MODERN APPROACHES TO TEACHING TELECOMMUNICATIONS DISCIPLINES

Background. The directions and methods of training telecommunications personnel are constantly evolving in accordance with the growing volume of information exchange in society. Telecommunications as a display of the means and methods of information transmission have come a long way from purely radio engineering systems to heterogeneous systems with a complex network infrastructure and intelligent methods of information processing. Accordingly, the approaches to the training of telecommunications personnel are also changing. If in the early 80s preference in training was given to radio technologies, now it is network and software technologies. Objective. The purpose of this work is to present the possibilities of increasing the efficiency of the educational process in standard and mixed modes, structuring subjects in accordance with the requirements of the modern labor market. Methods. The unpredictable deep essence and uncertainty of the information space of the professions for which higher education prepares students today leads to a change in the teaching paradigm. Methods and structuring of building the learning process with obtaining the maximum effect of the student's readiness for their practical activities are investigated. Results. Possible ways of implementation of new requirements for personnel training for the new paradigm of the unified industry "Information Technologies and Telecom" are presented; the main directions of the formation of the general structure of training of telecommunications personnel on the example of the educational program "Engineering and programming of infocommunications"; recommendations for the organization of the educational process in full-time and remote modes. It is shown that with the correct organization of the educational process, blended learning can improve the quality of learning, especially in the context of reducing the hours of "classroom lessons" by transferring part of the educational process to the online environment. Conclusions. University graduates constitute the potential foundation of today's specialist market. Nevertheless, the problem of their professional adaptation, at the moment, remains relevant. Therefore, the paper proposes to solve this problem using the presented multilateral approach.

BLOCK DIAGRAM OF A MULTI-FREQUENCY RADIOMETRIC COMPLEX FOR UAV DETECTION IN DIFFERENT METEOROLOGICAL CONDITIONS

Background. Technologies for the production of unmanned aerial vehicles (UAVs) of various classes are rapidly developing in Ukraine and the world. Small in terms of weight and dimensions and almost invisible for most information and measurement systems, UAVs began to be used in various industries - from the national economy to multimedia and advertising. Together with their useful application, new dangers and incidents have appeared - a collision of UAVs with people, structures, cultural monuments, the transportation of criminal goods, terrorist acts, flights over prohibited areas and within airports. UAV detection and control of their movement in populated areas and near critical objects are becoming one of the most important tasks of air traffic control services. The existing systems of the optical, acoustic and radar ranges cannot effectively perform such tasks in difficult meteorological conditions. As an addition to the already developed detection systems, it is proposed to use radiometric systems that register the UAV's own radio-thermal radiation. The authors have developed the theoretical foundations for the construction of multifrequency complexes necessary for the specification of their structural schemes. Objective. The purpose of the paper is development of a scheme for a multi-frequency radiometric complex for detecting UAVs in different meteorological conditions based on optimal algorithms. Methods. Analysis of the experience in the development of radiometric systems and methods for dealing with fluctuations in the gain of receivers, optimal operations for processing signals of intrinsic radio-thermal radiation, investigations of the probabilistic characteristics of detection and analysis of the domestic market of microwave technology developers will make it possible to develop a scheme of a multifrequency radiometric complex that will perform reliable measurements in various meteorological conditions. Results. A block diagram of a four-frequency radiometric complex is proposed, which can be implemented in practice and is capable of performing reliable measurements in various meteorological conditions. The frequencies 10 GHz, 20 GHz, 35 GHz, and 94 GHz were chosen as the resonant frequencies for tuning the radiometric receivers. For a given design and characteristics of receivers, the probabilities of detecting a UAV were calculated depending on the range of its flight. Conclusions. From the results of the analysis of the existing achievements in the development of radiometric systems in Ukraine and the elemental base of microwave components available on the market, it follows that the Ku and K bands have the worst characteristics of spatial resolution, but are all-weather. The Ka and W bands are highly sensitive to radio-thermal radiation against the background of a clear sky, but are completely "blind" in a cloudy atmosphere and in rain. The results of calculating the detection ranges with a probability of 0.9 lie in the range from 1 to 3 km, depending on the condition of the atmosphere. These results coincide with the known detection ranges of optical, acoustic and radar systems, but the selected parameters of the receivers do not correspond to potential world achievements and can be improved.

DETECTION OF A HARMONIC SIGNAL AGAINST THE BACKGROUND OF A NONSTATIONARY GAUSSIANINTERFERENCE WITH COMPLEX SPECTRUM

Background. Modern radar stations for various purposes operate in the conditions of interference created by the imprints of the radar signal from the background surface, from metrological formations (precipitation, clouds, etc.) and artificial radiation sources. Ensuring the operation of the radar in such difficult conditions requires the construction of adaptive signal processing algorithms that have high efficiency and maintain them when changing signal-to-noise situations. Objective. The purpose of the paper is creation of an adaptive algorithm for detecting a harmonic signal against the background of spatially correlated interference and estimating its parameters. Methods. Construction of a two-dimensional autoregressive model of a mixture of correlated spatial noise and harmonic signal and application of the empirical Bayesian approach to the synthesis of an adaptive algorithm for detecting and evaluating signal and noise parameters. Results. A two-dimensional adaptive space-time algorithm for detecting a radar signal reflected from a moving target against the background of a space-correlated interference is synthesized. The analysis of the efficiency of the algorithm by the Monte Carlo method is carried out. Conclusions. It is shown that the empirical Bayesian approach is an effective working methodology in solving the problem of detecting a harmonic signal and estimating its parameters under conditions of interference with a complex frequency spectrum under different conditions of a priori uncertainty of their parameters.

OBTAINING CONDITIONS FOR TECHNOLOGY NEUTRALITY OF COMMUNICATION SYSTEMS WITH MINIMUM COUPLING LOSS METHOD

Background. Technology neutrality is widely used in frequency bands, where communication systems are evolving, but there are strict restrictions on the parameters and deployment of base stations of different technologies using adjacent channels. Ways to mitigate this effect have not been sufficiently studied and require further analysis and development. Objective. The purpose of this article is to investigate the methodology for obtaining technical conditions of technological neutrality with minimum coupling loss method to determine the value of additional filtering requirements and present the results of practical implementation of this technique. Methods. The method of detailed power analysis of frequency characteristics of filters for base stations’ transmitter and receiver is applied. Results. The article presents the results of obtaining minimal guard band and additional filtering requirements in the adjacent channels of transmitter and receiver belonging to different technologies. Examples of practical implementation of the minimum guard band and frequency characteristics of additional filters are given. Conclusions. The general method of determining the technical conditions for ensuring technology neutrality is presented and the value of the minimal required guard band between the adjacent transmitter and receiver channels is obtained.

EVALUATION OF VOICE TRANSMISSION QUALITY IN THE LTE NETWORKS

Background. LTE mobile networks combine packet network technology and radio technology. Parameters of packet and radio subsystems significantly affects the quality of all traffic types transmission, especially telephone traffic, as the most demanding to such parameters of network transmission as delay, jitter and packet loss rate. The recommendations of the International Telecommunication Union and the documents of the partner organization of telecommunications operators (3GPP) contain hypothetical reference models, targets for end-to-end connection quality, and lists the factors that affect the quality (QoS) of VoLTE services. In addition, the network points are shown where you need to measure the quality of telephone traffic and tools for quality assessment. The quality of telephony services is assessed according to the E-model using the method of determining the mean opinion score (MOS). However, this technique is intended primarily to determine the MOS during the network planning. To calculate the MOS in a working network, you have to measure such network performance first such as voice delay and packet loss rate. This article presents the method of calculating MOS in the LTE network based on the E-model and presents the results of practical quality studies. Objective. The purpose of this article is research the impact of delay and packet loss ratio and voice codec characteristics in the real LTE network on quality of telephone services. Methods. Analysis of factors affecting on telephone services quality and analysis MOS assessment methods. Practical studies of the delay and packet loss ratio affect the MOS level in various conditions of radio coverage and network load. Results. Practical results of delay and packet loss ratio influence on the telephone services quality in the LTE network. Calculated MOS based on the practically measured delay and packet loss ratio. Conclusions. The combination of packet technologies, modern AMR-WB codecs and QoS support mechanisms in the LTE networks provides high quality perception of voice messages at the level of not less than 4 on the MOS scale. With a delay not exceeding 180 ms, a sufficiently high quality of voice transmission is ensured (MOS ≈ 4). VoLTE technology using the AMR-WB codec is quite resistant to packet loss and provides high quality perception of voice messages at a packet loss ratio of up to 1%.

DEVELOPMENT OF METHODS OF POSITIONING, LOCALIZATION AND DATA COLLECTION FROM NODES OF A FREE MOBILE SENSOR NETWORK USING INTELLIGENT ADAPTIVE TELECOMMUNICATION AEROPLATFORMS

Background. The article presents the results of a study of methods of positioning, localization and data collection from nodes of a mobile wireless sensor network using intelligent adaptive telecommunication air platforms. To implement the study of this research topic, an analysis of literary sources on this topic was carried out. Based on a fairly rich bibliographic material, this work has the main task of examining, analyzing and systematizing already known approaches to positioning objects in wireless sensor networks using intelligent adaptive telecommunication air platforms and suggesting options for their development. Objective. The aim of the work is to improve the methods of direct data collection of TA from the nodes of BSM, the general directions of synthesis of which are defined in the work. Methods. Methods of cluster analysis (network clustering), graph theory (research of analytical models of BSM with TA functioning, construction of cluster topology), theory of telecommunication networks (when calculating bandwidth in BSM with TA radio channels) and theory were used to solve the formulated problem. (when developing a positioning model for telecommunications air platforms) Results. A technique for evaluating the effectiveness of methods for collecting data from wireless sensor networks using intelligent adaptive telecommunication air platforms is proposed. Conclusions. The method of collecting TA monitoring data from the main nodes of clustered BSM has been improved. The method of estimation of efficiency of methods of data collection with BSM by telecommunication air platforms is offered.

THROUGHPUT INCREASE IN THE OFFICE LI-FI SYSTEM

Background. Wi-Fi has many disadvantages, such as how the maximum bandwidth is limited by the frequency of the range. The work uses Li-Fi technology, which uses visible light for data transmission. The frequency range of Li-Fi is 1000 times greater than the entire radio range. Feedback is used to increase the throughput. But the feedback decreases the bandwidth of the downstream signal. Objective. The purpose of the paper is to analyse what parameters are advisable to change to increase the throughput of the Li-Fi system. Methods. Study of the simulated dependence of the optimal interval change for using the feedback, and using this interval plot the dependence of the throughput on the change in the parameters of the Li-Fi system with a mobile user. Results. With an increase in the area of the photodiode and its refractive index, the throughput increases. As the receiver speed increases, the throughput decreases slightly <0.1%. Reducing the angle of the photodiode field of view and the half-angle of radiation significantly increases the throughput (by 50%) only when decreasing to small angles (<10 °). Conclusions. It is advisable to make photodiode from a material with a high refractive index, with a big area. Since mobile devices are often used in the office Li-Fi network, it is not advisable to reduce the receiver's viewing angle, as well as to reduce the half-angle of radiation. It may also be beneficial to give mobile users more download throughput than upload throughput.

IMPLEMENTATION OF THE APPROACH TO ONTOLOGICAL MODELING OF THE MUSICAL SUPERGENRE “METAL”

Background. The relevance of the article is due to the development of modern ontological methods of structuring information and the need to systematize data in many new specific subject areas. Such subject areas include the musical art of the "metal" variety, which is quite common today, but insufficiently studied within the terminology. The subject of the article are ontological models and tools for creating ontological knowledge bases. Objective. The purpose of the paper is to increase the correctness of the semantic search in the knowledge base of the musical supergenre "metal". The scientific problem is the need to improve the terminology in this subject area and build an ontological knowledge model that increases the accuracy of information retrieval for the target audience, compared to the existing relational model implemented on one of the known web resources. Methods. Classification method, generalization method, software optimization methods, analytical method. The way to solve the problem: selection based on the comparative characteristics of the best web resource of the subject area and identifying the shortcomings of its model of knowledge representation, designing an ontological knowledge model and testing its effectiveness. Results. The average SUM for all users is 83.85%, which is a good indicator for ontological knowledge bases. At the same time, a similar method of checking the database of the supergenre "metal" on the basis of the site "Encyclopedia Metallum", which used the classical relational model of database organization, showed much lower results. Thus, the average SUM for 10 users was 75.32%, respectively. Conclusions. The scientific novelty of the obtained results is as follows: For the first time an ontological model (ontology) of the subject area was created: musical supergenre "metal", which showed much higher efficiency of semantic search than the best relational model of this subject area, implemented as a web resource. The developed structure can be used to create ontologies of related musical supergenres with similar terminology. Future research also plans to integrate this ontological knowledge model with applied web-based and desktop applications.

MUTUAL COUPLING COEFFICIENTS OF ROTATING RECTANGULAR DIELECTRIC RESONATORS IN CUT-OFF RECTANGULAR WAVEGUIDE

Background. A further increase in the speed of information transfer is determined by more stringent requirements for the elements of communication devices. One of the most important components of such devices is various filters, which are often made on the basis of dielectric resonators. Calculation of the parameters of multi-section filters is impossible without further development of the theory of their design. The development of filter theory is based on electrodynamic modelling, which involves calculating the coupling coefficients of dielectric resonators in various transmission lines. Objective. The aim of the research is to calculate and study the coupling coefficients of rectangular dielectric resonators with a rectangular metal waveguide when their axes rotate. Investigation of new effects to improve the performance of filters and other devices based on them. Methods. Methods of technical electrodynamics are used to calculate and analyse the coupling coefficients. The end result is to obtain new analytical formulas for new structures with rectangular dielectric resonators, which make it possible to analyse and calculate their coupling coefficients. Results. New analytical expressions are found for the coupling coefficients of dielectric resonators with the rotation of their axes in a rectangular waveguide. Conclusions. The theory of designing filters based on new structures of dielectric resonators with rotation of their axes in metal waveguides has been expanded. New analytical relationships and new patterns of change in the coupling coefficients are found. Keywords: dielectric filter; rectangular dielectric resonator; rotation; coupling coefficients.

RESEARCH OF SDN NETWORK PERFORMANCE PARAMETERS USING MININET NETWORK EMULATOR

Background. The implementation of the new modern services on existing networks requires replacement or modernization of the old equipment. This negatively affects the efficiency of providing users with new types of services and their cost. Therefore, the issues/tasks of implementing SDN technology in the construction of networks are in the center of attention of representatives of science-research organizations and telecom operators. SDN networks have the advantages of flexible scaling of the system without replacing existing server and network equipment, eliminating operator dependence on specific vendor solutions, and rapid implementation of the new network technologies and services. To determine the numerical values of indicators of the functioning of SDN networks and check their compliance with the requirements, it is proposed to use in working process simulation modelling. For these goals, the Open Networking Foundation consortium developed the Mininet network emulator, the elements of that are published publicly. The formation of the simulation model and the procedure for determining the performance indicators of the SDN network that uses Mininet has a number of features that are considered in the work. Objective. The purpose of the article is to build a simulation model based on the Mininet network emulator and to determine the performance indicators of SDN networks of various structures/topologies. Methods. Creation of a SDN network segment for testing process of its functioning in the overload mode of various communication routes. Results. The Mininet network emulator allows simulating SDN networks of a rather complex structure, change the performance of network branches and the amount of load in communication routes, to create a network-wide overload mode. During the simulation, it is possible to determine a number of indicators of network performance, such as the RTT (Round Trip Time) parameter for each route of communication, the bandwidth of branches and routes of communication, the amount of delay on network elements, loading of OpenFlow Switch ports/interfaces, network elements with the highest delay, the number of served and lost packets. Conclusions. Use of the Mininet network emulator is a fairly convenient tool for determining the performance indicators of SDN networks. However, there are also some problems. First of all, setting up the system's operability requires writing programs to ensure the interaction among standard elements from the Mininet library. Secondone, is when congestion occurs in the communication routes, the Floodlight Controller does not automatically balance traffic along the work-around route. This task has to be solved manually by making changes to the OpenFlow Switch routing tables. Keywords: Software Defined Networking; SDN; Mininet; OpenFlow; Floodlight Controller; OpenFlowSwitch; NFV; virtualization.