HDG explains: how does Wi-Fi work?

WiFi is a wireless network technology that allows you to connect your WiFi-enabled devices to a local area network. With Wi-Fi, you can exchange data between local network devices or connect to the Internet, if a connection is available. Most people probably know this as we all use Wi-Fi every day, but how does Wi-Fi actually work?

WiFi is radio

The most basic fact about Wi-Fi is that it uses radio waves to transmit information. Radio waves are what we call a specific frequency range of electromagnetic radiation. Light is the part of the spectrum that our eyes are sensitive to, but it’s made of the same “stuff” as radio waves.

WiFi uses two different frequencies for transmission: 2.4 GHz and 5 GHz. That’s 2,400,000,000 and 5,000,000 cycles per second, respectively. This is quite high compared to FM radio with a frequency of only about 100 Mhz.

The exact frequency of a radio wave changes a lot in its characteristics. With a higher frequency you can put more information in your signal. However, some frequencies do not have a very wide range.

Different frequencies also penetrate matter differently. Some frequencies can be reflected from the atmosphere, so your transmitter and receiver don’t need a line of sight to work. Other frequencies just shoot straight into space. This is useful if you want to communicate with a satellite, not so much if the receiver is on Earth.

Waves on the Wi-Fi operating frequencies can reach hundreds of miles if you put enough wattage into the transmit power, nothing gets in the way, and use the right antenna. However, standard household Wi-Fi usually has an unobstructed range of 30-50 meters (about 100/150 feet). 2.4 Ghz wifi has the longer range, 5 Ghz wifi has faster speeds.

WiFi is digital

WiFi is radio but it is digital radio. That means the radio waves are modulated to carry digital code. WiFi is absolutely packed with digital information.

The latest and greatest Wi-Fi technology has a theoretical speed limit of 4.8 Gbps, using four 1.2 Gbps data streams simultaneously. That’s 600 megabytes per second! Of course, theoretical speeds are determined in a lab under optimal conditions, but even in the real world, modern Wi-Fi is very fast.

WiFi has standards and protocols

WiFi has been around for a long time. The first commercial version of the technology was released as early as 1997. The Institute of Electrical and Electronics Engineers (IEEE) has codified the WiFi standard, which is officially known as IEEE 802.11. The first generation of Wi-Fi is known as 802.11a, but as time went on, newer, better versions of Wi-Fi were developed:

  • 802.11a
  • 802.11b
  • 802.11g
  • 802.11n
  • 802.11ac
  • 802.11ax

WiFi is not fully backwards compatible. You won’t find many modern devices that can still communicate with 802.11a devices. Many Wi-Fi devices out there are “bgn” and work with those three standards, all of which use the 2.4GHz frequency band. 802.11ac uses the 5 Ghz band, but most of these routers are “dual band” and also offer 2.4 Ghz to talk to older devices that use older standards.

In practice, backwards compatibility with Wi-Fi is spotty, as some devices within each respective standard are locked at certain speeds. Newer routers may not let it go that slow!

Incidentally, the whole naming convention “802.11” has been dropped. The latest 802.11ax is now known as Wi-Fi 6where 802.11 is WiFi 5 and so on.

WiFi is encrypted

Anyone can intercept Wi-Fi radio waves, but digital encryption means they can’t just eavesdrop on what’s being sent and received. This is certainly the case if your WiFi network is protected with a password.

Your Wi-Fi password is also the encryption key, so anyone with the password can see all data packets unfiltered. Therefore, only use websites that HTTPS enabled and always use a VPN service when using a public WiFi hotspot!

Your Wi-Fi devices are most likely using WPA2. WPA is an abbreviation for WiFi Secure Access and is a very strong encryption scheme for WiFi connections. However, over the years, hackers have discovered several exploits that allow them to break the WPA2 encryption protocols in some cases.

In 2018 the WiFi alliance, the custodian of WiFi technology, announced WPA3. This new version improves security and closes the vulnerabilities in WPA2. It will, of course, be some time before all the hardware available in the wild will support the new security standard.

WiFi Direct is one thing

WiFi is designed to use a central device such as a router to manage communication between devices. However, WiFi can also be used to directly connect two devices in a so-called ‘peer-to-peer’ connection. This is very useful when, for example, you want to send a large file from yours to someone’s smartphone.

This is also the type of Wi-Fi commonly used to cast video from a phone to a smart TV. When you use devices such as GoPro cameras or certain WiFi camera drones, you also use a direct WiFi connection. Bluetooth gets the most attention in the world of peer-to-peer wireless connections, mainly because it’s so energy-efficient, but WiFi direct is fast and just as easy to use.

Routers, Repeaters & Mesh Networks

While direct Wi-Fi connections are commonplace these days, the Wi-Fi we all use mostly uses a hub-and-spoke design. In other words, all your Wi-Fi devices connect to a central device, which acts as an intermediary. For most people, this becomes the regular WiFi router.

Modern routers have multiple antennas, separating different frequency bands, as well as the hardware that sends and receives Wi-Fi data. These routers also handle your Internet connection and any wired Ethernet devices on your network, allowing the wired and wireless networks to communicate with each other.

However, as we mentioned above, the Wi-Fi signal range is quite limited. Which means the further you are from the router, the worse the signal strength is. A Wi-Fi repeater can be used to extend that signal at the edge of the coverage range.

While repeaters work well enough, there is a new trend toward “mesh” Wi-Fi systems. There is no central router here. Instead, several smaller routers are scattered around your home, interconnected and provide a seamless cloud of Wi-Fi. This is the most widely used Wi-Fi technology in large businesses, but it has become affordable for home use.

Beyond Wi-Fi

WiFi is around us more than ever, now that all kinds of devices need a network connection. However, WiFi is not the only competing technology when it comes to wireless data transfer. Bluetooth is the boss when it comes to low-power, short-range connections. Future versions of Bluetooth may even give WiFi a run for its money when it comes to speed and range.

However, Wi-Fi’s biggest competitor may well be 5G. Fifth-generation mobile technology offers cheaper data rates and dense urban coverage. 5G shouldn’t replace home Wi-Fi, but 5G offers an alternative to public Wi-Fi hotspots, which have become particularly popular due to the high cost of mobile data.

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