They have performed high altitude balloon communication trials in Sweden in 2005. They had supported data rates of 11Mbit/s and throughputs up to 4Mbit/s, using WiFi (IEEE802.11b), at distances ranging up to 60km. Dr David Grace, the project's principal scientific officer said: "Proving the ability to operate a high data rate link from a moving stratospheric balloon is a critical step in moving towards the longer term aim of providing data rates of 120Mbits/s." DLR, a German partner, performed the first known optical 1.25 Gbit/s downlink from the stratosphere to an optical receiver on the ground over a link distance of up to 64 km. The very high data rates offered by free space optical communications will be used for future inter platform and platform to satellite backhaul links.
The CAPANINA project, which uses balloons, airships or unmanned solar-powered planes as high-altitude platforms (HAPs) to relay wireless and optical communications, is due to finish its main research at the end of October. The consortium, drawn from Europe and Japan, have demonstrated how the system could bring low-cost broadband connections to remote areas and even to high-speed trains. It promises data rates 2,000 times faster than via a traditional modem and 100 times faster than today's 'wired' ADSL broadband.