## 1 Introduction  
Drones are one of the most fastest growing business of the decade 2010-2020, either for professional or personal uses, and scientific purposes [1, 2, 3]. New applications in unmanned aerial systems (UAS) are expected to become increasingly useful to accelerate productivity, save costs and risks, and to extend the current limitations of these systems, adapting them to the next decade. The technological challenge of this study is to develop a flexible solution to remotely and in real time control fixed-wing aircrafts by means of the 3G-4G LTE telecommunication network, that is ready to be adapted to 5G. The innovation aims at providing high control range Beyond the View Line of Sight of the pilot (BVLOS), accordingly with the aircraft flight autonomy. Furthermore, this will allow the integration of deep learning tools, such as Computer Vision (CV) technologies, and big data analysis, adapted to the new autonomous drone fleet paradigm. In recent years, drone communications have been increasingly addressed by both the academia and the industry [4]. Unmanned vehicles and battery technologies have evolved to provide increasing endurance, currently allowing flight distances that exceed the range of the local radio link with the Ground Control Station (GCS)--where the pilot is usually located--especially when dealing with fixed wing drones. To fix this issue many researchers and companies have proposed alternatives to the local link that involve the connection of the UAS to the internet [5], thus being accessible from almost any connected device. For instance, flying ad hoc networks (FANETs) have become a hot topic since they represent a step further, enabling communications from single drones to multiple drones [6]. However, a challenge that is still pending to be solved is the BVLOS communication, which inherently implies long-range links. Moreover, if the desired solution requires high-capacity links, such as real-time video applications, the use of cellular network (i.e., 4G) is one of the best choices we can aim at. In this direction, [7] analyzed the main advantages and drawbacks of such schemes and provided some recommendations. [8] further discusses technological challenges including interferences and mobility issues and gives potential solutions. This also caused the appearance of dedicated protocols and communication network architecture solutions for a wide range of drone use cases. The use of cellular networks requirements for the connectivity of drones was already analyzed in 2015 [9] but it is fully in development since the implementation of 4G technology in most developed countries (around 2016), which has entailed further network design proposals [10] and even drone-to-drone communications [11]. This technology allows the transmission of relatively large data, exceeding mere telemetry packets, being able to handle video and images especially. Recent implementations like LARUS [12] have used 4G/LTE networks to connect various drones for long-range rescue missions [13]. However, some threats are still concerning the community, such as the on-board energy consumption, the handover rate between antennas, or the bandwidth [14]. Some alternatives to the use of the terrestrial antenna network as the main way to connect the drone to the internet are focusing upwards, to the High-Altitude Pseudo Satellites (HAPS) [15; 16] or to satellite constellations [17], but these are in experimental stage and currently there are not available options. The problem addressed in this work is to supplement the drone-to-local GCS data link with a drone-to-remote server data link. This new framework, based on 4G communications to directly link the drone to internet, allows the real-time processing of the drone acquired data in powerful servers located in the headquarters of the data user (Figure 1). In this work, we provide application details of our own-operated UAS, while discussing implementation and component details in the system and sharing the resultant complete architectural scheme.