How Does Wi-Fi Work?

Find out how your internet connection travels through the air.

W-Fi uses modified radio waves to send internet data through the air. Devices (like your smartphone) have little radios and antennas that receive these waves and convert them into usable data. That’s a simplified explanation, but we’ll go into more detail if you’re curious about the specifics.

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What is Wi-Fi?

Wi-Fi is a form of communication that uses radio waves to carry data through the air. It eliminates the need for wired connections, so you can access the internet tether-free. Just tap on a network name displayed on your wireless device and you’re connected to the internet.

However, the terms Wi-Fi and internet are not one and the same. You need a modem for an internet connection and a router for a Wi-Fi connection. If you don’t have a modem, then your Wi-Fi connection can’t access the internet.

What do you need for Wi-Fi?

To get Wi-Fi, you need a wireless router to create a wireless local area network (WLAN). But to get wireless internet, you must have a modem connected to your router. The modem is the only device that can translate your provider’s internet signals into data your router can use.

Pro tip:

Check out our article about modems and why you need them for internet to see how your router interacts with your modem.

How Wi-Fi works simplified

Before you can even use Wi-Fi, your wireless device must connect to an access point—in this case, your router.

Connecting to a router

First, your wireless device sends out a query asking, “Who’s out there?” Your router responds by saying, “I’m here, and this is my MAC address.”

Your wireless device then asks, “Can I join? Here’s my MAC address.” The router verifies that your device’s address isn’t banned from the network and says, “Sure, you can join.”

What is a MAC address?

A media access control (MAC) address is a 12-character identifier assigned to a device’s networking component. It’s the device’s physical address so it can be identified on a network.

After the initial introduction, your device sends information about its preferred encryption types. The router receives the information, creates an Association ID for your device, and sends a response.2

Finally, your device and router enter the four-way handshake phase—this process encrypts their connection. After that, the router assigns an IP address to your device so you can surf the internet.

When you disconnect and attempt to reconnect, most of the initial introductions are already done. Your device shakes hands with the router and receives its new IP address.

We detail the step-by-step process in the how Wi-Fi devices technically connect section.

Communicating with the router

Your router places the two basic units of data (ones and zeroes) into an ordered line called a bitstream and converts that stream into a digital wave. On paper, it looks more like a cityscape than the typical hills and valleys of analog radio.

Your router then places that digital wave—think of it as an oddly shaped boat—onto a river of energy (radio waves) that’s conformed to carry the boat upstream or downstream on the 2.4 GHz or 5 GHz band.

After that, your device receives and removes the digital boat from the river and converts it into data your device can use. Reverse the process when your device sends data to the router.

If you want a more detailed explanation, we list the steps in the how Wi-Fi technically works section.

Pro tip:

Are you looking to upgrade your router? We list our favorites with the best parental controls. Are you a gamer? We list our favorite routers for online gaming.

How Wi-Fi is similar to AM and FM radio

Wi-Fi is another form of transmitting a signal over the air. We’ll compare it with AM and FM radio so you can see where Wi-Fi resides compared to music radio and why it has a limited reach.

Wi-Fi is the cousin to AM and FM radio

A radio wave is an oscillation of electromagnetic energy used in communication. Amplitude modulation (AM) and frequency modulation (FM) are the two most familiar types of radio, which place audio signals onto carrier radio waves—again, the river and boat scenario.

Why use carrier waves?

Carrier waves are needed because you can’t send raw audio and data signals through the air without a very tall antenna. Raw signals have an extremely low frequency with really long wavelengths that require lots of amplification. The antenna needs to be at least one-fourth the size of a wavelength.

Carrier waves enable the use of small antennas because they use higher frequencies and shorter wavelengths than audio and data signals. The lowest Wi-Fi frequency (2.401 GHz) requires an antenna just over an inch long because it’s one-fourth the size of the wavelength.

What is a frequency?

If you map a radio wave on a graph, it resembles a series of peaks and valleys. A radio wave cycle consists of one peak and one valley. This cycle repeats, creating a continuous flow of energy.

Frequency is the number of cycles per second. The higher the frequency, the more peaks and valleys you’ll see each second. Frequency is measured in hertz, so if 1 Hz equals one cycle per second, 5 Hz equals five cycles per second.

For example, let’s compare AM to FM radio:

Lowest frequencyCycles per second
AM radio535 kHz535,000
FM radio87.5 MHz8,750,000

That’s a lot of cycles per second for sure, but it doesn’t come close to Wi-Fi.

How Wi-Fi fits in

Wi-Fi uses radio waves with a faster frequency than AM and FM radio. While AM radio is measured in kilohertz and FM radio in megahertz, Wi-Fi is measured in gigahertz. This measurement is why you see Wi-Fi connections labeled as 2.4 GHz and 5 GHz—which are a generalization of frequency ranges.

The lowest 2.4 GHz frequency (2.401 GHz) packs 2,401,000,000,000 cycles into each second. Crazy, right? Now just imagine how much data you can cram into each cycle (we can’t), and you’ll see why Wi-Fi uses the 2.4 GHz and 5 GHz bands.

How to improve your Wi-Fi performance

If you’re looking to find ways to improve your Wi-Fi connection, here’s a list of a few common problems and how to fix them.

Problem: Your Wi-Fi speeds are slow

Unplug your router, wait 30 seconds, and then plug it back in to see if your speeds improve. If not, you may need to change bands on your wireless device, change the channel on your router, or upgrade to a faster router. You may even need a faster internet plan if your current connection can’t handle your traffic.

Problem: You have a weak Wi-Fi signal

Move your router to a central location. Position at least one external antenna horizontally (if you can) for better Wi-Fi access on another floor. You can also try moving closer to the router if it’s already placed in the best location.

My problem isn’t listed

We have additional resources to use if you’re experiencing other problems with your Wi-Fi connection:

Problem: You have dead spots in your home

If there are areas where your Wi-Fi can’t reach, you may want to consider purchasing a mesh Wi-Fi system, the best long-range router, or an amplifier to boost your current router’s signal strength.

FAQ about Wi-Fi

What does Wi-Fi mean?

The term “Wi-Fi” was created by the non-profit Wi-Fi Alliance as a user-friendly name for the set of technological standards used to transmit internet data in a home network. Products must complete certification testing before they can display the Wi-Fi brand. Wi-Fi is not short for Wireless Fidelity.

Who manages Wi-Fi?

The Institute of Electrical and Electronics Engineers (IEEE) manages all wireless local area networking (WLAN) standards for specific spectrums. It releases new standards when a new spectrum becomes available. There are currently six standards—each one faster than the previous while keeping backward compatibility intact.

What frequencies does Wi-Fi use?

Wi-Fi uses ultra high frequency and super high frequency ranges in the radio spectrum. Most routers broadcast Wi-Fi signals with 2.4 GHz and 5 GHz, although some may include a 60 GHz connection. Here are the actual ranges:

2.4 GHz5 GHz60 GHz
2.412–2.4725.15–5.35
5.725–5.85
57.34–70.20
What are the Wi-Fi specifications?

A Wi-Fi specification (IEEE 802.11) dictates how data is delivered using radio waves. All Wi-Fi specifications fall under the IEEE 802 standard family that specifies how a local area network functions.

Modern routers are based on Wi-Fi 5 and Wi-Fi 6.

SpecificationWi-Fi name*Max speed (per stream)Max streamsFrequency bandsChannel widths
802.11aN/A54 Mbps15 GHz20 MHz
802.11bN/A11 Mbps12.4 GHz20 MHz
802.11gN/A54 Mbps12.4 GHz20 MHz
802.11nWi-Fi 4150 Mbps42.4 GHz20 MHz
40 MHz
802.11ac Wave 1Wi-Fi 5433 Mbps85 GHz20 MHz
40 MHz
80 MHz
802.11ac Wave 2Wi-Fi 5866 Mbps85 GHz20 MHz
40 MHz
80 MHz
160 MHz
802.11axWi-Fi 61,200 Mbps82.4 GHz
5 GHz
20 MHz
40 MHz
80 MHz
160 MHz
802.11axeWi-Fi 6E1,200 Mbps86 GHz20 MHz
40 MHz
80 MHz
160 MHz
Why does Wi-Fi have such a short range?

Wi-Fi has a short range because it uses high frequencies.

A frequency is the number of times you can count a cycle—one peak and one valley—in a second. To determine the base length of a wave, you measure the distance between a common point on two peaks, like the very tip.

For a clearer picture, imagine a Slinky. Pull it apart as wide as you can, and you have AM radio because the peaks are far and wide, creating long wavelengths. Compress the Slinky, and you basically have Wi-Fi.

To give you an idea of how frequency affects range, here’s a chart showing example distances between two peaks in a radio wave:

TypeLowest frequencyDistance (between each wave)Typical max range
Wi-Fi 5 GHz5.150 GHz0.1909 feet75 feet indoors
150 feet outdoors
Wi-Fi 2.4 GHz2.401 GHz0.4096 feet150 feet indoors
300 feet outdoors
FM radio87.5 MHz11.22 feet40+ miles
AM radio530 kHz1,856 feet100 miles in the daytime
200+ miles at night
HAM radio136 kHz7,230 feet480,000 miles

Don’t let those numbers fool you. A router can broadcast a 2.4 GHz signal up to 150 feet indoors and up to 300 feet outdoors. The 5 GHz band has half the range. In contrast, AM radio can broadcast hundreds of miles at night because the radio waves can bounce off the ionosphere.3

In all the cases above, higher frequencies translate into shorter ranges.

How do mesh routers work?

A mesh router kit typically includes two or more units that communicate with each other. One unit connects directly to the modem, while the other units can be placed anywhere within range.

Each unit broadcasts 2.4 GHz and 5 GHz connections, creating a blanket of coverage from several points rather than a single point like traditional routers. Your wireless devices can easily move from one mesh unit to another without having to reconnect.

Some mesh router kits include a third 5 GHz connection that only the nodes use to send data back and forth between them.

Is Wi-Fi secure?

Wi-Fi can be secure if you have encryption enabled, use a strong password, and use a different SSID than the one set by your router’s manufacturer.

Most modern routers include Wi-Fi Protected Access II (WPA2) or III (WPA3) security. They use the Advanced Encryption Standard (AES) protocol that converts blocks of plaintext into ciphertext. The Temporal Key Integrity Protocol (TKIP) is an optional component that creates an encryption key for every data packet.

Nearly all modern wireless devices support WPA2. These include smartphones, tablets, laptops, game consoles, and Internet of Things devices. You typically can’t change security protocols on your wireless devices, but you can on your router. Apple suggests using WPA3 Personal for the best security, and WPA2/WPA3 Transitional for better compatibility for older devices.4

If you want to know how you can better secure your wireless network, check out our guides on how to secure your Wi-Fi router and how to change your network name and password.

Technical explanations

Here’s what goes on between a host and client device using a step-by-step format.

Step-by-step breakdown of Wi-Fi

In this example, your router is the transmitter and your smartphone is the receiver.

On the transmitter

Step 1: The router receives electrical impulses from the Ethernet port (WAN) and interprets them as a bitstream.

Step 2: The router converts the bitstream into a digital wave.

Step 3: The digital wave (or input signal) is moved to the modulator, where it’s superimposed onto an analog radio frequency carrier wave.

Step 4: The modulated wave moves to the amplifier. The router increases the signal’s amplitude to transmit it across the open air.

Step 5: The amplified modulated RF signal moves to the antenna(s) and is released.

On the receiver

Step 1: The smartphone absorbs the weakened modulated RF signal via its antenna(s).

Step 2: The weakened signal passes through an amplifier.

Step 3: The amplified modulated RF signal moves to the demodulator in your device.

Step 4: The demodulator separates the digital wave (or output signal) from the analog RF carrier wave.

Step 5: The digital wave is converted back into ones and zeroes your smartphone can use.

The receiver includes an amplifier because radio waves weaken and disperse over distance according to the inverse-square law of physics. That means the intensity of emitted radiation decreases as you move away from the source.1 A modulated radio wave must be at a specific strength before the receiver can remove the data wave, so it’s amplified.

For example, modified radio waves must have an amplitude above -69 dBm to remove data transferred over the air at 300 Mbps from a Wi-Fi 4 router.

Every device that supports Wi-Fi has a radio frequency transceiver consisting of a transmitter and a receiver.

Step-by-step breakdown of connecting to Wi-Fi

Here’s a detailed step-by-step list of how your wireless device—a smartphone in this example— connects to a router for the first time.

Step 1: Your smartphone sends a probe request to discover all Wi-Fi networks within range. This request includes information about the smartphone’s supported Wi-Fi standards and its data rates.

Step 2: A router receives the probe, verifies that it can support at least one data rate, and then replies with a probe response containing its MAC address.

Step 3: Your smartphone sends an authentication probe containing its MAC address, asking to join the wireless network.

Step 4: The router consults its list of banned devices and verifies that your smartphone’s MAC address is or is not on the list. The router then replies with an authentication response.

Step 5: Your approved smartphone sends an association request containing information about its preferred encryption types.

Step 6: The router creates an Association ID for your smartphone and replies with an association response.

Step 7: The router and your smartphone enter a four-way handshake phase in which they establish an encrypted connection.

Step 8: The router assigns a private IP address to your smartphone.

Related topics:

Sources

  1. Georgia State University, “Inverse Square Law, Radiation.” Accessed October 5, 2021.
  2. NetBeez, “Station Authentication and Association,” July 25, 2018. Accessed October 7, 2021.
  3. Federal Communications Commission, “Why AM Stations Must Reduce Power, Change Operations, or Cease Broadcasting at Night.” Accessed October 25, 2021.
  4.  Apple. “Recommended Settings for Wi-Fi Routers and Access Points.” Accessed November 3, 2021.

Author -

Kevin Parrish has more than a decade of experience working as a writer, editor, and product tester. He began writing about computer hardware and soon branched out to other devices and services such as networking equipment, phones and tablets, game consoles, and other internet-connected devices. His work has appeared in Tom’s Hardware, Tom's Guide, Maximum PC, Digital Trends, Android Authority, How-To Geek, Lifewire, and others. At HighSpeedInternet.com, he focuses on internet security.

Editor - Rebecca Lee Armstrong

Rebecca Lee Armstrong has more than six years of experience writing about tech and the internet, with a specialty in hands-on testing. She started writing tech product and service reviews while finishing her BFA in creative writing at the University of Evansville and has found her niche writing about home networking, routers, and internet access at HighSpeedInternet.com. Her work has also been featured on Top Ten Reviews, MacSources, Windows Central, Android Central, Best Company, TechnoFAQ, and iMore.

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