26 Nov

Did You Know: How Does in-flight Wi-Fi Work?

Have you ever wondered how your cell phone’s Wi-Fi works in the height of almost 12 kilometres and children around can watch “Shrek” on their iPads? You may have already realised that in-flight Wi-Fi availability on aircraft is increasing. And the reason for that is the decreased cost of better hardware (including its installation), which allows more airlines to upgrade to faster speeds and smaller airlines to adopt Wi-Fi for the first time. In fact, there exist two operating systems that help us to stay in touch with family and friends during a flight: ground-based and satellite.

Ground-based Wi-Fi works in a similar way as your cell phone. A small antenna underneath the aircraft body connects with the nearest cell towers and then the aircraft becomes a hotspot every passenger can connect to. Imagine it as a phone, which is connected to several routers, and when you move, it automatically disconnects from routers with weaker signal. Unfortunately, cell towers are not presumptuously situated everywhere, Wi-Fi connection can decrease above regions with lower cell tower density. Therefore, the speed of this technology isn’t fast enough to let us enjoy watching online TV and it doesn’t work above oceans. For this reason, ground-based Wi-Fi is only available on domestic flights.

However, there are some satellites which can overcome the limitations of ground-based satellites. They can connect to an aircraft via microwave frequencies called the Ku-band. A process there is quite simple: the satellite activates reflective mirror which gets signals from a cell tower and then the signal is reflected to the aircraft’s receiver. Well, there are also some limitations of this technology, as it can connect to several aircraft at the same time and decrease the connection speed.

Fortunately, there also exists Ka-band, the most powerful in-flight Wi-Fi technology. With the help of ViaSat1 satellite, this system can supply us with the internet speed, similar to the one we use at home or office. Currently, Ka-band equipment is more expensive due to the high cost of Ka-band microwave power components and the higher accuracies required for waveguides and antennas. Therefore, this technology is only available to a few airlines that can afford it.

We should be grateful to engineers who keep making advancements in wireless technologies. They are developing thinner, lighter and more cost-effective antennas to save a lot of money and increase the overall internet speed on aircraft. Seems like in the near future even more of us will be able to watch our favourite TV series on Netflix during our flight.