Pathloss Modelling and Evaluation for A Wireless Underground Soil Moisture Sensor Network

Wireless Underground Sensor Network (WUSN) is well known to monitor the soil quality for precision agriculture application. However, the uncertain property of the soil leads to many difficulties in designing a WUSN, one of them being the pathloss determination in different channels. In this study, we investigate the pathloss and the effect of soil moisture content on the pathloss in the Vietnam popular type of soil. From that foundation, we will construct a WUSN based on 920 MHz LoRa wireless technology. The experiment is implemented to validate underground wireless communication. The results show a good performance and stability of the network, where the connection between two underground sensor nodes could be extended up to 3 m with 5% soil moisture content.