Design and Analysis of Low-Power IoT in Remote Areas with NTN Opportunistic Connectivity

This paper deals with a Non-Terrestrial Network (NTN) where an Unmanned Aerial Vehicle (UAV), combined with backhaul satellite connectivity, can provide Internet access to remote areas for a wide range of 5G/6G Internet of Things (IoT) applications. We consider environmental monitoring and smart agriculture applications for unconnected areas where battery-powered sensors on the ground use opportunistic connectivity with a fixed-wing UAV to deliver measurement data to the Internet. Adopting the intermediate NTN layer with the UAV allows low-power transmissions from ground IoT devices. A detailed model has been provided to study the communication from ground low-power IoT devices and the UAV hosting a LoRa Gateway (GW). A modified LoRaWAN access protocol based on beacons transmitted by the GW has been proposed to coordinate the UAV passes with sensor transmissions. An analytical approach has been described to determine the mean delay for detecting an area where sensors report critical measurements. This model, validated by simulations, has allowed optimizing key LoRa access protocol parameters jointly with the UAV speed under sensor energy consumption constraints. The proposed access protocol has been shown to achieve good performance compared to other schemes, thus proving the feasibility of our IoT-NTN system.