STUDY OF QUALITY OF SERVICE IN 5G AND NEXT-GENERATION NETWORKS
A.A. Alzagir, The Bonch-Bruevich Saint-Petersburg State University of Telecommunications (SPbSUT), department of communication networks and data transmission (CN&DT), postgraduate; email@example.com
A.I. Paramonov, SPbSUT, department of CN&DT, professor, Dr.Sci.(Tech.); firstname.lastname@example.org
A.E. Koucheryavy, SPbSUT, head of the department of CN&DT, Dr.Sci.(Tech.); email@example.com
A model is proposed for analyzing traffic flows in 5G and next-generation networks: tactile Internet (TI), augmented reality (AR) and the Internet of Things. At the same time, the key requirement for the implementation of AR and TI is to provide ultra-low latency. The influence of such heterogeneous traffic on the main indicators of quality of service, reflecting the probability of packet loss and delivery delay in time, is estimated. A queuing system with a combined service discipline is used as a communication network model.
Keywords: tactile internet, augmented reality, internet of things, IoT, traffic, queuing system, quality of service, QoS.
METHOD OF ANALYSIS OF PROBABILISTIC CHARACTERISTICS OF PACKET TRAFFIC SERVICE IN NB-IoT SYSTEMS
N.V. Stepanov, Saint-Petersburg State University of Aerospace Instrumentation (SUAI), department of infocommunication systems, assistance lecturer; firstname.lastname@example.org
A.M. Tyurlikov, SUAI, head of the department of infocommunication systems, Dr.Sci.(Tech.); email@example.com
V.O. Begishev, Peoples' Friendship University of Russia (RUDN University), department of applied probability and informatics, associate professor, Ph.D.; firstname.lastname@example.org
A method is proposed for analyzing the NB-IoT technology defined by the 3GPP consortium to support machine-to-machine communication services in 5G networks under the simultaneous load of batch and Poisson traffic types. Estimates of average delays for the considered types of traffic are obtained. The proposed method, based on the use of Markov processes, allows evaluating the performance of NB-IoT networks in the context of a heterogeneous traffic structure on a subscriber access site.
Keywords: NB-IoT, random access, batch traffic, burst arrival, delay.
IMPROVING THE RESISTANCE OF CAPTCHA TESTS AGAINST AUTOMATED RECOGNITION BY CONVOLUTIONAL NEURAL NETWORKS
G.O. Timofeev, Moscow Aviation Institute (MAI), bachelor; email@example.com
A.B. Roshchin, MAI, associate professor, Ph.D.; firstname.lastname@example.org
Capabilities of machine learning algorithms for estimation of CAPTCHA tests resistance against automated recognition are considered. Various improvements of these tests, which reduce the probability of correct recognition by automated systems are also discussed. Using the ResNet-18 convolutional neural network, the recognition efficiency and the possibility of using pre-learned models for recognizing new objects are evaluated. After analyzing the images, the main vulnerabilities were identified that allow automated systems to easily manage CAPTCHA tests. To increase the stability of lexicographic tests, it is proposed to use a random and independent color variation in the original RGB image for some pixels that are included in meaningful characters. The effectiveness of these actions was 11.8%.
Keywords: CAPTCHA, machine learning, convolutional neural networks, image recognition, information security.
A C# MODEL OF COMMUNICATION SYSTEM FOR DEMODULATION SOFTWARE ELABORATION. ULTIMATE PARAMETERS
A.V. Sumin, FSUE NIIR, leading engineer; email@example.com
A program model of a communication system for demodulation software development of frequency multiplexed geostationary satellite transponders signals is presented. The mathematical model uses signal discretization constants in time and frequency domains. The analytic form of modulated signals representation allows using the entire frequency domain — from zero to quadratures discretization frequency. The maximum value of the Nyquist band of the modulated carrier signal implemented in the model is equal to the quadrature sampling rate. The noise immunity of the model demodulator in the mode with apriori known signal characteristics is estimated using the parameter «output signal-to-noise ratio in the absence of input noise».
Keywords: communication system, program model, demodulation, discretization frequency, discretization constants, analytic signal, frequency representation band, signal transmission rate, noise immunity.
STUDY OF ELECTROMAGNETIC COMPATIBILITY BETWEEN MSS FEEDER LINKS AND 5G NETWORKS IN THE 6700−7075 MHZ FREQUENCY BAND
A.S. Pastukh, FSBI NIIR, head of a laboratory; firstname.lastname@example.org
A.A. Zaharov, FSBI NIIR, deputy director general, associate professor, Ph.D.; email@example.com
This study presents simulation of interference from 5G networks on the earth stations of the mobile satellite service feeder links operating as fixed satellite service (FSS) stations. Globalstar earth stations are considered as an example of the victim receiver in the simulations. The evaluation of the interference effect is carried out in the associated channel. The simulation considers in-band interference from 5G base stations and user equipment. The simulation results represent minimum protection distances between FSS earth stations and 5G networks that allow to achieve electromagnetic compatibility.
Keywords: 5G, IMT-2020, Globalstar, FSS, MSS, Monte-Carlo simulation, spectrum engineering, frequency management, electromagnetic compatibility, SEAMCAT, MATLAB, ITU-R.
ANALYSIS OF METHODS FOR CONSTRUCTING MARINE ANTENNA SYSTEMS WITH REFLECTOR ANTENNAS FOR MOBILE SATELLITE COMMUNICATION SYSTEM TERMINALS
A.A. Gavrilov, FSUE NIIR, deputy head of a division, Ph.D.; firstname.lastname@example.org
I.N. Prishepa, FSUE NIIR, head of a division; email@example.com
A.V. Proreshkin, FFSUE NIIR, senior engineer; firstname.lastname@example.org.
The analysis of modern methods of constructing antenna systems for small-sized mobile marine satellite communication terminals with reflector antennas is carried out. A review of VSAT antenna terminal design for marine communication satellite systems is presented.
Keywords: sea terminal VSAT, marine antenna, VSAT, reflector antenna, antenna system, Ku-band antenna, tracking antenna, slewing device.
RADIO WAVE PROPAGATION MODELS AT FREQUENCIES ABOVE 100 GHZ
O.I. Yastrebtsova, FSBI NIIR, head of laboratory, Ph.D.; email@example.com
A.A. Zaharov, FSBI NIIR, deputy director general, associate professor, Ph.D.; firstname.lastname@example.org
The article describes existing propagation models applicable to frequencies above 100 GHz, developed by the International Telecommunication Union. Some general effects typical for radio wave propagation at frequencies above 100 GHz are indicated. Regarding propagation in an urban environment, an increase in the impact of path shielding due to a decrease in diffraction is shown. The value of additional attenuation due to the obstacles blocking line-of-sight by a height lower than 1 m can be more than 35 dB. The presence or absence of obstacles with such height may be due to the inaccuracy of the digital map used in the calculations and/or measurement errors. So the correctness of the models at these frequencies depends more strongly on the input data than it did at lower frequencies, which can lead to a significant overestimation or, conversely, an underestimation of the signal propagation losses.
Keywords: radio wave propagation, radio wave propagation in an urban environment, clutter loss, building entry loss, 6G.
EXPERIMENTAL STUDY OF FREQUENCY TUNING DYNAMICS OF VOLTAGE-CONTROLLED SINUSOIDAL SIGNAL GENERATORS
N.V. Lemeshko, JSC Corporation Cometa, head of a department, Dr.Sci.(Tech.); email@example.com
S.S. Zaharova, High School of Economics, teacher, Ph.D.; ZaharovaSvetlana@yandex.ru
The article proposes a method for measuring the characteristics of the tuning dynamics of voltage-controlled generators of sinusoidal signals, based on the estimation of the frequency within each half-cycle using regression equations. The features of the use of voltage-controlled oscillators (VCO) as part of tunable frequency synthesizers are considered. The nomenclature of measured VCO characteristics is presented. A description of the algorithm that implements this method is given. Simulation results are presented that confirm its effectiveness for measuring VCO signals during frequency tuning.
Keywords: voltage controlled oscillator, frequency tuning, phase locked loop, dynamics, measurement.
RUSSIAN NATIONAL STANDARD R 53 111−2008 (STABILITY OF THE PUBLIC COMMUNICATION NETWORK. REQUIREMENTS AND VERIFICATION METHODS): ARGUMENTS PRO AND CONTRA
Yu.Yu. Terentyeva, Federal State Autonomous Research Institution Centre of Information Technologies and Systems for Executive Authorities (FSARI CIT&S), head of the department of analysis and methodology for improving information and telecommunications systems, Ph.D.; firstname.lastname@example.org
P.P. Starikov, FSARI CIT&S, director; email@example.com
S.G. Sinev, FSARI CIT&S, first deputy director, Dr.Sci.(Tech.); firstname.lastname@example.org
The analysis of the well-known and frequently used regulatory document GOST R 53 111−2008, which defines the requirements for the stability of the operation of telecommunication networks that are part of the public communication network, and also contains methods for their verification, is carried out. Various debatable aspects are considered, which are discussed among specialists faced with this regulatory document. During the analysis of the document, its undoubted advantages are emphasized, but its shortcomings are also indicated, which is the purpose of the research.
Keywords: network stability, graph of communication network