Vol 9, No 2 (2023)
Articles
Mathematical Model of the Unbalanced Monopole Feed. Part 2. Determination of Complex Capacitance of Normally Open Wire Antennas, Small with Respect to the Wavelength
Abstract
A method for calculating the complex capacitance of small with respect to the wavelength, normally open antennas is proposed. Analytical expressions for determination of mutual potential coefficient of any two arbitrarily arranged linear conductors are obtained. The proposed technique can be useful in assessing the losses of normally open wire antennas placed in close proximity to the semiconductor surface, as well as in determination of their input resistance.
Proceedings of Telecommunication Universities. 2023;9(2):6-21
6-21
Prototype of High-Speed Data Transmission Receiving and Transmitting Equipment in the 57‒64 GHz Frequency Range
Abstract
The purpose of this work is to create and study the characteristics of a prototype of receiving and transmitting equipment operating in the millimeter wavelength range in high-speed data transmission networks. During the work, the task of developing and software implementation of digital signal processing algorithms was solved, the hardware part was developed and implemented, experimental measurements of characteristics and field tests of the prototype were carried out. Experimental studies have shown that the developed equipment transmits and receives signals in the frequency range 57‒64 GHz with the possibility of discrete change of the signal frequency bandwidth: 100, 200, 400, 800 MHz and supports 12 modulation and coding schemes with low-density parity check code. The use of an adaptive algorithm for demodulation and decoding at the receiver made it possible to increase the efficiency of signal transmission and reduce the probability of packet errors by half. The developed prototype provides a data transmission rate of 2 Gbit/s at distances up to 100 m and of 500 Mbit/s at distances up to 300 m.
Proceedings of Telecommunication Universities. 2023;9(2):23-39
23-39
Recursive Selection of Hyperexponential Distributions in Approximation of Distributions with "Heavy Tails"
Abstract
It is known that many quantities that determine the network characteristics of the functioning of an infocommunication network have probability distributions with "heavy tails", which can have a significant impact on network performance. Models with heavy-tailed distributions tend to be difficult to analyze. The analysis can be simplified by using an algorithm to approximate a heavy-tailed distri-bution by a hyperexponential distribution (a finite mixture of exponentials). The paper presents a algorithm for calculating the parameters of the hyperexponential distribution components, which is based on a recursive selection of parameters. This algorithm allows you to analyze various models of queues, including G/G/1. It is shown that the approach under consideration is applicable to the approxi-mation of monotonically decreasing distributions, including those with a "heavy tail". Examples of approximation of Pareto and Weibull distributions are given.
Proceedings of Telecommunication Universities. 2023;9(2):40-46
40-46
Quasi-Soliton Mode in a Multi-Span Fiber-Optic Communication System Using Optical Amplifiers
Abstract
The paper considers a method for maintaining a quasi-soliton mode in a multi-span fiber-optic communication system using discrete Erbium optical amplifiers, as well as Raman amplifiers with distributed amplification with counter and bidirectional pumping. The OptiSystem 19 and OptiPerformer 19 programs were used to model quasi-soliton fiber-optic communication systems. The simulation results are compared with theoretical data, and the advantages of a fiber-optic communication system with a Raman amplifier and bidirectional pumping are demonstrated.
Proceedings of Telecommunication Universities. 2023;9(2):47-56
47-56
Superposition of the Similarity Images by Contour
Abstract
Superposition of the similarity images is implemented by the methodology with divided estimation of parameters. The offsets along the coordinate axes are estimated in the Cartesian coordinate system. The scale and the rotate are estimated in the log-polar coordinate system. The accurate estimation of parameters of similarity models (offsets, scale and rotate) is achieved by the iteration processing. Optimization of the processing time is achieved by contour comparison instead of the image comparison. The test data for experiment is image with the freight car. The decreasing of the processing time for the modified methodology of “contour comparison” was estimated by comparison with the source methodology of “image comparison”.
Proceedings of Telecommunication Universities. 2023;9(2):57-64
57-64
Numerical Evaluation of the MU-MIMO Beamforming Performance with User Selection Algorithm
Abstract
This paper presents the numerical evaluation of the ZF beamforming algorithm using the user selection in the multiuser multiantenna (MU-MIMO) downlink system. Two user selection algorithm – semiorthogonal user selection and greedy user selection are numerically evaluated based on the open source MIMO channel model. The sum rate performance depending on number of users are presented. The arising inter user correlation degrades the sum rate (spectral efficiency) performance of multiuser MIMO system especially in scenarios where the number of users is larger than the number of antennas at the BS. The selection of users is based on the orthogonality of the channels among selected users. For MIMO channel simulation the QUADRIGA channel model reflecting the real propagation conditions is used. The obtained performance of MU-MIMO ZF precoding in spatially correlated channel are compared based on the empirical cumulative density function of the sum rate of multiple users. Numerical results show that the ZF precoder using user selection (G ZF) outperforms the ZF precoder with random user selection in spectral efficiency. The greedy user selection in spatially correlated channel has advantage to semi-orthogonal user selection. It isobserved that as the increasing the number of served users used for selection the greedy user selection gives better performance than semi-orthogonal algorithm.
Proceedings of Telecommunication Universities. 2023;9(2):65-71
65-71
Model of a Self-Organizing Radio Network, Operating in a Complex Signal and Interference Environment.
Abstract
Radio communication networks, including those that use adaptation, are designed for information exchange between individual correspondents and are usually built via radio routes, functioning ones in a complex signal and interference environment. It is necessary to take into account the degree of influence values adaptive parameters for indicators that describe accordance requirements communication requirements, the energy component of the radio link, as well as the amount of radio link resources spent on maintaining and restoring communication. Getting estimates of the boundaries of primary and secondary user traffic service characteristics in a self-organizing radio network, functioning in difficult signal-to-noise conditions it is relevant. The aim of the research is to increase the reliability of the simulation results by obtaining the boundary values of the throughput when transmitting information in a self-organizing radio communication network. Modeling of processes occurring in the radio communication network is carried out, and the following parameters are determined: boundary parameters of delay and loading; parameters of the output stream in a complex signal-interference environment. Conclusions about the advantages of the network calculus method based on the results of a series of calculations are presented. Analytical estimates of the quality of service provision in the radio communication system are obtained using the theory of network calculus. The developed mathematical model makes it possible to study the delay and load indicators in a self-organizing radio network during the information exchange of traffic of various types under the influence of intentional and unintentional interference. The results of analytical calculations obtained by applying the network calculus method can be used in the formation of control actions, as well as solving problems of increasing the stability of radio links.
Proceedings of Telecommunication Universities. 2023;9(2):72-80
72-80
Controller Location and Load Balancing Integrated Solution
Abstract
The usage of multi-controller SDNs is currently the most efficient approach for constructing the core of communication networks of the fifth and following generations. One of the top priorities in the study of this topic is occupied by the optimisation of the network core construction since it involves relatively high expenses when developing communication networks of the fifth and future generations. Due to the complexity of the problems being tackled, there are currently a number of load balancing algorithms and algorithms for arranging controllers in multicontroller networks that are based on meta-heuristic methods. These algorithms allow for the optimum possible utilisation of controller resources in such networks. However, a comprehensive solution to the load balancing and controller placement issues has yet to be discovered. The answer to such an issue is the focus of this article. The report suggests using network clustering in conjunction with the meta-heuristic chaotic salp swarm technique, which has shown to be effective in prior research on the challenges of creating multi-controller networks, to accomplish this goal. The salp swarm algorithm in the paper is adjusted to take into account the integral solution to the problem of deploying controllers based on clustering of a multi-controller network and load balancing. By contrasting the simulation results with those from the well-known meta-heuristic particle swarm algorithms optimization and the grey wolf GWO, as well as the previous version of the chaotic salp swarm algorithm CSSA, the effectiveness of the proposed solution was evaluated.
Proceedings of Telecommunication Universities. 2023;9(2):81-93
81-93
Modeling a Program with Vulnerabilities in the Terms of Its Representations Evolution. Part 2. Analytical Model and Experiment
Abstract
The investigation results of the creating programs process and the resulting vulnerabilities are presented. In the second part of the articles series, a program life cycle generalized analytical model of the based on its representations is proposed, taking into account the direct and reverse transformation methods. Also, the model reflects the occurrence and detection of vulnerabilities and their classification. A particularly model is synthesized from it, reflecting the current state of the program representations evolution, and on the basis of which a number of fundamental statements were derived, written in an analytical form. To base the performance of models in reflecting vulnerabilities terms, the following two experiments are carried out: retrospective-factual, comparing real-life vulnerabilities with a particularly model; and practical demonstration the evolution of vulnerability in representations in the process of the simplest program evolution. As a result of the second experiment, the increase in coverage by the vulnerability of representations in the development process is clearly shown.
Proceedings of Telecommunication Universities. 2023;9(2):95-111
95-111
Hierarchical Model and Decision Optimization Algorithm for Distributed Data Storage and Processing
Abstract
The task of optimizing distributed data storage and processing is difficult to solve in a limited time. In this regard, a hierarchical approach has been applied to solve it, which provides for the presentation of a generalized problem in the form of a set of hierarchically ordered subtasks, for each of which locally optimal solutions are determined at the appropriate hierarchy level. To optimize solutions for distributed data storage and processing, a process model has been formed, presented in the form of a set of hierarchically ordered components, a mathematical model of a hierarchical game, which is a way to optimize solutions at hierarchy levels. In order to determine effective solutions at hierarchy levels, an algorithm for local optimization of solutions based on genetic algorithms has been developed. The construction of data processing schedules assigned to computing devices is implemented using the proposed heuristic procedure. The application of the developed models of the distributed data storage and processing process, hierarchical game models and algorithms for optimizing solutions made it possible to significantly increase the dimension of the problem, take into account the parameters characterizing data transmission channels when optimizing solutions at hierarchy levels, and minimize the amount of unused resources.
Proceedings of Telecommunication Universities. 2023;9(2):112-127
112-127
Methods of Protection against Threat: Incorrect Ballot Filling by Voter in the Remote Electronic Voting System
Abstract
A generalized scheme of remote electronic voice based on homomorphic encryption is considered. Two methods of protecting the voting system from the threat from the voter, consisting in incorrect filling of the ballot by the voter, are investigated. Both methods are based on the algorithms of “zero-knowledge proof”. Evaluations of the complexity of calculations in the formation of proof of the correctness of filling in the ballot by the voter and Evaluations of the complexity of verification of the proof by the controlling party are obtained. A comparative analysis of the complexity of the implementation of both methods has shown that the method based on the proof based on the equality of logarithms has less complexity of calculations on the voter's side compared to the method based on the mixing of votes. At the same time, the second method (the method of mixing votes) requires 1.67 times less calculations in the blockchain, which becomes a significant factor in choosing the second method in favor of a large number of voters.
Proceedings of Telecommunication Universities. 2023;9(2):128-142
128-142