A real-life situation
A company buys new "Wi-Fi 6" access points, but laptops on the second floor still connect at Wi-Fi 5 speeds. The APs are fine: those laptops have Wi-Fi 5 adapters, and a connection runs at the best standard both ends support. Knowing what each standard brings tells you what to expect from an upgrade.
The standards at a glance
| Standard | Wi-Fi name | Year | Bands | Max rate | Key addition |
|---|---|---|---|---|---|
| 802.11 | – | 1997 | 2.4 GHz | 2 Mbps | The original |
| 802.11b | – | 1999 | 2.4 GHz | 11 Mbps | DSSS; first popular Wi-Fi |
| 802.11a | – | 1999 | 5 GHz | 54 Mbps | OFDM on 5 GHz |
| 802.11g | – | 2003 | 2.4 GHz | 54 Mbps | OFDM on 2.4 GHz, compatible with b |
| 802.11n | Wi-Fi 4 | 2009 | 2.4 and 5 GHz | 600 Mbps | MIMO (up to 4 streams), 40 MHz channels |
| 802.11ac | Wi-Fi 5 | 2013 | 5 GHz | about 6.9 Gbps | 80/160 MHz, 256-QAM, downlink MU-MIMO |
| 802.11ax | Wi-Fi 6 | 2019 | 2.4 and 5 GHz | about 9.6 Gbps | OFDMA, 1024-QAM, uplink MU-MIMO, BSS colouring, TWT |
| 802.11ax | Wi-Fi 6E | 2020 | adds 6 GHz | about 9.6 Gbps | The same technology on the new 6 GHz band |
| 802.11be | Wi-Fi 7 | 2024 | 2.4, 5 and 6 GHz | about 46 Gbps | 320 MHz channels, 4096-QAM, multi-link operation |
What makes each generation faster
Every speed increase comes from one of four levers:
- Wider channels: 20 → 40 → 80 → 160 → 320 MHz. Twice the width, roughly twice the rate.
- Denser modulation: 64-QAM → 256 → 1024 → 4096-QAM, more bits per symbol (needs a better signal).
- More spatial streams: MIMO sends separate streams from separate antennas: 4 in Wi-Fi 4, 8 in Wi-Fi 5 and 6.
- Better sharing: MU-MIMO and OFDMA serve several clients at once instead of one after another.
- 20 MHz: 8 separate channels: most room for many APs
- 40 MHz: 4 channels, each about twice as fast
- 80 MHz: 2 channels: the usual home setting on 5 GHz
- 160 MHz: 1 channel: fastest, but uses the whole block
Wi-Fi 6 and 7 in more detail
- OFDMA (Wi-Fi 6): one transmission is split into resource units for several clients, which helps busy networks with many small packets.
- BSS colouring (Wi-Fi 6): each AP marks its frames with a colour, so devices can ignore distant cells on the same channel instead of waiting for them.
- Target Wake Time (Wi-Fi 6): clients and the AP agree when to wake, saving battery for phones and IoT devices.
- 6 GHz (Wi-Fi 6E): up to 1200 MHz of new spectrum, used only by new devices, and WPA3 is required.
- Multi-link operation (Wi-Fi 7): a device can use links in two or three bands at the same time, for more speed or reliability.
Why it works this way
Spectrum is limited and shared, so making Wi-Fi faster means using it more efficiently. Early standards improved how much data fits in a channel. Later ones improved how many devices can use the channel at once, because modern networks are limited more by the number of clients than by one client's speed.
Common mistakes
- Thinking 802.11ac works on 2.4 GHz. It is 5 GHz only; dual-band APs use 802.11n on 2.4 GHz.
- Expecting the headline rate in practice. Real throughput is much lower.
- Assuming an AP upgrade alone speeds up old clients. They keep their own standard.
💡 Exam tip: link the names: n = Wi-Fi 4, ac = Wi-Fi 5, ax = Wi-Fi 6/6E, be = Wi-Fi 7. Remember which bands each uses: b/g 2.4 GHz, a and ac 5 GHz, n and ax both, 6E adds 6 GHz.
Key takeaways
- 802.11n/ac/ax/be are Wi-Fi 4/5/6/7; 6E is 802.11ax on 6 GHz.
- Speed comes from wider channels, denser QAM, more spatial streams and better sharing.
- Wi-Fi 6 adds OFDMA, BSS colouring and TWT; Wi-Fi 7 adds 320 MHz channels and multi-link operation.
- A connection uses the best standard both the AP and the client support.
Check yourself
Which standard is marketed as Wi-Fi 5?
Which standard operates only in the 5 GHz band?
Which Wi-Fi 6 feature lets an AP serve several clients in a single transmission by dividing the channel?