The Internet of Things: Architecture, Communication Protocols, and Applications

Abstract

The Internet of Things connects large numbers of physical objects, embedded with sensors and communication, to networks and to one another, and this paper reviews its architecture, communication protocols, and applications. It describes the layered architecture of an Internet-of-Things system: a perception layer of sensors and actuators that interacts with the physical world; a network layer that provides connectivity and carries data; an edge or fog layer that processes data near its source; and an application layer that provides analytics and services, commonly in the cloud. It describes the communication technologies, distinguishing the radio and network technologies that carry the data, from short-range technologies to wide-area low-power and cellular networks, from the messaging protocols that structure the data, such as the lightweight publish-subscribe and constrained application protocols. It describes the processing of data at the edge, including the running of machine learning on constrained devices, andsurveys the principal application domains, including the smart home, thesmart city, industrial systems, healthcare, agriculture, and transportation. The study finds that the Internet of Things provides a flexible architecture for connecting the physical and digital worlds, that its communication protocols are chosen to suit the constraints of devices and networks, and that it faces significant challenges of security, interoperability, and scale. It notes that specific technologies and standards are representative of a rapidly evolving field. It concludes with the outlook for the field. Certain figures are illustrative. KEYWORDS: Internet of Things, IoT Architecture, Edge Computing, MQTT,CoAP, LPWAN, Wireless Sensor Networks, Smart Systems, IoT Security