How does WiFi magically connect us to the Internet?

WiFi is so integral to our daily lives yet we often take it for granted. It’s the invisible thread that connects us to the vast world of the internet. But how does it actually work?

To understand WiFi, let’s start with the basics. At its core, WiFi uses radio waves to send and receive data over the air. This might sound similar to how radio or television works, but WiFi involves sending data — not just receiving data like those systems.

Imagine the air around us as a vast ocean, with waves of different frequencies travelling through it. Just like boats on the sea, waves can interfere with each other. That’s why WiFi needs to manage these interferences. WiFi uses a set of standards known as IEEE 802.11, which define how data is communicated over wireless networks. It works in specific frequency bands — mainly 2.4 GHz and 5GHz. These WiFi frequencies are like designated lanes in our ocean such that other radio waves don’t interfere with WiFi traffic.

To use WiFi, you need a router. A router is like a lighthouse, sending out a signal that carries information about the network and authentication details. When you want to connect to a WiFi network, your device and WiFi router exchange signals with each other.

Once connected, data transfer begins. Internet data is broken down into small packets — similar to letters in a mail system. Each packet has some information, the address of where it’s from and where it’s going. Here’s where the magic happens. The contents of the packets are stored in binary (i.e. the data is only 1’s and 0’s). These packets are transferred into radio waves — using techniques like quadrature amplitude modulation (QAM) — and sent across the air. QAM works by changing the phase (timing) and amplitude (strength) of radio waves based on the data stored in the packets.

Since we’re relying on radio waves to transmit the WiFi data, we can expect errors and interference. So WiFi uses error correction algorithms like cyclic redundancy check, which adds a checksum (i.e. a block of additional data) that’s calculated from the original data and is checked at the end to ensure the data is correct.

The way WiFi works is much more complicated than how I’ve described it, but I hope it gives you a high-level idea of how it works. It’s an innovation that’s helped us make incredible progress over the years.

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© Ali Sarraf 2024