future internet Article 5G Cross-Border Operation for Connected and Automated Mobility: Challenges and Solutions Apostolos Kousaridas 1, *, Andreas Schimpe 2 , Sebastian Euler 3 , Xavier Vilajosana 4 , Mikael Fallgren 3 , Giada Landi 5 , Francesca Moscatelli 5 , Sokratis Barmpounakis 6 , Francisco Vázquez-Gallego 7 , Roshan Sedar 7 , Rodrigo Silva 8 , Laurent Dizambourg 8 , Stefan Wendt 9 , Maciej Muehleisen 10 , Kurt Eckert 11 ,Jérôme Härri 12 and Jesus Alonso-Zarate 7 1 Huawei Technologies, Munich Research Center, Riesstraße 25, 80992 Munich, Germany 2 Technical University of Munich, Arcisstraße 21, Munich, 80333 Bavaria, Germany; schimpe@ftm.mw.tum.de 3 Ericsson Research, Torshamnsgatan 23, 164 83 Stockholm, Sweden; sebastian.euler@ericsson.com (S.E.); mikael.fallgren@ericsson.com (M.F.) 4 Worldsensing S.L., Viriat 47, 10th floor, Barcelona, 08014 Catalonia, Spain; xvilajosana@worldsensing.com 5 Nextworks S.r.l., Via Livornese 1027, 56122 Pisa, Italy; g.landi@nextworks.it (G.L.); f.moscatelli@nextworks.it (F.M.) 6 Department of Informatics and Telecommunications, National and Kapodistrian University of Athens, Panepistimiopolis, Ilisia, 15784 Athens, Greece; sokbar@di.uoa.gr 7 Centre Tecnològic de Telecomunicacions de Catalunya (CTTC/CERCA), Av. Carl Friedrich Gauss, 7, Castelldefels, 08860 Barcelona, Spain; francisco.vazquez@cttc.es (F.V.-G.); roshan.sedar@cttc.es (R.S.); jesus.alonso@cttc.es (J.A.-Z.) 8 PSA Group, Route de Gisy, 78140 Vélizy-Villacoublay, France; rodrigo.silva1@mpsa.com (R.S.); laurent.dizambourg@mpsa.com (L.D.) 9 Orange, Orange Labs, 44 avenue de la République, 92326 Châtillon, France; stefan.wendt@orange.com 10 Ericsson GmbH, Ericsson Allee 1, 52134 Herzogenrath, Germany; maciej.muehleisen@ericsson.com 11 Robert Bosch GmbH, Renningen, 70465 Stuttgart, Germany; kurt.eckert@de.bosch.com 12 EURECOM, Communication System Department, 06904 Sophia-Antipolis, France; jerome.haerri@eurecom.fr * Correspondence: apostolos.kousaridas@huawei.com; Tel.: +49-89-158834-4005 Received: 9 November 2019; Accepted: 20 December 2019; Published: 24 December 2019   Abstract: The vision of cooperative, connected and automated mobility (CCAM) across Europe can only be realized when harmonized solutions that support cross-border traffic exist. The possibility of providing CCAM services along different countries when vehicles drive across various national borders has a huge innovative business potential. However, the seamless provision of connectivity and the uninterrupted delivery of services along borders also poses interesting technical challenges. The situation is particularly innovative given the multi-country, multi-operator, multi-telco-vendor, and multi-car-manufacturer scenario of any cross-border layout. This paper introduces the challenges associated to a cross-border deployment of communication technologies through the analysis of three use cases: tele-operated driving, high-definition map generation and distribution for autonomous vehicles, and anticipated cooperative collision avoidance. Furthermore, a set of 5G solutions have been identified to ensure that CCAM services can be supported efficiently in cross-border scenarios. Faster handover of a data connection from one operator to another, generalized inter-mobile edge computing (MEC) coordination, and quality of service (QoS) prediction are some of the solutions that have been introduced to reduce the uncertainties of a real 5G cross-border deployment. Keywords: V2X; 5G; wireless communication; cross-border; trials Future Internet 2020, 12, 5; doi:10.3390/fi12010005 www.mdpi.com/journal/futureinternet