The Technology Behind Virgin Atlantic’s Mid-Flight Cellphone System

The Technology Behind Virgin Atlantic’s Mid-Flight Cellphone System:

Your new phone booth. Photo: Virgin Atlantic

Whether you want it or not, phone calls are coming to commercial airplane flights. But like any new service, there are technical limitations, a premium price point, and a chance someone is going to be upset sitting next to a Chatty Kathy.
On Tuesday, Virgin Atlantic announced that customers would be able to make cellphone calls and send text messages while traveling across the Atlantic. The airline announced the immediate availability of the service on select aircraft, with the feature expanding to 20 aircraft by the end of 2012.
So how will the airline keep passengers in contact with their friends back home? Virgin is using satellites and microcells.
The technology behind the system is quite straightforward. According to Virgin Atlantic’s technology partner, AeroMobile, each plane with the feature will be equipped with a picocell installed in the cabin above the heads of passengers. The picocell acts as a tiny GPRS cell tower. Because the picocell is so close to passengers, user cellphones will actually emit relatively modest signals because they won’t have to work very hard in securing a network handshake. Airplane instruments are extremely sensitive, so the less random signal in the air, the better.
To communicate with people on the ground, the picocell uses the same satellite communications system as the airplane to connect calls. AeroMobile told Wired that because of capacity restraints in existing satellite communications systems, their picocell could only connect to six mobile devices at a time.
Whether the in-flight calls will be a convenience or nuisance remains to be seen. But before you start charging your phones or purchase a pair of noise-canceling headphones, consider a few caveats.
Initially, only customers of British carriers O2 and Vodafone will be able to use the service. If and when the service is adopted by U.S. carries, it will work with GMS phones only — Virgin’s system does not work with the CDMA networks used by Sprint and Verizon. So if you’re a Sprint or Verizon customer, you may as well put your phone back into airplane mode.
Because of an FCC ban on cellphone calls from airplanes in flight, the AeroMobile system is disabled when an aircraft is within 250 miles of the U.S. border. The FCC had proposed easing the restrictions on in-flight calling in 2007, but nixed the plan, citing technical issues and complaints from the public. Apparently no one wants to sit next to someone calling his doctor for test results while 30,000 feet in the air.
Virgin Atlantic says that the new call feature is targeted at business travelers, and is intended for use in exceptional situations. These exceptional situations appear to come down to a passenger’s willingness to pay a premium for a quick call or text message. Indeed: Customers can expect to pay premium international rates for keeping in touch while in the air.
The upshot: The chances are slim you’ll be stuck next to a someone gabbing away on your next flight. Unless, of course, you’re sitting next someone with a story to tell and money to burn.