Drones, deployable LTE networks and sunshine
It was a very nice and quite warm sunny day today in Espoo, Finland. So it was time to go out with some equipment and other stuff. The list was roughly following:
- a drone with LTE connection for mission control
- plenty of drone batteries
- a smartphone running LTE radio measurement software (carried by the drone)
- a compact LTE network (eNB + embedded EPC) - about 5 kg
- a small directional X-pol antenna
- a small telescope mast for the antenna
- feeder cables, Ethernet cables, power cables
- Windows and Linux PCs (drone control, LTE throughput measurements, LTE network management)
- a portable AC generator (power for PCs, drone battery charger and LTE network)
- duct tape
- a van
- licenses for flying drones and using LTE spectrum
And the questions was that how well the LTE uplink performs when a drone is flying up to 150 meters above the ground. And it worked very well.
Before any results were available, there were of course many problems. The linux PC, which was the FTP server for throughput testing, did not run like the day before. Finally it was working somehow for testing purposes in non-GUI mode although some reboots were necessary during the day. Of course the EPC did not have all USIMs provisioned so some HSS re-configuration was necessary. Also some changes had to be made to the firewall of the LTE network before all IP flows were working. The test smartphone with test software had some difficulties to continue FTP upload in case the radio signal was too weak. Luckily the radio parameters were optimized correctly the day before so there was a nice over 20 Mbps uplink throughput with 10 MHz FDD channel.
The result was that the area with permission to fly drones was too small. The drone was in 150 m above ground about 430 m from the eNB antenna and uplink throughput was still very nice 18-20 Mbps.
Conclusion is that a larger area is needed to test the limits of using drones with a small deployable LTE network.