Since the last decade, researchers have been continuously trying to implement and evaluate the performance of Drone Assisted Vehicular Network (DAVN). A DAVN efficiently integrates the networking and communication technologies of drones with connected vehicles. DAVNs have a huge potential to offer a wide range of features for Intelligent Transport Systems (ITS) applications to improve traffic safety on roads. In this paper, we first discuss the architecture of a DAVN and outline its potential services for vehicular networks. Drones cooperate with infrastructure and vehicles to improve Vehicle-to-Vehicle (V2V) and Vehicle-to-Infrastructure (V2I) network coverage, data collection capability, and efficiency of communication interworking. In this paper, we demonstrate the DAVN concept with regard to Drone-to-Vehicle (D2V) and Drone-to-Infrastructure (D2I) communications utilizing road meteorological data exchange. To perform these pilot scenarios, we use real-time weather and traffic data collected during our pilot measurements in Northern Finland. The executed and generated test scenarios are added to Wireshark and NS-2 (Network Simulators) to evaluate the performance of ITS-G5 and 5G Test Network (5GTN). The performance evaluation for DAVN is carried out by considering the following parameters: end-to-end delay, packet delivery ratio (PDR), packet loss and average throughput. Our results revealed that ITS-G5 performs better and more efficiently than 5G in D2V PDR scenarios, and 5G performs well in D2I PDR scenarios. Moreover, the 5G network presents better performance in the average throughput and D2I (in our case drone-to-RWS (Road-Weather-Station)) delay scenario in contrast to ITS-G5, and this is due to vehicles, haphazard nature of test track and the distance between the cars.

5G mobile communications have received enormous attention from the communication community, in particular for applications requiring low latency, as in Vehicle-to-vehicle (V2V) and Vehicle-to-infrastructure (V2I) communications in Intelligent Transport systems (ITS). 5G has already been studied through simulations and pilot use-cases in vehicular ad-hoc networks (VANETs) scenarios. Currently, the other prominent wireless technology is ITS-G5, a networking technology standardized by the European Telecommunications Standards Institute (ETSI) for vehicular communications. By integrating the ITS-G5 and 4G/5G networks, the advantages of both systems can be readily exploited by the V2I, V2V and V2X systems. In this article, we have investigated low-latency vehicular communications considering the combined operation of ITS-G5 and 5G networks. We specifically analyze the seamless handover process between ITS-G5 and 5G Test Network (5GTN) by conducting field measurements at the Finnish Meteorological Institute (FMI) test track in Northern Finland. We analyze the latency and packet drop during the seamless hand-off between the two wireless technologies. This article also discusses an advanced road weather services architecture that assures stable communication links for heterogeneous networking technologies. Results show that the heterogeneous network considerably improves the load balancing and communication link availability between VANETs and infrastructure.

In recent years, the vehicular ad hoc networking (VANET) concept has supported the development of emerging safety related applications for vehicles based on cooperative awareness between vehicles. This cooperative awareness can be achieved by exploiting wireless sensors and technologies to transmit periodic messages to neighboring vehicles. These messages normally contain information regarding vehicles, such as position, speed, distance between vehicles, etc. For the transfer of safety messages, Wi-Fi and the suit of IEEE 802.11p/WAVE protocols were commonly used initially but now cellular-based LTE and 5G are the emerging technologies for VANETs. In this paper, a comparison is performed considering the European ITS-G5 standard, Wi-Fi, LTE and 5G by exchanging safety messages in VANETs. We have exchanged real-time road weather and traffic observation data to evaluate the performance of the aforementioned wireless technologies in terms of successful message delivery probability. Our results reveal that due to weak communication links and the lack of line of sight (LOS) communication for Vehicle to Infrastructure (V2I) and Vehicle to Vehicle (V2V) scenarios, Wi-Fi and 802.11p are outperformed by LTE and 5G networks.

In recent years, the research community has shown increasingly interest in the study, design and implementation of DAVNs (Drone-assisted Vehicular-Network). DAVN can play a crucial role to provide a broad range of vital characteristics for Intelligent Transport Systems (ITS) applications to enhance the road traffic safety. A DAVN provides a dynamic platform by effectively combining the ground networks, namely Connected Vehicles (CV) and aerial communication technologies of drones. In DAVN, due to the small sizes of drones, payload constraints as well as capabilities and flight time limitations, cooperating with traffic infrastructure and vehicles is very important. DAVNs help to improve the Vehicle-to-Infrastructure (V2I) and Vehicle-to-Vehicle (V2V) communication range, the information gathering capability, and the efficiency of vehicular networking. In this paper, we develop a novel cooperative DAVN architecture consisting of drones, vehicles, Road Weather Stations (RWS), on-board embedded sensors, processing entities, Global-Positioning-System (GPS), and communication capabilities. We use real-time field measurements of V2V and V2I communications considering weather and vehicular traffic information for drone assisted vehicular communication simulations in Network Simulator-2 (NS-2). DAVN simulations are carried out based on measurements on a real environment (1.7km long test track) at the Finnish Meteorological Institute (FMI) in Sodankylä, Finland. The performance of DAVN was evaluated by considering three parameters: packet loss, network latency and average throughput. Simulation results revealed that ITS-G5 performance is stable in short range, but in long range DAVN, the 5G Test Network (5GTN) and its 4G feature outperformed ITS-G5. Moreover, we identified key challenges in the design and implementation of DAVNs in real environments.

Wireless communication in the traffic with Intelligent Transportation Systems (ITS) is growing into elemental part of the traffic entity. Entirely new types of safety and convenience services can be offered directly to the vehicular environment, enhancing considerably the traffic safety. Vehicles can also make their own observations, further developing the accuracy of these services. It is obvious that the safety and security of ITS communication needs to be ensured. The ITS communication environment (of vehicles, roadside units and core systems) is one entity of Co-operative Cyber-Physical Systems (CO-CPS). SafeCOP (Safe Co-operating Cyber-Physical Systems using Wireless Communication) project targets to a safety assurance approach, ensuring the safety within single Cyber-Physical element, as well as Co-CPS. Finnish Meteorological Institute (FMI) has created one SafeCOP use case for vehicular CO-CPS entity, for the road weather station and vehicle interaction. In this paper we present the vehicles and roadside unit interaction general structure and the motivation behind it. To ensure the safety and security of our communication environment, we have built CO-CPS functionalities to both vehicle and road weather station units. SafeCOP CO-CPS defines a runtime manager continuously detecting the behavior of CPS and in case of any abnormality performing runtime triggering. Furthermore, specific SafeCOP safety layer functionalities are introduced to ensure safety in entire Co-CPS. The proposed solution is analysed by comparing the vehicles and roadside unit communication procedure with and without SafeCOP functionalities, in terms of throughput latency and number of lost packets.