Written by tuzs
You can read the electronic version of the journal issue - Volume 4, Issue 2, 2018.
Contents of the issue
- Al-Odhari A., Fokin G.
Positioning of Radio Emission Sources in Hilly Terrain Using Unmanned Aerial Vehicles
- Abstract: In the present work mathematical and simulation models of the positioning of radio emission sources in three-dimensional space on the basis of a distance-ranging method with the use of unmanned aerial vehicles have been developed and an accuracy estimation of positioning of mobile and stationary sources of radio emission sources in three-dimensional space with the use of an unmanned aerial is evaluated. Also, an algorithm and methods for identifying and compensating of sources of measurement with NLOS measurements for the positioning of radio emission sources using fixed reception points as part of the ground segment and mobile receiving points on board of an unmanned aerial vehicle as part of an air segment in three-dimensional space was generalized.
- Keywords: radiation source, receiving point, Non-Line-of-Sight, time difference of arrival, simulation model, three-dimensional space
- Andreev V., Bourdine A., Burdin V.
Research of Real Few-Mode Optical Fiber Geometry Deviation from the Optimal Form Influence on Differential Mode Delay Spectral Characteristics Degradation
- Abstract: This work presents some results of theoretical research of few-mode optical fiber geometry deviation from the optimal form influence on differential mode delay spectral characteristics degradation. We considered non-symmetrical non-circular 16-mode optical fibers 42/125 with reduced differential mode delay over “C”-band provided by special refractive index profile form. Optimized profile form was distorted by local refractive index fluctuations. Core ellipticity and profile distortions were set via parameters been got by reports of real commercially available multimode optical fibers 50/125 Cat. OM2 and OM2+/OM3 refractive index profile measurements.
- Keywords: few-mode optical fibers, few-mode regime of optical signal transmission, differential mode delay, non-symmetrical optical fibers, refractive index profile
- Andreeva E., Bylina M., Glagolev S., Chaimardanov P.
Properties of temporary optical solitons in optical fibers and the possibility of their use in telecommunications. Part 2
- Abstract: In the second part of the work, a theoretical study of the propagation processes of pulses having the form of a hyperbolic secant is performed using single-mode optical fibers with allowance for losses. It is shown that the quasisoliton regime in optical fibers disintegrates with increasing distance, but it can be supported by attenuation control, i.e. periodic optical amplification, which can be realized using discrete or distributed amplifiers. The questions of the choice of the lengths of the amplifying regions, the levels of the input signal, the amplification factors of the discrete amplifiers, the levels of the pump radiation of the distributed amplifiers are considered. Simulation modeling of processes in linear paths of fiber-optic communication systems using the OptiSystem and AltPhotonic Simulation Tool is performed.
- Keywords: optical soliton, temporary optical soliton, single-mode optical fiber, fiber optic communication system, group velocity dispersion, self-phase modulation, optical amplification.
- Babaev N., Simonina O.
Methodology of Upgrading the TETRA Communication System
- Abstract: The article proposes a method of modernization of the section of the October railway station Chudovo – station Gryadi, equipped with a trunking system TETRA standard. The technique is based on the developed mathematical model verified on the basis of full-scale measurements. The purpose of full-scale measurements was to find weak coverage areas and visualize the real values of the signal level on the coverage map. The model includes expressions for the calculation of TETRA network coverage based on the Okamura-Khat model adjusted for the specifics of train communication. On the basis of the developed recommendations, it was proposed to modernize the section of the station Chudovo – station Gryadi by installing a new base station.
- Keywords: TETRA, railway, trunking, measurement
- Voloshinov D.
Constructive Geometric Model of Four-Dimensional Space as a Basis for Solving Problems of Zoning and Positioning in the Design Mobile Network
- Abstract: It is proved in the article, that the Apollonius problem and its analogues have a single method of solution, in contrast to the current notion, that these problems can be solved only in individual ways. The concept of the geometric experiment, proposed by the author, made it possible to discover many previously unknown laws, discussed in the article, thanks to the carrying out of numerous computational tests in the system Simplex, developed for visual design of geometric models. In this paper it is considered an example of a solution on the analog of the Apollonius problem for four-dimensional space, but the developed algorithm is universal, and it can be applied with equal success to solving similar problems in spaces of arbitrary dimensions. The obtained results demonstrate the possibilities of constructive modeling methods and multidimensional descriptive geometry in the application to solving complex mathematical problems, determine the trends in the development of automation systems for constructive geometric modeling.
- Keywords: mobile network, Voronoi Diagrams, scientific visualization, multidimensional constructive geometric modeling, geometric experiment, projective geometry, the problem of Apollonius, imaginary geometric objects, zoning, positioning.
- Vorobiev O., Prasolov A.
Comparison of Methods for Increasing the Dynamic Range of ADC in Digital Radio Receivers
- Abstract: This article discusses methods for increasing the dynamic range of Analog-to-digital converter in digital radio receivers and its comparative analysis. Analytic equations and experimental results are given. Conclusions about the performance of the discussed methods are drawn.
- Keywords: dynamic range, digital radio receivers, Analog-to-digital converter, oversampling, post-correction, companding, dither
- Dvornikov S.
Bilinear Time-Frequency Distributions with a Lowered Level of the Interference Background in the Frequency-Temporary Space: Continued Review
- Abstract: An overview of the theoretical foundations of the synthesis of various types of pseudo-distributions of the Wigner class is presented. The possibilities of known approaches to reduce the negative consequences of processing multicomponent signals based on bilinear distributions are analyzed. Analytical expressions for time-frequency distributions with a low level of interference background are presented. The reasons for applying smoothing window functions in the frequency and time spaces are substantiated. Analytical expressions and experimental results of the most known forms of bilinear distributions with a reduced level of interference background are presented.
- Keywords: frequency-time pseudo-distributions, methods for controlling the interference background, processing multicomponent signals, distribution of the Cohen class
- Makarenko S.
The Improved OSPF Protocol for High Network Stability
- Abstract: The improved OSPF routing protocol is presents in the paper. The improved OSPF protocol is to use topological network redundancy and create backup paths. This protocol provides high network stability, if the network topology changes rapidly.
- Keywords: network, routing protocol, network stability, network convergence time, OSPF
- Makarov L., Protasenya S.
The Fractal Simulation Image of Atom of Silicon in Microelectronics
- Abstract: The questions of synthesis of fractal model considering features of technology of creation of semiconductor structures on the basis of stable isotopes of silicon are considered. The general principle of aprioristic creation of the semiconductor materials capable to realize a high rate of heat conductivity for products of the microelectronics operated at high frequencies is established. The components of the general concept of synthesis of new samples of products of microelectronics showing the prospects of computer modeling of fractal images of atomic designs of semiconductors are presented.
- Keywords: simulation, microelectronics, fractal image, isotope, semiconductors