LAUSR

MCS is an emerging paradigm that leverages the pervasiveness of mobile, wearable, and vehicle-mounted devices to collect data from urban environments for ubiquitous service provisioning. In order to manage MCS application data streams efficiently, a scalable computing infrastructure hosting heterogeneous and distributed resources is critical. FC, as a geo-distributed computing paradigm, is a key enabler for this requirement as it bridges cloud servers and smart mobile devices. Research on the integration of MCS with FC has recently started to be explored, recognizing the requirements of MCS and their coexistence with cyber-physical systems. In this article, we analyze the state of the art of FC solutions in MCS systems. After a brief overview of MCS, we emphasize the link between MCS and FC. We then investigate the existing fog-based MCS architectures in detail by focusing on their building blocks, as well as the challenges that remain unaddressed. Our detailed review on the subject results in a taxonomy of FC solutions in MCS systems. In particular, we highlight the node structures, the information exchanged, the resource and service management, and the type of solutions adopted concerning privacy and security. Moreover, we provide a thorough discussion on the open issues and challenges by reporting useful insights for researchers in MCS and FC.