**2. Related Work**

The current revolution towards a universal connection between things, named IoT, is considered part of the Internet of the future. The long-term plan is to have approximately 28 billion connected devices by 2021 [6].

IoT is currently considered to be one of the most outstanding areas of future technology. In the following subsections we explain about the global applications in this area from smart houses, smart campuses, and smart cities; then we explain some research work focused on identifying the main challenges dealing with IoT. We conclude the section detailing previous works that have performed comparative studies between wireless protocols.
