The primary indicator of IoT, which provides a practical network application, is the overall life expectancy of a network and the tasks that are related to modelling the life expectancy as well as the practical application. The concept of an IoT provides that any network element uses an independent power supply. Any network element performs specific tasks in the common IoT network, which, according to the network scenario, are pre-programmed.

Looking at the life cycle of the IoT, it is essential to pay attention to the device energy efficiency. The energy efficiency of each device is dependent on the characteristics of the applied standards, the algorithm used and the network protocol. While developing the project of a network, one of the most important factors is increasing energy efficiency and the operating cycle of the network depends on it.

Often when actions are related to IoT the term “network energy efficiency” is equated to the operating cycle of the autonomous devices and it is believed that longer operating time of each IoT device ensures a higher energy efficiency of the network.

It is understandable that IoT devices can be seen as active for as long as they are capable of reading the information from the sensors correctly as well as transferring it to the coordinator node within a network. IoT energy consumption depends on several factors:

• the technical parameters of the node battery capacity as well as the parameters of the processor, the transmitter, the sensors and the other elements;
• data collection frequency, which may depend on the situation and the environment in which the network operates;
• physical and channel level protocols that determine the control of access mechanism in the environment;
• network topology that defines the amount of the transmitted information within each node including the flow of technical information;
• the use of routing protocols that complement the network with the additional service data flow.

Any IoT network has three node types – the terminals, the routers and the coordinator or data collector. Data collectors do not affect the overall life expectancy of a system because they are provided with a permanent power supply or are equipped with a much more powerful autonomous power supply.