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How Does Satellite Wi-Fi Actually Work on Planes?

March 31, 2017
4 min read
How Does Satellite Wi-Fi Actually Work on Planes?
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Though Wi-Fi availability is something to which we are now accustomed while flying, our experiences can range vastly in terms of both speed and connection quality, depending on the airline and aircraft type. The way these magic beams reach our laptops, tablets and smartphones is pretty incredible if you break it down and have a chance to look at what's going on over our heads while we hurtle through the air, seven miles above the earth.

I was invited to Malta last week by Lufthansa Technik (LHT) to learn about how it installs Wi-Fi on commercial aircraft. LHT doesn't only work on Lufthansa planes; it actually does work of varying degrees for over 800 airlines around the globe, in 8 countries. Last year over 5,000 employees completed more than 6,000,000 hours of work. One of the many tasks performed at LHT Malta is the installation of Wi-Fi on commercial planes.

Airlines are currently using two primary types of satellite connectivity: Ku-band and Ka-band. The Ku has a slower wavelength frequency, at 12-18GHz, while Ka runs at 26-40 GHz. As a passenger, I don't really have a preference between the two, as long as the service being offered is strong enough to meet my work and entertainment needs. There is also L-band but that's super slow in comparison. Oddly enough, some of the world's top airlines — including Emirates, Etihad and Singapore — use L-band Wi-Fi. It's like using a dial-up modem in 1992.

This device connects to the antenna atop the aircraft, and directs the antenna toward the most powerful satellite signal.

Both satellite Ku and Ka Wi-Fi types work pretty much the same way. First, the antenna on top of the plane links up with the closest satellite in orbit above the plane's path. Some services buy bandwidth from vendors. For example, Gogo gets its bandwidth from SES, IntelSat and AeroSat, who own their own satellites. But ViaSat, which provides Wi-Fi for JetBlue and Virgin America, owns its own satellites. ViaSat is scheduling the launch of its second satellite on April 25 of this year.

Lufthansa Technik developed its own Wireless Access Portal (WAP) to provide Wi-Fi to aircraft.

After the plane is connected to the satellite, the signal is then distributed to the Wireless Access Portal (WAP), kind of like the router you have at home for your own Wi-Fi. On airplanes, there needs to be a WAP for about every 50 people. So for the Lufthansa Airbus A321 I witnessed having Inmarsat GX Wi-Fi installed in Malta last week, there would need to be up to four WAPs, because the plane holds 190 people. Based on where you're sitting on the plane, the closest WAP will serve your device.

Later this year, a new Inmarsat network on the S-band frequency is slated to launch and support the European Aviation Network (EAN) over all 28 EU nations. The S-band is faster than L-band, but nowhere close to as fast as Ku or Ka. Inmarsat says it's developed specifically for high-traffic flight paths and busy airport hubs.

In its annual Wi-Fi report, Routehappy says that 79.8% of all US domestic seat miles flown had Wi-Fi available, while only 18.5% of flights outside the US had a full chance of Wi-Fi availability. According to the report, only Virgin America has 100% Wi-Fi availability. Southwest will join that list once its older Boeing 737-300s are phased out on September 30. Delta and United are also very close to hitting that mark.