Перегляд Проблеми телекомунікацій за назвою
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ПублікаціяAdaptive control signal parameters in LTE technology with MIMO(Проблеми телекомунікацій, 2012) Loshakov, V. A.; Al-Janabi H. D.; Al-Zayadi H. K.In this paper are considering ability of increasing the LTE performance by using the adaptation CQI feedback. The Block Error Rate of the Channel Quality Indicator performance has to be investigated depending on different configuration of MIMO. ПублікаціяAnalysis of data and real time traffic model(Проблеми телекомунікацій, 2012) Popovskaya, K. O.In the article the experimental study of a multi-service network is carried out. In the assumption of a Poisson entrance flow of demands likelihood characteristics of multiservice system are received by transfer of real time traffic and traffic of data. These characteristics allow forming indicators of service quality of various services. Dependence of average of the macro packages being in turn, on intensity of an arriving traffic of data is received at its aspiration to limiting value. At aspiration λg to limiting value the average of macro packages in turn sharply increases. At the same time serving system passes to an unstable, critical mode. Dependence of probability of the lost macro packages on the size of the buffer and on pulse nature of receipt of macro packages is investigated. Results show that pulse nature of receipt of macro packages leads to considerable growth of losses in comparison with the smoothed traffic. At the same time, buffer existence damp pulse character of traffic and leads to reduction of losses. Researches of transmission quality of multiservice flows with use of machine experiment and the ns-2 program are carried out. The given results allow knowing about cross impact of different services flows, and their difficult character speaks features of the used technologies. Obviously, the greatest influence renders increase of real time flows. Results of the carried-out machine experiment allow choosing correctly loading of routers and can be used at design and balancing of network. ПублікаціяAnalysis of productivity of distributed systems with service oriented architecture under conditions of limited link and buffer resources of telecommunication network(Проблеми телекомунікацій, 2012) Kovalenko, T. N.Analysis of productivity of a distributed system with service-oriented architecture and request loss probability in SOA system is done, as well as dependence of these characteristics on network throughput and buffer size at high load levels and under overload conditions. ПублікаціяImproving the performance of LTE technology by using MIMO and OFDM(Проблеми телекомунікацій, 2011) Al-Janabi, H. D.; Vadia, Z.In this paper we consider the ability to increase the LTE performance using MIMO systems and frequency diversity methods like as OFDMA and SC-FDMA. The effect of using the adaptive modulation in time and frequency domain by taking advantage MIMO and OFDMA and SC-FDMA in LTE technology is investigated. ПублікаціяModel guaranteed transmission rate providing in WiMAX downlink(Проблеми телекомунікацій, 2013) Al-Janabi H. D.; Al-Dulaimi A. M.; Abed A. H.Found that the provision of the required transmission rate of WiMAX can be achieved by solving the problem of frequency resource allocation in the downlink. As a result analyzed by the existing mechanisms of the frequency distribution of resources between subscriber stations in a downlink wireless network, operating using the technology of WiMAX. Based on the identified drawbacks of making a mathematical model the distribution of sub-channels in the network standard, IEEE 802.16, which provides a guaranteed rate subscriber stations in the downlink and submitted by a number of linear constraint equations. The novelty of the model lies in the formulation of the problem the frequency distribution of the resource allocation problem as a sub-channel with a firmly fixed number of subcarriers in each of them. The solution to the optimization problem sub-channel allocation proposed to carry out a multiple objective functions that the available frequency resources in order to allocate a minimum number of sub-channels, the distribution of the available frequency resources in order to allocate a minimum transfer speed of each the subscriber stations, the distribution of the available frequency resources to jointly minimize the number of used sub-channels and a transmission rate allocated to subscriber stations in a downlink. A comparative analysis of the solutions obtained by using different objective functions. ПублікаціяModels of structural coherence in telecommunication systems(ХНУРЭ, 2013) Popovsky, V. V.Mathematical models of structural connectivity for fixed and dynamic systems are considered. Ezary-Proshan and Polessky estimations are given for fixed systems while for dynamic systems these estimations are determined in the state space. Quality of state estimation under different connectivity of vector components of dynamic system nodes is analyzed. It is shown that Tchebotarev-Achaev basic model approaches the procedure of stochastic synchronization of states. The presence of connectivity in the network structures, such as infocommunication systems, provides the acquisition of properties for the reliability and survivability of networks. For fixed (invariable with time parameters) networks connection is displayed as connectivity matrix, which may have a binary structure or consist of quantitative data de-fining the level of the connection (probability, number of channels, distance, etc.). The co-efficient of connectivity or connectivity probability for such networks is found by the approximate methods of Ezary-Proschan, Polesski etc. For dynamic (with time-varying elements of connection) network connectivity values can be obtained through the current assessment of the state of connectivity for each node from all adjacent nodes. For real posteriori evaluation of connectivity it is appropriate to use the state-space model that allows us to characterize the dynamic systems as deterministic and stochastic. Practice has shown that the state of the process allows to use the methods of stochastic approximation under the condition of choosing the sampling rate. The analysis of multi-dimensional differential systems shows that the existence of connections between components of the system cannot have arbitrary values. A large number of connections leads to unstable regimes. In the other extreme case: under the absence of reciprocal connection the system loses its system properties (integrity, emergence). The connection between random processes improves accuracy (reduced values of a posterior variance) of the estimates of the components for these processes compared to that case when data of the process are independent. ПублікаціяPatterns for reliable Web-services(Проблеми телекомунікацій, 2012) Amer Tahseen Salameh Abu-Jassar; Tkachova, O. B.This paper is devoted to developing an approach to ensure the reliability of Web-services in SOA which based on the use of special design patterns. Proposed patterns provide reliable delivery of messages and patterns that allow estimate the current level of reliability. ПублікаціяSuccessive interference cancellation in tree algorithms of random multiple access(Проблеми телекомунікацій, 2012) Vasilenko, Yu. A.; Tur, B. S.Nowadays Wireless Broadband Networks (WBN) are dynamically developed sphere of science and technology. The given work is devoted to analysis of Random Multiple Access method called Successive Interference Cancellation (SIC), which is widely used in IEEE 802.16 standard. The direction of research is rather up-to-date and its importance is very high. We only use the Kalman filtering techniques to reduce distortion, which has a positive effect on the main index of the tree algorithms — the speed of conflict resolution. After analysis it is clear that among the various methods of random multiple access to the highest potential speed of conflict resolution have a tree algorithms using SIC. Potential SIC algorithms properties can be implemented in condition of the adjacent slots signal structure identity, one hundred is achieved by selecting amplitude — phase equalizers. An efficient algorithm for the amplitude and phase equalizer can be obtained, if taken into account the statistical structure of the received signals, taking into account the correlation of these signals on adjacent slots, the degree of coherence of the received signals, which directly determines the magnitude of the sampling step for transmitting a reference signal and the number of taps of the delay line. ПублікаціяSynthesis of Moore FSM with expanded of coding space for telecommunication systems(Проблеми телекомунікацій, 2011) Barkalov, A. A.; Titarenko, L. A.; Hebda, O. P.The proposed method is targeted on reduction of hardware amount in logic circuit of Moore finite-state machine implemented with customized matrices. The method is based on using more than minimal amount of variables in codes of FSM internal states. ПублікаціяАдаптивный буфер компенсации джиттера задержки прибытия пакетов на основе робастного фильтра Калмана(Проблеми телекомунікацій, 2013) Кобрин, А. В.In the paper author has suggested a model of the delay included jumps and emissions, it allows simulating a more real process of delays. Multimedia streaming transmission might be affected by jitter. To avoid transmissions errors there are jitter buffer used, therefore it is necessary to estimate the current jitter although it is impossible to calculate straight value online. Author has proposed to use the robust Kalman filter to estimate the delay. We have suggested the algorithm for adaptive playback buffer, which allows to smooth jumps and emissions. Filter ignores individual emissions of delay and switch to the new delay value when delay switches the trend or the level of value. The filter allows you to switch quickly, because it has window of observation allows us to take a decision about the type of distortion delay. The buffer was developed for use at boundary separating media, for example, at boundary wired and wireless media. Because there are huge quality loss. ПублікаціяАлгоритм оценки качества передачи речи с анализом характеристик эффективных потерь пакетов на основе вейвлет-преобразования(Проблеми телекомунікацій, 2011) Бобрицкий, С. М.The proposed in paper method VqMW belongs to the family and the E-model can be used in evaluating the transmission quality of voice traffic in terms of grouping voice packets losses and high levels of jitter one-way delays. ПублікаціяАнализ возможностей искусственных нейронных сетей для решения задач однопутевой маршрутизации в ТКС(Проблеми телекомунікацій, 2011) Павленко, М. А.A comparative analysis of the possibilities of using artificial neural networks such as multilayer perceptron, RBF network and the Hopfield network to solve the routing problem in telecommunication networks. ПублікаціяАнализ качественных показателей биометрических систем аутентификации пользователей(Проблеми телекомунікацій, 2012) Пастушенко, О. Н.; Невлюдов, И. Ш.The scientific optimization problem for decision-making in biometric systems from the perspective of the minimum average risk criterion is considered. Rapid development and rather wide use of biometric systems in various spheres of human activity, including in modern telecommunication systems, highlights the reliability of their performance. The work is based on the method of biometric systems theory of mathematical statistics, which is widely and effectively used in a number of modern engineering systems. For example, in modern radars conditional probability of false alarm is at the level and below. The requirements for errors of the 1st kind are not so stringent. It is this way is a key to select the requirements for the quality characteristics of biometric systems. A common approach for the equality of errors of the first and the second kind, which is widely used in present-day biometric systems, is not constructive, because it is valid only for the particular case, which is far from practical needs. In this article the weight optimization criterion of quality parameters for biometric identification systems (authentication), based on a more general criterion for minimum average risk of erroneous decisions, is obtained. Practical recommendations for the choice of their quality indicators are given. Further research will focus on the synthesis of decision rules for specific biometric systems. ПублікаціяАнализ моделей сверхширокополосных сигналов для инфокоммуникационных сетей(Проблеми телекомунікацій, 2012) Шостко, И. С.; Алмакадма, Таха; Соседка, Ю. Э.The radiation, reception and processing of signals in UWB systems is considerably different from the processes in narrow band systems. The main difference is due to the change in shape of the signal at its emission, distribution in space and at the reception. Changing the shape of the signal at the receiver, leading to difficulties in processing the correlate or matched filter. Changing the shape of the pulse, and hence the spectrum of the signal, reduces the reliability of the transmitted messages. The probability of occur-rence bit error rate increases. Thus, the quality of communication in telecommunication systems UWB radio, urgent problem of correcting the signal pa-rameters in the process of emission and reception. To improve the spectral efficiency, with the concurrence of characteristics of UWB signal and the receiver in the spectrum, it is proposed to adjust the pulse spectrum, depending on the conditions of the signal in the radio channel. The paper proposes a systematic description of the models UWB signals and analysis of their characteristics. In the model introduced by the pulse scaling factor that allows you to change the shape of the pulse. By changing the pulse duration and the scale factor, you can control the central frequency and the width of the spectrum, which allows for maximum spectral efficiency, or adjust the spectral characteristics of the signal according to the problem under consideration. If the formation of the code sequence used pulses whose parameters can be adjusted using the scale factors, the characteristics of the code sequence and acquire new properties. ПублікаціяАнализ нелинейных искажений в радиотракте с применением различных методов оценки нелинейности(Проблеми телекомунікацій, 2011) Селиванов, К. А.; Москалец, Н. В.; Никитенко, Т. В.Different approaches as evaluated by nonlinear effects on the basis of description of hysteresis, the Nussbauma functions and the Volterra series are considered. Expressions of responses of nonlinear chain for different types of influences are got, that enables to expect the coefficient of accordions from by a greater degree exactness. ПублікаціяАнализ устойчивости и оптимизация ТСР-сеансов в мультисервисных ТКС(Проблеми телекомунікацій, 2010) Старкова, Е. В.The dynamic TCP-sessions model is proposed. The model is represented by a system of nonlinear differential equations. On the bifurcation theory basis the TCP-sessions stability conditions are obtained. A TCP-sessions optimization method for calculation of the TCP and RED-algorithm basic parameters is proposed. ПублікаціяАнализ эффективности адаптивного компенсатора кросс-поляризационных искажений(Проблеми телекомунікацій, 2011) Коляденко, Ю. Ю.; Ельченко, С. В.The compensate algorithms for cross-interference with cross-polarization orthogonal channel are considered in the article. With the help of mathematical modeling in Matlab was made the analysis of the effectiveness of the adaptive noise canceller cross-polarization distortions. ПублікаціяАналитическая модель оценки капитальных затрат на построение городской оптической сети доступа следующего поколения(Проблеми телекомунікацій, 2012) Крикун, В. С.; Ощепков, М. Ю.; Бриндзий, А. В.The paper proposed an analytical model to estimate the capital cost of deployment next generation optical access (NGOA) network for the urban area. This model is used for solution the problems: of optical access technology selection; the optimal topology and network access scenario determination; the active and the passive network components on the site, backbone, distribution and subscriber areas definitions. One of the main objectives of the analytical model is to perform a techno-economic evaluating of different proposed solution for NGOA networks. This evaluation comprises a cost assessment of infrastructure and equipment which are dependent on the network dimensioning and the area where they will be used. Proposed in paper an analytical model is different from the earlier known more fully into account the factors and components which form the optical access network. In this paper the problem of synthesizing the structure of next generation urban optical access network is formulated as an optimization, and it is based on the proposed analytical model. Demonstrated an example of using this analytical model for structural and parametric synthesis of urban next generation optical access network for the one of the Kharkiv regions. ПублікаціяАналіз критеріїв оптимальності функціонування транспортних телекомунікаційних мереж(Проблеми телекомунікацій, 2010) Шебанова, Л. О.; Турупалов, В. В.In this article the reliability evaluation method based on vector synthesis for transport telecommunications networks is proposed. The methods with uncertainty or partial uncertainty conditions and fuzzy-possibilistic approach are used to resolve the uncertainties of multicriterion problem.