Reliability Evaluation of a Hexacopter-Based Flight Module of a Tethered Unmanned High-Altitude Platform D. V. Kozyrev 1,2(B ) , Nguyen Duy Phuong 3 , H. G. K. Houankpo 2 , and Alexander Sokolov 1 1 V. A. Trapeznikov Institute of Control Sciences of Russian Academy of Sciences, 65 Profsoyuznaya street, Moscow 117997, Russia 2 Department of Applied Probability and Informatics, Peoples’ Friendship University of Russia (RUDN University), 6 Miklukho-Maklaya Street, Moscow 117198, Russian Federation kozyrev-dv@rudn.ru, gibsonhouankpo@yahoo.fr 3 Moscow Institute of Physics and Technology (National Research University), 9 Institutskiy per., Dolgoprudny, Moscow Region 141701, Russia ndphuong2207@gmail.com Abstract. This article discusses a model on the basis of a multidimen- sional Markov process applied for evaluation of the reliability character- istics of a tethered multirotor high-altitude platform based on a hexa- copter. The proposed model takes into account the increase in the func- tional load after the failure of an element on the remaining operating ones, and also takes into account the location of the failed elements. Keywords: UAV · High-altitude platform · Hexacopter · Reliability · k-out-of-n system 1 Introduction and Motivation One of the promising directions in the framework of the concept of creating the next-generation 5G/IMT-2020 networks is the development of broadband wireless networks based on autonomous and tethered unmanned aerial vehicles (UAVs). The advantage of such networks is their fast and flexible deployment, a wider area of telecommunication coverage and enhanced reliability of wire- less communications, controllable mobility, reduced operating costs, etc., which ensures their effective application in both civil and defense industries [1–4]. At present time, tethered high-altitude unmanned telecommunication plat- forms, whose long-term operation is ensured by transmission of electric energy from ground to board via a thin cable rope [6], have received widespread develop- ment. The tethered high-altitude platforms fall in-between satellite systems and terrestrial systems whose equipment (cellular base stations, radio-relay and radar equipment, etc.) is deployed at high-rise structures. The tethered high-altitude platforms, as compared with expensive satellite systems, are highly cost efficient. c  Springer Nature Switzerland AG 2019 V. M. Vishnevskiy et al. (Eds.): DCCN 2019, CCIS 1141, pp. 646–656, 2019. https://doi.org/10.1007/978-3-030-36625-4_52