Soldiers in the field rely on short-range radios (usually the PRC series) or satellites for communications. Not surprisingly, those devices will sometimes become useless, especially in remote and rugged terrain where gaining a direct Line of Sight (LOS) to the receiver is impossible. The same can be said for wireless smart devices, such as phones, tablets, and laptops, which require a stable wireless connection to send and receive data.
Chances are, soldiers in remote areas probably won't find a cellular/WiFi tower anywhere near their vicinity, so the data that is acquired is usually stored on those devices until they return to base and upload the information. In an effort to bring a mobile hotspot to those serving in those remote locations, DARPA is looking to outfit UAVs with a "millimeter-wave communications backhaul network" capable of providing 1 Gbps. Like all of DARPA's projects, their Mobile Hotspots program is broken down into three phases, with the first phase already completed. The first phase consisted of developing smaller, steerable millimeter wave antennas that are capable of acquiring, tracking, and establishing a link between moving platforms on the ground and in the air.
DARPA’s drone-based wireless hotspot concept.
The initial phase also required the integration of low-noise amplifiers to filter distortions, as well as more efficient power amplifiers for extended-range (over 30 miles) E-band transmissions. The final portion of phase-1 was to make the network low-powered, lightweight, and fit into relatively small pods fastened to the underside of the UAVs wings.
The second phase consists of integrating that network into the US Army and Marine Corps RQ-7 Shadow UAV and subsequent ground vehicles and the third phase will round-out the Mobile Hotspots program with field-testing of multiple UAVs and ground vehicles. As always, we civilians will probably never hear anything after the tests are successful unless of course, you join the military.