# SURROGATES: Virtual OBUs to Foster 5G Vehicular Services
## 2 Related Work  
Virtualization of vehicular resources has been considered in the last years to improve performance, perception and context-awareness by using cloud architectures [11; 12]. The research has passed from vehicles using cloud resources to real vehicular cloud computing, involving infrastructures and OBUs in the cloud, or even hybrid approaches. On the OBU side, the usage of virtualization has been also explored. In [13], the authors presented the idea of improving security of vehicular units by using virtualization and controlling the access to real hardware. A more up-to-date conception of this idea is the usage of NFV in the same OBU to create a flexible architecture that could be updated and managed remotely [14]. In this case, a proper architecture is provided to grant access to resources depending on service needs. Even migration schemes of virtual machines between OBUs have been considered to offer services adapted to available resources [15]. The SURROGATES proposal is just between the cloud and OBU planes, by exploiting the computing capabilities of network nodes near the edge of the access networks. This novel network architecture, known as MEC, is a very recent area of study in vehicular scenarios, as the related works included in this section reflect. An MEC layer implemented in road-side units was presented in [16]. The novelty here comes from the distribution and kind of road-side units used, developed as drones, but the MEC layer is directly mapped on physical devices without presenting a real advance. The improvement implied by MEC for vehicle to vulnerable road user communications was evaluated in [17], using 4G simulation and observing up to 80% of latency reduction as compared with a cloud-based system. In [18], the MEC paradigm was used to improve the performance of a delay-tolerant network, by providing caching of messages at the access network for temporally disconnected vehicles. In [19], a way to orchestrate computing and caching in vehicular scenarios between MEC and remote servers was proposed. In [20], an MEC layer was proposed to process information coming from vehicles implementing a vehicular social network, although the potential of NFV and MANO was not exploited to cope with the dynamism of the system. The same lack is found in [21], in which a content delivery network used a MEC-based architecture to speed-up data sharing among vehicles. An interesting feature included in the architecture presented in [22] is the combination of MEC and a hybrid vehicular communication system, which is also considered in the current work. The authors describe the usage of MEC for local storage and processing, and 4G together with G5 (European profile of 802.11 OCB) for vehicle connectivity. Unfortunately, NFV flexibility was not exploited, and the architecture was only partially developed and evaluated. The architecture presented in [23], although it was not validated, is a generic 5G platform supporting NFV and orchestration following ETSI guidelines, and hybrid communications are supported at the infrastructure side by the MEC layer, in order to be open for different vehicular communication media. In the same way, the work in [24] implemented a MEC layer by using VNFs, which is also the implementation strategy followed in our solution. Authors described a procedure to process status information collected from vehicles and detect potential collisions. However, this comprises the development over a 5G platform of a reference -vehicular application that is not open to further ITS services and is not evaluated in terms of validation and performance. Being also a solution addressing MEC computation, SURROGATES bets on a novel idea that has not been considered in the literature up to now: virtualizing real OBUs at the edge in order to create always available OBUs where computing intensive operations are executed while saving current and past state information.