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How Does WiFi Work?

Have you ever stopped to consider exactly how email or streaming video gets into your smartphone or tablet so quickly, seamlessly, and in real time? That's WiFi in action. This week, Tech Talker delves into the technology behind wireless devices.

By
Eric Escobar
Episode #119
The Quick And Dirty

When you use your laptop, all of your internet traffic is converted into 1’s and 0’s which is then sent to your device’s wireless chip. From there, your wireless chip converts the 1’s and 0’s to into a radio frequency. Your router receives the signal and converts it back to 1’s and 0’s and then into the traffic from your device.

Do you ever have that moment where you step back and think about how something you use every day actually works? More specifically have you ever wondered how the heck computers actually communicate wirelessly?

Well, that's exactly the question we're going to be tackling in today's podcast.

What is WiFi?

First, let's cover some of the basics. WiFi stands for Wireless Fidelity and is the same thing as saying WLAN which stands for "Wireless Local Area Network."

WiFi works off of the same principal as other wireless devices—it uses radio frequencies to send signals between devices. The radio frequencies are completely different say from walky talkies, car radios, cell phones, and weather radios. For example your car stereo receives frequencies in Kilohertz and Megahertz range (AM and FM stations), and WiFi transmits and receives data in the Gigahertz range.

To break it down even further, Hertz (Hz) is simply a unit of frequency. Let's say you're standing on a pier watching waves come in. As you look down at the waves you can see the crest of each wave roll on by. If you counted how many seconds between each wave crest this would be the frequency of the waves. So if the time between each crest was 1 second that would meant the wave frequency was 1 hertz or one cycle per second.

Comparing sea waves to Mhz and Ghz, these waves are moving at 1 million and 1 billion cycles per second in the air! And to receive the information found in these waves, your radio receiver needs to be set to receive waves of a certain frequency.

For WiFi this frequency happens to be 2.4Ghz and 5Ghz. These waves are very similar to the frequency found in your microwave! Your microwave uses 2.450Ghz to heat up food and your router uses 2.412 GHz to 2.472 GHz to transmit your data over WiFi. This is why some people with old or faulty microwaves experience a problem with their WiFi signal when they try to make popcorn.

Just to clear up a popular misconception: These microwaves are non-ionizing radiation. That means that they do not cause cancer. That’s right kids, microwaves will not make you radioactive and glow in the dark!

How does WiFi work?

I mentioned before that WiFi uses both 2.4Ghz and 5Ghz frequencies. Generally older devices only have 2.4Ghz because that was the standard before 5Ghz came out.

But whether you are in the 2.4Ghz range or the 5Ghz range, there will be a set of channels your router will communicate on. These channels are a slightly different frequency from one another and they allow multiple routers to communicate in the same area without causing a lot of traffic. Just picture yourself driving on the freeway—if there was only one lane, it would cause a traffic jam; but with multiple lanes traffic flows smoothly.

You've probably noticed that you don’t have to worry about setting channels or anything when connecting to WiFi. That's because this is usually set up automatically when you connect your router. Your computer and router will work out the details between them.

Just for your reference, 2.4Ghz has around 12 channels and 5Ghz has around 30 channels. I say around because the number of channels is dictated by the country you are in.

So now we know that radio waves can fly through the air and pass through a lot of things on their way to your router and wireless device. These waves are also high in frequency, which allows them to carry a lot more data than most other radio frequencies. This high speed and high capacity is what allows you to watch Netflix on your smartphone and laptop while being several rooms away from your router.

But the real magic of WiFi has to do with the processing that happens on the end of your WiFi chip. Each device's WiFi chip converts 0’s and 1’s into radio waves to be sent out unto their destination, while at the same time converting a steady stream of 0’s and 1’s into data that your device can interpret as email, web pages, or anything else that you do on the web.

Let’s take a look at a standard wireless router that has a transfer speed of 54mbps (that’s megabits per second). As I’ve mentioned before, a bit consists of a 1 or a 0. At any given point while you’re using a wireless device, your wireless chip is transferring and receiving 54 million 1’s or 0’s in a single second. That would be about 13,000 pieces of paper, if printed out.

Needless to say it’s pretty impressive.

These 1’s and 0’s are the same signals that your wireless device would send if it were directly connected to your network with a wire. At this point your router considers your device to be exactly like any other device on the network. All of the communication is the same, your router just has to decide whether or not to send the signal over a wire or wirelessly using its radio.

So to sum it all up, when you use your laptop, all of your internet traffic is converted into 1’s and 0’s which is then sent to your device’s wireless chip. From there your wireless chip converts the 1’s and 0’s to into a radio frequency. Your router receives the signal and converts it back to 1’s and 0’s and then into the traffic from your device.

This all happens ultra fast and it is incredible!

Well, that’s it for today! Be sure to check out all my earlier episodes at quickanddirtytips.com/tech-talker

Until next time, I’m the Tech Talker, keeping technology simple!