An overview on IoUT and the performance of WiFi low-cost nodes for IoUT Applications

It is evident that the Internet of Things (IoT) is a technology that is not only already being implemented but it is also going to be part of our everyday life in many aspects regarding our homes, workplace and the cities we live in. As the concept of IoT evolves, new terminologies are being developed to specify certain characteristics of the IoT network. The Internet of Underground Things (IoUT) is an example of these new terms, considering, in this case, the soil medium. IoUT is then separated from IoT in the fact that the requirements of underground communications and the underground nodes are different from those in regular IoT networks and, therefore, IoUT should be studied separately. However, as IoUT is a new concept, there are not many studies available. Therefore, in this paper, an overview of the IoUT concept and the most important conclusions that have been reached on this topic is presented. Furthermore, transmission experiments between underground and above-ground low-cost WiFi nodes deploying them at different depths, heights, and distances to determine the suitability of the currently available low-cost nodes for this new IoT concept have been performed. The results show that the optimal height is 1.5 meters and the optimal depth is 20 cm. Furthermore, the connection was able to reach distances up to 10 m. Lastly, an underground transmission decision-making algorithm for soil monitoring nodes in precision agriculture has been provided.