Sweden’s Ericsson yesterday launched an airborne GSM base station intended to enable passengers to use their cellphones on board aircraft. Commercial availability is scheduled for the end of this year and the vendor is in “very detailed discussions” with some existing operators, said Christian Jansson, senior specialist for high-capacity networks.
Dubbed RBS 2708, the new 12 MCU box weighs less than 45 pounds and requires less than 300 kW of power. It is designed to communicate with the cellphones via leaky cable antennas that would probably be installed on either side of the cabin in the overhead bins. The frequency chosen as standard is 1800 Mhz, which is common to both U.S. and European GSM phones.
Each box can handle 58 simultaneous calls, which would be relayed to a ground station via a satellite communications network, and each call would require bandwidth of 8 kbps. Two or more telephone network operators could share a single box, with other networks’ customers logging on as roaming subscribers as on the ground, and it would be possible to add WiFi functionality, Jansson said.
To prevent passengers’ cellphones communicating directly with ground stations, which can severely disrupt terrestrial networks, the airborne system includes an electromagnetic screening device–effectively a noise generator–to hide the signals from the ground.
The principle behind the design was to make the level of service on the aircraft the same as that anywhere else, Jansson said, with no waiting to make a call. So the 58-call ceiling was chosen to cater for peak demand on breakfast-time flights that typically carry a high proportion of business travelers. Additional boxes would enable the ceiling to be increased.
Ericsson’s fundamental mission is to make telecommunications available everywhere at a rate that is both affordable for users and commercially viable for operators, Jansson said. Affordability means calls should cost no more than e1 per minute, he said, but the commercial side of the equation is complicated by the additional players such as airlines and satellite operators involved in providing an airborne service, and the larger number of people who would want to share the revenue.
The ground stations would require additional functionality to handle the transmission delay resulting from the satellite relay, but that will be included in the next software release to operators using Ericsson ground stations. Ericsson’s background as a maker of airborne systems such as radar and electronic warfare equipment as well cellphones and telecommunications network equipment means it would be able to provide installation and any other services operators required, Jansson added.
