friger, Michael; Schwartz, Doron; Sergienko, Ruslan; Pereg, Avihu; Vardi, Hillel; Singer, Terri; Chernin, Elena; Greenberg, Dan; Odes, Shmuel

    2017-05-01

    We published that threatening life experiences and adverse family relations impact Crohn's disease (CD) adversely. In this study, we examine the influence of these stressors in ulcerative colitis (UC). Patients completed demography, economic status (ES), the Patient-Simple Clinical Colitis Activity Index (P-SCCAI), the Short Inflammatory Bowel Disease Questionnaire (SIBDQ), the Short-Form Health Survey (SF-36), the Brief Symptom Inventory (BSI), the Family Assessment Device (FAD), and the List of Threatening Life Experiences (LTE). Analysis included multiple linear and quantile regressions and structural equation modeling, comparing CD. UC patients (N=148, age 47.55±16.04 years, 50.6% women) had scores [median (interquartile range)] as follows: SCAAI, 2 (0.3-4.8); FAD, 1.8 (1.3-2.2); LTE, 1.0 (0-2.0); SF-36 Physical Health, 49.4 (36.8-55.1); SF-36 Mental Health, 45 (33.6-54.5); Brief Symptom Inventory-Global Severity Index (GSI), 0.5 (0.2-1.0). SIBDQ was 49.76±14.91. There were significant positive associations for LTE and SCAAI (25, 50, 75% quantiles), FAD and SF-36 Mental Health, FAD and LTE with GSI (50, 75, 90% quantiles), and ES with SF-36 and SIBDQ. The negative associations were as follows: LTE with SF-36 Physical/Mental Health, SIBDQ with FAD and LTE, ES with GSI (all quantiles), and P-SCCAI (75, 90% quantiles). In structural equation modeling analysis, LTE impacted ES negatively and ES impacted GSI negatively; LTE impacted GSI positively and GSI impacted P-SCCAI positively. In a split model, ES had a greater effect on GSI in UC than CD, whereas other path magnitudes were similar. Threatening life experiences, adverse family relations, and poor ES make UC patients less healthy both physically and mentally. The impact of ES is worse in UC than CD.

  10. 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.

  11. A wide bandwidth fractional-N synthesizer for LTE with phase noise cancellation using a hybrid-ΔΣ-DAC and charge re-timing

    NARCIS (Netherlands)

    Ye, D.; Lu, Ping; Andreani, Pietro; van der Zee, Ronan A.R.

    2013-01-01

    This paper presents a 1MHz bandwidth, ΔΣ fractional-N PLL as the frequency synthesizer for LTE. A noise cancellation path composed of a novel hybrid ΔΣ DAC with 9 output bits is incorporated into the PLL in order to cancel the out-of-band phase noise caused by the quantization error. Further, a

  12. Simple Analytic Collisional Rates for non-LTE Vibrational Populations in Astrophysical Environments: the Cases of Circumstellar SiO Masers and Shocked H2

    Science.gov (United States)

    Bieniek, Ronald

    2008-05-01

    Rates for collisionally induced transitions between molecular vibrational levels are important in modeling a variety of non-LTE processes in astrophysical environments. Two examples are SiO masering in circumstellar envelopes in certain late-type stars [1] and the vibrational populations of molecular hydrogen in shocked interstellar medium [cf 2]. A simple exponential-potential model of molecular collisions leads to a two-parameter analytic expression for state-to-state and thermally averaged rates for collisionally induced vibrational-translational (VT) transitions in diatomic molecules [3,4]. The thermally averaged rates predicted by this formula have been shown to be in excellent numerical agreement with absolute experimental and quantum mechanical rates over large temperature ranges and initial vibrational excitation levels in a variety of species, e.g., OH, O2, N2 [3] and even for the rate of H2(v=1)+H2, which changes by five orders of magnitude in the temperature range 50-2000 K [4]. Analogous analytic rates will be reported for vibrational transitions in SiO due to collisions with H2 and compared to the numerical fit of quantum-mechanical rates calculated by Bieniek and Green [5]. [1] Palov, A.P., Gray, M.D., Field, D., & Balint-Kurti, G.G. 2006, ApJ, 639, 204. [2] Flower, D. 2007, Molecular Collisions in the Interstellar Medium (Cambridge: Cambridge Univ. Press) [3] Bieniek, R.J. & Lipson, S.J. 1996, Chem. Phys. Lett. 263, 276. [4] Bieniek, R.J. 2006, Proc. NASA LAW (Lab. Astrophys. Workshop) 2006, 299; http://www.physics.unlv.edu/labastro/nasalaw2006proceedings.pdf. [5] Bieniek, R.J., & Green, S. 1983, ApJ, 265, L29 and 1983, ApJ, 270, L101.

  13. CT-guided Irreversible Electroporation in an Acute Porcine Liver Model: Effect of Previous Transarterial Iodized Oil Tissue Marking on Technical Parameters, 3D Computed Tomographic Rendering of the Electroporation Zone, and Histopathology

    Energy Technology Data Exchange (ETDEWEB)

    Sommer, C. M., E-mail: christof.sommer@med.uni-heidelberg.de [University Hospital Heidelberg, Department of Diagnostic and Interventional Radiology (Germany); Fritz, S., E-mail: stefan.fritz@med.uni-heidelberg.de [University Hospital Heidelberg, Department of General Visceral and Transplantation Surgery (Germany); Vollherbst, D., E-mail: dominikvollherbst@web.de [University Hospital Heidelberg, Department of Diagnostic and Interventional Radiology (Germany); Zelzer, S., E-mail: s.zelzer@dkfz-heidelberg.de [German Cancer Research Center (dkfz), Medical and Biological Informatics (Germany); Wachter, M. F., E-mail: fredericwachter@googlemail.com; Bellemann, N., E-mail: nadine.bellemann@med.uni-heidelberg.de; Gockner, T., E-mail: theresa.gockner@med.uni-heidelberg.de; Mokry, T., E-mail: theresa.mokry@med.uni-heidelberg.de; Schmitz, A., E-mail: anne.schmitz@med.uni-heidelberg.de [University Hospital Heidelberg, Department of Diagnostic and Interventional Radiology (Germany); Aulmann, S., E-mail: sebastian.aulmann@mail.com [University Hospital Heidelberg, Department of General Pathology (Germany); Stampfl, U., E-mail: ulrike.stampfl@med.uni-heidelberg.de [University Hospital Heidelberg, Department of Diagnostic and Interventional Radiology (Germany); Pereira, P., E-mail: philippe.pereira@slk-kliniken.de [SLK Kliniken Heilbronn GmbH, Clinic for Radiology, Minimally-invasive Therapies and Nuclear Medicine (Germany); Kauczor, H. U., E-mail: hu.kauczor@med.uni-heidelberg.de [University Hospital Heidelberg, Department of Diagnostic and Interventional Radiology (Germany); Werner, J., E-mail: jens.werner@med.uni-heidelberg.de [University Hospital Heidelberg, Department of General Visceral and Transplantation Surgery (Germany); Radeleff, B. A., E-mail: boris.radeleff@med.uni-heidelberg.de [University Hospital Heidelberg, Department of Diagnostic and Interventional Radiology (Germany)

    2015-02-15

    PurposeTo evaluate the effect of previous transarterial iodized oil tissue marking (ITM) on technical parameters, three-dimensional (3D) computed tomographic (CT) rendering of the electroporation zone, and histopathology after CT-guided irreversible electroporation (IRE) in an acute porcine liver model as a potential strategy to improve IRE performance.MethodsAfter Ethics Committee approval was obtained, in five landrace pigs, two IREs of the right and left liver (RL and LL) were performed under CT guidance with identical electroporation parameters. Before IRE, transarterial marking of the LL was performed with iodized oil. Nonenhanced and contrast-enhanced CT examinations followed. One hour after IRE, animals were killed and livers collected. Mean resulting voltage and amperage during IRE were assessed. For 3D CT rendering of the electroporation zone, parameters for size and shape were analyzed. Quantitative data were compared by the Mann–Whitney test. Histopathological differences were assessed.ResultsMean resulting voltage and amperage were 2,545.3 ± 66.0 V and 26.1 ± 1.8 A for RL, and 2,537.3 ± 69.0 V and 27.7 ± 1.8 A for LL without significant differences. Short axis, volume, and sphericity index were 16.5 ± 4.4 mm, 8.6 ± 3.2 cm{sup 3}, and 1.7 ± 0.3 for RL, and 18.2 ± 3.4 mm, 9.8 ± 3.8 cm{sup 3}, and 1.7 ± 0.3 for LL without significant differences. For RL and LL, the electroporation zone consisted of severely widened hepatic sinusoids containing erythrocytes and showed homogeneous apoptosis. For LL, iodized oil could be detected in the center and at the rim of the electroporation zone.ConclusionThere is no adverse effect of previous ITM on technical parameters, 3D CT rendering of the electroporation zone, and histopathology after CT-guided IRE of the liver.

  14. CT-guided Irreversible Electroporation in an Acute Porcine Liver Model: Effect of Previous Transarterial Iodized Oil Tissue Marking on Technical Parameters, 3D Computed Tomographic Rendering of the Electroporation Zone, and Histopathology

    International Nuclear Information System (INIS)

    Sommer, C. M.; Fritz, S.; Vollherbst, D.; Zelzer, S.; Wachter, M. F.; Bellemann, N.; Gockner, T.; Mokry, T.; Schmitz, A.; Aulmann, S.; Stampfl, U.; Pereira, P.; Kauczor, H. U.; Werner, J.; Radeleff, B. A.

    2015-01-01

    PurposeTo evaluate the effect of previous transarterial iodized oil tissue marking (ITM) on technical parameters, three-dimensional (3D) computed tomographic (CT) rendering of the electroporation zone, and histopathology after CT-guided irreversible electroporation (IRE) in an acute porcine liver model as a potential strategy to improve IRE performance.MethodsAfter Ethics Committee approval was obtained, in five landrace pigs, two IREs of the right and left liver (RL and LL) were performed under CT guidance with identical electroporation parameters. Before IRE, transarterial marking of the LL was performed with iodized oil. Nonenhanced and contrast-enhanced CT examinations followed. One hour after IRE, animals were killed and livers collected. Mean resulting voltage and amperage during IRE were assessed. For 3D CT rendering of the electroporation zone, parameters for size and shape were analyzed. Quantitative data were compared by the Mann–Whitney test. Histopathological differences were assessed.ResultsMean resulting voltage and amperage were 2,545.3 ± 66.0 V and 26.1 ± 1.8 A for RL, and 2,537.3 ± 69.0 V and 27.7 ± 1.8 A for LL without significant differences. Short axis, volume, and sphericity index were 16.5 ± 4.4 mm, 8.6 ± 3.2 cm 3 , and 1.7 ± 0.3 for RL, and 18.2 ± 3.4 mm, 9.8 ± 3.8 cm 3 , and 1.7 ± 0.3 for LL without significant differences. For RL and LL, the electroporation zone consisted of severely widened hepatic sinusoids containing erythrocytes and showed homogeneous apoptosis. For LL, iodized oil could be detected in the center and at the rim of the electroporation zone.ConclusionThere is no adverse effect of previous ITM on technical parameters, 3D CT rendering of the electroporation zone, and histopathology after CT-guided IRE of the liver

  15. Ultra-metal-poor Stars: Spectroscopic Determination of Stellar Atmospheric Parameters Using Iron Non-LTE Line Abundances

    Science.gov (United States)

    Ezzeddine, Rana; Frebel, Anna; Plez, Bertrand

    2017-10-01

    We present new ultra-metal-poor stars parameters with [Fe/H] LTE in their atmospheric parameters and show that they can grow up to ˜1.00 dex in [Fe/H], ˜150 K in {T}{eff} and ˜0.5 dex in log g toward the lowest metallicities. Accurate NLTE atmospheric stellar parameters, in particular [Fe/H] being significantly higher, are the first step to eventually providing full NLTE abundance patterns that can be compared with Population III supernova nucleosynthesis yields to derive properties of the first stars. Overall, this maximizes the potential of these likely second-generation stars to investigate the early universe and how the chemical elements were formed.

  16. Enhancing Radio Access Network Performance over LTE-A for Machine-to-Machine Communications under Massive Access

    Directory of Open Access Journals (Sweden)

    Fatemah Alsewaidi

    2016-01-01

    Full Text Available The expected tremendous growth of machine-to-machine (M2M devices will require solutions to improve random access channel (RACH performance. Recent studies have shown that radio access network (RAN performance is degraded under the high density of devices. In this paper, we propose three methods to enhance RAN performance for M2M communications over the LTE-A standard. The first method employs a different value for the physical RACH configuration index to increase random access opportunities. The second method addresses a heterogeneous network by using a number of picocells to increase resources and offload control traffic from the macro base station. The third method involves aggregation points and addresses their effect on RAN performance. Based on evaluation results, our methods improved RACH performance in terms of the access success probability and average access delay.

  17. A Low-Complexity Subgroup Formation with QoS-Aware for Enhancing Multicast Services in LTE Networks

    Science.gov (United States)

    Algharem, M.; Omar, M. H.; Rahmat, R. F.; Budiarto, R.

    2018-03-01

    The high demand of Multimedia services on in Long Term Evolution (LTE) and beyond networks forces the networks operators to find a solution that can handle the huge traffic. Along with this, subgroup formation techniques are introduced to overcome the limitations of the Conventional Multicast Scheme (CMS) by splitting the multicast users into several subgroups based on the users’ channels quality signal. However, finding the best subgroup configuration with low complexity is need more investigations. In this paper, an efficient and simple subgroup formation mechanisms are proposed. The proposed mechanisms take the transmitter MAC queue in account. The effectiveness of the proposed mechanisms is evaluated and compared with CMS in terms of throughput, fairness, delay, Block Error Rate (BLER).

  18. Packet-Scheduling Algorithm by the Ratio of Transmit Power to the Transmission Bits in 3GPP LTE Downlink

    Directory of Open Access Journals (Sweden)

    Gil Gye-Tae

    2010-01-01

    Full Text Available Packet scheduler plays the central role in determining the overall performance of the 3GPP long-term evolution (LTE based on packet-switching operation. In this paper, a novel minimum transmit power-based (MP packet-scheduling algorithm is proposed that can achieve power-efficient transmission to the UEs while providing both system throughput gain and fairness improvement. The proposed algorithm is based on a new scheduling metric focusing on the ratio of the transmit power per bit and allocates the physical resource block (PRB to the UE that requires the least ratio of the transmit power per bit. Through computer simulation, the performance of the proposed MP packet-scheduling algorithm is compared with the conventional packet-scheduling algorithms by two primary criteria: fairness and throughput. The simulation results show that the proposed algorithm outperforms the conventional algorithms in terms of the fairness and throughput.

  19. A Cost-Based Adaptive Handover Hysteresis Scheme to Minimize the Handover Failure Rate in 3GPP LTE System

    Directory of Open Access Journals (Sweden)

    Gil Gye-Tae

    2010-01-01

    Full Text Available We deal with a cost-based adaptive handover hysteresis scheme for the horizontal handover decision strategies, as one of the self-optimization techniques that can minimize the handover failure rate (HFR in the 3rd generation partnership project (3GPP long-term evolution (LTE system based on the network-controlled hard handover. Especially, for real-time operation, we propose an adaptive hysteresis scheme with a simplified cost function considering some dominant factors closely related to HFR performance such as the load difference between the target and serving cells, the velocity of user equipment (UE, and the service type. With the proposed scheme, a proper hysteresis value based on the dominant factors is easily obtained, so that the handover parameter optimization for minimizing the HFR can be effectively achieved. Simulation results show that the proposed scheme can support better HFR performance than the conventional schemes.

  20. Modified Dynamic Decode-and-Forward Relaying Protocol for Type II Relay in LTE-Advanced and Beyond.

    Science.gov (United States)

    Nam, Sung Sik; Alouini, Mohamed-Slim; Choi, Seyeong

    2016-01-01

    In this paper, we propose a modified dynamic decode-and-forward (MoDDF) relaying protocol to meet the critical requirements for user equipment (UE) relays in next-generation cellular systems (e.g., LTE-Advanced and beyond). The proposed MoDDF realizes the fast jump-in relaying and the sequential decoding with an application of random codeset to encoding and re-encoding process at the source and the multiple UE relays, respectively. A subframe-by-subframe decoding based on the accumulated (or buffered) messages is employed to achieve energy, information, or mixed combining. Finally, possible early termination of decoding at the end user can lead to the higher spectral efficiency and more energy saving by reducing the frequency of redundant subframe transmission and decoding. These attractive features eliminate the need of directly exchanging control messages between multiple UE relays and the end user, which is an important prerequisite for the practical UE relay deployment.

  1. Performance Analysis of Scheduling Schemes for Femto to Macro Interference Coordination in LTE-Femtocell Deployment Scenario

    Directory of Open Access Journals (Sweden)

    Rafina Destiarti Ainul

    2016-08-01

    Full Text Available Deploying femtocells that have low power level in LTE with small coverage area is an alternative solution for mobile operators to improve indoors network coverage area as well as system capacity. However deploying femtocells (HeNB that were used co-channel frequency, can be brought about interference problem to the Macro BTS (eNB. Close Subscriber Group (CSG of HeNB allows only User equipment (UE to access HeNB. HeNB is the source of interference for UE who cannot access it. Therefore it is necessary for interference coordination methods among the HeNB and eNB. The methods are ICIC (Intercell Interference Coordination and eICIC (enhanced Intercell Interference Coordination.  This paper proposed performance analysis of scheduling schemes for Femto to macro interference coordination that allocated resource in the frequency and time domain using LTE-Femtocell suburban and urban deployment scenario. Simulation result using ICIC methods can improve SINR performance 15.77 % in urban and 28.66 % in suburban, throughput performance 10.11 % in urban and 21.05 % in suburban. eICIC methods can improve SINR performance 17.44 % in urban and 31.14 % in suburban, throughput performance 19.83% in urban and 44.39 % in suburban.The result prove using eICIC method in time domain resource have better performance than using ICIC method in frequency resource. However using eICIC method in suburban deployment scenariocan increase the performance of SINR and throughput more effective than using eICIC method in urban deployment scenario.

  2. Congruency sequence effects are driven by previous-trial congruency, not previous-trial response conflict

    OpenAIRE

    Weissman, Daniel H.; Carp, Joshua

    2013-01-01

    Congruency effects in distracter interference tasks are often smaller after incongruent trials than after congruent trials. However, the sources of such congruency sequence effects (CSEs) are controversial. The conflict monitoring model of cognitive control links CSEs to the detection and resolution of response conflict. In contrast, competing theories attribute CSEs to attentional or affective processes that vary with previous-trial congruency (incongruent vs. congruent). The present study s...

  3. Ab-initio modeling of an iron laser-induced plasma: Comparison between theoretical and experimental atomic emission spectra

    International Nuclear Information System (INIS)

    Colgan, J.; Judge, E.J.; Kilcrease, D.P.; Barefield, J.E.

    2014-01-01

    We report on efforts to model the Fe emission spectrum generated from laser-induced breakdown spectroscopy (LIBS) measurements on samples of pure iron oxide (Fe 2 O 3 ). Our modeling efforts consist of several components. We begin with ab-initio atomic structure calculations performed by solving the Hartree–Fock equations for the neutral and singly ionized stages of Fe. Our energy levels are then adjusted to their experimentally known values. The atomic transition probabilities and atomic collision quantities are also computed in an ab-initio manner. We perform LTE or non-LTE calculations that generate level populations and, subsequently, an emission spectrum for the iron plasma for a range of electron temperatures and electron densities. Such calculations are then compared to the experimental spectrum. We regard our work as a preliminary modeling effort that ultimately strives towards the modeling of emission spectra from even more complex samples where less atomic data are available. - Highlights: • LIBS plasma of iron oxide • Ab-initio theoretical Modeling • Discussion of LTE versus non-LTE criteria and assessment • Boltzmann plots for Fe—determination of when LTE is a valid assumption • Emission spectra for Fe—comparison of theoretical modeling and measurement: good agreement obtained

  4. The effect of the user's body on high-Q and low-Q planar inverted F antennas for LTE frequencies

    DEFF Research Database (Denmark)

    Barrio, Samantha Caporal Del; Pelosi, Mauro; Franek, Ondrej

    2012-01-01

    The influence of the user's body degrades small antenna performances. This paper investigates the detuning and the losses on high-Q planar antennas for small devices due to user proximity. The results at low frequencies for the Long Term Evolution (LTE) standard are compared to the results for a ...... for a low- Q antenna. Two hand grips are studied and combined to a SAM(Specific Anthropomorphic Mannequin)phantom. It is shown that using the high-Q antennas the loss due to the mismatch is reduced but the absorption loss is increased.......The influence of the user's body degrades small antenna performances. This paper investigates the detuning and the losses on high-Q planar antennas for small devices due to user proximity. The results at low frequencies for the Long Term Evolution (LTE) standard are compared to the results...

  5. Placental complications after a previous cesarean section

    OpenAIRE

    Milošević Jelena; Lilić Vekoslav; Tasić Marija; Radović-Janošević Dragana; Stefanović Milan; Antić Vladimir

    2009-01-01

    Introduction The incidence of cesarean section has been rising in the past 50 years. With the increased number of cesarean sections, the number of pregnancies with the previous cesarean section rises as well. The aim of this study was to establish the influence of the previous cesarean section on the development of placental complications: placenta previa, placental abruption and placenta accreta, as well as to determine the influence of the number of previous cesarean sections on the complic...

  6. 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).

  7. Validation of the Long-term Difficulties Inventory (LDI) and the List of Threatening Experiences (LTE) as measures of stress in epidemiological population-based cohort studies.

    Science.gov (United States)

    Rosmalen, J G M; Bos, E H; de Jonge, P

    2012-12-01

    Stress questionnaires are included in many epidemiological cohort studies but the psychometric characteristics of these questionnaires are largely unknown. The aim of this study was to describe these characteristics for two short questionnaires measuring the lifetime and past year occurrence of stress: the List of Threatening Events (LTE) as a measure of acute stress and the Long-term Difficulties Inventory (LDI) as a measure of chronic stress. This study was performed in a general population cohort consisting of 588 females (53.7%) and 506 males (46.3%), with a mean age of 53.5 years (s.d.=11.3 years). Respondents completed the LTE and the LDI for the past year, and for the age categories of 0-12, 13-18, 19-39, 40-60, and >60 years. They also completed questionnaires on perceived stress, psychological distress (the General Health Questionnaire, GHQ-12), anxiety and depression (the Symptom Checklist, SCL-8) and neuroticism (the Eysenck Personality Questionnaire - Revised Short Scale, EPQ-RSS-N). Approximately 2 years later, 976 respondents (89%) completed these questionnaires for a second time. The stability of the retrospective reporting of long-term difficulties and life events was satisfactory: 0.7 for the lifetime LDI and 0.6 for the lifetime LTE scores. The construct validity of these lists is indicated by their positive associations with psychological distress, mental health problems and neuroticism. This study in a large population-based sample shows that the LDI and LTE have sufficient validity and stability to include them in major epidemiological cohort studies.

  8. 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.

  9. A Dual-Wideband Double-Layer Magnetoelectric Dipole Antenna with a Modified Horned Reflector for 2G/3G/LTE Applications

    Directory of Open Access Journals (Sweden)

    Botao Feng

    2013-01-01

    Full Text Available A novel dual-wideband double-layer magnetoelectric dipole unidirectional antenna with a modified horned reflector for 2G/3G/LTE applications is proposed. Firstly, a double-layer electric dipole structure is presented to provide a dualwideband, whose folded lower layer mainly serves the lower frequency band while the inclined upper layer works for the upper frequency band. In addition, to reduce the size of the antenna and improve impedance matching, a new feeding structure designed with inverted U-shaped and tapered line is introduced. Finally, a modified horn-shaped reflector, instead of a ground plane, is employed to achieve stable and high gains. The antenna prototype can achieve a bandwidth of 24.4% (790 MHz–1010 MHz with a stable gain of 7.2 ± 0.6 dBi for the lower band, and a bandwidth of 67.3% (1.38 GHz–2.78 GHz with a gain of 7.5 ± 0.8 dBi for the upper band covering all the frequency bands for 2G/3G/LTE systems. To the best of our knowledge, it is the first double-layer magnetoelectric dipole antenna proposed. Compared with the existing ME dipole antennas, the proposed antenna, which is completely made of copper, can be easily fabricated at low cost and thus is practicable for 2G/3G/LTE applications.

  10. Expression of glial fibrillar acidic protein in the sensorimotor cortex of the cerebral hemispheres in the modeling of transient ischemia against the background of previous sensitization by brain antigen and immunocorrection

    OpenAIRE

    Yaremenko, L. M.; Grabovoy, A. N.; Shepelev, S.E.

    2017-01-01

    Aim. In order to analyze the dynamics of expression of glial fibrillar acidic protein in the sensorimotor cortex of the large hemispheres in the simulation of transient ischemia against the background of previous sensitization by brain antigen and immunocorrection.Materials and methods. The study is conducted on 185 male mature white rats from Wistar line weighing 260-290 g, in which the damage of the brain was modulated. The brain for study was taken on the 1st, 3rd, 10th, 30th and 90th days...

  11. Expression of glial fibrillar acidic protein in the sensorimotor cortex of the cerebral hemispheres in the modeling of transient ischemia against the background of previous sensitization by brain antigen and immunocorrection

    OpenAIRE

    L. M. Yaremenko; A. N. Grabovoy; S. E. Shepelev

    2017-01-01

    Aim. In order to analyze the dynamics of expression of glial fibrillar acidic protein in the sensorimotor cortex of the large hemispheres in the simulation of transient ischemia against the background of previous sensitization by brain antigen and immunocorrection. Materials and methods. The study is conducted on 185 male mature white rats from Wistar line weighing 260-290 g, in which the damage of the brain was modulated. The brain for study was taken on the 1st, 3rd, 10th, 30th and 90th...

  12. Preoperative screening: value of previous tests.

    Science.gov (United States)

    Macpherson, D S; Snow, R; Lofgren, R P

    1990-12-15

    To determine the frequency of tests done in the year before elective surgery that might substitute for preoperative screening tests and to determine the frequency of test results that change from a normal value to a value likely to alter perioperative management. Retrospective cohort analysis of computerized laboratory data (complete blood count, sodium, potassium, and creatinine levels, prothrombin time, and partial thromboplastin time). Urban tertiary care Veterans Affairs Hospital. Consecutive sample of 1109 patients who had elective surgery in 1988. At admission, 7549 preoperative tests were done, 47% of which duplicated tests performed in the previous year. Of 3096 previous results that were normal as defined by hospital reference range and done closest to the time of but before admission (median interval, 2 months), 13 (0.4%; 95% CI, 0.2% to 0.7%), repeat values were outside a range considered acceptable for surgery. Most of the abnormalities were predictable from the patient's history, and most were not noted in the medical record. Of 461 previous tests that were abnormal, 78 (17%; CI, 13% to 20%) repeat values at admission were outside a range considered acceptable for surgery (P less than 0.001, frequency of clinically important abnormalities of patients with normal previous results with those with abnormal previous results). Physicians evaluating patients preoperatively could safely substitute the previous test results analyzed in this study for preoperative screening tests if the previous tests are normal and no obvious indication for retesting is present.

  13. Automatic electromagnetic valve for previous vacuum

    International Nuclear Information System (INIS)

    Granados, C. E.; Martin, F.

    1959-01-01

    A valve which permits the maintenance of an installation vacuum when electric current fails is described. It also lets the air in the previous vacuum bomb to prevent the oil ascending in the vacuum tubes. (Author)

  14. Expression of glial fibrillar acidic protein in the sensorimotor cortex of the cerebral hemispheres in the modeling of transient ischemia against the background of previous sensitization by brain antigen and immunocorrection

    Directory of Open Access Journals (Sweden)

    L. M. Yaremenko

    2017-12-01

    Full Text Available Aim. In order to analyze the dynamics of expression of glial fibrillar acidic protein in the sensorimotor cortex of the large hemispheres in the simulation of transient ischemia against the background of previous sensitization by brain antigen and immunocorrection. Materials and methods. The study is conducted on 185 male mature white rats from Wistar line weighing 260-290 g, in which the damage of the brain was modulated. The brain for study was taken on the 1st, 3rd, 10th, 30th and 90th days after the start of the experiment. The histological, immunohistochemical, morphometric and statistical methods were used. Results. Observations have shown that sensitization by the brain antigen causes neurodegenerative changes in the sensorimotor cortex and a moderate increase in the number of GFAP+-gliocytes, which is gradually increasing. The discirculatory changes that occurred with PO and BCA against the background of previous sensitization practically do not lead to changes in the number of GFAP+-cells. Against the background of sensitization by brain antigen, brain ischemia leads to an increase in the number of gliocytes that are GFAP labeled. In the affected hemisphere, their number reaches a maximum in the end of the acute period of ischemia, after which it decreases. But even in 3 months after transient vascular lesion, there are almost twice as many as in conditionally intact rats. This can be a factor that will significantly affect the function of brain regions after a vascular accident. The increase in the number of GFAP+-gliocytes in the contralateral hemisphere allows us to speak about a certain systemic response of astrocytic glia after ischemic trauma. An early reaction to increase of the number of labeled astrocytes just a day after ischemic attack suggests that some of this type of gliocytes does not expresses GFAP under normal conditions. The action of Imunofan in MEAs results in a less significant decrease in manifestations of

  15. A Fast and Reliable Broadcast Service for LTE-Advanced Exploiting Multihop Device-to-Device Transmissions

    Directory of Open Access Journals (Sweden)

    Giovanni Nardini

    2017-11-01

    Full Text Available Several applications, from the Internet of Things for smart cities to those for vehicular networks, need fast and reliable proximity-based broadcast communications, i.e., the ability to reach all peers in a geographical neighborhood around the originator of a message, as well as ubiquitous connectivity. In this paper, we point out the inherent limitations of the LTE (Long-Term Evolution cellular network, which make it difficult, if possible at all, to engineer such a service using traditional infrastructure-based communications. We argue, instead, that network-controlled device-to-device (D2D communications, relayed in a multihop fashion, can efficiently support this service. To substantiate the above claim, we design a proximity-based broadcast service which exploits multihop D2D. We discuss the relevant issues both at the UE (User Equipment, which has to run applications, and within the network (i.e., at the eNodeBs, where suitable resource allocation schemes have to be enforced. We evaluate the performance of a multihop D2D broadcasting using system-level simulations, and demonstrate that it is fast, reliable and economical from a resource consumption standpoint.

  16. Modified Dynamic Decode-and-Forward Relaying Protocol for Type II Relay in LTE-Advanced and Beyond

    KAUST Repository

    Nam, Sung Sik

    2016-11-29

    In this paper, we propose a modified dynamic decode-and-forward (MoDDF) relaying protocol to meet the critical requirements for user equipment (UE) relays in next-generation cellular systems (e.g., LTE-Advanced and beyond). The proposed MoDDF realizes the fast jump-in relaying and the sequential decoding with an application of random codeset to encoding and re-encoding process at the source and the multiple UE relays, respectively. A subframe-by-subframe decoding based on the accumulated (or buffered) messages is employed to achieve energy, information, or mixed combining. Finally, possible early termination of decoding at the end user can lead to the higher spectral efficiency and more energy saving by reducing the frequency of redundant subframe transmission and decoding. These attractive features eliminate the need of directly exchanging control messages between multiple UE relays and the end user, which is an important prerequisite for the practical UE relay deployment. Copyright: © 2016 Nam et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

  17. An Adaptive Measurement Report Period and Handoff Threshold Scheme Based on SINR Variation in LTE-A Networks

    Directory of Open Access Journals (Sweden)

    Jenhui Chen

    2015-01-01

    Full Text Available This paper deals with the problem of triggering handoff procedure at an appropriate point of time to reduce the ping-pong effect problem in the long-term evolution advanced (LTE-A network. In the meantime, we also have studied a dynamic handoff threshold scheme, named adaptive measurement report period and handoff threshold (AMPHT, based on the user equipment’s (UE’s reference signal received quality (RSRQ variation and the moving velocity of UE. AMPHT reduces the probability of unnecessarily premature handoff decision making and also avoids the problem of handoff failure due to too late handoff decision making when the moving velocity of UE is high. AMPHT is achieved by two critical parameters: (1 a dynamic RSRQ threshold for handoff making; (2 a dynamic interval of time for the UE’s RSRQ reporting. The performance of AMPHT is validated by comparing numerical experiments (MATLAB tool with simulation results (the ns-3 LENA module. Our experiments show that AMPHT reduces the premature handoff probability by 34% at most in a low moving velocity and reduces the handoff failure probability by 25% in a high moving velocity. Additionally, AMPHT can reduce a large number of unnecessary handoff overheads and can be easily implemented because it uses the original control messages of 3GPP E-UTRA.

  18. Kinetic Requirements for the Measurement of Mesospheric Water Vapor at 6.8 (microns) under Non-LTE Conditions

    Science.gov (United States)

    Zhou, Daniel K.; Mlynczak, Martin G.; Lopez-Puertas, Manuel; Russell, James M., III

    1999-01-01

    We present accuracy requirements for specific kinetic parameters used to calculate the populations and vibrational temperatures of the H2O(010) and H2O(020) states in the terrestrial mesosphere. The requirements are based on rigorous simulations of the retrieval of mesospheric water vapor profiles from measurements of water vapor infrared emission made by limb scanning instruments on orbiting satellites. Major improvements in the rate constants that describe vibration-to- vibration exchange between the H2O(010) and 02(1) states are required in addition to improved specification of the rate of quenching Of O2(1) by atomic oxygen (0). It is also necessary to more accurately determine the yield of vibrationally excited O2(l) resulting from ozone photolysis. A contemporary measurement of the rate of quenching of H2O(010) by N2 and O2 is also desirable. These rates are either highly uncertain or have never before been measured at atmospheric temperatures. The suggested improvements are necessary for the interpretation of water vapor emission measurements at 6.8 microns to be made from a new spaceflight experiment in less than 2 years. The approach to retrieving water vapor under non-LTE conditions is also presented.

  19. Non-LTE radiative transfer with lambda-acceleration - Convergence properties using exact full and diagonal lambda-operators

    Science.gov (United States)

    Macfarlane, J. J.

    1992-01-01

    We investigate the convergence properties of Lambda-acceleration methods for non-LTE radiative transfer problems in planar and spherical geometry. Matrix elements of the 'exact' A-operator are used to accelerate convergence to a solution in which both the radiative transfer and atomic rate equations are simultaneously satisfied. Convergence properties of two-level and multilevel atomic systems are investigated for methods using: (1) the complete Lambda-operator, and (2) the diagonal of the Lambda-operator. We find that the convergence properties for the method utilizing the complete Lambda-operator are significantly better than those of the diagonal Lambda-operator method, often reducing the number of iterations needed for convergence by a factor of between two and seven. However, the overall computational time required for large scale calculations - that is, those with many atomic levels and spatial zones - is typically a factor of a few larger for the complete Lambda-operator method, suggesting that the approach should be best applied to problems in which convergence is especially difficult.

  20. Coverage extension and balancing the transmitted power of the moving relay node at LTE-A cellular network.

    Science.gov (United States)

    Aldhaibani, Jaafar A; Yahya, Abid; Ahmad, R Badlishah

    2014-01-01

    The poor capacity at cell boundaries is not enough to meet the growing demand and stringent design which required high capacity and throughput irrespective of user's location in the cellular network. In this paper, we propose new schemes for an optimum fixed relay node (RN) placement in LTE-A cellular network to enhance throughput and coverage extension at cell edge region. The proposed approach mitigates interferences between all nodes and ensures optimum utilization with the optimization of transmitted power. Moreover, we proposed a new algorithm to balance the transmitted power of moving relay node (MR) over cell size and providing required SNR and throughput at the users inside vehicle along with reducing the transmitted power consumption by MR. The numerical analysis along with the simulation results indicates that an improvement in capacity for users is 40% increment at downlink transmission from cell capacity. Furthermore, the results revealed that there is saving nearly 75% from transmitted power in MR after using proposed balancing algorithm. ATDI simulator was used to verify the numerical results, which deals with real digital cartographic and standard formats for terrain.

  1. Enhanced Quality of Service of Cell-Edge User by Extending Modified Largest Weighted Delay First Algorithm in LTE Networks

    Directory of Open Access Journals (Sweden)

    Hasibur Rashid Chayon

    2017-05-01

    Full Text Available Long Term Evolution (LTE is the prominent technology in Fourth Generation (4G communication standards, which provides higher throughput and better Quality of Service (QoS to all users. However, users in the cell-edge area are receiving comparatively low QoS due to the distance from eNodeB (eNB and bad channel conditions. The Conventional Modified Largest Weighted Delay First (MLWDF algorithm is unable to resolve this issue, as it does not consider the location of the user. This paper proposes an extended MLWDF (EMLWDF downlink scheduling algorithm to provide better services to the cell-edge user as well as to the cell-center user. The proposed algorithm divides the eNB cell area into inner and outer regions. It includes the distance of the user from attached eNB, received Signal to Interference plus Noise Ratio (SINR and error probability into the original algorithm. The simulated results are compared with other well-known algorithms and the comparison shows that the proposed algorithm enhances overall 56.23% of cell-edge user throughput and significantly improves the average user throughput, fairness index, and spectral efficiency.

  2. Effect of Electromagnetic Waves from Mobile Phones on Spermatogenesis in the Era of 4G-LTE

    Directory of Open Access Journals (Sweden)

    Jong Jin Oh

    2018-01-01

    Full Text Available Objective. To investigate the effect of long duration exposure to electromagnetic field from mobile phones on spermatogenesis in rats using 4G-LTE. Methods. Twenty Sprague-Dawley male rats were placed into 4 groups according to the intensity and exposure duration: Group 1 (sham procedure, Group 2 (3 cm distance + 6 h exposure daily, Group 3 (10 cm distance + 18 h exposure daily, and Group 4 (3 cm distance + 18 h exposure daily. After 1 month, we compared sperm parameters and histopathological findings of the testis. Results. The mean spermatid count (×106/ml was 398.6 in Group 1, 365.40 in Group 2, 354.60 in Group 3, and 298.60 in Group 4 (p=0.041. In the second review, the mean count of spermatogonia in Group 4 (43.00 was significantly lower than in Group 1 (57.00 and Group 2 (53.40 (p<0.001 and p=0.010, resp.. The sum of the germ cell counts was decreased in Group 4 compared to Groups 1, 2, and 3 (p=0.032. The mean Leydig cell count was significantly decreased in Group 4 (p<0.001. Conclusions. The longer exposure duration of electromagnetic field decreased the spermatogenesis. Our findings warrant further investigations on the potential effects of EMF from mobile phones on male fertility.

  3. Concomitant and previous osteoporotic vertebral fractures.

    Science.gov (United States)

    Lenski, Markus; Büser, Natalie; Scherer, Michael

    2017-04-01

    Background and purpose - Patients with osteoporosis who present with an acute onset of back pain often have multiple fractures on plain radiographs. Differentiation of an acute osteoporotic vertebral fracture (AOVF) from previous fractures is difficult. The aim of this study was to investigate the incidence of concomitant AOVFs and previous OVFs in patients with symptomatic AOVFs, and to identify risk factors for concomitant AOVFs. Patients and methods - This was a prospective epidemiological study based on the Registry of Pathological Osteoporotic Vertebral Fractures (REPAPORA) with 1,005 patients and 2,874 osteoporotic vertebral fractures, which has been running since February 1, 2006. Concomitant fractures are defined as at least 2 acute short-tau inversion recovery (STIR-) positive vertebral fractures that happen concomitantly. A previous fracture is a STIR-negative fracture at the time of initial diagnostics. Logistic regression was used to examine the influence of various variables on the incidence of concomitant fractures. Results - More than 99% of osteoporotic vertebral fractures occurred in the thoracic and lumbar spine. The incidence of concomitant fractures at the time of first patient contact was 26% and that of previous fractures was 60%. The odds ratio (OR) for concomitant fractures decreased with a higher number of previous fractures (OR =0.86; p = 0.03) and higher dual-energy X-ray absorptiometry T-score (OR =0.72; p = 0.003). Interpretation - Concomitant and previous osteoporotic vertebral fractures are common. Risk factors for concomitant fractures are a low T-score and a low number of previous vertebral fractures in cases of osteoporotic vertebral fracture. An MRI scan of the the complete thoracic and lumbar spine with STIR sequence reduces the risk of under-diagnosis and under-treatment.

  4. Uterine rupture without previous caesarean delivery

    DEFF Research Database (Denmark)

    Thisted, Dorthe L. A.; H. Mortensen, Laust; Krebs, Lone

    2015-01-01

    OBJECTIVE: To determine incidence and patient characteristics of women with uterine rupture during singleton births at term without a previous caesarean delivery. STUDY DESIGN: Population based cohort study. Women with term singleton birth, no record of previous caesarean delivery and planned...... vaginal delivery (n=611,803) were identified in the Danish Medical Birth Registry (1997-2008). Medical records from women recorded with uterine rupture during labour were reviewed to ascertain events of complete uterine rupture. Relative Risk (RR) and adjusted Relative Risk Ratio (aRR) of complete uterine...... rupture with 95% confidence intervals (95% CI) were ascertained according to characteristics of the women and of the delivery. RESULTS: We identified 20 cases with complete uterine rupture. The incidence of complete uterine rupture among women without previous caesarean delivery was about 3...

  5. Radio Channel Modelling for UAV Communication over Cellular Networks

    DEFF Research Database (Denmark)

    Amorim, Rafhael Medeiros de; Nguyen, Huan Cong; Mogensen, Preben Elgaard

    2017-01-01

    The main goal of this paper is to obtain models for path loss exponents and shadowing for the radio channel between airborne Unmanned Aerial Vehicles (UAVs) and cellular networks. In this pursuit, field measurements were conducted in live LTE networks at the 800 MHz frequency band, using a commer...

  6. INTRODUCTION Previous reports have documented a high ...

    African Journals Online (AJOL)

    pregnancy if they were married, educated, had dental insurance, previously used dental services when not pregnant, or had knowledge about the possible connection between oral health and pregnancy outcome8. The purpose of this study was to explore the factors determining good oral hygiene among pregnant women ...

  7. Empowerment perceptions of educational managers from previously ...

    African Journals Online (AJOL)

    The perceptions of educational manag ers from previously disadvantaged primary and high schools in the Nelson Mandela Metropole regarding the issue of empowerment are outlined and the perceptions of educational managers in terms of various aspects of empowerment at different levels reflected. A literature study ...

  8. Management of choledocholithiasis after previous gastrectomy.

    Science.gov (United States)

    Anwer, S; Egan, R; Cross, N; Guru Naidu, S; Somasekar, K

    2017-09-01

    Common bile duct stones in patients with a previous gastrectomy can be a technical challenge because of the altered anatomy. This paper presents the successful management of two such patients using non-traditional techniques as conventional endoscopic retrograde cholangiopancreatography was not possible.

  9. Laboratory Grouping Based on Previous Courses.

    Science.gov (United States)

    Doemling, Donald B.; Bowman, Douglas C.

    1981-01-01

    In a five-year study, second-year human physiology students were grouped for laboratory according to previous physiology and laboratory experience. No significant differences in course or board examination performance were found, though correlations were found between predental grade-point averages and grouping. (MSE)

  10. 3D non-LTE spectrum synthesis for Type Ia supernovae

    OpenAIRE

    Kromer, M.; Sim, S. A.; Hillebrandt, W.

    2009-01-01

    Despite the importance of Type Ia supernovae as standard candles for cosmology and to the chemical evolution of the Universe, we still have no consistent picture of the nature of these events. Much progress has been made in the hydrodynamical explosion modelling of supernovae Ia in the last few years and fully 3-D explosion models are now available. However those simulations are not directly comparable to observations: to constrain explosion models, radiative transfer calculations must be car...

  11. Spectral diagnostics of late-type stars: Non-LTE and approach

    Directory of Open Access Journals (Sweden)

    Collet R.

    2012-02-01

    Full Text Available We determine effective temperature, metallicity, and microturbulence for a number of well-studied late-type stars. We use the new NLTE atomic model of Fe, and discuss the results for the MARCS models, as well as for the spatial and temporal averages of full 3D hydrodynamical simulations of stellar convection. It is shown that, contrary to the mean 3D models, certain limitations shall be imposed on the line formation and spectrum synthesis calculations with classical hydrostatic 1D models to obtain physically-realistic results.

  12. ALICE: A non-LTE plasma atomic physics, kinetics and lineshape package

    Science.gov (United States)

    Hill, E. G.; Pérez-Callejo, G.; Rose, S. J.

    2018-03-01

    All three parts of an atomic physics, atomic kinetics and lineshape code, ALICE, are described. Examples of the code being used to model the emissivity and opacity of plasmas are discussed and interesting features of the code which build on the existing corpus of models are shown throughout.

  13. Previously unknown organomagnesium compounds in astrochemical context

    OpenAIRE

    Ruf, Alexander

    2018-01-01

    We describe the detection of dihydroxymagnesium carboxylates (CHOMg) in astrochemical context. CHOMg was detected in meteorites via ultrahigh-resolving chemical analytics and represents a novel, previously unreported chemical class. Thus, chemical stability was probed via quantum chemical computations, in combination with experimental fragmentation techniques. Results propose the putative formation of green-chemical OH-Grignard-type molecules and triggered fundamental questions within chemica...

  14. [Placental complications after a previous cesarean section].

    Science.gov (United States)

    Milosević, Jelena; Lilić, Vekoslav; Tasić, Marija; Radović-Janosević, Dragana; Stefanović, Milan; Antić, Vladimir

    2009-01-01

    The incidence of cesarean section has been rising in the past 50 years. With the increased number of cesarean sections, the number of pregnancies with the previous cesarean section rises as well. The aim of this study was to establish the influence of the previous cesarean section on the development of placental complications: placenta previa, placental abruption and placenta accreta, as well as to determine the influence of the number of previous cesarean sections on the complication development. The research was conducted at the Clinic of Gynecology and Obstetrics in Nis covering 10-year-period (from 1995 to 2005) with 32358 deliveries, 1280 deliveries after a previous cesarean section, 131 cases of placenta previa and 118 cases of placental abruption. The experimental groups was presented by the cases of placenta previa or placental abruption with prior cesarean section in obstetrics history, opposite to the control group having the same conditions but without a cesarean section in medical history. The incidence of placenta previa in the control group was 0.33%, opposite to the 1.86% incidence after one cesarean section (pcesarean sections and as high as 14.28% after three cesarean sections in obstetric history. Placental abruption was recorded as placental complication in 0.33% pregnancies in the control group, while its incidence was 1.02% after one cesarean section (pcesarean sections. The difference in the incidence of intrapartal hysterectomy between the group with prior cesarean section (0.86%) and without it (0.006%) shows a high statistical significance (pcesarean section is an important risk factor for the development of placental complications.

  15. 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.

  16. Books average previous decade of economic misery.

    Science.gov (United States)

    Bentley, R Alexander; Acerbi, Alberto; Ormerod, Paul; Lampos, Vasileios

    2014-01-01

    For the 20(th) century since the Depression, we find a strong correlation between a 'literary misery index' derived from English language books and a moving average of the previous decade of the annual U.S. economic misery index, which is the sum of inflation and unemployment rates. We find a peak in the goodness of fit at 11 years for the moving average. The fit between the two misery indices holds when using different techniques to measure the literary misery index, and this fit is significantly better than other possible correlations with different emotion indices. To check the robustness of the results, we also analysed books written in German language and obtained very similar correlations with the German economic misery index. The results suggest that millions of books published every year average the authors' shared economic experiences over the past decade.

  17. Induced vaginal birth after previous caesarean section

    Directory of Open Access Journals (Sweden)

    Akylbek Tussupkaliyev

    2016-11-01

    Full Text Available Introduction The rate of operative birth by Caesarean section is constantly rising. In Kazakhstan, it reaches 27 per cent. Research data confirm that the percentage of successful vaginal births after previous Caesarean section is 50–70 per cent. How safe the induction of vaginal birth after Caesarean (VBAC remains unclear. Methodology The studied techniques of labour induction were amniotomy of the foetal bladder with the vulsellum ramus, intravaginal administration of E1 prostaglandin (Misoprostol, and intravenous infusion of Oxytocin-Richter. The assessment of rediness of parturient canals was conducted by Bishop’s score; the labour course was assessed by a partogram. The effectiveness of labour induction techniques was assessed by the number of administered doses, the time of onset of regular labour, the course of labour and the postpartum period and the presence of complications, and the course of the early neonatal period, which implied the assessment of the child’s condition, described in the newborn development record. The foetus was assessed by medical ultrasound and antenatal and intranatal cardiotocography (CTG. Obtained results were analysed with SAS statistical processing software. Results The overall percentage of successful births with intravaginal administration of Misoprostol was 93 per cent (83 of cases. This percentage was higher than in the amniotomy group (relative risk (RR 11.7 and was similar to the oxytocin group (RR 0.83. Amniotomy was effective in 54 per cent (39 of cases, when it induced regular labour. Intravenous oxytocin infusion was effective in 94 per cent (89 of cases. This percentage was higher than that with amniotomy (RR 12.5. Conclusions The success of vaginal delivery after previous Caesarean section can be achieved in almost 70 per cent of cases. At that, labour induction does not decrease this indicator and remains within population boundaries.

  18. Previous experiences shape adaptive mate preferences

    NARCIS (Netherlands)

    Fawcett, Tim W.; Bleay, Colin

    2009-01-01

    Existing models of mate choice assume that individuals have perfect knowledge of their own ability to attract a mate and can adjust their preferences accordingly. However, real animals will typically be uncertain of their own attractiveness. A potentially useful source of information on this is the

  19. Departures from LTE Populations Versus Anomalous Abundances: the Effects of Heating

    Science.gov (United States)

    Underhill, A. B.

    1985-01-01

    The deposit of nonradiative heat and momentum in the mantle of a hot star affects the interpretation of the stellar spectrum in two ways. First, a superheated and moving plasma should be considered when doing the analysis, and second, a model atom which is appropriate for the physical state of the line forming regions. Some examples are presented for H and He showing how the changes in the electron temperature affect the solution of the equations of statistical equilibrium. The observed spectra of the Wolf-Raynet stars HD 191765, HD 192103, and HD 192163 are compatible with a normal H/He abundance ratio.

  20. 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)

  1. Energy Efficiency vs. Throughput Trade-Off in an LTE-A Scenario

    DEFF Research Database (Denmark)

    Mihaylov, Mihail Rumenov; Mihovska, Albena D.; Prasad, Ramjee

    2014-01-01

    . This paper proposes an approach to optimizing network performance by introducing an estimation of the energy consumption associated with the allocation of physical resources to users, as well as their offload from one serving base station to another (macro or pico). An algorithm for minimizing the energy......The growing demand of throughput, coverage and capacity has motivated the deployment of small cells as a cheaper option to macro base stations. Such heterogeneous scenario has also introduced novel advanced resource allocation and load balancing mechanisms for increased system performance...... consumption while optimizing resource allocation to pico-cell users in a wireless heterogeneous scenario is proposed and evaluated. The adopted model uses the information about the distance between the cells, their load and the quality of service (QoS) requirements of the mobile users together...

  2. Performance of green LTE networks powered by the smart grid with time varying user density

    KAUST Repository

    Ghazzai, Hakim

    2013-09-01

    In this study, we implement a green heuristic algorithm involving the base station sleeping strategy that aims to ensure energy saving for the radio access network of the 4GLTE (Fourth Generation Long Term Evolution) mobile networks. We propose an energy procurement model that takes into consideration the existence of multiple energy providers in the smart grid power system (e.g. fossil fuel and renewable energy sources, etc.) in addition to deployed photovoltaic panels in base station sites. Moreover, the analysis is based on the dynamic time variation of daily traffic and aims to maintain the network quality of service. Our simulation results show an important contribution in the reduction of CO2 emissions that can be reached by optimal power allocation over the active base stations. Copyright © 2013 by the Institute of Electrical and Electronic Engineers, Inc.

  3. Dynamics of quiescent prominence fine structures analyzed by 2D non-LTE modelling of the Hα line

    Czech Academy of Sciences Publication Activity Database

    Gunár, Stanislav; Mein, P.; Schmieder, B.; Heinzel, Petr; Mein, N.

    2012-01-01

    Roč. 543, July (2012), A93/1-A93/15 ISSN 0004-6361 R&D Projects: GA ČR GP205/09/P554; GA ČR GAP209/12/0906 Institutional support: RVO:67985815 Keywords : Sun * filaments * prominences Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 5.084, year: 2012

  4. Design for LTE EOS and opacity experiments using supersonic radiation waves

    Science.gov (United States)

    Tierney, T. E.; Peterson, R. R.; Tierney, H. E.

    2007-11-01

    Opacity and EOS at 100-200 eV are important physical parameters in ICF experiments. We describe an experiment design that uses the supersonic propagation of hohlraum radiation in foams to isochorically heat samples. Laser and Z-pinch experiments frequently use 150 to 220-eV quasi-blackbody emission from hohlraums to drive physics experiments. A foam target encapsulated in a gold-wall cylinder is placed next to the hohlraum. The low density and opacity foam captures some hohlraum emission and generates a supersonically-propagating radiation wave. The material heated by the wave is cooler towards the high-albedo gold wall. Modeling and past measurements show that core regions of the foam have small thermal gradients. We place a small, thin sample (e.g., Al, Si, or Fe) in the thermally-uniform region. X-ray emission of tracers and the sample as well as quasi-continuum x-ray absorption will be measured using time-resolved x-ray spectroscopy. The foam's EOS can be measured to ±5% by blast waves with a well characterized drive. This experiment could use the OMEGA, Z-Beamlet, and/or ZR facilities to explore temperature-dependent conditions.

  5. Theory of extended stellar atmospheres. II. A grid of static spherical models for O stars and planetary nebula nuclei

    International Nuclear Information System (INIS)

    Kunasz, P.B.; Hummer, D.G.; Mihalas, D.

    1975-01-01

    Spherical static non-LTE model atmospheres are presented for stars with M/M/sub sun/=30 and 60 at various points on their evolutionary tracks, and for some nuclei of planetary nebulae at two points of a modified Harman-Seaton sequence. The method of Mihalas and Hummer was employed, which uses a parametrized radiation force multiplier to simulate the force of radiation arising from the entire line spectrum. However, in the present work the density structure computed in the LTE models was held fixed in the calculation of the corresponding non-LTE models; in addition, the opacity of an ''average light ion'' was taken into account. The temperatures for the non-LTE models are generally lower, at a given depth, than for the corresponding LTE models when T/sub eff/<45,000 K, while the situation is reversed at higher temperatures. The continuous energy distributions are generally flattened by extension. The Lyman jump is in emission for extended models of massive stars, but never for the models of nuclei of planetary nebulae (this is primarily a temperature effect). The Balmer jumps are always in absorption. The Lyman lines are in emission, and the Balmer lines in absorption; He ii lambda4686 comes into emission in the most extended models without hydrogen line pumping, showing that it is an indicator of atmospheric extension. Very severe limb darkening is found for extended models, which have apparent angular sized significantly smaller than expected from the geometrical size of the star. Extensive tables are given of monochromatic magnitudes, continuum jumps and gradients, Stomgren-system colors, monochromatic extensions, and the profiles and equivalent widths of the hydrogen lines for all models, and of the He ii lines for some of the 60 M/sub X/ models

  6. Executive Function in Previously Institutionalized Children.

    Science.gov (United States)

    Merz, Emily C; Harlé, Katia M; Noble, Kimberly G; McCall, Robert B

    2016-06-01

    In studies of children adopted from institutions, being raised in an institution has been associated consistently with an increased risk of persistent cognitive, academic, and social-emotional problems. These findings raise questions about the neurocognitive mechanisms that contribute to these negative outcomes. Theory and models based on studies of animals indicate that development of the prefrontal cortex (PFC) and executive function (EF) may be particularly susceptible to environmental influences during early childhood. In this article, we review recent studies of postinstitutionalized children that examined EF components such as inhibitory control, working memory, shifting, and planning. We then describe emerging research on the structure and function of the PFC. Converging evidence suggests both EF difficulties and alterations in development of the PFC following early institutionalization. We conclude by discussing possible explanations for these findings and implications for prevention and intervention, and by offering suggestions for ongoing research.

  7. A high-linearity CMOS receiver achieving +44dBm IIP3 and +13dBm B1dB for SAW-less LTE radio

    NARCIS (Netherlands)

    Lien, Yuan-Ching; Klumperink, Eric A.M.; Tenbroek, Bernard; Strange, Jon; Nauta, Bram

    2017-01-01

    LTE-advanced wireless receivers require high-linearity up-front filtering to prevent corruption of the in-band signals by strong out-of-band (OOB) signals and self-interference from the transmitter. SAW duplexer filters are generally used for this purpose, but supporting the plethora of existing and

  8. Nicotine Elicits Methamphetamine-Seeking in Rats Previously Administered Nicotine

    OpenAIRE

    Neugebauer, N. M.; Harrod, S. B.; Bardo, M. T.

    2009-01-01

    Research has indicated a high correlation between psychostimulant use and tobacco cigarette smoking in human substance abusers. The objective of the current study was to examine the effects of acute and repeated nicotine administration on responding for intravenous methamphetamine (0.03 mg/kg/infusion) in a rodent model of self-administration, as well as the potential of nicotine to induce reinstatement of previously extinguished drug-taking behavior in male Sprague-Dawley rats. In addition, ...

  9. Modelling of high-enthalpy, high-Mach number flows

    International Nuclear Information System (INIS)

    Degrez, G; Lani, A; Panesi, M; Chazot, O; Deconinck, H

    2009-01-01

    A review is made of the computational models of high-enthalpy flows developed over the past few years at the von Karman Institute and Universite Libre de Bruxelles, for the modelling of high-enthalpy hypersonic (re-)entry flows. Both flows in local thermo-chemical equilibrium (LTE) and flows in thermo-chemical non-equilibrium (TCNEQ) are considered. First, the physico-chemical models are described, i.e. the set of conservation laws, the thermodynamics, transport phenomena and chemical kinetics models. Particular attention is given to the correct modelling of elemental (LTE flows) and species (chemical non-equilibrium-CNEQ-flows) transport. The numerical algorithm, based on a state-of-the-art finite volume discretization, is then briefly described. Finally, selected examples are included to illustrate the capabilities of the developed solver. (review article)

  10. Rates of induced abortion in Denmark according to age, previous births and previous abortions

    Directory of Open Access Journals (Sweden)

    Marie-Louise H. Hansen

    2009-11-01

    Full Text Available Background: Whereas the effects of various socio-demographic determinants on a woman's risk of having an abortion are relatively well-documented, less attention has been given to the effect of previous abortions and births. Objective: To study the effect of previous abortions and births on Danish women's risk of an abortion, in addition to a number of demographic and personal characteristics. Data and methods: From the Fertility of Women and Couples Dataset we obtained data on the number of live births and induced abortions by year (1981-2001, age (16-39, county of residence and marital status. Logistic regression analysis was used to estimate the influence of the explanatory variables on the probability of having an abortion in a relevant year. Main findings and conclusion: A woman's risk of having an abortion increases with the number of previous births and previous abortions. Some interactions were was found in the way a woman's risk of abortion varies with calendar year, age and parity. The risk of an abortion for women with no children decreases while the risk of an abortion for women with children increases over time. Furthermore, the risk of an abortion decreases with age, but relatively more so for women with children compared to childless women. Trends for teenagers are discussed in a separate section.

  11. A fusion networking model for smart grid power distribution backbone communication network based on PTN

    Directory of Open Access Journals (Sweden)

    Wang Hao

    2016-01-01

    Full Text Available In current communication network for distribution in Chinese power grid systems, the fiber communication backbone network for distribution and TD-LTE power private wireless backhaul network of power grid are both bearing by the SDH optical transmission network, which also carries the communication network of transformer substation and main electric. As the data traffic of the distribution communication and TD-LTE power private wireless network grow rapidly in recent years, it will have a big impact with the SDH network’s bearing capacity which is mainly used for main electric communication in high security level. This paper presents a fusion networking model which use a multiple-layer PTN network as the unified bearing of the TD-LTE power private wireless backhaul network and fiber communication backbone network for distribution. Network dataflow analysis shows that this model can greatly reduce the capacity pressure of the traditional SDH network as well as ensure the reliability of the transmission of the communication network for distribution and TD-LTE power private wireless network.

  12. General LTE Sequence

    OpenAIRE

    Billal, Masum

    2015-01-01

    In this paper,we have characterized sequences which maintain the same property described in Lifting the Exponent Lemma. Lifting the Exponent Lemma is a very powerful tool in olympiad number theory and recently it has become very popular. We generalize it to all sequences that maintain a property like it i.e. if p^{\\alpha}||a_k and p^\\b{eta}||n, then p^{{\\alpha}+\\b{eta}}||a_{nk}.

  13. LTE Part I

    DEFF Research Database (Denmark)

    Bogineni, K.; Ludwig, R.; Mogensen, Preben

    2009-01-01

    a session while the user is moving and roaming. Services have to be delivered to users based on serving network functionality (quality of service [QoS], bandwidth, etc.), availability, and user preferences. The network and users must be protected through various authentication, encryption, and other...... security mechanisms at the access, network, and application layers. Mobility has to be provided through coordinated link, network, and application layer mobility mechanisms that ensure user expectations of service performance are met. Requirements on the radio technology include improved performance...

  14. Response to health insurance by previously uninsured rural children.

    Science.gov (United States)

    Tilford, J M; Robbins, J M; Shema, S J; Farmer, F L

    1999-08-01

    To examine the healthcare utilization and costs of previously uninsured rural children. Four years of claims data from a school-based health insurance program located in the Mississippi Delta. All children who were not Medicaid-eligible or were uninsured, were eligible for limited benefits under the program. The 1987 National Medical Expenditure Survey (NMES) was used to compare utilization of services. The study represents a natural experiment in the provision of insurance benefits to a previously uninsured population. Premiums for the claims cost were set with little or no information on expected use of services. Claims from the insurer were used to form a panel data set. Mixed model logistic and linear regressions were estimated to determine the response to insurance for several categories of health services. The use of services increased over time and approached the level of utilization in the NMES. Conditional medical expenditures also increased over time. Actuarial estimates of claims cost greatly exceeded actual claims cost. The provision of a limited medical, dental, and optical benefit package cost approximately $20-$24 per member per month in claims paid. An important uncertainty in providing health insurance to previously uninsured populations is whether a pent-up demand exists for health services. Evidence of a pent-up demand for medical services was not supported in this study of rural school-age children. States considering partnerships with private insurers to implement the State Children's Health Insurance Program could lower premium costs by assembling basic data on previously uninsured children.

  15. Circumnuclear Multi-phase Gas in the Circinus Galaxy. I. Non-LTE Calculations of CO Lines

    Science.gov (United States)

    Wada, Keiichi; Fukushige, Ryosuke; Izumi, Takuma; Tomisaka, Kohji

    2018-01-01

    In this study, we investigate the line emissions from cold molecular gas based on our previous “radiation-driven fountain model,” which reliably explains the spectral energy distribution of the nearest type 2 Seyfert galaxy, the Circinus galaxy. Using a snapshot of the best-fit radiation-hydrodynamic model for the central r≤slant 16 pc, in which non-equilibrium X-ray-dominated region chemistry is solved, we conduct post-processed non-local thermodynamic equilibrium radiation transfer simulations for the CO lines. We obtain a spectral line energy distribution with a peak around J≃ 6, and its distribution suggests that the lines are not thermalized. However, for a given line of sight, the optical depth distribution is highly non-uniform between {τ }ν \\ll 1 and {τ }ν \\gg 1. The CO-to-H2 conversion factor ({X}{CO}), which can be directly obtained from the results and is not a constant, depends strongly on the integrated intensity and differs from the fiducial value for local objects. {X}{CO} exhibits a large dispersion of more than one order of magnitude, reflecting the non-uniform internal structure of a “torus.” In addition, we found that the physical conditions differ between grid cells on a scale of a few parsecs along the observed lines of sight; therefore, a specific observed line ratio does not necessarily represent a single physical state of the interstellar medium.

  16. Optimal temperature for malaria transmission is dramaticallylower than previously predicted

    Science.gov (United States)

    Mordecai, Eerin A.; Paaijmans, Krijin P.; Johnson, Leah R.; Balzer, Christian; Ben-Horin, Tal; de Moor, Emily; McNally, Amy; Pawar, Samraat; Ryan, Sadie J.; Smith, Thomas C.; Lafferty, Kevin D.

    2013-01-01

    The ecology of mosquito vectors and malaria parasites affect the incidence, seasonal transmission and geographical range of malaria. Most malaria models to date assume constant or linear responses of mosquito and parasite life-history traits to temperature, predicting optimal transmission at 31 °C. These models are at odds with field observations of transmission dating back nearly a century. We build a model with more realistic ecological assumptions about the thermal physiology of insects. Our model, which includes empirically derived nonlinear thermal responses, predicts optimal malaria transmission at 25 °C (6 °C lower than previous models). Moreover, the model predicts that transmission decreases dramatically at temperatures > 28 °C, altering predictions about how climate change will affect malaria. A large data set on malaria transmission risk in Africa validates both the 25 °C optimum and the decline above 28 °C. Using these more accurate nonlinear thermal-response models will aid in understanding the effects of current and future temperature regimes on disease transmission.

  17. Aspirin-Intolerant Asthma (AIA Assessment Using the Urinary Biomarkers, Leukotriene E4 (LTE4 and Prostaglandin D2 (PGD2 Metabolites

    Directory of Open Access Journals (Sweden)

    Noritaka Higashi

    2012-01-01

    Full Text Available The clinical syndrome of aspirin-intolerant asthma (AIA is characterized by aspirin/nonsteroidal antiinflammatory drug intolerance, bronchial asthma, and chronic rhinosinusitis with nasal polyposis. AIA reactions are evidently triggered by pharmacological effect of cyclooxygenase-1 inhibitors. Urine sampling is a non-invasive research tool for time-course measurements in clinical investigations. The urinary stable metabolite concentration of arachidonic acid products provides a time-integrated estimate of the production of the parent compounds in vivo. AIA patients exhibits significantly higher urinary concentrations of leukotriene E4 (LTE4 and 1,15-dioxo-9α-hydroxy-2,3,4,5-tetranorprostan-1,20-dioic acid (tetranor-PGDM, a newly identified metabolite of PGD2, at baseline. This finding suggests the possibility that increased mast cell activation is involved in the pathophysiology of AIA even in a clinically stable condition. In addition, lower urinary concentrations of primary prostaglandin E2 and 15-epimer of lipoxin A4 at baseline in the AIA patients suggest that the impaired anti-inflammatory elements may also contribute to the severe clinical outcome of AIA. During the AIA reaction, the urinary concentrations of LTE4 and PGD2 metabolites, including tetranor-PGDM significantly and correlatively increase. It is considered that mast cell activation probably is a pathophysiologic hallmark of AIA. However, despite the fact that cyclooxygenease-1 is the dominant in vivo PGD2 biosynthetic pathway, the precise mechanism underlying the PGD2 overproduction resulting from the pharmacological effect of cyclooxygenease-1 inhibitors in AIA remains unknown. A comprehensive analysis of the urinary concentration of inflammatory mediators may afford a new research target in elucidating the pathophysiology of AIA.

  18. SCROLL, a superconfiguration collisional radiative model with external radiation

    International Nuclear Information System (INIS)

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

    2000-01-01

    A collisional radiative model for calculating non-local thermodynamical-equilibrium (non-LTE) spectra of heavy atoms in hot plasmas has been developed. It takes into account the numerous excited an autoionizing states by using superconfigurations. These are split systematically until the populations converge. The influence of an impinging radiation field has recently been added to the model. The effect can be very important. (author)

  19. A Hybrid Networking Model for the Access Layer of the Communication Network for Distribution in Smart Grid

    Directory of Open Access Journals (Sweden)

    Wang Hao

    2016-01-01

    Full Text Available The access layer in the communication network for distribution is an important link in the automation of smart distribution power grid. In current access layer of communication network for distribution in Chinese power grid systems, several communication methods like optical fiber, mediumvoltage carrier communication, 1.8GHz TD-LTE power private wireless network, 230MHz TD-LTE power private wireless network, public wireless network are constructed concurrently and running simultaneously in an identical power supply area. This traditional networking model will cause repeated construction and operation and maintenance difficulties in the communication network of power grid. On the basis of giving a detailed analysis of the radio link budget of TD-LTE power private wireless network in two frequencies, this paper present a multi-communication methods hybrid networking model, which gives a clear boundary for different communication methods based on the isoline with equal signal strength of the TD-LTE power private wireless network and accomplish the optimization of communication resources for distribution.

  20. Optimization of hydraulic machinery by exploiting previous successful designs

    Energy Technology Data Exchange (ETDEWEB)

    Kyriacou, S A; Giannakoglou, K C [National Technical University of Athens, Parallel CFD and Optimization Unit, PO Box 64069, Athens 15710 (Greece); Weissenberger, S; Grafenberger, P, E-mail: stelios.Kyriacou@gmail.co [Andritz HYDRO, RD, Lunzerstrasse 78, 4031 Linz (Austria)

    2010-08-15

    A design-optimization method for hydraulic machinery is proposed. Optimal designs are obtained using the appropriate CFD evaluation software driven by an evolutionary algorithm which is also assisted by artificial neural networks used as surrogate evaluation models or metamodels. As shown in a previous IAHR paper by the same authors, such an optimization method substantially reduces the CPU cost, since the metamodels can discard numerous non-promising candidate solutions generated during the evolution, at almost negligible CPU cost, without evaluating them by means of the costly CFD tool. The present paper extends the optimization method of the previous paper by making it capable to accommodate and exploit pieces of useful information archived during previous relevant successful designs. So, instead of parameterizing the geometry of the hydraulic machine components, which inevitably leads to many design variables, enough to slow down the design procedure, in the proposed method all new designs are expressed as weighted combinations of the archived ones. The archived designs act as the design space bases. The role of the optimization algorithms is to find the set (or sets, for more than one objectives, where the Pareto front of non-dominated solutions is sought) of weight values, corresponding to the hydraulic machine configuration(s) with optimal performance. Since the number of weights is much less that the number of design variables of the conventional shape parameterization, the design space dimension reduces and the CPU cost of the metamodel-assisted evolutionary algorithm is much lower. The design of a Francis runner is used to demonstrate the capabilities of the proposed method.