# A Context-Aware Edge-Based VANET Communication Scheme for ITS +
## 1 Introduction  
Due to the rapid increase of the number of cars in China, people are facing increasing traffic congestion, car accidents, and CO\({}_{2}\) pollution, as well as longer commuting time and increasing difficulty in finding parking. The intelligent transportation systems (ITS) become more and more important for supporting day-to-day commuter mobility management, tourism industry as well as large city event (e.g., events such as football matches, music events, or even bigger events like Olympic games) or even at unexpected events (e.g. flood, earthquake, etc.). All these applications require an efficient networking architecture to collect/disseminate information from/to vehicles, and other sensors/actuators. Vehicular ad hoc networks (VANETs) are capable of utilizing decentralized communication technologies to support efficient collection and dissemination of traffic related information. However, due to the limited wireless resources, high mobility of vehicles, and possible large node density, it is difficult to provide a satisfactory throughput with the conventional networking technologies. Recently, mobile edge computing is introduced to conduct computation, caching task at the edge nodes that are closer than the cloud in order to reduce the response delay and improve the throughput. Some studies have proposed the use of vehicles as edge nodes [1; 2; 3; 4]. However, the existing works do not sufficiently discuss the selection of edge nodes in a decentralized network environment. The joint operation of route selection and edge selection is not discussed as well. There have been many studies discussing the routing problem in VANETs [5; 6; 7; 8; 9; 10; 5; 11; 12; 13; 14; 15; 16; 17; 18; 19; 20]. However, the unicast routing problem and broadcast problem have been discussed separately. Different applications could possibly require different levels of quality of services (QoS). Therefore, it is particularly important to consider context information, such as communication type (unicast or broadcast), end-to-end connection-dependency, and packet payload size, in the route selection. In the unicast communications, frame retransmissions can be conducted at the MAC layer while this is impossible for broadcast communications. As a result, the edge node selection criteria for unicast and broadcast communications are totally different. If an application only cares about the throughput, a delay tolerant approach could be a solution [21]. The packet payload size is another important context information that should be considered for the route selection. A larger packet will face a higher packet loss probability. The performance of a communication system can be improved by taking into account the context information for the routing decision. However, the design of an edge-based approach that is capable of handling different types of applications with different context information is still an under-explored research issue. In this paper, we propose a context-aware edge-based general communication scheme for data exchange in vehicular networks. The proposed scheme uses a distributed approach to select edge nodes which are responsible to conduct packet forwarding. As compared with the conventional approach, the edge-based approach could efficiently reduce the number of concurrent sender nodes by aggregating user traffics at the edge nodes (Here the number of concurrent sender nodes denotes the number of nodes that content for the same wireless resources). When different devices acquire the same content, content cashing can be easily achieved at edge nodes. Since edge nodes are selected by considering the context information of the communications, the proposed scheme is able to handle various traffic patterns including unicast communications and broadcast communications. This paper is an extension of our previous conference paper [22].