  We present a transmission scheme aimed at integrating wake-up radios (WuR)
into LoRa sensor networks featuring UAV-mounted gateways. The sensors are
informed of the UAV's arrival with the help of WuR, followed by sensor-to-UAV
data transfer with frequency and spreading-factor hopping. The proposed scheme
provides significant energy savings at the sensors while maintaining similar
reliability levels compared to a scheme in which Class B LoRa beacons are used
to perfectly synchronize the sensors with the UAV's data-collection window.
