The old tablet on new Wi-Fi
A school buys a new Wi-Fi system that promises great speed. But an old tablet in the library is still slow.
The tablet is an old model. It cannot use the new standard, so it falls back to an older, slower one.
To plan Wi-Fi, you must know the standards.
Key words
| Word | What it means |
|---|---|
| Wi-Fi | joining devices with radio waves and no cables, set out in the 802.11 standards |
| Standard | an agreed set of rules, so devices from different makers work together |
| 802.11 | the family of standards for Wi-Fi, with a letter at the end for each version |
| Frequency band | a range of radio waves used for Wi-Fi, such as 2.4 GHz |
| GHz | gigahertz, a measure of how fast a radio wave changes |
| Mbps | megabits per second, a measure of speed |
| Gbps | gigabits per second, one thousand megabits per second |
| Backwards compatible | able to work with older devices that use an older standard |
| Interference | unwanted noise that damages a signal |
| Access point | a device that gives Wi-Fi to nearby devices |
The cells students fill in are left blank in this preview.
By the end of this lesson
Note
I can name the Wi-Fi standards from 802.11b to Wi-Fi 7, say which bands they use, and put them in order of speed.
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3 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.
Three frequency bands
Wi-Fi uses radio frequency bands. Each band is a range of radio waves.
2.4 GHz goes furthest and passes through walls well. It is slower and crowded, because many gadgets use it.
5 GHz is faster and less crowded. Its range is shorter.
6 GHz is the newest band. It is fast and clear, with the shortest range, and needs newer devices.
The standards, oldest first
| Standard | Brand name | Year | Band | Top speed in theory |
|---|---|---|---|---|
| 802.11b | None | 1999 | 2.4 GHz | 11 Mbps |
| 802.11g | None | 2003 | 2.4 GHz | 54 Mbps |
| 802.11n | Wi-Fi 4 | 2009 | 2.4 and 5 GHz | 600 Mbps |
| 802.11ac | Wi-Fi 5 | 2013 | 5 GHz | Several Gbps |
| 802.11ax | Wi-Fi 6 (and 6E) | 2019 | 2.4 and 5 GHz, and 6 GHz for 6E | Up to about 9.6 Gbps |
| 802.11be | Wi-Fi 7 | 2024 | 2.4, 5 and 6 GHz | Up to about 46 Gbps |
The cells students fill in are left blank in this preview.
Real speeds are lower
Important
The top speeds are the most a standard allows in perfect conditions. Real speeds are lower: walls, distance, noise and other users all slow a link. Always read "up to" as a ceiling.
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4 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.