How Exactly Does Wi-Fi Work?

Chances are you are using a Wi-Fi network to read this very article. But what is this 'magical' thing and how does it work?

Here we briefly provide an overview of Wi-Fi, explore the different types of it and discuss its pros and cons. Please note this is not intended to be a comprehensive guide. 

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How do Wi-Fi systems work?

Wi-Fi or Wireless Fidelity to give it its full name is a telecommunication technology that uses radio waves to send and receive digital signals and, by extension, data. The shorthand Wi-Fi is actually a brand name that was introduced by the Wi-Fi Alliance to describe the tech as its technical name (IEEE 802.11) was deemed a bit too complex for consumers. 

Interestingly Wi-Fi as a brand is owned by the Wi-Fi Alliance who is a non-profit organization that promotes the development of Wi-Fi tech and products.

Wi-Fi, also known as  Wireless Local Area Network (WLAN) is technically known as IEEE 801.11 technology. This is a set of standards for the technology that are maintained and issued by the Institute of Electrical and Electronics Engineers (IEEE), that are used to implement WLAN communication in select frequency bands.

Wi-Fi is primarily used to provide internet access to any, and all, devices connected to a Wi-Fi network. 

Wi-Fi's greatest benefit over more traditional forms of telecommunication connection is the fact that it doesn't require devices to be connected using wires - hence the name. 

The technology relies, as previously mentioned, on the transmission and receipt of radio waves, electromagnetic waves with frequencies in the Gigahertz range. 

Data is converted by a router or a wireless adaptor to either send or receive Wi-Fi radio waves. When this encoded radio signal is received by either the router or the adaptor, it is decoded back into the original data.

This is a two-way process with both wireless adaptor and router working in tandem to encode and decode the radio Wi-Fi signals in the blink of an eye to transfer data between devices. 

The frequencies used by Wi-Fi are significantly different from those of other "wireless" technology like car radios, "walky-talkies" or cell phones. Car stereos, for example, operate at frequencies in the Kilohertz or Megahertz range (AM and FM). 

Hertz, in case you are unaware, is a unit of frequency - or the time interval between each peak/crest in an EM wave. The higher the frequency the closer the peaks, and troughs, of EM waves, are. 

To put things into perspective, 1 Hertz is about 1 cycle per second or 1 second between each wave crest. 

"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 Wi-Fi, 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 Wi-Fi. This is why some people with old or faulty microwaves experience a problem with their Wi-Fi signal when they try to make popcorn." - Scientific American. 

What frequencies do Wi-Fi signals use?

As previously mentioned, Wi-Fi networks tend to operate at either 2.4 or 5 GHz. This usually adapts depending on the amount of data being sent by the user. 

The IEEE 802.11 standard sets out the following standards for Wi-Fi types:- 

• 802.11a is the standard used to denote the use of frequencies of 5 GHz. This allows for the transmission of up to 54 megabits a second. It uses a complex technique, known as OFDM (orthogonal frequency division multiplexing) for generating the wireless signal. 
• 802.11b transmits data at a frequency of around 2.4 GHz. This is on the "slower" end of Wi-Fi data transmission rates and is usually enough to send about 11 megabits a second. It has a range of up to 150 feet (46 meters) and is today largely redundant. 
• 802.11g transmits data also at 2.4 GHz but can allow the transmission of a maximum of 54 megabits a second. It uses the same OFDM as 802.11b and is backward compatible with older standards. 
• The more recent 802.11n, a newer standard, is able to transmit 140 megabits (though it theoretically supports up to 450 Mbps) and operates and 5 GHz. Introduced in 2009 it is also termed Wi-Fi 4. This standard use uses MIMO (Multiple Input Multiple Output) where multiple transmitters/receivers operate simultaneously at one or both ends of the link. 
• 802.11ac, or Wi-Fi 5, is one of the newest of the pack and has data transfer rates of between 433 Mbps and 1 gigabit per second. It works solely within the 5GHz range and can support up to eight spatial streams. It also uses the MIMO technique introduced with 802.11n. 
• 802.11ax (Wi-Fi 6) - This is the newest iteration and promises to be a gamechanger. 

Pros and cons of Wi-Fi

There are a number of key advantages and disadvantages of Wi-Fi. These include, but are not limited to: -

Pros

• Increased efficiency - Faster connectivity enables rapid data transfer.
• Access and availability - The ability to communicate without wires means Wi-Fi provides a very convenient method of data transfer.
• Flexibility - Networking is incredibly easy and versatile. using Wi-Fi.
• Cost savings - Wireless networks are usually cheaper and easier to install.
• New opportunities - Wi-Fi has enabled many businesses to offer new opportunities for their staff and clients. For example internet access in cafes, hotels, airports, etc. 

Cons

• Security - Wi-Fi is more exposed to unauthorized access than some more traditional networking techniques.
• Installation problems - Wi-Fi signals can be interrupted if many users are connected to other sources or if other radio signals are present. This can lead to poor communication or even complete loss of signal.
• Coverage - Wi-Fi networks often suffer from "black spots" where the signal is not available. This is usually due to the inherent nature of building construction, e.g. steel-reinforced building materials can block Wi-Fi signals.
• Transmission speeds - Data transmission can be slower or less efficient than wired solutions. 

What is the difference between the Internet and Wi-Fi?

You've probably already worked this one out, but although the terms are sometimes used as synonyms they are quite different things. Wi-Fi is a form of telecommunications that transmits data wirelessly using radio waves. 

This enables devices to be connected together locally without the need to have an internet connection. For example, consider a Wi-Fi-enabled printer.

You can send and print documents from your computer without ever needing to be connected to the web. 

The internet, on the other hand, is a global network of computers that use the Internet protocol suite (TCP/IP) to link devices worldwide.