This paper presents the most valuable theoretical results that confirm the possibility of practical realization of a wideband volume horn array antenna with the switchable polarization capability. Among key features of the proposed antennas are their high stability of switchable linear polarization tilt angle of radiated electromagnetic wave, radiation pattern of sector type and wide operating frequency band. The paper focuses on characteristics of linear horn antenna subarrays as key components of the described volume array antenna. Subarrays fully comprise double-ridge waveguide sections. The cutoff wavenumbers calculation algorithm is developed for the symmetrical double-ridge waveguides to estimate frequency bandwidth of power dividers in their different cross sections. The problem is solved numerically by partial regions method taking into account field singularity on rectangular metal ridges.

Проведено исследование многоагентной системы управления телекоммуникационной сетью. Рассмотрен процесс кооперации агентов на основе модели договорных сетей применительно к решению задачи оптимальной загрузки телекоммуникационной системы. Приведены математические соотношения, описывающие взаимодействие агентов в кооперации. Изложена методика расчета стоимости системы в зависимости от ее технических параметров. Описан предложенный метод выбора одного реального агента-исполнителя из множества агентов-исполнителей по результатам оценки стоимости одной и той же сети в условиях влияния на результат решения задачи других агентов.

The International Crimean Microwave Conference (CriMiCo) is convened in Sevastopol since 1991. 20 years saw this conference become the flagship venue for far reaching research into theoretical, experimental, manufacturing, applied and historical aspects of microwave engineering and telecommunication technology. Solely in 2010 over 500 reports were delivered by scientists and experts from 208 universities and 17 countries: Belarus, Belgium, Bosnia and Herzegovina, Germany, Israel, Iran, Kazakhstan, Canada, China, Korea, Lithuania, Moldova, Poland, Russia, USA, Ukraine and the Republic of South Africa.

High-tunable low-loss microwave dielectric devices are designed by electromechanical alteration in the configuration of device components. Specifically, this device consists of dielectric and metallic parts with an air gap between them. The gap location provides the largest perturbation in the electromagnetic field and a mini-actuator controls the device. Through experiments conducted, we test and apply the high-tunable dielectric resonators and filters as well as wide-band low-loss phase shifters.

The basic principles of GSM railway network planning are examined. The method of the frequency channels distribution between cells is described. The development of frequency channel reuse scheme is performed. The procedure of an operational planning is proposed. The principles of even radio coverage are considered for cells with mainly free radio propagation and for urban areas.

The processes of useful signal formation in the short-range radar systems constructed on the heterodyne, homodyne and autodyne principles are considered. The mathematical fundamentals of the fulfilled analysis are described in brief. It is shown that the autodyne configuration is much more complicated for the examination compared to the heterodyne and homodyne configurations due to the necessity of taking into account its own re-reflected signal. To simplify the theoretical analysis, the examination of the autodyne effect is performed under an assumption of reflected signal smallness. The comparison results of the considered configurations, which show that the homodyne and autodyne signal processing in the usual Doppler short-range radar turns out similar, are given. However, the autodyne short-range radar configuration itself has its own specific peculiarities, which should be taken into consideration in practice. It is proved that in the autodyne configuration one can meet the accompanying frequency modulation of the probing oscillation. It appears even at the absence of the forced frequency modulation, which is widely used to improve the short-range radar noise immunity. It is found out that this accompanying frequency modulation at weak reflected signals does not affect noticeably on the autodyne converter operation. The main theoretical conclusions of this paper are in the good conformity with the published results.

Предложены метод приема импульсных сигналов сверхмалой длительности (IR-UWB) и реализующий его приемник, использующий не накопление энергии этих импульсов, а селекцию их временного положения. Вероятность ошибки при приеме оценивается отношением количества импульсов, сгенерированных одновибратором и соответствующих коду сигнала, к количеству импульсов, вызванных шумами и помехами. Исследованы вероятность правильной селекции импульсов кода и вероятность обнаружения импульсов шума. Проведено моделирование приема ультракоротких импульсных сигналов, подтвердившее реализуемость предложенного приемника и правильность результатов теоретических исследований.

На основании генетического подхода решена задача оптимального размещения базовых станций при создании беспроводной широкополосной сети передачи информации. Сформирована математическая модель генетического подхода применительно к решению рассматриваемой задачи. Данная модель реализована в виде генетического алгоритма и соответствующего программного обеспечения, позволяющего эффективно решать задачи размещения большой размерности. Корректность теоретического анализа подтверждена данными, полученными методом полного перебора. Проведена оценка времени счета в зависимости от параметров задачи. Показано, что для задач малой и средней размерности разработанный алгоритм обеспечивает минимальное время счета. Результаты решения задачи для конкретного примера продемонстрировали неоспоримое преимущество генетического подхода. Полученные результаты можно успешно применять для создания муравьиных алгоритмов оптимизации размещения базовых станций.

Cooperative communication can improve the performance of cellular mobile networks. The optimization techniques based on duality theory, decomposition and subgradient method were applied for such wireless cellular cooperative systems. It was shown that the joint optimization and resource allocation problem can be solved efficiently within a network utility maximization framework. A concept of proportional fairness was used to achieve fair distribution of quality of service among users. Simulation results confirm the validity of the theoretical work.

Modern companies including telecommunication companies and mobile operators working in the global environment should guarantee technological effectiveness and innovation, renewing their technologies and services. Operation Support System/Business Support System is used in telecommunication companies. In current state-of-the-art approaches, several iterations involving analysts and system architects are necessary, methodologies allow modeling non-functional or functional requirements but they do not take into account the interaction between functional and non-functional requirements as well as collaboration between services. Web Services Agreement is a convenient way to contain QoS parameters but state-of-the-art SLA-aware methods cannot support all classes of non-functional parameters and provide run-time support and dynamic reconfiguration at the same time. The approach proposed in this paper fills this gap. It employs a well-defined workflow and analysis model for developing and adapting complex software systems including support of all classes of non-functional parameters and providing run-time support and dynamic reconfiguration of provided services.

Data crashes can cause unpredictable and even hard-out effects for an enterprise or authority. Backup strategies as antidote unify a complex of organizational and technical measures that are necessary for data restoring, processing and transfer as well as for data security and defense against its loss, crash and tampering. High-performance modern Internet allows delivery of backup functions and is complemented by attractive (mobile) services with a Quality of Service comparable to that in Local Area Networks. One of the most efficient backup strategies acts the delegation of this functionality to an external provider, an online or Cloud Storage system. This article argues for a consideration of intelligently distributed backup over multiple storage providers in addition to the use of local resources. Some examples of Cloud Computing deployment in the USA, the European Union as well as in Ukraine and the Russian Federation are introduced to identify the benefits and challenges of distributed backup with Cloud Storage.

The mathematical modeling of amplitude and phase distribution of the electromagnetic fields at the aperture of the receiving antenna system has been performed. The possibility of frequency reuse in radio relay link under condition when two transmitters operate simultaneously on the same frequency and with same polarization is substantially investigated by using the phenomenon of phase front curvature of electromagnetic wave. An effective approach to optimal spatial processing of two radio signals from two transmitters at the receiving side of radio relay link is developed. The mathematical expressions allowing the theoretical analysis of spatial processing of radio relay link signals are obtained. The results of theoretical investigations are extensively discussed. The references for practical application of obtained results at the development of microwave link equipment are given.

The new procedure of sequential noise suppression in transient signals has been developed. The additive, convolutional and multiplicative noises are reduced to the additive forms by appropriate homomorphic transformation. In the decomposition of the signal by wavelets, the additive noise component is identified with the detailizing parts of this expansion. It is found that the Daubechies wavelets would be used as the basis functions. The specific features of the thresholds choice for noise suppression are discussed. According to the results of numerical simulations, it is ascertained that in certain cases the main role in the forming of transients belongs to convolutional noise.

An effective technique to the design of dual band coaxial waveguide feed horn for reflector antenna excitation has been developed and tested. Matching the feed horn with free space in upper frequency range is achieved by dielectric insert disposed inside the circular waveguide fabricated in interior conductor of open ended coaxial waveguide. The presence of dielectric insert causes the high level of reflection in lower frequency range from the boundary between the open end of coaxial waveguide and free space. A novel technical solution of highly complicated matching problem has been proposed. The matching design was performed as the series of finite thickness diaphragm arranged on outer surface of interior conductor of coaxial waveguide. To obtain the rigorous solution of given electromagnetic problem for the complicated structure consisting of a great number of connected coaxial waveguide sections and dielectric insert, a new effective approach has been proposed. The distinctive feature of this approach consists in combination of rigorous procedure based on computation of generalized scattering matrices and another rigorous procedure based on the finite difference time domain method. To combine these essentially different approaches, the metallic discontinuity equivalent to overall investigated structure was employed. An optimization of equivalent matching structure has been performed by the variant of the evolution strategy method. The obtained design with metallic discontinuities was converted into real structure comprising the dielectric insert. The final calculations of real structure were performed by the finite difference time domain methods. The effectiveness of proposed technique was confirmed by the results of testing the developed feed horn in reflector antenna system.

A method of impulse ultra-wideband signals relaying in ad hoc radio networks is described. As the relaying signals a group of chipsets is used to represent various minimal information units. A system of markers is introduced to unambiguous determine the relaying routes. The chipset representation of transmitted signals reduces the delays coursed by multistep relaying and increases the data transfer rate.

An ultra-wideband wireless communication system based on continuous carrier noise signals with low radiation level for digital information transfer in terahertz frequency range has been investigated. Autocorrelation and spectral methods of processing received ultra-wideband noise signals with coded spectral modulation are considered. The error probability on bit of transmit information versus the energetic signal to noise ratio at the receiver input is theoretically analyzed for different bit rate performance and frequency band of carrier noise signals. The proposed terahertz wireless communication system is characterized by high interference immunity and information transmission reliability under conditions when the amplitude of desired signal becomes lower then the interference level. The range of radio communication at low radiation power of ultra-wideband carrier noise signals is evaluated. The performed investigations confirm the development possibility of prospective ultra-wideband systems of noise communication.

General relations for the analysis of autodyne and modulation characteristics are obtained in the form of differential equations with the retarded argument. Solutions for characteristics of frequency response of autodyne variations of the oscillation amplitude and phase as well as the auto-detecting signal of UHF oscillator under influence of the proper reflected radiation are derived. The solution of the same equation system is given for frequency responses of the modulation deepness of oscillation amplitude and frequency as well as the auto-detecting signal in the case of the reflection factor modulation by the high-frequency signal. Calculations of autodyne and modulation characteristics are fulfilled at different values of inherent parameters of UHF oscillators. Non-isochronous and non-isodromous properties of autodyne oscillators are investigated. Phenomena of frequency auto-detecting are considered. A method for dynamic properties determination is substantiated according to its modulation characteristics at the oscillation amplitude registration. The results of theoretical analysis are confirmed by experimental data obtained on the example of hybrid-integrated oscillator of 8mm-range on the Gunn diode.

A multiroute cross-layer transport protocol with data delivery capabilities for mobile networks is proposed. Protocol combines routing functionality with reliable data delivery. It is shown that finding multiple routes to the destination can be successfully combined with a connection establishment for connection-oriented protocols such as TCP. Establishing a connection over multiple routes can significantly decrease the time of the connection recovery when some routes become unavailable thus increasing total throughput of transport protocol in mobile networks environment. Performance analysis of the proposed protocol indicated that in mobile sensor networks with 5 - 10 % of packet losses its throughput is approximately 60 % higher than throughput of TCP-Reno2 flowing over shortest path.

Computer aided microstrip structures modeling has been performed by conformal mapping technique. A new approach to reduce the connectivity order of the original cross-section geometry of the structure is proposed. The multiply connected domain is reduced to simply connected ones by implementation of magnetic slits concept. The microstrip structures analysis is carried out by numerical conformal transformations technique realized in Schwarz - Christoffel toolbox for MATLAB. This technique is applied to the quasi-static analysis of coupled microstrip lines taking into account the conductor thickness. Described approach ensures high numerical efficiency and can be used for accurate analysis of complex microstrip structures.

A method of capacity increasing of sensor telecommunication networks has been proposed and investigated. The method proposed is based on a placement control of unmanned aerial vehicles in view of the rapid and unpredictable movement of mobile subscribers. A distinctive feature of developed method is combining mathematical models of connectivity estimation taking into account a quality of service of mobile subscribers and an advanced search algorithm of quasi-optimal placement of unmanned aerial vehicles in a single computational procedure. An application of the method proposed allows increasing the throughput of telecommunication networks to 15 — 20 percent in comparison with existing methods. Deviations of obtained sub-optimal solutions from optimal ones received by exhaustive method do not exceed 5 — 7 percent.