Cloud Computing in VANETs: Architecture, Taxonomy, and Challenges
IETE Technical Review
Cloud Computing in VANETs (CC-V) has been investigated into two major themes of research including Vehicular Cloud Computing (VCC) and Vehicle using Cloud (VuC). VCC is the realization of autonomous cloud among vehicles to share their abundant resources. VuC is the efficient usage of conventional cloud by on-road vehicles via a reliable Internet connection. Recently, number of advancements have been made to address the issues and challenges in VCC and VuC. This paper qualitatively reviews CC-V
... ith the emphasis on layered architecture, network component, taxonomy, and future challenges. Specifically, a four-layered architecture for CC-V is proposed including perception, co-ordination, artificial intelligence and smart application layers. Three network component of CC-V namely, vehicle, connection and computation are explored with their cooperative roles. A taxonomy for CC-V is presented considering major themes of research in the area including design of architecture, data dissemination, security, and applications. Related literature on each theme are critically investigated with comparative assessment of recent advances. Finally, some open research challenges are identified as future issues. The challenges are the outcome of the critical and qualitative assessment of literature on CC-V. Keywords: Cloud Computing, Vehicular Ad-hoc Networks, Architecture, Taxonomy, Vehicular Cloud, Vehicle using Cloud. for cloud computing. In fact, huge resources of vehicles are underutilized at various places (where a group of vehicles assemble), which is needed to be explored and tap into  . The framework of CC-V improves the usability, reliability and efficiency of intelligent transportation system applications  . Subsequently, it enhances safety in transportation, reduces traffic congestion, decreases air pollution, and augments comfort in driving  . Some of the cloud computing services realized in CC-V include Network as a Services (NaaS), Storage as a Service (STaaS), Cooperation as a Service (CaaS), Computing as a Service (COaaS), and Sensing as a Service (SEaaS)    . Since, vehicles are considered to be able to connect to Internet, NaaS can be used by passengers to connect to the Internet in VuC. Applications and data of vehicles, which require more memory for storage can utilize STaaS of VCC  . CaaS can be utilized to share traffic information among vehicles in case of accident, and road maneuverer. Vehicles can realize smart ITS applications using COaaS to fulfill higher computation power requirement of smart-applications. SEaaS can be utilized for monitoring real time condition of car as well as driver's behavior  . Whaiduzzaman et al.  has explored VCC by presenting a taxonomy based on strategic management, security and privacy, cloud formations, inter-cloud communication and applications issues. An architecture for VCC, comparison with cloud computing and open research issues has been presented. However, the architecture has not been explicitly defined considering layer-wise function, representation, and protocol. Template for submitting papers to IETE Technical Review. 2 The network components related to VCC are also not explored. Although various contributions have been made for realizing these cloud services in CC-V, yet there are number of issues that needs to be addressed in near future. In this paper, a qualitative review of cloud computing in VANETs has been presented. The review focuses on layered architecture, network component of CC-V, taxonomy of recent advances, and open challenges and issues for future direction of investigation in the area. A four layered architecture for CC-V is designed including perception, co-ordination, artificial intelligence and smart application layers. The representative components, responsibilities and protocols of each layer are described. The three network components of CC-V namely, vehicle, communication, and computation have been explored with their cooperative roles. From the best of our knowledge, there is no layered architecture available for CC-V. The major network components with their cooperative roles have not been explored previously. The taxonomy of CC-V is presented considering four major issues including design of architecture, data dissemination, security and application development. Each issue has been qualitatively, and critically reviewed with comparative assessments of recent advancements. Finally, some future challenges are identified according to the qualitative, and critical review of related literature. The rest of this paper is organized as follows. Section 2 presents four layered architecture of CC-V. Section 3 describes three network components of CC-V. Section 4 presents a taxonomy of CC-V with qualitative and critical review of related literature. Some future challenges in CC-V are identified in Section 5, followed by conclusion made in Section 6. that the vehicles do not have some of the challenges of mobile devices in Mobile Cloud Computing (MCC), such as, lower computing capability, smaller memory size and battery life. The resources of vehicles can be shared under the framework of VCC at many places while travelling. It include parking lot, garage and traffic light. In case of extensive computing need for longer duration, vehicle's in-built technologies can be utilized for establishing durable connection to a conventional cloud. The communication is known as VuC. For both the cases, VCC and VuC, vehicles equipped with modern communication technologies are one of the most important constituent. Connection The connection refers to the network or communication devices of the heterogeneous networks architecture considered in CC-V. The network devices are utilized to establish reliable communication between vehicles and cloud. In the case of VuC, the connection is either a direct communication between vehicles and cloud infrastructure, or a multi-hop communication using Road Side Units (RSUs) with vehicles. In the case of VCC, connection is mostly direct communication between a vehicle and vehicular cloud infrastructure. The connection also defines Services Level Agreement (SLA) between a vehicular client and cloud infrastructure. It is due to the fact that SLA represents the level of QoS of an application based on the architecture of CC-V. Therefore, connection determines delivery and acceptances of the services.