# Cellular and Virtualization Technologies for UAVs:
###### Abstract
In this context, the Labyrinth project aims at creating and validating new UAV applications to enhance the safety, security, and efficiency of civil system transportation and urban areas. Labyrinth will create a centralized system able to communicate with all the UAVs  
Figure 1: Different types of UAS following UTM: Beyond Radio LoS (BRLoS), and Radio LoS (RLoS). located in a defined area, processing their source and destination waypoints to compute their potential paths and avoid collisions (accomplishing this with the SESAR policy). Moreover, Labyrinth will build fully-operational use cases in four relevant transportation environments: (i) road (e.g., speed control, accident management, plate identification); (ii) waterborne (e.g., seaport facilities supervision); (iii) air (e.g., bird scaring, airport facilities supervision), and (iv) emergency (e.g., provisioning of medical supplies, discover escape routes). The Labyrinth consortium includes both research institutions and industrial partners, involving relevant key-adopters such as the Spanish General Directorate of Traffic (DGT), the Municipal Emergency Assistance and Rescue Service--Civil Protection (SAMUR--Protecion Civil) from Madrid, and the Port Authority of the Eastern Ligurian Sea from Italy. This article presents as the main result a functional testbed in the context of the Labyrinth project, focusing on its communications aspects by including all the required ingredients to complete a UAV mission following the U-space requirements. For this purpose, UAVs are connected to the cellular network to enable connectivity with the UAV controller (the entity in charge of computing flight trajectories and sending instructions to the UAVs) and other UAVs. Moreover, all the corresponding trajectories and instructions are sent from the UAV controller to the UAVs using an automation platform. This system runs on top of a lightweight virtualization platform to further test applications and functionalities beyond the Command and Control (C2). Besides, all this technology has been validated in an indoor flight set of experiments. This article also evaluates the 4G cellular network performance using commercial deployments with different communication prototypes and different network operators and the 5G Stand Alone (SA) cellular network in a laboratory environment. The obtained results highlight that the cellular network properties are adequate for managing the UAVs. Although the 5G commercial deployment is still imminent and does not reach a large part of the population, it serves as a proof of concept to highlight the potential of 5G networks. The rest of the article is organized as follows: Section 2 reviews the related work and background regarding UAV technologies and communications, as well as the advances of the combination of UAV technology with virtualization. Section 3 provides details about the testbed, describing in detail all of the technologies chosen for its design, highlighting its main characteristics, functionalities, and the role each one of them in the system. Section 4 presents a set of experiments to validate the feasibility of the testbed, including a performance evaluation achieved by the communications prototype, and an indoor flight mission to demonstrate the testbed functionality. Finally, Section 5 presents the main conclusions and future work for the article.