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.

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.

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.

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.