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  • Print publication year: 2021
  • Online publication date: January 2021

3 - Predecessors of IoT


Learning Outcomes

After reading this chapter, the reader will be able to:

  • Interpret the foundation of IoT

  • List the basic terminologies and technologies associated with wireless sensor networks (WSN)

  • List the basic terminologies and technologies associated with machine-to-machine communications (M2M)

  • List the basic terminologies and technologies associated with cyber-physical systems (CPS)

  • Differentiate between WSN, M2M, and CPS

  • Relate new concepts with concepts learned before to make a smooth transition to IoT


Before delving into the details of the Internet of Things (IoT), a discussion on the base technologies, which make up the crux of IoT, is required. A majority of these technologies, before the IoT era, were used separately for sensing, decision making, and automation tasks. The range of application domains of these technologies extended from regular domains like healthcare, agriculture, home monitoring, and others to specialized domains such as military and mining. Some of these precursor technologies still being used and often re-engineered for IoT are wireless sensor networks (WSN), machine-to-machine (M2M) communications, and cyber physical systems (CPS). All of these precursor paradigms have their distinct signatures and application scopes. A basic overview of these precursor technologies is covered in the subsequent sections in this chapter.

Wireless Sensor Networks

Wireless sensor networks (WSN), as the name suggests, is a networking paradigm that makes use of spatially distributed sensors for gathering information concerning the immediate environment of the sensors and collecting the information centrally. Here, the sensors are not standalone devices but a combination of sensors, processors, and radio units—referred to as sensor nodes—sensing the environment and communicating the sensed data wirelessly to a remote location, which may or may not be connected to a backbone network. Figure 3.1 shows the block diagram of the various standard components of a typical WSN node [4]. The exact specifications of each of these blocks vary depending on the implementation requirements and the network architect's choice.

Figure 3.2 shows a typical WSN implementation, where the master node aggregates data from multiple slave nodes, forwards it to a remote server utilizing access to the Internet through cellular connectivity. The stored data on the server can be visualized by a user or a subscriber to the system from anywhere in the world over the Internet. WSNs mainly follow a system of communication known as master–slave architecture.

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