  We consider a LoRa sensor network featuring a UAV-mounted gateway for
collecting sensor data (messages). Wake-up radios (WuR) are employed to inform
the sensors of the UAV's arrival. Building on an existing random access scheme
for such setups, we propose and evaluate two redundancy transmission protocols
for enhancing the reliability of the data transfer. One protocol employs
fountain-coded transmissions, whereas the other performs message replication.
Our results illustrate how redundancy transmission can be beneficial under the
time constraints imposed by the UAV's limited hovering duration, and how node
density, hovering time, and sensor energy budget impact the performance of the
schemes.
