How do Wi-Fi and hotspots work?


You have high-frequency radio waves to thank for your wireless internet access. Jake Port explains how it works in the latest of his tech explainers.


Watching cat videos has never been so easy and convenient ... but how does the information travel from router to smartphone?
Ezra Bailey

If you're reading this article on your smartphone or laptop, it’s more than likely you’re connected to a wireless router. No need for bulky cables – just pick the wireless signal you want and the World Wide Web is at your fingertips.

This is all thanks to the power of Wi-Fi. So how does it actually work?

If you wanted to connect to the internet before Wi-Fi (which, by the way, doesn’t stand for wireless fidelity – it doesn’t actually stand for anything) you needed a cable known as an ethernet cable.

This cable converts 1s and 0s of binary, the language of computers, into electrical signals which are sent down a wire and converted back into binary by the computer.

But in the case of Wi-Fi, those electrical signals are converted by a router to radio waves that carry the electrical signal to the computer, where they’re converted to binary again.

Information is sent as lots of small packets that are then stitched together.

The process also works in reverse. If you need to send an email, your computer or smartphone shoots radio waves to the router.

The radio waves are very similar to those used in mobile phones, walkie-talkies and other devices.

So how can radio waves carry the amount of information needed to watch a high-resolution cat video?

It’s true: the amount of information transmitted to make a phone call (audio) is far less than to watch an online video (audio and visual).

This boils down to the radio wave frequency. Wi-Fi uses either 2.4 gigahertz or 5 gigahertz – far higher than those used by mobile phones at less than 1 gigahertz.

A higher frequency means more radio waves – and more data – can be packed into a given space.

The trade-off is that the waves can’t travel as far and are heavily influenced by nearby objects, including other Wi-Fi signals.

That’s why your Wi-Fi signal gets weaker the more walls you put between your computer and router.

You can get around this by linking lots of routers together to boost the signal. This is how the internet hotspots found in places such as cafes, universities and office buildings manage to reach out across multiple levels and large distances.

For instance, the University of Twente in the Netherlands has a hotspot covering 1.4 square kilometres. It combines more than 600 individual routers from one massive signal that all students and staff can access at the same time.

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