# A Roadside and Cloud-Based Vehicular Communications Framework for the Provision of C-ITS Services
## 2 Related Work
This is especially important in urban scenarios, where the presence of buildings and other urban infrastructure can severely degrade the quality of communications among vehicles. [PERSON] et al. [11] measured how buildings, bridges/terrain elevation, trees and vegetation, roundabouts, and traffic, influence the performance of 802.11p-based vehicular communications, and showed that these are heavily influenced by the environment. The authors also provide guidelines for the deployment of RSUs. These include placing RSU antennas high when trees/vegetation are not present and placing them low if trees/vegetation are present. Placing the RSU antennas high can also be advantageous in scenarios with high traffic density and in the presence of heavy vehicles (trucks, buses, etc.). [PERSON] et al. [12] aim to optimize the RSU locations in urban scenarios in order to ensure maximum network coverage while minimizing the number of RSUs required and the associated deployment cost. Using simulations, the authors show that the proposed approach is more cost-efficient when compared to a greedy approach. The large scale deployment of C-ITS infrastructure and traffic management systems is largely boosted by research projects and public-private initiatives. Some examples include SCOOP@F (Systeme Cooperattif Pilote at France) [13], InterCor (Interoperable Corridors) [14], CONCORDA (Connected Corridor for Driving Automation) [15], NordicWay [16], and C-MobILE (Accelerating C-ITS Mobility Innovation and depLoyment in Europe) [17], among others. To provide service continuity for vehicles in cross-borderscenarios, some deployments, such as the InterCor project, span multiple countries. These deployments include the installation of RSUs for direct communication with vehicles and the associated backhauling network interconnection. This project addresses the interconnection and interoperability issues of several international C-ITS European corridors. The vehicular networks of roads in the Netherlands, France, Belgium, and the United Kingdom are interconnected. A communication network architecture is defined for this purpose, where the interface between the roadside system and the vehicle is established using ETSI ITS-G5. An additional interface for the exchange information of between the roadside system and the back-office system is also included in the architecture. In some pilots, such as the PASMO (Open Platform for the development and experimentation of Mobility Solutions) project [18], a myriad of road sensors is deployed, including RSUs, traffic radars, Internet Protocol (IP) cameras, parking sensors, and weather stations, whose operations depend on different protocols. In such a scenario, a cloud software platform based on the Machine-to-Machine (M2M) paradigm must handle high device heterogeneity using diverse communication protocols, such as Hypertext Transfer Protocol (HTTP), MQTT, Constrained Application Protocol (CoAP), and Advanced Message Queuing Protocol (AMQP), among others. Moreover, these systems must also handle various communication technologies for data collection and information exchange, such as ITS-G5, Long Term Evolution (LTE), Long Range (LoRa), radio links, fiber optics, etc., increasing the integration complexity of all components. [PERSON] et al. [19] provide the design of a C-ITS (Cooperative Intelligent Transport Systems) architecture that was implemented in a pilot project in Dresden, Germany, as part of the \"Synchrone Mobilitat 2023\" initiative. The architecture comprises three main components: vehicles, RSUs, and cloud-side infrastructure. The cloud-side infrastructure provides centralized backend services that facilitate data exchange between all entities using the MQTT protocol. The RSUs and the backend services, such as the traffic monitoring system, are designed to be highly modular. This means that they consist of several independent software modules, each running in Docker containers.