Collision-Free Sensor Data Collection using LoRaWAN and Drones

An open issue in Wireless Sensor Networks (WSNs) is the data collection from nodes placed at distant positions where no Internet or fixed gateway coverage is available. In this paper, we propose a reliable and energy-efficient solution using drones as mobile gateways that periodically fly over the network and collect data. We consider a point-to-point communication model between the nodes and the drones using the LoRaWAN communication protocol. Due to the nature of the default LoRaWAN MAC protocol, we modify its ALOHA-style transmission policy introducing a synchronized time-scheduled transmission mechanism to eliminate potential packet collisions. Simulation results show that a single drone can collect the data of an entire day (5760 bytes) of an area of more than $1500\times 1500m^{2}$ and 80 nodes while achieving 0% packet collisions.