Smartphone based LoRa in-soil propagation measurement for wireless underground sensor networks

LoRa offers new communication solution for wireless underground sensor networks in soil. A smartphone based LoRa in-soil propagation measurement is proposed in this paper. The measurement system (named LoRa Wizard) consists of smartphones and testing nodes. The design of App in Android smartphone and the corresponding testing node is discussed in detail. The LoRa in-soil propagation characteristics in municipal garden area and farmland are experimentally measured with LoRa Wizard. The LoRa Wizard has shown some advantages of low cost, high reliability, high flexibility and ease of use. It can provide technical supports for design, installation and maintenance of LoRa wireless underground sensor networks in agriculture, accident prevention and other fields.