Background. At present, the demand in tropospheric over-the-horizon communication systems determines the inherent advantages of these systems over satellite and radio-relay systems of direct visibility, especially in combat and emergency situations. Although the fundamentals of the theory of tropospheric scattering were developed as early as the middle of the last century, the development of over-the-horizon systems requires constant refinements of known theoretical positions in accordance with new data on the nature of tropospheric scattering, atmospheric inhomogeneities, capabilities of new methods for calculating and estimating radio propagation. Objective. The aim of the work is to develop a radio link model of a trans-horizon tropospheric communication to study the possibility of controlling (improving) attenuation on such a route by changing the electrophysical characteristics of the environment, in particular atmospheric turbulence, or using artificial formations in the atmosphere. Methods. The created model is based on the Ray-tracing method. Results. A model of radio link losses in the over-horizon tropospheric communication (long-range tropospheric propagation) was developed, based on the ray-tracing technique in two versions: simplified, with homogeneous layers, and full, with a combination of blocks of structures of scattering spheres in each of the layers. A study of the possibility of improving attenuation along the tropospheric scattering pathway by regulating changes in the electrophysical parameters of inhomogeneities and artificial formations in the atmosphere was conducted. Conclusions. The convergence of the results of the simulation with the data obtained by known / traditional analytical models for calculating the losses on the tropospheric scattering path confirms the adequacy of the proposed model to the statistical data of the real losses in tropospheric scattering. The obtained results indicate that, for practical purposes, the accuracy of calculations of the loss characteristics is sufficient and that they can be used to form a tropospheric dispersion route with significantly reduced loss values by artificially adding a certain liquid or solid substance to the atmospheric heterogeneity.

Background. Currently, a new direction in the technology of mobile systems is rapidly developing, associated with the use of a set / group of mobile multifunctional elements that can create different spatially-distributed structures for various applications: from entertainment shows to intelligence networks. This is a technique of small unmanned aerial vehicles (UAV), often called drones, and their use in the field of building telecommunication systems. Objective. The aim of the work is to develop the basic principles and strategies for the formation of a heterogeneous wireless communication system based on a swarm of unmanned aerial vehicles. Methods. We study the structural and functional methods of building a wireless network. Results. Scenarios of centralized and distributed building of a wireless network of control of a swarm of UAVs are presented, assessment of the complexity of the functionality of swarm nodes in the case of a distributed scenario is carried out. A scheme of phased implementation of the life cycle of a UAV swarm for communication services has been developed. The "molecular" scenario of spatial self-organization of the swarm-nodes of the swarm is presented, which can be implemented using the "chain" and "flash" procedures. The proposed construction of some strategies for managing the swarm: centralized and decentralized with the Leader, collective self-management with information sharing, decentralized management with forecasting, self-organization without information sharing. Conclusions. The basic principles and strategies for the formation of a heterogeneous wireless communication system based on a swarm of unmanned aerial vehicles have been developed. A collective management strategy for a swarm of drones was developed.

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Background. Intensive development of the unmanned aerial vehicle manufacturing industry has led to the emergence of many of their options for various applications. A separate class of low-flying drones, the work of which takes place within the framework of a certain self-organizing (robotic) group, was made up of drones, combined in a constellation or swarm. All drones of such a swarm together can perform one common function as an independent robotic complex.Objective. The aim of this work is experimental testing and development of the basic principles of controlling a swarm (constellation) of drones and the formation of a cooperative relay system.Methods. The structural and functional methods of constructing a wireless network based on a drone swarm are investigated.Results. Testing a swarm of drones was carried out according to two relay scenarios: passive using metallized reflectors and active using additional SDR radio units. Drones were formed on the basis of the quadcopter model Syma X8 PRO. For testing, radio channels in the 2.4 and 5.8 GHz bands were involved.The developed kit based on the Raspberry Pi and ADALM-Pluto programmable modules allows you to use them very flexibly both on drones and on the ground control station by changing the software on them.Each of the drones has many degrees of freedom with respect to the choice of wireless connection to other swarm drones or external devices, including ground control station. This increases the noise immunity, fault tolerance and functionality of such a system, as well as the possibility of building it up.Conclusions. Experimental testing and testing of the basic principles of controlling a swarm (constellation) of drones and the formation of a cooperative relay system were carried out. Scenarios for centralized and distributed construction of a collective drone swarm management network for communication services have been developed.

Background. Improving the efficiency of modern wireless systems requires the development of new wireless technologies and the introduction of new paradigms for building wireless networks, one of which is a distributed approach to network architectures. An important role here is played by the interaction between the wireless terminals or terminals and the base station through additional relay terminals. An important technology that implements this interaction in order to increase the efficiency of communication in a cell is cooperative relaying. Objective. The aim of the paper is to increase the efficiency of cooperative relaying schemes of information by filling all time phases/slots entering synchronous transmission through the pair number of repeaters. Methods. We study the structural and functional methods of building a wireless network. Results. In order to increase the capacity of the traditional cooperative relay scheme, a scheme is proposed with the addition of another auxiliary relay to the existing one so that each of the relays operates only during one of its data transmissions phases. Mathematical models of a number of cooperative relay schemes have been developed, which allow us to describe the main radio technical characteristics of the schemes (SNR, BER and C). It is proposed that a decision regarding the inclusion of traditional cooperative relaying should occur when a certain distance is reached between the source and the target receiver, when the capacity with and without cooperative relaying are equal. Connecting a cooperative relay scheme without a direct connection allows not only increasing the SNR value, but also maintaining its level only with a slight decrease. Conclusions. A new scheme of cooperative relaying without maintaining a direct connection between the source terminals and the target receiver is proposed. Compared to the traditional cooperative relay scheme, such a scheme demonstrates more stable radio link characteristics over a wide range of attenuation changes between the source and target receiver terminals.