Optimization of Energy Efficiency in Wireless Sensor Networks and Internet of Things: A Review of Related Works

Introduction

In recent years, covering a wide field of application, Wireless Sensor Networks (WSNs) play an important role in collecting data from an environmental context, monitoring, monitoring or other applications. The fact that the network is wireless allows more flexibility for deployment compared to a wired deployment that requires cabling. On the other hand, the WSNs are a very important technology in the Internet of Things (IoT). These networks allow presenting the characteristics and the state of the objects (or environments) in which are implanted (or deployed) like Web services on Internet. Sensors are therefore invited to play the role of hosts of the Internet (often client/server) and communicate with each other and with hosts already connected to the Internet. In addition, the WSNs and IoT are being solicited and must respond to new constraints of WSN and IoT applications. Among these constraints, we can cite:

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  Autonomy: Sensors and connected objects are usually able to operate autonomously in terms of energy source. The consideration of all the elements contributes to the energy consumption in the electronic circuits of the sensor or object, since the data communication consumes more energy, and again the communication power in terms of transmission to a big effect on the amount of energy used.

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  Mobility: Sensors or moving objects in the network can move freely and independently. At any time, new equipment can join or leave the network. The change of the topology of a network during the time results from the failures of the sensors or the breaks of the links between them.

In this chapter, we first present a general overview of the WSNs, their architectures, their characteristics, their principal applications, their protocol architecture, their characterized models and their factors, their routing protocols and their constraints. Then we present the IoT, its architecture, its different application domains, its communication paradigms, its life cycle, its constraints related to the deployment and its data routing. Finally, we present the different wireless communication technologies used by the WSNS and the IoT.

Wireless Sensor Networks

WSNs generally consist of a large number of sensors, stationary or mobile, communicating with each other by radio, often randomly deployed in an area of interest (refer Figure 1). The latter is usually a hostile environment, isolated or difficult to control, where the mission of a sensor is each time to collect, in an autonomous way, accurate data from the deployment area. Depending on the type of sensor, the information detected may be temperature, humidity or movement or other physical quantity. The data collected by these sensors are routed directly or by other sensors step by step to a base station (BS). The BS can be connected to a data processing server, called a task manager, usually via the Internet or satellite. In addition, the user can address his requests to the sensors by specifying the information of interest and by targeting the sensors that should be interested.

Figure 1.

Architecture of a WSN

Typical Architecture Of A Sensor

The typical hardware architecture of a sensor consists of four-unit units, an acquisition unit, a processing unit, a communication unit, and a battery, which are shown in figure 2.

Figure 2.

Sensor architecture

The operation of each unit is defined as follows: