Items of № 4, 2009

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

Architecture of SS7 network security


In article general provisions of architecture of security network infrastructures are stated. Infrastructures networks will consist of communication networks and means of access of users to the necessary information, its storage and processing. In work the developed architecture of network safety of concrete system SS7 is offered, being a component of public networks of Russia — public telephone network PSTN/ISDN, a cellular communication network of standard GSM and intelligent network IN.

Key words: architecture security network, signaling system 7, mobile network GSM, intelligent network, threats «denial of services».

16-bit key crypto secure encoding possible?


Described RNG-16 algorithm, it’s structure chart, cycles, cryptosecurity. Evaluated RNG-16 key length and it’s encryptor’s capacity and simulation tolerance.

Key words: Random number generation, stream encryptor, cryptosecurity, random-number sequence.

Issues of ensuring long term operation for communication satellites' onboard avionics


The methods of providing and enhancing lifetime of communication satellite avionics exposed to space ionizing radiation which limit spacecraft lifetime are presented in this article. These conditions are the main destabilizing factors. The methods include: direct monitoring of space ionizing radiation in a spacecraft, methods of spacecraft electronic components hardness to space ionizing radiation characteristic determination, constructional technological methods of spacecraft electronic components hardness to space ionizing radiation enhancing, informational methods of spacecraft electronic components hardness to space ionizing radiation development, development of a branch electronic components space ionizing radiation hardness testing facility. Also, Federal Unitary State Enterprise Institute of Space Device Engineering (FUSI SDE) strands of works printed above are considered.

Key words: onboard avionics hardness, spacecraft lifetime, space ionizing radiation, space ionizing radiation monitoring, structural algorithmic methods, test-bench, electronic component hardness information system, branch space ionizing radiation hardness testing centre.

Web-servers search time distribution analysis


Distribution of the resources request time in various telecommunication systems of IP, GSM, ATM etc. technologies is investigated. The unified algorithm based on the processing in IP-networks is described as well as its mathematical formulation. Time of inquiries passage is divided into the components of the same type which distribution depends on hardware-software filling of servers or specific features of communication channels. For all components it is offered the analytical description based on the modern statistical investigations in terms of Gauss functions and generalized hyper geometrical functions convolutions with illustrations of numerical computations. The proposed approach considerably expands the possibilities of analysis and forecasting the characteristics of the service of users and the processing of self-similar traffic by telecommunication networks in comparison with the existing studies relating to separate servers.

Key words: Service model, telegraphy, telecommunication networks load, traffic’s analysis.

Using artificial processes for modeling traffic in network structures


The task of making the mathematical models long-term depending traffic can not be solved analytically. For analysis of network performance at building of the queues are used traffic routes, founded on real measurements. However, measured traffic routes are not suitable for practical use. In these conditions special urgency gains the problem of generation the artificial traffic. In the given article this problem is solved by using the transformations function casual argument for generation of the traffic with permanent dependency. In article are received the main correlations and is brought algorithm of the shaping сsingular pulsed sequences, resulting from functional transformations initial functions of distribution into casual processes with required characteristics.

Key words: сsingular intensity, variability, heavy «tails», permanent dependency, self-similarity load, traffic of the route, factor Hersta, index to dispersions.

A video information transmission system’s reliability evaluation

Zatuchny D.A.

In this article the problem of reliability’s evaluation of system for videoinformation’s broadcasting based on apriori information about element’s reliability is solved. Method of reliability’s evaluation this system based on known method for successive auхiliary structure is reduced.

Key words: probability of unfailured work, auхiliary structure, function of reliability.

Telemedicine images fractal compression


In this paper we address the problem of medical image transmission via narrowband (telephone) channels. It is experimentally shown, that the real-time transmission is only possible when high compression ratios are used. Currently used JPEG standard doesn’t allow reaching acceptable performance while preserving high image quality, which is necessary for medical images. In order to solve this problem we propose implementation of fractal image compression which has better rate-distortion curve than JPEG. But the main drawback of fractal image compression — long computing times in the encoding phase prevents it from using in real-time applications. We introduce different methods of fractal image compression acceleration that can be used separately or cumulatively. Application of these methods makes real-time fractal image compression possible.

Key words: telemedicine, fractal image compression, speed-up.

Reception and elementwise processing of n-class binary signals by means of predetection decoding


In radio engineering systems (RTS) of transfer of the discrete information (discrete messages) are widely used n-digit binary signals. Binary signals receive fast distribution and to RTS of transfer of analog messages in connection with transition to digital methods of processing.

Key words: n-class binary signals, predetection decoding, afterdetection decoding, coherent reception, quasi-coherent reception.

Method of digital signals' relative amplitude demodulation


In article is investigated method of demodulation digital AM-signals. Find a use comparison of accumulated signal-levels on neighboring bit-intervals. It is use also difference and summarize channels, comparators of zero- and some- thresholdswitch, equipment logicalanalysis of repetitions. It is recommend codification SM-1. It was make basing of some gain in comparison of optimal-AT.

Key words: demodulation, difference and summing channels, comparators, polarities coincidence means, coding.

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