The US military research agency that helped turn unmanned aerial vehicles from noisy hobbyist toys into far-ranging platforms for real-time surveillance (and sometimes attack) in war zones has a new role in mind for military drones: mobile hotspot.
The Defense Advanced Research Projects Agency (DARPA) has announced plans to convert some of the low-tech, unarmed RQ-7 Shadow drones used for surveillance and reconnaissance by the US Army in Afghanistan into wireless access points offering high-speed 1Gbit/sec wireless data connections to U.S. troops in the field.
If all this sounds far-fetched, then think again. On April 14, Google announced that it was buying Titan Aerospace. Its goal, according to Information Week, is to use high-flying, solar-powered drones that can stay in the air for weeks as roving WiFi hotspots that can bring Internet access to remote areas and increase the search engine giant’s customer base.
DARPA's propeller-driven drones stay in the air only nine hours at a time, but do provide military-spec'd network infrastructure in places where there is none.
DARPA launched the Fixed Wireless at a Distance program in 2012 to provide high-bandwidth, reliable network connections to forward operating bases and troops on patrol. The program is part of an ongoing effort by DARPA and the Pentagon to extend intelligence-distributing communications networks all the way down to individual troops in the field -- efforts that have often been frustrated by the almost complete lack of network infrastructure in the remote war fighters often operate.
Because of the range of devices and generations of communications gear in use by varying levels of mounted and foot troops, the fixed-wireless military mobile ad hoc networks (MANETS) had to support devices using old-fashioned military radio, special-function modern military wireless networks, as well as more routine and commercially available WiFi and cellular communications networks.
Portable MANETS not only have to be unusually heterogeneous, but also have to scale to support both thousands of individual users and to cover areas far larger areas than most commercial or military radio systems are designed to do, according to DARPA project documents that specify systems using steerable antennas, millimeter-wave wireless-network frequencies, and data rates of 1Gbit/sec from aerial, mobile and fixed nodes.
Millimeter-wave networks using wavelengths between 30GHz and 300GHz have significantly higher bandwidth and more reliable connections than existing cellular networks, including reliable non-line-of-sight connections at ranges of up to 200 meters even from low-power micro- or picocell base stations, especially in non-line-of-sight and urban-canyon environments, according to a January 11 analysis from IEEE.
In a military context, this means it's possible to set up a high-bandwidth wireless network that could cover large swathes of geography even using low-power, often battery-operated wireless access points whose own position is highly variable -- as it would be if the access point were circling blithely above a battlefield in an 11-foot-long, 185-pound remote controlled aircraft fitted out with directional antennas and amplifiers that allow it to fly high enough to be a difficult target without weakening the network links to the ground.