What is Wi-Fi?

Wi-Fi refers to a wireless networking technology that uses radio waves to create a Wireless Local Area Network (WLAN). The name of Wi-Fi doesn’t stand for anything, but just a logo and trademark chosen by Wireless Ethernet Compatibility Alliance (now Wi-Fi Alliance, renamed itself in 2002).

Specification

Wi-Fi generations/IEEE standards

Wi-Fi indeed bases on IEEE 802.11, but it is not totally equal to that standard, because not all sub standards under IEEE 802.11 are using by Wi-Fi. For example, IEEE 802.11c is an amendment to IEEE 802.1D MAC bridging standard.

In 2018, Wi-Fi Alliance changed the naming rule to make it easier to understand and recognize. Now Wi-Fi Alliance does not call Wi-Fi standards as IEEE 802.11b, a, g, n, x anymore, but simply names them like Wi-Fi 1,2,3…n, and changes their certification trademark also.

 NameProtocolYearFrequency Actual speedTheoretical speedIndoor rangeOutdoor range
Wi-Fi 1802.11b19992.4-2.5 GHz6.5 Mbit/s11 Mbit/sabout 30 metersabout 100 meters
Wi-Fi 2802.11a19995.15-5.35/5.47-5.725/5.725-5.875 GHz25 Mbit/s54 Mbit/sabout 30 metersabout 45 meters
Wi-Fi 3802.11g20032.4-2.5 GHz25 Mbit/s54 Mbit/sabout 30 metersabout 100 meters
Wi-Fi 4802.11n20092.4 GHz or 5 GHz bands300 Mbit/s(20MHz*4 MIMO)600 Mbit/s(40MHz*4 MIMO)about 70 metersabout 250 meters
Wi-Fi 5802.11ac2011.115 GHz433Mbit/s, 867Mbit/s(Optional 80MHz,160MHz)867Mbit/s, 1.73 Gbit/s, 3.47 Gbit/s, 6.93 Gbit/s(8 MIMO,160MHz)about 35 meters 
Wi-Fi 6802.11ax2018.122.4/5 GHz 10.53Gbps10 meters100 meters

Note: Wi-Fi 1 to 3 also called Legacy Wi-Fi since they are not widely in use now.

Wi-Fi_User_Guide

2.4GHz and 5GHz Frequency

2.4 GHz and 5 GHz are most common radio frequencies used for Wi-Fi today. Although you use them every day even for now, you may not completely know the difference between them: 2.4 GHz has long transmission range and strong through-wall penetration, but low transfer speed and more signal interference (micro-wave), while 5 GHz has high transfer speed, but short transmission range and weak penetration.

Channel

The wireless channel is a specific division of frequencies in a specific wireless band.

On 2.4 GHz

There are totally fourteen channels defined for the 2.4 GHz ISM band in IEEE 802.11, but not all these Wi-Fi channels are available in all countries. In USA, there are 11 channels allowed by the FCC, and 13 are allowed in Europe where channels have been defined by ETSI. The WLAN / Wi-Fi channels are spaced 5 MHz apart (except for a 12 MHz spacing between the last two channels).

ChannelCenter FrequencyUSACanadaMost Countries
12412YYY
22417YYY
32422YYY
42427YYY
52432YYY
62437YYY
72442YYY
82447YYY
92452YYY
102457YYY
112462YYY
122467NNY
132472NNY
142484NNN

With the use of IEEE 802.11n, it is possible to use signal bandwidths of either 20 MHz or 40 MHz. 2.4 Ghz Transmission can be on a 22MHz (802.11b), 20MHz (802.11g/n), or 40MHz (802.11n) wide channel. When 40 MHz bandwidth is used to gain more than twice data transfer speed than 20MHz bandwidth, this obviously speeds up the data throughput, but reduces the number of channels that can be used.

ChannelOr ChannelCenter FrequencyUSACanadaMost Countries
31+52422YYY
119+132462NNY

On 5 GHz

Transmission can be achieved on a 20 or 40MHz (802.11a/n), 80 or 160MHz (802.11ac) wide channel

Channel WidthValid Channel Numbers
20 MHz36, 40, 44, 48, 52, 56, 60, 64, 100, 104, 108, 112, 116, 120, 124, 128, 132, 136, 140, 144, 149, 153, 161, 165, 169
40 MHz38, 46, 54, 62, 102, 110, 118, 126, 134, 142, 151, 159
80 MHz42, 58, 106, 122, 138, 155
160 MHz50, 114
  • U-NII: Unlicensed National Information Infrastructure
  • TDWR = Terminal Doppler Weather Radar

Note: Devices must be professionally installed when operating in the U-NII-2C (5470 – 5725 MHz band)

ChannelLowest Frequency (MHz)Center Frequency (MHz)Highest Frequency (MHz)Available in North America 
36517051805190Y
40519052005210Y
44521052205230Y
48523052405250Y
52525052605270DFS
56527052805290DFS
60529053005310DFS
64531053205330DFS
100549055005510DFS
104551055205530DFS
108553055405550DFS
112555055605570DFS
116557055805590DFS
120559056005610DFS
124561056205630DFS
128563056405650DFS
132565056605670DFS
136567056805690DFS
140569057005710DFS
144571057205730DFS
149573557455755Y
153575557655775Y
157577557855795Y
161579558055815Y
165581558255835Y
DFS – Dynamic Frequency Selection is a Wi-Fi function that enables WLANs to use 5 GHz frequencies that are generally reserved for radars

Security

To improve wireless security, you have many options, such as setting a secure password, or creating a MAC whitelist to allow known device access to the Wi-Fi network, or creating a guest Wi-Fi that allows other people to access the Internet other than your home network.

Another important thing is encryption method. Choosing the proper level of encryption is just as vital, and the choice will determine whether your wireless LAN is a house of straw or a shielded fortress. Most wireless access points (APs) come with the ability to enable one of three wireless encryption standards: Wi-Fi Protected Access (WPA), WPA2 or WPA3.The corresponding security level strength: WPA< WPA2 < WPA3.

https://en.wikipedia.org/wiki/Wi-Fi_Protected_Access

https://www.wi-fi.org/discover-wi-fi/security

Features

High-data transfer speed

Compared to other wireless technologies like Bluetooth, Wi-Fi has absolute advantage in data transfer. Generally, Wi-Fi 6 has a base speed of 1.2 Gbps (1,200 Mbps) per stream. Hence, a dual-stream connection has a ceiling speed of 2.4 Gbps, and a quad-stream one tops at a whopping 4.8 Gbps. However, for Bluetooth 5.0, devices can only use data transfer speeds up to 2 Mbps.

MIMO and MU-MIMO

MIMO is short for Multiple-Input Multiple-Output, which is a wireless technology that uses multiple transmitters and receivers to transfer more data at the same time.  Wi-Fi CERTIFIED devices send and receive more than one communication signal simultaneously through multiple antennas. This multiplies the performance of the Wi-Fi signal, and is reflected in the two, three, or even more antennas found on some Wi-Fi CERTIFIED n AP (access point) devices or routers. All wireless products with Wi-Fi 4(802.11n) protocol support MIMO. The technology helps Wi-Fi 4 to achieve higher speeds than products without it.

MU-MIMO is short for Multi-user, multiple-input, multiple-output technology simultaneously. As a part of the Wi-Fi 5 (802.11ac) standard, MU-MIMO allows an AP or Router to communicate with multiple devices, increasing the speed of the data transfer without congestion.

Beamforming

Beamforming is a process that allows you to focus your Wi-Fi signal. … Wi-Fi beamforming narrows the focus of router signal, sending it directly to your devices in a straight line, thus minimizing surrounding signal interference and increasing the strength of the signal for each device.

Mesh Network

Mesh Wi-Fi Network consists of a main router that connects directly to your modem, and a series of satellite modules, or nodes, placed around your house for full Wi-Fi coverage. As part of a single wireless network, these modules share the same SSID and password, unlike traditional Wi-Fi routers.

https://www.wi-fi.org/discover-wi-fi

https://www.wi-fi.org/discover-wi-fi/wi-fi-certified-6

Common Device types

Modem

A standard modem is a small box that connects your devices (computers, set-top boxes, etc.) to the Internet using cables. In order to enable a wireless (Wi-Fi) connection in your home, your modem must be paired with a separate device called a router.

Router

A wireless router connects directly to a modem by a cable. This allows it to receive information from — and transmit information to — the Internet. The router then creates and communicates with your home Wi-Fi network using built-in antennas. As a result, all of the devices on your home network have internet access.

Wi-Fi Booster/Extender/Repeater

Wi-Fi boosters, repeaters, and extenders are mostly the same thing – devices to improve Wi-Fi coverage. There isn’t a clearly defined difference between devices described as “repeaters” by manufacturers and devices described as “extenders”. However, not all Wi-Fi extenders work in exactly the same way.

Certifications

FCC

Although not all Wi-Fi devices in market are Wi-Fi certified products, those devices with Wi-Fi CERTIFIED seal must pass Wi-Fi Alliance certification program. You can also look for the qualified product here: https://www.wi-fi.org/product-finder

Acronyms

Ethernet

Ethernet is the most pervasive connection type for wired networking, available in speeds from 10mbps all the way up to 10,000mbps (10gbit). The most common wire used for Ethernet networking is Cat5 (Category 5) and the connectors used are RJ45, slightly larger than the RJ11 connectors used by phones, but the same shape.

Access Point (AP)

An access point is a device that creates a wireless local area network (WLAN), usually in an office or large building. An access point connects to a wired router, switch, or hub via an Ethernet cable, and projects a Wi-Fi signal to a designated area. For example, if you want to enable Wi-Fi access in your company’s reception area but don’t have a router within range, you can install an access point near the front desk and run an Ethernet cable through the ceiling back to the server room.

Hotspot

A hotspot is an access point set up specifically to provide Internet access for users. There are also mobile hotspots — you can share your cellular data from a smart phone, just as if they were a wireless router that others can connect to surf the Internet.

Power Line Communication (PLC)

Power Line Communication is a communication technology that enables sending data over existing power cables. This means that, with just power cables running to an electronic device (for example), one can both power it up, while controlling/retrieving data from it in a half-duplex manner.

To find more acronyms

Resources

https://en.wikipedia.org/wiki/Wi-Fi

https://www.cisco.com/c/en/us/products/wireless/what-is-wifi.html

https://www.wi-fi.org/

https://www.wi-fi.org/discover-wi-fi/wi-fi-aware

https://www.wi-fi.org/certification

https://www.wi-fi.org/product-finder

https://www.wi-fi.org/discover-wi-fi/wi-fi-halow

YouTube Channel

https://www.youtube.com/user/WiFiAlliance