Wi-Fi has changed shape many times since 1997. Each generation kept what worked and added one or two ideas. This topic maps those ideas and the headline speeds they allow.
1. DefinitionStandards, amendments and names
- IEEE 802.11 is the family of standards. Each new feature is an amendment (802.11b, g, n, ac, ax, be) which is later merged into a new revision of the base standard.
- Wi-Fi Alliance names: Wi-Fi 4 (802.11n), Wi-Fi 5 (802.11ac), Wi-Fi 6 (802.11ax), Wi-Fi 6E (Wi-Fi 6 in 6 GHz) and Wi-Fi 7 (802.11be). Older generations never had an official brand.
- Certification by the Wi-Fi Alliance tests that devices interoperate. A standard being approved and a product being certified are separate events with different dates.
2. PurposeWhy there is a new generation
Every generation answers a limit of the one before: 802.11b needed more speed, 802.11g brought OFDM to 2.4 GHz, 802.11n added antennas, 802.11ac widened channels, 802.11ax fixed crowded networks, and 802.11be adds multi-link operation and very wide channels. A newer access point improves the experience of older clients less than people expect, because each client uses the best generation it supports.
3. MechanismExplore the generations
Click a generation to see its properties and how its top speed is built. Use the feature buttons to dim the generations that lack a feature.
4. VisualWhat each generation added
| Generation | Approved | New in this generation |
|---|---|---|
| 802.11b | 1999 | CCK, 5.5 and 11 Mbit/s in 2.4 GHz |
| 802.11a | 1999 | OFDM in 5 GHz, 54 Mbit/s |
| 802.11g | 2003 | OFDM in 2.4 GHz, compatible with 802.11b |
| 802.11n (Wi-Fi 4) | 2009 | MIMO (4 streams), 40 MHz channels, frame aggregation |
| 802.11ac (Wi-Fi 5) | 2013 | 80 and 160 MHz channels, 256-QAM, downlink MU-MIMO, 5 GHz only |
| 802.11ax (Wi-Fi 6, 6E) | 2021 | OFDMA, 1024-QAM, uplink MU-MIMO, BSS colouring, target wake time, 6 GHz |
| 802.11be (Wi-Fi 7) | 2024 | 320 MHz channels, 4096-QAM, multi-link operation, multi-RU and puncturing, 16 streams |
Approval dates are from the IEEE 802.11 Working Group timelines; 802.11ac was approved in December 2013. 802.11bn (the working name for a following amendment, aimed at reliability) is in development.
5. MathematicsHow a headline speed is built
Highest rate = data subcarriers × bits per subcarrier × coding rate × spatial streams / symbol time, with the widest channel, the highest modulation and the most streams. For example:
- 802.11a/g: 48 × 6 × 3/4 / 4 µs = 54 Mbit/s.
- 802.11n: 108 × 6 × 5/6 × 4 / 3.6 µs = 600 Mbit/s (40 MHz, 4 streams, short guard interval).
- 802.11ac: 468 × 8 × 5/6 × 8 / 3.6 µs = 6933 Mbit/s (160 MHz, 8 streams).
- 802.11ax: 1960 × 10 × 5/6 × 8 / 13.6 µs = 9608 Mbit/s (160 MHz, 8 streams).
- 802.11be: 3920 × 12 × 5/6 × 16 / 13.6 µs = 46 118 Mbit/s (320 MHz, 16 streams).
Read the number with care. These are theoretical physical-layer rates. A real phone with two antennas on an 80 MHz channel reaches a small fraction, and the airtime model in the MAC topic shows that about half of any link rate goes on overhead.
6. Real-world behaviourWhat users actually see
- The client limits the link. Most phones have two antennas and a modest channel width, so the generation of the access point matters less than the client’s.
- Backward compatibility has a cost. Legacy rates and protection mechanisms use airtime. Turning off old rates in a network with only modern clients helps everyone.
- Bands matter as much as generations. 6 GHz is only for 802.11ax and newer, which is why Wi-Fi 6E networks have no legacy clients.
- Features need both ends. OFDMA, MU-MIMO, MLO and 4096-QAM only work when the client supports them too.
Practical validationProve it in a capture and on a spectrum analyser
Reading about a band is one thing; seeing it in your own evidence is the skill. These checks work with any monitor-mode capture:
- In a beacon or an association request, find the HT Capabilities, VHT Capabilities and HE Capabilities elements to see which generations a device supports.
- Compare the rates a 2×2 phone reaches on the same access point in 20, 40 and 80 MHz channels.
- Question to answer: why is the highest 802.11ac rate in this topic not reachable on 2.4 GHz?
Check your understandingQuick quiz
ReferencesSources and further reading
- IEEE 802.11 Working Group
- IEEE 802.11 Working Group: standards timelines (approval and publication dates)
- Wi-Fi Alliance: “Wi-Fi 6E” name introduced (3 January 2020)
- Wi-Fi Alliance: Wi-Fi CERTIFIED 7 (8 January 2024)
- Wi-Fi Alliance: Wi-Fi CERTIFIED 7
- Wi-Fi Alliance: specifications
Approval dates follow the IEEE 802.11 Working Group timelines (802.11ac: December 2013). The highest rates are computed from the numerology of each PHY (clauses 17, 19 and 21 of IEEE Std 802.11-2020 for a/g/n/ac; the 802.11ax and 802.11be figures follow from the same relationships and amendments).