Here are some frequently asked questions for the Telemetry over IP/cellular group.

1) Why not just use DroneCell

DroneCell is definitely one of the possibilities. If so, it would need significant documentation, some wiring diagrams and pictures as well as software library in APM to initialize the modem. 

2) Why not just use Xbee

Xbee has served this community very well. However, it has limited range and requires additional equipment on the ground. Cellular networks are ubiquitous, require no ground equipment other than an IP connection and have unlimited range, as long as you stay within the signal area. 

3) Can we still use Mission Planner with IP?

Yes, as well as other MAVLINK GCS systems. An IP/cellular solution would transfer the MAVLINK data just like Xbee does, so you would not need to change much, if anything in the software. Perhaps we will need to add a few lines of code to init a modem with AT commands, but the rest should remain the same

4) Will I need a server?

Not really. It is possible that some sort of server will be necessary to find the IP addresses (a dynamic DNS server), or to route MAVLINK if you want to do more stuff in the cloud. While there may be a need for a server in the backend to support such a solution, it should not be necessary for every user of an IP solution to run a server.