Information and telecommunication sciences: international research journal, Vol. 13, N. 2
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Документ Відкритий доступ Сomprehensive method of energy-efficient workload processing in the information and communication network(National Technical University of Ukraine "Igor Sikorsky Kyiv Polytechnic Institute", 2022) Prokopets, Nataliia; Globa, LarysaBackground. Peculiarities of the workload in a modern information and communication network (ICN) determine specific requirements for energy efficiency, performance and availability of its processing system. Existing approaches to increase en ergy efficiency and performance of workload processing do not take into account the possibility of dynamic changes in ICN workload arrival rate and individual energy consumption characteristics of computing nodes of the system. Objective. The purpose of the paper is to increase the energy efficiency and performance of ICN workload processing while meeting the requirements for the availability of the processing system, taking into account dynamic changes in the input workload arrival rate and the individual characteristics of the computing nodes’ energy consumption. Methods. A mathematical model of the workload processing system was built using the queueing theory methods, and an ontological model of this system was built using intelligent data analysis methods, which made it possible to quantitatively and qualitatively describe the complex relationships between system parameters and workload processing efficiency indicators. On the basis of the built models, a comprehensive method of energy-efficient workload processing was proposed, which differs from the known ones by the use of individual energy consumption models of computing nodes, combining the advantages of horizontal scaling and energy-efficient scheduling taking into account dynamic changes in workload arrival rate. Results. The efficiency of ICN workload processing is increased by 15.722% according to the efficiency criterion, which includes energy efficiency and performance indicators, compared to the known energy-efficient Backfill approach while meet ing the requirements for the availability of the processing system. Conclusions. The energy efficiency, performance and availability of the ICN workload processing system can be improved by combining horizontal scaling and energy-efficient scheduling approaches using individual energy consumption models of computing nodes and taking into account dynamic changes in the input workload arrival rate.Документ Відкритий доступ Development of the concept for the computational resources management software in the customer service systems(National Technical University of Ukraine "Igor Sikorsky Kyiv Polytechnic Institute", 2022) Skulysh, Mariia; Pastrana Brincones, José Luis; Parhomenko, DmytroBackground. To date, there is no customer service system that does not involve information and computer systems. One of the most important issues in ensuring the reliability and reliability of such systems is the task of dynamic scaling and providing the required amount of computing resources at any time. This study was focused on the planning and deployment of computing infrastructure that is able to respond to significantly increased volumes of request flows, changes in the dynamics of load intensity, strict requirements for the quality of their service, etc. Objective. The purpose of the paper is to create a concept of virtual computing space to meet the needs of distributed customer service system, which takes into account the peculiarities of service, the computing node load nature, service quality requirements, and provides energy efficient. Developed models, methods will control the performance of distributed computing infrastructure and flow maintenance processes, reduce downtime of computing resources and provide services to end users at a given level of quality. Methods. Analysis of the operation of the node load assessment mechanism, which consists in a dynamic change in the intensity of control of the state of function nodes, showed the effectiveness of planning for a group of computing nodes.. Results. The proposed approach to managing a heterogeneous computation environment to improve the efficiency of the service maintenance process in new generation systems is a unified solution for highly loaded distributed systems. The developed concept made it possible to avoid a decrease in the quality of service during surges of congestion and to maintain the indicators of the quality of service at a given level, provided that the resource utilization ratio is kept within the given limits Conclusions. In summary, a mathematical model of the problem of determining the maximum allowable load volume with a QoS level guarantee for a service node in a heterogeneous telecommunications environment was proposed.Документ Відкритий доступ Evaluation of the multipath effect on the quality of radio communication in the technological range IEEE 802.11xx(National Technical University of Ukraine "Igor Sikorsky Kyiv Polytechnic Institute", 2022) Uryvsky, Leonid; Solianikova, ValeriiaBackground. As a result of the rays’ reflection from buildings, from the surface of the Earth or from horizontal boundaries between different layers of the atmosphere, occur multipath effects that cause fast fading, which degrades the quality of service. Objective. The purpose of the paper is to determine the multipath effect on the signal-to-noise ratio in a wireless communication channel. Compare the results obtained for a communication channel at operating frequencies of the IEEE 802.11xx standard: 5 GHz and 2.4 GHz. Methods. The useful signal powers and the total interference powers for a communication channel with multipath are calculated. The signal-to-noise ratio for such a channel is compared at operating frequencies of 5 GHz and 2.4 GHz. Results. The results of the study showed that the higher the frequency of the carrier of the wireless radio link, the less pronounced the effect of multipath is. The frequency rating significantly affects the quality of communication in multipath conditions. In this case, lowering the frequency significantly improves the reception condition outside of multipath effect. However, it deteriorates significantly due to the effects of rays reflected from the Earth's surface. In the considered case, the useful signal power in the 2.4 GHz band is 4.2 times higher; at the same time, the power of reflected interference is 19 times higher than in the 5 GHz band. Conclusions. Suggested model makes it possible to determine the effect of interference power in the ranges traditionally assigned in IEEE 802.11xx technology, specifically 2.4 GHz and 5 GHz.Документ Відкритий доступ Soft frequency reuse for miligation of intercelluler intereference(National Technical University of Ukraine "Igor Sikorsky Kyiv Polytechnic Institute", 2022) Papushoi, Olha; Mogylevych, DmytroBackground. The appearance of femtocells in LTE networks has provided indoor coverage and overcome large data flows for operators. However, strong interference occurs in neighbouring femtocell users due to the limited available spectrum in cellular networks that transmit data in the same radio range. In densely deployed environments, interference issues in single channel femtocells cause significant performance degradation. In this study, we mitigate inter-cell interference in femtocell networks by combining femtocells as a result of common interference and soft frequency reuse in downlink and uplink by moving and exchanging interfering physical blocks. Objective. The purpose of the paper is to improve the efficiency of ensuring the quality of services in wireless networks by reducing any interference due to the distribution of traffic, which is able to provide uninterrupted connection to the user. Methods. Enabling conditions for inter-cell interference mitigation in LTE-based femtocell networks with soft frequency reuse. Results. Interference is a key issue in the deployment of LTE femtocells. Closely located femtocells interfere with each other if they transmit on the same frequency. Therefore, crossing femtocells and enabling them to allocate resources and reuse soft frequencies effectively reduces interference and prevents the loss of network resources. The scheme is triggered whenever the user's femto equipment experiences strong interference from neighbouring femtocells. By assigning a separate set of physical resource blocks to users at the edge of the cell, our scheme significantly reduces interference, which automatically increases cell throughput. The simulation results show the advantages of applying our scheme, in particular, the interference of the user's femto-equipment is reduced by 14% and the throughput is improved by 25%. That is, we observe a significant improvement in the performance of femtocells. Conclusions. A femtocell crossing scheme with soft frequency reuse is presented to reduce interference between femtocells of LTE networks, which allows effectively ensuring the quality of service transmission in wireless networks by reducing interference and increasing performance through traffic distribution.Документ Відкритий доступ Heuristic algorithms for finding the minimum Steiner tree in the problem of optimizing the deployment and motion control of several flying information and telecommunication robots(National Technical University of Ukraine "Igor Sikorsky Kyiv Polytechnic Institute", 2022) Lysenko, Olexandr; Valuiskyi, Stanislav; Novikov, Valeriy; Sushyn, Ihor; Chumachenko, Serhii; Guida, OleksandrBackground. The article explores the problem of combining the motion control of existing FITRs and the deployment of new FITRs so that the number of new FITRs deployed to support the communication of terrestrial subscribers can be minimized. This problem is formulated as the Steiner Minimum Tree Problem (SMT) with existing mobile Steiner points with a constraint on the edges length of the network graph. Objective. Improve the mathematical model for ensuring the connectivity of episodic radio networks using FITRs and improve the algorithms for providing the connectivity of episodic radio networks using FITRs. Methods. The two algorithms (deploying new FITRs before moving existing FITRs, and moving existing FITRs before deployment of new FITRs) separate the problem and solve the deployment problem, the movement one after the other. In contrast, the algorithm for deploying new FITRs while moving existing FITRs optimizes the deployment problem and the control of movement across and solves these two problems simultaneously. Results. A proposed method includes three heuristic algorithms for placing new FITRs, taking into account the movement of existing FITRs (that is, considering scenarios for moving existing FITRs: deploying new FITRs before, after, or during the movement of existing FITRs) for the SMT problem with existing mobile Steiner points with a constraint on the edges length of the network graph. Conclusions. Evaluation of the effectiveness of the proposed algorithms in various scenarios shows that algorithms taking into account the movement of existing FITRs are always more efficient (in terms of the number of newly added FITRs) than an algorithm without taking into account the movement of existing FITRs.Документ Відкритий доступ Accurate detection of multiple targets by uniform rectangular array radar with threshold soft update and area rescanning(National Technical University of Ukraine "Igor Sikorsky Kyiv Polytechnic Institute", 2022) Romanuke, VadimBackground. If the intensity of moving targets within a surveyed area is low, an optimal number of uniform rectangular array (URA) radar sensors is in either the minimally-sized URA (or close to it) or maximally-sized URA (or close to it), where the URA size is regulated by (symmetrically) turning off vertical and horizontal sensors. However, this does not guarantee detection of any target because sometimes the threshold detection, by which the main parameters of a pair of two targets are estimated, fails even by using the soft threshold approach when the threshold is gradually decreased while the detection fails. Objective. In order to improve detection of multiple ground-surface targets by a URA radar, the goal is to decrease a number of detection fails, when targets are just missed. For this, the approach of threshold soft update and a set of quasioptimal URA sizes included 20 25 and 35 35 URAs are to be used by rescanning the area if the detection fails. Methods. To achieve the goal, the functioning of the URA radar is simulated for a set of randomly generated targets, where roughly a half of the set is to be of single targets, and the other half is to be of pairs of targets. The simulation is configured and carried out by using MATLAB® R2021b Phased Array System ToolboxTM functions based on a model of the monostatic radar. Results. Neither the soft threshold approach, nor the rescanning increase the detection accuracy. However, when either the soft threshold or rescanning is applied, or they both are applied, the number of detections is increased. The increment can be evaluated in about 2.7 %, but the expected high-accurate detection performance slightly drops. This is caused by that the soft thresholding and rescanning attempt at retrieving at least some information about the target instead of the detection fail. Conclusions. Using the threshold soft update approach along with a more frequent rescanning decreases a number of detection fails. Besides, the soft thresholding and rescanning allow slightly decreasing the number of URA sensors sufficient to maintain the same detection accuracy by increasing the averaged number of single-target and two-target detections at least by 2.5 %. The increment in a number of detected targets on average is equivalent to increasing the probability of detection.Документ Відкритий доступ Static and dynamic assessments of information signs in recognition of sources and objects of observation in the process of radio monitoring(National Technical University of Ukraine "Igor Sikorsky Kyiv Polytechnic Institute", 2022) Ilnytskyi, Аnatoliy; Tsukanov, OlegBackground. The current state and problems of the surveillance and radio monitoring systems of Ukraine require fundamentally new approaches to increasing their efficiency and the level of informatization. At the same time, the informatization of the radio monitoring system should be understood as the process of implementation and application in various areas of their activity of methods and means of collecting, transmitting, processing, saving and using information in order to increase the effectiveness of conducting radio monitoring and meet the needs of national security based on the formation and use of information resources. Objective. The purpose of the paper is to increase the effectiveness of radio monitoring by using the calculation of estimates of dynamic and static informational features when recognizing sources and objects of radio radiation and determining their phase (operational) state and level of possible danger. Methods. Recognition is based on the method of least squares by calculating the degree of "similarity" (similarity coefficient) of the recognized object with objects whose classes are known. Both the researched and reference objects are presented as a set of values of informational features of various nature, some of which are unchanged over the entire period of observation, that is, static, while others change dynamically. Results. The structure of the automated system of classification and recognition of surveillance objects and the recognition algorithm based on the calculation of static and dynamic information features and the similarity coefficient are proposed. Conclusions. A distinctive feature of deciding whether an object or a source of information belongs to one or another class feature is the calculation of the degree of "similarity" (similarity coefficient) of the recognized object to objects whose classes are known. To eliminate recognition errors associated with a violation of the synchronicity of measurements of the values of dynamic informational features of reference objects and objects to be recognized, a calculation is required taking into account possible time shifts.Документ Відкритий доступ New Barker’s composite codes as modulation signals in broadband communication systems(National Technical University of Ukraine "Igor Sikorsky Kyiv Polytechnic Institute", 2022) Maksymov, Volodymyr; Noskov, Vyacheslav; Khrapovytsky, IgorBackground. Currently noise-like signals (NLS) are widely used and provide high level of jamming immunity and security in broadband communication systems (BСS) when transmitting confidential information in an open radio channel, especially in emergencies. Increasing the efficiency of the NLS is possible when using more advanced code structures. Objective. The purpose of this research is to study new Barker’s composite codes as modulation signals in broadband communication systems. Method. Simulation modeling based on MatLab software package and analytical calculation methods are used. Results. Modeling in the MatLab software package showed the possibility for using new Barker’s composite codes as modulation signals in direct spread spectrum systems but efficiency depends on code words length as well as type synchronization signal. Conclusions. Analysis of research results shows that the new Barker composite codes 21a, 33a, 49, 77a, 121 can be effectively used as modulation code words in broadband systems with direct spectrum expansion.Документ Відкритий доступ Improvement of the gps signal receiving resistance against electromagnetic interference, jamming, and spoofing is based on the use of the antenna array system with digital beamforming and NORAD TLE information(National Technical University of Ukraine "Igor Sikorsky Kyiv Polytechnic Institute", 2022) Narytnik, Teodor; Prysiazhnyi, Volodymyr; Kapshtyk, Segii; Denysenko, Maksym; Narushkevych, OleksandraBackground. Currently, in radio navigation systems of the various purposes, the urgent issue is stability increase of the GPS signal reception under such a jamming and spoofing types of the interference influence. In this article, the authors propose a new solution to the stability increase problem of the GPS signal reception against the jamming and spoofing interference based on the spatial selectivity of the receiver antenna. Spatial selectivity is provided through the integrated application of phased array digital beamforming technology and the use of the TLE NORAD information. Objective. The research goal is to develop a methodology for the integrated identification of interference sources to the radio navigation system and to increase the noise immunity for receiving radio navigation signals via spatial selection through the digital beamforming technologies utilization. Methods. For the research process, theoretical methods for the digital beamforming of receiving phased antenna system were used as well as the description of a two-line NORAD information element content, and calculation algorithms for the spacecraft current position. Results. As a result of the research, the GPS signal reception model was formed using spatial selection of GPS signal sources and interference sources, the technique to increase the stability of GPS signal reception under the jamming and spoofing types of interference influence was developed, the block diagram was suggested for the receiving device that implements the developed technique through the integrated application of the digital beamforming technology of the phased array antenna and the TLE NORAD information utilization. Conclusion. A conceptual idea of the method and a technical solution for the proposed method implementation were submitted. The method implementation will improve the stability of GPS signal reception under the influence of jamming and spoofing types of interference.