Items of № 7, 2011

The Electrosvyaz Magazine is one of the leading science & technical magazines in Russia.


Advancement of wireless access theory

Learning the handle centimeter radio-waves to realize wireless access to the information and computing resources resulted in intensive developments of technical facilities for the different classes of wireless networks. The paper gives a short review of the three new direction of wireless access theory. The method of sparse recovery using sparse matrices supports the algorithms with low computational complexity and makes it easy to perform incremental updates to signals. The compressed channel sensing can collect available information about multipath channels. And the trust and reputation management systems can open the new possibilities in improving the operationof the mobile ad hoc networks (MANET), wireless sensor networks and cognitive radio networks. Key words: MANET, wireless networks, management, multipath channels.



Standardization of services and issues of their global interoperability

The rapid development of new technologies is currently allows operators to expand the range of communication services.
International experience in implementing new technologies and services shows that, despite many opportunities to introduce new services, however, there are a number of important problems that inhibit this process, most of which is associated with the incompatibility of hardware from different vendors.
As a result, development of requirements for the service and order of its delivery is becoming one of the most pressing challenges facing the telecommunications industry and services testing assume a new significance and practical value to telecom operators.
Key words: NGN, telecommunication services, standardization, testing, model network.



Assessing energy consumption efficiency in nonlinear load AC circuits

It Is Discussed problem to efficiency of the use to electric energy of alternating current in single-phase and three-phase set with electronic load. The Problem is caused no sinusoidal consumed current. Accounting correlations are received for estimation of the power consumption leading indexes.
Key words: nonlinear consumers to energy, electronic load, factors to efficiency of энергопотребления alternating current.



Estimation of a network’s voltage distortion factors in a nonlinear user’s connection point

They are discussed dependencies quality voltages to electric network, controlled in point of the connection of the nonlinear load, from parameter of the load. Analytical expressions are received for estimation factor distortion.
Key words: nonlinear (electronic) load, factors of voltage distortion, point connection to network.


Comparative evaluation of industrial high-frequency buffer rectifiers’ output resistance

In the article is given estimation of the output dynamic resistance of stabilized rectifiers [VBV], which is absent from the specifications. It plays important role in the work of rectifier. Thus, article has practical value. Key words: VBV, specification, rectifier.



Capacity of communication channels in a power supply network

This article contains results of experimental determination of speed of information transmission in communication channels, realized in a power network, but using different structures, which are directing electromagnetic waves of signal. The conclusion about the superiority of a single-wire structure over the two-wire structure in the presence of electricity consumers, filters, and uninterruptible power supplies.
Key words: guided electromagnetic waves, single-wire guide system, the transfer of information in the supply network, single-wire communication in the supply network, the standard HomePlug AV.



Modeling of optical fibers for differential mode delay minimization in multimode fiber links

Method for modeling of multimode optical fibers to minimize the differential mode delay (DMD) in multimode fiber links is represented. Based on proposed method, a several samples of refractive index profiles of reverse DMD fibers (RDMDF) for DMD compensation and multimode fibers with low DMD for multi-Gigabit low-mode optical signal transmission were obtained. Correctness of developed method is submitted by results of numerical modeling of low mode optical signal propagation over multimode link with mentioned fiber samples.
Key words: Multimode optical fibers, differential mode delay (DMD), DMD compensation, multimode fibers with low DMD.



Method of probabilistic assessment of a multiple-beam satellite mass service network’s throughput

An approach to analyze the capacity of multi-beam queuing satellite Ka-band systems is presented. The formulas to estimate the basic parameters of the network are given, allowing to assess the capacity in each beam of multi-beam satellite system, based on the use of «over-subscription ratio” and taking into account the link availability.
As a result, the presented method allows to perform rapid assessment of the allowable number of subscribers of the network at given link performance, or to solve the inverse problem.
Key words: satellite communication, VSAT, Ka-band.



Studing the algorithm of Kalman filtering of a voice signal observed in noise

On a basis the zero — polar (autoregressions with a slipping average) of model of the vocal tract set by the equations of a condition and supervision which is the synthesis of an optimum linear filter for an estimation of a speech watched against noise. It is used in theoretical and an experimental research of the filter taking into account an estimation of its parameters on the basis of a recurrent method of least squares with final memory. Best values «factor forgetings» ensuring maximum values of improving signal/noise ratio on a filter output in comparison with its entry which are experimentally installed. Key words: zero — polar, linear filter, final memory, signal/noise.



Analyzing the RCC member countries’ infocommunication development accomplished in 2009

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