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Blockchain Technology

The IoT architecture in Figure 16.6a has a basic high-level three-tier structure,

while Figure 16.6b has three additional layers to make up a five-tier structure.

These architectures are classified on the basis of their protocols. These will be

briefly explained. The layers common to both architectures perform the same

functions.

16.2.4.1  Application Layer

In both architectures, this layer is responsible for defining and delivering various

application areas where IoT can be used, such as e-health, air or water quality moni­

toring, etc.

16.2.4.2  Network Layer

This defines the interconnectivity of things and various media through which sensor

data can be transmitted, such as 4G, 5G, RFID, WiFi, WiMaX, ZigBee, GSM, 3G,

etc., with protocols like IPv4, IPv6, MQTT, DDS, etc.

There are five key aspects to consider in network connectivity (Konezny

et al., 2021):

• Range: How close or how far are the devices going to be to each other? Is

the deployment on a single floor or city-wide?

• Data Rate: What amount of bandwidth will be required, and how often does

the data change? The key here is to know the type of data beforehand. Will

the network transmit text, audio or video?

• Power: Though most IoT devices are low-powered, it is essential to know

the power source: mains or battery power supply? And, for how long will

these devices be expected to be on? It is also essential here to plan for

power management schemes to conserve power, especially if the devices

are installed in remote locations.

• Frequency: Each device has an operational frequency range specified by

the manufacturer according to industry standards. But, there is the need

to consider channel blocking and signal interference during design and

deployment.

• Security: One of the challenges facing IoT is the issue of security. Knowing

beforehand if the sensors will be supporting mission-critical applications

is vital. Studies show that the DLT attempts to address the security issues

in IoT.

16.2.4.3  Perception Layer

This is the physical layer on which the sensors are installed for gathering infor­

mation from their environments. Environmental parameters like temperature, rela­

tive humidity, water level, etc., are sensed and collected by smart devices and then

transmitted.