In today’s date internet has become a mainstream and also a part of our daily life. It has become so important that just imagine what would happen all around the world if people could not access the internet for about 10 minutes including NASA, ISRO, Google, Facebook, etc. Can you imagine or feel what would be the impact?
Getting to the topic. Some years ago, we used to control and sit without using the internet when we used to travel in flights depending on the journey time because the internet was not accessible there.
But from some year’s technology has impressed, improved a lot and we can use the internet in flights with ease by using In-flight Wifi. But have you ever thought how the internet works up there? About 25k feet above ground level?
So, today I’ll be explaining you,
How In-flight Wifi works.
Every one of you have been using 2g, 3g, 4g, broadband connection in your mobile phones and in your houses. But how’s it possible to provide internet to the airplanes which are moving at a speed of say 800kmph and at a height of say 30k feet?
So, we take the help of 2 types of concepts for the In-flight Wifi to work.
Ground-based transmission (A2G).
By using satellites.
1} Air to ground (A2G)
This is same as using the internet in mobile for which you take the help of mobile towers, in the same way, there are towers which emits signals to the airplanes. Here, what happens is, the bottom face of the airplane is fitted with Transponder which receives the signals from the ground.
But in this system, there is a lot of drawbacks, firstly, this process can happen only if the flight is above the ground because in the sea we haven’t installed any towers yet and it is not necessary that the flight has to be above the ground all the time. Secondly, since the land is spread vastly, and the flight can move around anywhere, it is not possible to install towers everywhere, which is next to impossible. And thirdly the bandwidth is not huge since there will be, say 500 to 1k passengers onboard so, the speed will definitely be very less. This is the entire concept of A2G.
2} Satellite-based communication
Till now we have taken KU band (the frequency range from 10.5 to 17 GHz; where 13.75 to 14.50 GHz is for transmission and 10.7 to 12.75 GHz is used for reception) into work. This is the same band which you use in your house to avail internet. Here the transponder is placed above the body of the flights which communicates with the satellite in the space which in turn acts as a moderator between towers in the earth and the airplane itself. But since the frequency of this KU band is mediocre the speed available will be around 50 – 70 Mbps. Now when I tell the speed is 50 Mbps you might think it’s quite fast but NO, this speed is for the whole plane. The speed for individual passengers depends upon the number of passengers traveling in the plane, how many of them have bought wifi for themselves. In that case, the speed gets distributed and you will be able to get bad speeds as an end user by which you can hardly post a photo on social media.
But this situation is going to change in the future because we will be taking KA band (Frequency range: 26.5 – 40 GHz) into to work. The frequency of this band is almost double of that of KU band. By this we will have 2 advantage, firstly the speed from KU band is not that great and the antennas used by KU band is large, by which the weight of the plane will increase which in turn increases the fuel cost which in turn increases your ticket fare.
Secondly, since KU band’s frequency is more, the antennas size will be small, and it’ll weigh less. And also, it’ll increase the bandwidth and speed. But there is a drawback here also since the frequency is more, the more unstable the connection is. In that case, during days of bad weather, you might see a little of fluctuation in the internet connection.
So this is the entire concept of how internet reaches the plane. But right after it reaches the plane, there is a necessity to distribute this to the entire plane for which they use metallic pipes embed inside the body of the plane. The placements for wifi routers is done, after doing certain research on many aspects like interference etc., because a person sitting at one position might get very good speed while the person sitting at some other end might get poor speed. So there is a necessity for the right place.
Below is an infographic on how the process of In-flight wifi works in a simplified manner.
Stay tuned for more informative posts.
Thank you, hope you liked it. Please do comment if you have any queries regarding this topic, and you can also suggest me to write about any other technology topic and I will consider it.