Internet of Things, Smart Spaces, and Next Generation Networks and Systems

Currently, 5G/IMT-2020 networks with their possibilities become more and more services of new areas. These services are integrated into different human life activities. And in several cases, human life depends on Artificial Intelligence technologies, Autonomous Systems, and the Internet of Things (IoT), etc. Autonomous vehicles provide very strict requirements to the network in terms of ultra-low latency, high throughput, and wide coverage. To support these requirements, additional technologies must be employed. The current paper discusses the possibility of the use of airborne platforms aiming to support the terrestrial networks for autonomous vehicles realization as a part of delay-critical applications. Airborne platforms will help in the provisioning of safe road trips by delivering time-critical information to the vehicles globally, even in remote areas. In this paper, we discuss requirements and potential solutions for supporting the autonomous vehicle infrastructure, as a part of an intelligent transportation system. It’s proposed to use a sensor network along the road, consists of energy-efficient sensors that can connect in a Mesh network. Also, a novel approach for the detection of biological objects activity on the roadside, based on Artificial Intelligence technologies are suggested.

Widely usage of LPWAN networks allows us to think about the further development of this technology, which develops networks to work not only with the star topology but also with a mesh topology. With such development, a procedure should be provided for determining the coordinates of nodes in the network. In this article, we propose a method for constructing a map of sensor nodes in the wireless mesh network. In particular, we analyzed rangefinder methods based on the received signal strength or the signal propagation duration to calculate the distances between nodes. With determined distances, a method is considered for constructing a three-dimensional model of each network fragment, then spatial transformations are carried out for the subsequent construction of a three-dimensional model of the whole network.

Nowadays, many networks are deployed in a mesh topology. Especially, most wireless sensor networks also use multi-hop or mesh communication to exchange sensor data between devices. Increasing the number of nodes leads to the requirement of flexible deployment and configuration in such networks. Taking advantage of software-defined networking (SDN), this article discusses applying the SDN concept to manage wireless mesh sensor networks, in which the network management is carried out with the assisted SDN controller. Based on the simulation models, a series of computer experiments was performed to evaluate the network performance with and without SDN support. Based on the simulation results, the wireless mesh network supported by the SDN controller showed more efficiency in bandwidth, jitter time, and packet loss.

In this work a software defined network (SDN) is studied as a queueing network. The main point of the system is that the switch memory node, storing routing rules is modeled separately. The memory node impacts the distribution of the newly arrived packets among the other nodes. In this work we propose analytical and simulation model to analyze the performance of the considered network. Analytical model covers a simplified network case with one flow type, while simulation model let us analyze a general-case of SDN network segment with multiple flow types.

Minimum bandwidth regenerating (MBR) array codes are a class of regenerating codes that provide reliability of data while ensuring low repair bandwidth or, in other words, the amount of information downloaded for the repair of temporally unavailable node. An important aspect of all distributed storage systems is security. In this paper, we address the security issues of MBR array codes in the presence of eavesdropper with access to limited number of elements from each node. We provide an explicit construction of MBR array codes secure against such eavesdropper and prove the bound on the total amount of information stored in such a system.

The development of an optical polarimetric scheme for improvement of fingerprint systems is presented in this paper. It is based on Mueller matrix imaging (with 36 measurements) of scattering object using Lu-Chipman polar decomposition algorithm for calculation of polarimetric characteristics. Experiments were made with real fingers and several dummies made of gelatin and white glue. The proposed scheme and the algorithm have showed promising results for solving the problem of improving the security of fingerprint sensors.

The vulnerability of neural networks to adversarial attacks has long been revealed. However, the structure of neural networks is not given due attention during the attack. The article deals with the impact of different parameters of a neural network on its resistance to adversarial attacks. The main purpose of this research is to determine which parameters increase resistance to attacks. The way by which neural networks can be compared has been proposed. Several neural networks were selected for comparison and a number of adversarial attacks were conducted on them. As a result, certain conditions were identified under which the attack took place over a longer time. It was also found that different changes in neural network parameters were required to protect against different attacks.

Managing cryptographic keys can be a complex task for an enterprise and particularly difficult to scale when an increasing number of users and applications need to be managed. In order to address scalability issues, typical IT infrastructures employ key management systems that are able to handle a large number of encryption keys and associate them with the authorized requests. Given their necessity, recent years have witnessed a variety of key management systems, aligned with the features, quality, price and security needs of specific organisations. While the spectrum of such solutions is welcome and demonstrates the expanding nature of the market, it also makes it time consuming for IT managers to identify the appropriate system for their respective company needs. This paper provides a list of key management tools which include a minimum set of features, such as availability of secure database for managing keys, an authentication, authorization, and access control model for restricting and managing access to keys, effective logging of actions with keys, and the presence of an API for accessing functions directly from the application code. Five systems were comprehensively compared by evaluating the attributes related to complexity of the implementation, its popularity, linked vulnerabilities and technical performance in terms of response time and network usage. These were Pinterest Knox, Hashicorp Vault, Square Keywhiz, OpenStack Barbican, and Cyberark Conjur. Out of these five, Hachicorp Vault was determined to be the most suitable system for small businesses.

This work studies Tor, an anonymous overlay network used to browse the Internet. Apart from its main purpose, this open-source project has gained popularity mainly because it does not hide its implementation. In this way, researchers and security experts can fully examine and confirm its security requirements. Its ease of use has attracted all kinds of people, including ordinary citizens who want to avoid being profiled for targeted advertisements or circumvent censorship, corporations who do not want to reveal information to their competitors, and government intelligence agencies who need to do operations on the Internet without being noticed. In opposition, an anonymous system like this represents a good testbed for attackers, because their actions are naturally untraceable. In this work, the characteristics of Tor traffic are studied in detail in order to devise an inspection methodology able to improve Tor detection. In particular, this methodology considers as new inputs the observer position in the network, the portion of traffic it can monitor, and particularities of the Tor browser for helping in the detection process. In addition, a set of Snort rules were developed as a proof-of-concept for the proposed Tor detection approach.

The possible sets of joint distribution of the word occurrence frequencies in the finite state machine input and output sequences are considered. A geometric description of such sets as convex polyhedra in a real unit cube of suitable dimension is proposed. A method has been developed for comparison of unknown and reference automata by the observed input and output sequence fragments. The method does not require installation to the fixed initial state.

An approaching to the transmission channel capacity with a limited frequency band ΔF is achieved by using signals with length Ts exceeding the duration of the symbol’s transmission interval T. Such signals are transmitted under conditions of significant intersymbol interference. This leads to the fact that a random sequence of transmitted signals will have significant values of the peak to average power ratio (PAPR). To estimate the value of PAPR, it is necessary to determine the statistical characteristics of the random process emission. This will help to form the conditions for the permissible amplitude limitation of the output signal. In the work we find probability distributions of instantaneous amplitude values of the random optimal signal sequences with different durations (Ts = 8T…16T). The conditions for approximating the distribution histograms to the Gaussian process are found. As a information source, a Gaussian source with quantization of levels of sampled values was selected. It is shown that with the number of quantization levels exceeding 32, the histograms approach a truncated Gaussian distribution. Simulation results are given for the transmission speed of the channel alphabet symbols from R = 1/T to R = 10/T, which corresponds to the faster-than-Nyquist transmission rate. Recommendations are given on the required dynamic range of operation for power amplifiers in transmitting devices in accordance with the obtained value of FTN signal sequences PAPR.

The reduction of multiplicative speckle noise in synthetic aperture radar (SAR) images is an important problem. Many speckle noise reduction filters have been proposed. Most of them have several parameters that control their operation. Finding the optimal values of these parameters is often a non-trivial task. A method of automating the search for optimal parameters is proposed. The method uses two variants of a specially designed test image, original noise free image and the same image but with speckle noise added. Then the Structural Similarity Index (SSIM) metric is used for finding the parameters that make the filtered image as close to the original noise free image as possible. The application of the method is illustrated using the Frost filter applied to various images, but the method can be used for any filter type.

The paper concerns research on the efficiency of the communication system and MIMO radar cooperating with each other. For this system a measure of efficiency was determined, which is the speed of radar estimation and the speed of data transfer. The combination of these measures made it possible to set a performance limit for this system. The original the solution is to optimize the efficiency of the communication system cooperating with MIMO radar. Using derivative-free optimization method has been maximized radar estimation speed and information transfer speed. This makes it possible to find optimal parameters for both systems, which is helpful in its design or analysis. Simulation tests confirmed the correctness of the analysis.

This paper presents the performance analysis of Single User Multiple Input Multiple Output (SU-MIMO) 5G cellular communication when combined with frequency-domain precoding technique in spatially correlated Tapped-delay-line (TDL) Rician channel. We investigated how calculation of precoder coefficients at individual resource blocks (RB) by performing singular value decomposition (SVD) of channel estimate would improve performance of multiple input multiple output (MIMO) system, compared to single coefficient per bandwidth-averaged channel estimate. We compared gains for systems with 1 and 2 transmission layers over channels with different delay spreads (DS), K-factors, spatial correlations and found such technique provides small but quantifiable gains in throughput, the highest gains being in spatially correlated NLOS channels.

Noncoherent signal detection has a long history of application in the data transfer systems. Currently, this method is being considered for application in 6G communication standards. This article is devoted to the study of the possibility of joint use of noncoherent detection algorithm and optimal Faster than Nyquist (FTN) signals. The optimal FTN signals are obtained as a solution to the optimization problem in accordance with the criterion of the fixed reduction rate of out-of-band emissions. These signals are characterized by controlled interference in time, which allows you to get the desired level of bit error rate (BER) performance. The article presents the results of simulation modeling of data transmission in the channel with additive white Gaussian noise (AWGN) using the proposed optimal differential FTN (DFTN) signals and noncoherent symbol-by-symbol detection. A similar experimental study based on the software defined radio (SDR) platform was also conducted. The difference between the results of simulation and experiment is determined by the influence of symbol synchronization inaccuracy and is not more than 1 dB.

Simulation modeling of information transmission using spectrally efficient multi-frequency signals with using peak-to-average power ratio (PAPR) reduction methods (hard-clipping and soft-clipping) on transmission was held. Simulation results show that for SEFDM with optimal envelope, using soft-clipping method for PAPR reduction will reduce out-of-band emission (OOBE) of the signal at 50 dB of energy spectrum compared to hard-clipping method, thereby increasing the spectral efficiency. Besides that, for SEFDM with optimal envelope, soft-clipping method also slightly reduces the probability of bit errors when the PAPR reduction value is between 2–6 dB. However, for SEFDM with rectangular envelope, soft-clipping method increases the probability of bit errors.

Analyzing the performance parameters of IP-networks when processing multimedia streams is a very important task. There are many approaches to evaluating the quality of service parameters in the G/G/1 system.Changing the packet delay in the network is a very significant parameter that determines the quality of traffic processing. It is particularly important for multimedia streams. The delay variation is generally defined as a packet jitter.However, the analysis of the delay variation is often based on assumptions that do not allow the parameters to be determined with the required accuracy. This paper presents a new approach to defining packet delay variation in the G/G/1 system as delay variation. The presented approach is based on approximation of arbitrary distributions by hyperexponential distributions, i.e. modeling the G/G/1 system by the H2/H2/1 system. The EM algorithm is used to estimate the parameters of hyperexponential distributions. The paper presents the results of simulation. The packet delay variation was evaluated when processing traffic registered on a real network, CBR traffic, traffic with Pareto distribution of time intervals between packets and packet lengths, and traffic with exponential distribution of time intervals between incoming packets. Due to the fact that CBR traffic has explicit correlated properties, it can be noted that the presence of correlation inherent in CBR traffic leads to a decrease in delay variation.

The development and application of smart technologies in various fields is increasing every year. Different monitoring systems and sensors generate a large amount of data sets which allows to solve various tasks on data prediction and classification. This paper deals with data sets generated by a new tree monitoring system which evaluates in particular the sap flow density flux describing water transport in trees. The main task consists in prediction of the values of this characteristic which reflects the tree life state based only on observable air temperature during the predictable time interval and subsequent classification of trees according to some prespecified classes. The Fourier series based model is used to fit the data sets with periodic patterns. The multivariate regression model defines the functional dependencies between sap flow density and temperature time series. The paper shows that Fourier coefficients can be successfully used as elements of the feature vectors required to solve different classification problems. Artificial multilayer neural networks are used as classifiers. The quality of the developed model for prediction and classification is verified by numerous numerical examples.

We consider the communication between a source (user) and a destination in the presence of a jammer with latency as the user’s communication utility and two-sided incomplete information on network parameters. We study an impact of such incomplete information on equilibrium resource assignment strategies of the user and the jammer. The equilibrium strategies are found as a fixed point of the superposition of the best response strategies, and numerically illustrated. Uniqueness of equilibrium is proven.

We propose analytical model that investigates early Hybrid Automatic Repeat reQuest (HARQ) prediction scheme as a path towards Ultra-Reliable Low Latency Communication (URLLC). By incorporating early-HARQ (e-HARQ) and HARQ functionalities in terms of two phases in a model, we can evaluate the performance of their parallel processing. Moreover, we perform comparative analysis of the e-HARQ model with a random predictor model and a model that covers a traditional HARQ approach. We show a benefit of e-HARQ model in terms of various performance measures. We employ realistic data for transition probabilities obtained by means of 5G link-level simulations into e-HARQ model to get the evaluations of the main performance measures, such as false-negative and false-positive probabilities, in a fast and accurate way. The proposed model can be used as an efficient tool to get a quick estimate of the performance measures when selecting a classification-based parameter in an e-HARQ mechanism.

The paper provides a method for calculating characteristics of a Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) protocol to be used at the Medium Access Control (MAC) layer in an Industrial Internet of Things (IIoT) network. In particular, we consider a set of nodes equipped with sensors, deployed into an industrial machine, and having to transmit measured data to a final gateway. The gateway is equipped with multiple antennas and sweeps the entire area to gather data from the different nodes. A CSMA/CA protocol is used to limit interference among nodes. The mathematical model is based on an absorbing Discrete Time Markov Chain (DTMC) and the approach allows to estimate the average delay, the collision probability and the transmission probability by solving the system of transcendental equations. In addition, a queueing network method is also proposed for the modelling and compared to the absorbing DTMC solution. High accuracy of the absorbing DTMC method has been validated in numerical results by comparison with simulation results and with the queueing network method. The model obeys optimizing system parameters, such as the back-off time duration and other parameters of the CSMA/CA protocol.

We consider a class of so-called cesaro sequences over a finite alphabet, which possess the property of stability of the relative frequencies of occurrence of an arbitrary word in growing initial segments. This class includes a class of periodic sequences. A finite state automaton is called cesaro-hereditary if it processes cesaro sequences in the input alphabet into cesaro sequences in the output alphabet. Examples of automata that possess and do not possess the property of cesaro-heredity are given. The conditions are proposed so that the automaton possesses and does not possess the property of cesaro-heredity.

We developed the mechanism and tools of risk controlling in agile projects for companies in information and communication (ICT) industry. The relevance of this topic is underpinned by (1) the growing number of failures of agile projects due to realization of unique set of risks; and (2) the fact that standard agile practices neglect important risk management steps. The paper fills the research gaps in this area and addresses inefficiencies in explicit agile risk management frameworks. The results include the development of the mechanism’s concept and the block diagram for scrum framework. They also include risk controlling tools: risk-based release planning, system of key risk indicators and agile risk controlling effectiveness evaluation tree. Unlike peers mentioned in existing studies the mechanism provides holistic approach to the agile risk management while keeps the spirit of agile. It addresses risk governance issues, ensures integration and coordination of risk management activities both inside the team and across the company and provides for lightweight but efficient tools. The mechanism can be adapted for other agile frameworks and can be applied by scrum masters and project managers in ICT industry as well as by the researches who are interested in further enhancement in agile risk management practices.

Investing in the financial market is an effective way to save and increase any free money an investor might have. The success of the investments is based on knowing the fundamentals of the financial and technical analysis of securities. The current uncertainty around the negative effect of the coronavirus COVID-19 on the world economy and its possible negative outcome contribute to their mass sell-out. The situation has been aggravated as well by the price war on the oil market, which has led to a significant drop in oil prices. A number of analysts believe that, despite the current market situation being near a panic, several of the falling stocks present a certain interest for investment, including stocks of metallurgical, energy, and telecommunications companies. In order to answer the question, which securities in which economic sectors free money can be invested in with minimum risk, it is necessary to identify the sectors of the economy which have the biggest investment potential. Many analysts point to the telecommunications sector as one of these economic sectors. Due to the continuous daily demand for telecommunications services, as well as their fairly stable growth, the stocks of telecommunications companies, the main ones of which are VimpelCom, MegaFon, MTS, Rostelecom and T2 RTK Holding, are highly attractive for investment. Furthermore, specialists from the company International Data Corporation (IDC) concluded that the outbreak of the coronavirus in China is able to have a positive impact on the development of the ICT-sector, opening up new opportunities for developing digital platforms and Big Data solutions. As a result of the threat of the coronavirus spreading, an extra push to develop the telecommunications sector of our country’s economy is given by the transition of school-age and university students to distance learning, starting in mid-March 2020, as well as the transition to working from home, when possible. A fundamental analysis of the main companies of the telecommunications economic sector in our country has shown that, starting from 2015, they can be tentatively divided into groups of high performance companies and companies with lower performance. The first group includes MTS and MegaFon, while the second includes VimpelCom and Rostelecom. In this regard, the stocks of the companies from the first group are more attractive in terms of investment when compared to the second. In order to determine which stocks are the most attractive for investments, a fundamental analysis of the shares of the first group should be conducted. The analysis conducted showed a great investment attractiveness for shares of MTS.

The current level of management of the functioning and development of economic processes in Russian regions is characterized by the predominance of analog methodology in the collection, processing and issuance of important information and products that largely determine the relevance, direction and effectiveness of the implementation of functions and mechanisms of state regional management. The purpose of the work is to modernize the organizational and economic support of the regional economy management processes based on digital technologies. The system of scientific research methods that provided the author’s scientific results was formed on the basis of traditional and innovative methodological developments that provide the possibility of combining analog and digital assessments of the functioning of regional economic systems, applying qualitative and quantitative research procedures for the formation and transformation of research information arrays, developing promising directions for the introduction of digital telecommunications technologies as part of the functions and mechanisms for managing the economy of modern regions. Results: characteristics of the key features of the modern region as a subject of the digital economy, the specifics of electronic document management as the basis for rationalization of process management in the digital economy of the region, the organization of electronic document management on a regional scale based on the digital information node “Bank-business entity” and modern telecommunications technologies, localized banking structures as nodes of the regional digital infrastructure: resources, goals, functions, results, architecture and information and management flows of the digital node “Bank – economic entity” in the regional economic management system. Conclusions: the conclusion is made about the possibility and need for a qualitative increase in the scale and effectiveness of the use of digital telecommunications technologies in the implementation of the function of state management of the economy of regions, which will dramatically increase the effectiveness of its implementation.

The authors research the direction of the active development of information and communication techniques (ICT) in the world, which exceeds the growth of traditional sectors in the economy. It is reasonable for Russia, in relation to all the federal districts, to note the growing number of companies with telecommunications infrastructure, increased costs on the use of modern telecommunications techniques and creating “smart cities”. Nowadays this practice is widely acknowledged and successful in federal megacities, for example, Moscow is one of the TOP-5 megacities in the world with high digital readiness of urban infrastructure. It is necessary for other cities in Russia to involve the telecommunications business in this area, which actualizes the study of the conceptual basis of the “smart cities” idea as the prospect for the telecommunications sector and the current trend in the development of modern society based on modern telecommunications techniques. It is necessary for identifying prospects of telecommunications business in the development of “smart cities” and understanding this trend in modern society on the basis of modern telecommunication techniques: 1) to evaluate current promising trends in the telecommunications business; 2) to understand the “smart city” conception and its relevance in Russian conditions. Promising trends determining the telecommunications sector development include the transformation of the operating model under the influence of digitalization, the massive introduction of business intelligence techniques based on the Big Data analysis using artificial intelligence methods, the construction of business ecosystems with business partners, as well as the entry of telecommunications business into related market niches, connected with technological solutions, financial services and IT. This involves adjusting the organizational environment of the telecommunications business and requesting competencies for staff and society members. The ecosystem approach is fully manifested in the “smart cities” conception forming a promising market for telecommunications business, and it allows to focus the economy of urban agglomerations on positive evolution and contributes to the life standard of the population in the regions of Russia.

The article analyses the of telecommunications techniques in the transformation of the Russian economy, focus on supporting this direction in the Russia’s development. Telecommunications techniques create new opportunities for the health sector. There is a positive experience of some developed countries in the world actively implementing telecommunication techniques in health care practice for the social effect, the provision of quality medical services to people in the remote country’s regions, the transfer of the medical experience to the staff and also the increase of the medical care systems economic efficiency. In Russia also there are initiatives for the health system digitalization and the modern telecommunications techniques use. However, there are some difficulties and obstacles in the implementation, confirmed by expert opinions. It is important for the study of the role of telecommunications, information and communication techniques in the health care development at the present stage, the increase of medical care quality and the industry efficiency to evaluate the professional community’s perception of the healthcare digitalization; the foreign experience of the telecommunications techniques use in the health care development according to their economic efficiency; current prospects for the modern telecommunications techniques introduction taking into account the foreign experience. The foreign experience in patients’ remote diagnostics and medical professionals training, as well as regular evaluation of the processes economic efficiency, can and should be actively implemented in Russia’s practice. Such trends have been fully manifested only in Moscow, Moscow region, Saint-Petersburg, and Tatarstan. Other territories are significantly behind in providing telecommunications services to the healthcare sector. In Russia, the medical professional community realizes the importance of the health care digitalization, authorities supported and fixed the digitalization use at the institutional level, and the obstacles must be overcome on the basis of the expert community opinion and the international experience.

The purpose of this article is to describe, using a research case, how the leading mobile operator in Russia, MTS, was able to create an original and unique innovative business model in the ICT sector. This model leads to higher rates of successful product innovation, continuous updating of the product range in accordance with the constantly changing needs of consumers, and outstanding results in terms of reputation and customer loyalty. MTS’ platform-oriented business model is a good choice, as the company can build a solid foundation that integrates a wide range of products and services, sets rules, and provides opportunities to its customers. In addition, the company contributes to the creation of “traffic and attraction”, which can be determined by the size and activity of the user base and the potential ecosystem surrounding it. The advantage of the platform business model is the economy of scale and volume, based on the network effect and the integrity of offers, which makes the consumer’s choice of the platform long-term. The disadvantages of platforms include the fact that platforms have a longer lifecycle as compared to the offers that comprise it, in order to become the actual standard in the market.

The authors analyzed some features of changes in consumer behavior when shopping online in the context of the mass development of modern telecommunications and self-isolation. The study is based on the data of a sociological survey conducted in May 2020 and a comparative analysis of consumer reviews for January–May 2019 and 2020, presented on review aggregator websites. This paper studies the frequency of purchases, the assortment of goods purchased for the first time during the self-isolation, the structure and content of negative reviews about online shopping experience, as well as the opinion of consumers about the possibility of online shopping in the future, when self-isolation is canceled. The main trend in March–May 2020 was the increase in purchases, the average check and the number of orders online. But upon closer examination, one can observe groups of consumers who, on the contrary, have reduced the frequency of purchases on the Internet, have formed a negative or partially negative opinion about this method of purchasing goods, and, as before, are wary of expanding their purchasing activity using modern telecommunications. Online stores should carefully consider the existence of this segment of consumers, while trying to reduce negative user experiences in peak loads and form a loyal attitude to the new forms of trading.

This research is focused on γ-radiation, the main negative factor which causes significant losses in fiber-optical communication lines. We determine the methods for increasing the relaxation rate of color centers that are formed in an optical fiber under the influence of γ - radiation. Moreover, we develop the design of the fiber-optic communication line with the compensation of radiation-induced losses at the moment of exposure to the optical fiber γ - radiation. The results of experimental investigations are presented.

Two different approaches for dynamic range improvement of broad band analog fiber optic link were considered. They are based on the special lithium niobate modulators which was stabilized in specific working points. The first approach is the laser intensity noise suppression with dual output Mach-Zehnder modulator and balanced photodetector. The high noise suppression was achieved by precise balancing using modulator working point selection and stabilization as well as optical path adjustment. The second approach use a directional coupler modulator which was set to the specific working point corresponding to the minimum of third harmonic and linearized modulation. The requirements to characteristics of the modulators and working point stabilization systems were determined. Experimental demonstration and comparison two types of the photonic links were carried out. The spurries free dynamic range higher than 110 dB/Hz2/3 in 3 GHz spectral band was achieved.

The method for predicting the residual lifetime of a field aged optical cable with based on the test results of its samples taken from a cable line is considered. The test results of the proposed method are presented on the example of four samples of optical cables from cable lines installed in different years. According to the test results, the need to control the strength of the optical fibers of the cable line to predict the lifetime of the optical cable is confirmed.

Digital Twin technology as an idea of implementing simulation models of particularly every physical entity became universally adopted in the last five years thanks to a huge leap in computer hardware performance and software tools evolution. The early pioneers of Fiber Optic Current Sensors (FOCS) technology in the late 90-th had no access to such an advanced research tool as digital twin of the product being developed. As a result, nowadays FOCS remain undervalued due to its legacy problems including the lack of stability and high cost. However, the Connected World, Industrial Internet of Things open the great opportunities for new metering technologies in power grid. The modern computer simulation approaches helped us in this challenge to bypass the caveats of FOCS, to understand and improve this technology making it more accurate, robust and more competitive in its field.

The advances made in telecommunication technologies imply that new functional materials are developed for the components used in advanced electronics. Creating biomolecular films with certain impedance characteristics for telecommunication devices is an urgent task. This paper presents the results of experiments on preparing thin films by dehydration of water-salt solutions of albumin protein on a dielectric substrate. Periodic cellular structures forming in the films during the phase transition were studied. The values of the parameters and the results of the experiments were refined by computer simulation. We reached a conclusion about the significant value of the electric micro-potential, electrical conductivity and the flow of local currents in such processes. Depending on the conditions of formation, various spatial, frequency and energy characteristics of the transmission of electrical signals through self-assembled biomolecular films can be achieved, making it possible to use these films to create devices and elements of advanced electronics and telecommunications.

Laser modification of thin titanium film for precise loss control in lithium niobate optical waveguides was demonstrated. A simple ray model was used for analysis of optical losses induced by interaction of two orthogonal polarization modes of a Ti-indiffused channel optical waveguide in lithium niobate with a thin metal film on the substrate top surface. The theoretical estimations are in a good agreement with experimentally observed increase of the losses 0.95 and 1.05 dB/mm for TE- and TM-polarized modes respectively caused by 5 nm titanium film. Direct laser modification of the titanium film by a 976 nm laser beam with the threshold intensity up to 1 kW/mm2 was demonstrated. The formation of titanium oxide and titanium nitride during laser modification of the film was discovered via X-ray spectroscopy and explains optical losses reduction. The technique was applied for precise balancing of optical intensities in arms of Mach-Zehnder optical modulator, an associated increase of the extinction ratio from 30 to 48 dB was achieved.

With current advancements in communication technologies, video sharing and streaming are increasingly becoming popular among Internet users in applications like social-aware P2P video transmission. Peer-to-Peer (P2P) paradigm was proven to be the promising approach to efficiently deliver streaming services over the Internet. Several P2P-based streaming systems were successfully deployed. In such systems, the basic streaming quality parameters that affect the user Quality of Experience (QoE) are Playback Continuity and Startup Delay. Several research conducted have revealed that buffer filling strategies used in these systems play a key role on the streaming quality. The popularly used strategies are the Rarest First (RF) and Greedy (Gr) strategies, however, studies have shown that RF strategy outperforms Gr strategy in terms of playback continuity and Gr strategy outperforms RF strategy in terms of startup delay. In this paper, a problem of finding an optimal buffer filling strategy in form of mixed strategy was considered. The idea of the mixed strategy is to divide the buffer into two parts via demarcation point and apply one strategy to fill one part of the buffer and then the other strategy is applied to fill the other part of the buffer. Among the derived mixed strategies, an optimal was discovered which provides high probability of playback continuity with low startup delay.

Current cellular networks face outbreaks of an extremely high demand for communication capacity and coverage during the mass events. This article discusses a scenario with events in remote areas. It is expected that the unmanned aerial vehicles (UAVs) equipped with the directional antennas will become one of the key components of these networks and provide the solution. It attracts considerable attention in basic and applied research and commerce for its rapid deployment and flexible extension of the users coverage, mobility of UAV access points (APs) and a higher probability of line-of-sight channels. However, it also creates new issues to be addressed. The critical task is to maximize coverage area with the required quality of service to provide the connection for the maximum number of users. At the same time, analysis of the performance indicators of such networks, taking into account the mobility of both access points and users, is challenging. One of the key quality indicators is the probability of coverage. The aim of this work is to consider two drones’ mobility models to cover users with small cells, and to solve the problem of maximizing coverage probability using the simulation. With a given threshold signal-to-noise ratio, it is shown that using the particle swarm method as an adaptive navigation algorithm allows achieving higher coverage probability values as opposed to k-means algorithm. A comparative analysis of adaptive navigation is presented.

The telecommunication services rely on transmission of electromagnetic waves, increasing strength of electromagnetic field (EMF) in the environment, as well as corresponding human exposure to EMF. Thus, such inevitable exposure and their potentially unhealthy effects have been in focus of the general population concerns, requesting and initiating development of systems for daily and continuous EMF monitoring, such is the recently launched, the Serbian EMF RATEL system. This system has been established on spatially distributed wireless monitoring stations/sensors, performing long-term EMF observation over the Republic of Serbia territory, in order to timely inform the Serbian public on present level of EMF and associated exposure. The EMF RATEL system, as the world newest monitoring system, brings a feature of monitoring the EMF contribution from telecommunication services, in several predefined frequency sub-bands. Such service-based monitoring approach, some technical details and analysis/dissemination of measurement results will be presented in this paper, in order to highlight capability of EMF RATEL in prevention, protection and management of EMFs, particularly in the Republic of Serbia.

Currently, the demand to the capacity of mobile cellular deployments dictated by modern applications is rising rapidly. This especially holds true for cases where a small area contains great number of users simultaneously like stadium or festival venue. In some of these cases stationary base station can be replaced with timely-deployed UAVs. In this work we consider a scenario of data transmission between a user and UAV. During transmission UAV does not have any information on the user location but has information on its mobility model. Transmitted traffic has certain restrictions on SNR and the main objective is to lower the probability of breaching these restrictions. The current study is a proof of concept for the considered model, aimed to propose and verify the described approach through analysis of the derived results.