Access to the Internet has become so commonplace for many of us, that even a few minutes without being able to chat with friends, upload a selfie or just catch up on your friend’s Facebook activities is compared to a catastrophe. Be it basement carparks, elevators or even deep in the Yala forest, people need to be connected.
One of the few places that have remained relatively free from demands of constant Internet access has been the seat of an airplane. Many of us are probably used to switching off our mobile devices while in flight, and amusing ourselves with inflight entertainment or trying to take a nap within the constricted space assigned (unless you are in business class).
Making inflight phone calls has been possible for a while, through onboard phones that made use of satellite communication, since 1998. Wireless communication was deemed off limits due to fears of interference with on-board systems. After receiving the all clear from the aviation authorities, in 2008, passengers using Emirates (and now many other airlines) have been able to use their mobile phones in flight. However, a voice call requires comparatively smaller bandwidth and probably made more economic sense to airlines.
While most of the world’s major airlines all provide in air Wi-Fi, flight service ranking company Routehappy’s analysis[2] from its report on “Global state of in-flight Wi-Fi” shows that on a global scale, 24% of all air miles will have some form of Wi-Fi connectivity; while in the US, 68% of air miles will have Wi-Fi connectivity. It should be noted that only 15% of all air miles of non-US airlines had Wi-Fi connectivity.
So how do you provide broadband connectivity in air?
Firstly, you have to install the Wi-Fi system in the plane – which consists of an external antenna and in-cabin systems including the internal wireless access points. Inflight communication solution providers like OnAir – which is used by SriLankan Airlines – provides both inline and retrofitted solutions for most commercial airline types. Check this video of an installation taking place on a United Airlines plane for an idea of the work required.
The inside of a plane is a difficult environment for radio signals; the tunnel shape of the cabin causes lower losses but creates power addition of local signals causing fading at certain points, while the number of passengers in the plane provide additional obstacles. Therefore, careful modeling and planning of access point placement and power settings need to be done before deployment in each model of plane.
Connecting a plane to the World Wide Web (Backhaul)
- – Air to Ground (ATG) – Deployed in the US and Canada, cellular-based technologies are used, beaming 3G signals (EVDO in the 3GHz & 850MHz spectrum) from the ground-based towers into the sky and delivers peak speeds of 3.1Mbps. Newer versions of this technology (ATG4) increase the potential connection speed up to 9.8Mbps by using EVDO Rev B and directional antenna, which more efficiently captures the beam being sent up from the tower at ground level. [7]
- – Satellite – For satellite connectivity, an antenna is mounted onto the top of the plane, inside a “radome” (a domed enclosure). The antenna transmits data rates at 10-30 Mbps to the aircraft. Most satellite operators currently use the Ku band (12-18 GHz band) for mobile connectivity but are looking to use the Ka band (26-40 GHz) in the near future with the advent of technologies that mitigate the rain-fading issues with the band. [7]
- – Ground to Orbit (GTO) – This hybrid technology proposed by aero-communications service provider Gogo for planes flying in North America. GTO uses a combination of a satellite antenna on top of the plane to receive the signal and the ATG antenna under the plane to return the signal to earth and promising download speeds at a peak of 70 Mbps [1]. Inmarsat is also planning a hybrid satellite and ATG network partnering with Alcatel Lucent for the European continent [5].
Your Wi-Fi experience in the air, therefore, can vary significantly from airline/region to just the aircraft type. Inflight Wi-Fi has come a long way from the initial 332kbps incarnation when satellite bandwidth was at a premium. This year, satellite operator Inmarsat is set to launch more of its Global Xpress system [4] satellites which will be the first high-speed broadband network to span the world. This is set to offer improved downlink communications speeds of around 50 Mbps, with up to 5 Mbps on the uplink side, this version uses the Ka band and steerable spot beams to deliver high-speed broadband connectivity, and to provide capacity where and when it’s needed. With increased demand, we can expect other satellite operators to be planning to offer similar services along with GTA solutions in the near future.
References
- http://commercial.gogoair.com/connectivity/technologies
- https://www.routehappy.com/insights/wi-fi
- https://www.youtube.com/watch?v=OsuvlmDWYuA
- http://www.inmarsat.com/service/global-xpress/
- http://www.inmarsat.com/press-release/alcatel-lucent-joins-inmarsat-technology-partner-development-first-eu-aviation-network/
- http://airfax.com/blog/index.php/2013/07/09/flight-focus-ifec-with-a-wi-fi-focus/
- http://flightclub.jalopnik.com/how-in-flight-wifi-works-and-why-it-should-get-better-1593043880
