# IEEE 802.11 (legacy mode)

Wi-Fi generationsvte :
| Generation | IEEE standard | Adopted | Maximum link rate (Mb/s) | Radio frequency (GHz) |
| (Wi-Fi 0*) | 802.11 | 1997 | 1–2 | 2.4 |
| (Wi-Fi 1*) | 802.11b | 1999 | 1–11 | 2.4 |
| (Wi-Fi 2*) | 802.11a | 1999 | 6–54 | 5 |
| (Wi-Fi 3*) | 802.11g | 2003 | 6–54 | 2.4 |
| Wi-Fi 4 | 802.11n | 2009 | 6.5–600 | 2.4, 5 |
| Wi-Fi 5 | 802.11ac | 2013 | 6.5–6933 | 5 |
| Wi-Fi 6 | 802.11ax | 2021 | 0.4–9608 | 2.4, 5 |
| Wi-Fi 6E | 802.11ax | 2021 | 0.4–9608 | 2.4, 5, 6 |
| Wi-Fi 7 | 802.11be | exp. 2024 | 0.4–23,059 | 2.4, 5, 6 |
| Wi-Fi 8 | 802.11bn | exp. 2028 | 100,000 | 2.4, 5, 6 |
| *Wi‑Fi 0, 1, 2, and 3 are named by retroactive inference. They do not exist in the official nomenclature. |||||
IEEE 802.11 (legacy mode) – or more correctly IEEE 802.11-1997 or IEEE 802.11-1999 – refers to the original version of the IEEE 802.11 wireless networking standard released in 1997 and clarified in 1999. Most of the protocols described by this early version are rarely used today.

## Description

It specified two raw data rates of 1 and 2 megabits per second (Mbit/s) to be transmitted via infrared (IR) signals or by either frequency hopping or direct-sequence spread spectrum (DSSS) in the Industrial Scientific Medical frequency band at 2.4 GHz. IR remained a part of the standard until IEEE 802.11-2016, but was never implemented.
The original standard also defines carrier sense 0 access with collision avoidance (CSMA/CA) as the medium access method. A significant percentage of the available raw channel capacity is sacrificed (via the CSMA/CA mechanisms) in order to improve the reliability of data transmissions under diverse and adverse environmental conditions.
IEEE 802.11-1999 also introduced the binary time unit TU defined as 1024 μs.
At least seven different, somewhat-interoperable, commercial products appeared using the original specification, from companies like Alvarion (PRO.11 and BreezeAccess-II), BreezeCom, Digital / Cabletron (RoamAbout), Lucent, Netwave Technologies (AirSurfer Plus and AirSurfer Pro), Symbol Technologies (Spectrum24), and Proxim Wireless (OpenAir and Rangelan2). A weakness of this original specification was that it offered so many choices that interoperability was sometimes challenging to realize. It is really more of a "beta specification" than a rigid specification, initially allowing individual product vendors the flexibility to differentiate their products but with little to no inter-vendor interoperability.
The DSSS version of legacy 802.11 was rapidly supplemented (and popularized) by the 802.11b amendment in 1999, which increased the bit rate to 11 Mbit/s. Widespread adoption of 802.11 networks only occurred after the release of 802.11b which resulted in multiple interoperable products becoming available from multiple vendors. Consequently, comparatively few networks were implemented on the 802.11-1997 standard.

## Comparison

vte802.11 network standards :
| Frequency range, or type | PHY | Protocol | Release date | Freq­uency | Bandwidth | Stream data rate | Max. MIMO streams | Modulation | Approx. range | Approx. range |
| Frequency range, or type | PHY | Protocol | Release date | Freq­uency | Bandwidth | Stream data rate | Max. MIMO streams | Modulation | In­door | Out­door |
| Frequency range, or type | PHY | Protocol | Release date | (GHz) | (MHz) | (Mbit/s) | Max. MIMO streams | Modulation | In­door | Out­door |
| 1–7 GHz | DSSS, FHSS | 802.11-1997 | June 1997 | 2.4 | 22 | 1, 2 | — | DSSS, FHSS | 20 m (66 ft) | 100 m (330 ft) |
| 1–7 GHz | HR/DSSS | 802.11b | September 1999 | 2.4 | 22 | 1, 2, 5.5, 11 | — | CCK, DSSS | 35 m (115 ft) | 140 m (460 ft) |
| 1–7 GHz | OFDM | 802.11a | September 1999 | 5 | 5, 10, 20 | 6, 9, 12, 18, 24, 36, 48, 54 (for 20 MHz bandwidth, divide by 2 and 4 for 10 and 5 MHz) | — | OFDM | 35 m (115 ft) | 120 m (390 ft) |
| 1–7 GHz | OFDM | 802.11j | November 2004 | 4.9, 5.0 | 5, 10, 20 | 6, 9, 12, 18, 24, 36, 48, 54 (for 20 MHz bandwidth, divide by 2 and 4 for 10 and 5 MHz) | — | OFDM | ? | ? |
| 1–7 GHz | OFDM | 802.11y | November 2008 | 3.7 | 5, 10, 20 | 6, 9, 12, 18, 24, 36, 48, 54 (for 20 MHz bandwidth, divide by 2 and 4 for 10 and 5 MHz) | — | OFDM | ? | 5,000 m (16,000 ft) |
| 1–7 GHz | OFDM | 802.11p | July 2010 | 5.9 | 5, 10, 20 | 6, 9, 12, 18, 24, 36, 48, 54 (for 20 MHz bandwidth, divide by 2 and 4 for 10 and 5 MHz) | — | OFDM | 200 m | 1,000 m (3,300 ft) |
| 1–7 GHz | OFDM | 802.11bd | December 2022 | 5.9, 60 | 5, 10, 20 | 6, 9, 12, 18, 24, 36, 48, 54 (for 20 MHz bandwidth, divide by 2 and 4 for 10 and 5 MHz) | — | OFDM | 500 m | 1,000 m (3,300 ft) |
| 1–7 GHz | ERP-OFDM | 802.11g | June 2003 | 2.4 | 5, 10, 20 | 6, 9, 12, 18, 24, 36, 48, 54 (for 20 MHz bandwidth, divide by 2 and 4 for 10 and 5 MHz) | — | OFDM | 38 m (125 ft) | 140 m (460 ft) |
| 1–7 GHz | HT-OFDM | 802.11n (Wi-Fi 4) | October 2009 | 2.4, 5 | 20 | Up to 288.8 | 4 | MIMO-OFDM (64-QAM) | 70 m (230 ft) | 250 m (820 ft) |
| 1–7 GHz | HT-OFDM | 802.11n (Wi-Fi 4) | October 2009 | 2.4, 5 | 40 | Up to 600 | 4 | MIMO-OFDM (64-QAM) | 70 m (230 ft) | 250 m (820 ft) |
| 1–7 GHz | VHT-OFDM | 802.11ac (Wi-Fi 5) | December 2013 | 5 | 20 | Up to 693 | 8 | DL MU-MIMO OFDM (256-QAM) | 35 m (115 ft) | ? |
| 1–7 GHz | VHT-OFDM | 802.11ac (Wi-Fi 5) | December 2013 | 5 | 40 | Up to 1600 | 8 | DL MU-MIMO OFDM (256-QAM) | 35 m (115 ft) | ? |
| 1–7 GHz | VHT-OFDM | 802.11ac (Wi-Fi 5) | December 2013 | 5 | 80 | Up to 3467 | 8 | DL MU-MIMO OFDM (256-QAM) | 35 m (115 ft) | ? |
| 1–7 GHz | VHT-OFDM | 802.11ac (Wi-Fi 5) | December 2013 | 5 | 160 | Up to 6933 | 8 | DL MU-MIMO OFDM (256-QAM) | 35 m (115 ft) | ? |
| 1–7 GHz | HE-OFDMA | 802.11ax (Wi-Fi 6, Wi-Fi 6E) | May 2021 | 2.4, 5, 6 | 20 | Up to 1147 | 8 | UL/DL MU-MIMO OFDMA (1024-QAM) | 30 m (98 ft) | 120 m (390 ft) |
| 1–7 GHz | HE-OFDMA | 802.11ax (Wi-Fi 6, Wi-Fi 6E) | May 2021 | 2.4, 5, 6 | 40 | Up to 2294 | 8 | UL/DL MU-MIMO OFDMA (1024-QAM) | 30 m (98 ft) | 120 m (390 ft) |
| 1–7 GHz | HE-OFDMA | 802.11ax (Wi-Fi 6, Wi-Fi 6E) | May 2021 | 2.4, 5, 6 | 80 | Up to 5.5 Gbit/s | 8 | UL/DL MU-MIMO OFDMA (1024-QAM) | 30 m (98 ft) | 120 m (390 ft) |
| 1–7 GHz | HE-OFDMA | 802.11ax (Wi-Fi 6, Wi-Fi 6E) | May 2021 | 2.4, 5, 6 | 80+80 | Up to 11.0 Gbit/s | 8 | UL/DL MU-MIMO OFDMA (1024-QAM) | 30 m (98 ft) | 120 m (390 ft) |
| 1–7 GHz | EHT-OFDMA | 802.11be (Wi-Fi 7) | Sep 2024 (est.) | 2.4, 5, 6 | 80 | Up to 11.5 Gbit/s | 16 | UL/DL MU-MIMO OFDMA (4096-QAM) | 30 m (98 ft) | 120 m (390 ft) |
| 1–7 GHz | EHT-OFDMA | 802.11be (Wi-Fi 7) | Sep 2024 (est.) | 2.4, 5, 6 | 160 (80+80) | Up to 23 Gbit/s | 16 | UL/DL MU-MIMO OFDMA (4096-QAM) | 30 m (98 ft) | 120 m (390 ft) |
| 1–7 GHz | EHT-OFDMA | 802.11be (Wi-Fi 7) | Sep 2024 (est.) | 2.4, 5, 6 | 240 (160+80) | Up to 35 Gbit/s | 16 | UL/DL MU-MIMO OFDMA (4096-QAM) | 30 m (98 ft) | 120 m (390 ft) |
| 1–7 GHz | EHT-OFDMA | 802.11be (Wi-Fi 7) | Sep 2024 (est.) | 2.4, 5, 6 | 320 (160+160) | Up to 46.1 Gbit/s | 16 | UL/DL MU-MIMO OFDMA (4096-QAM) | 30 m (98 ft) | 120 m (390 ft) |
| 1–7 GHz | UHR | 802.11bn (Wi-Fi 8) | May 2028 (est.) | 2.4, 5, 6, 42, 60, 71 | 320 | Up to 100000 (100 Gbit/s) | 16 | Multi-link MU-MIMO OFDM (8192-QAM) | ? | ? |
| 1–7 GHz | WUR | 802.11ba | October 2021 | 2.4, 5 | 4, 20 | 0.0625, 0.25 (62.5 kbit/s, 250 kbit/s) | — | OOK (multi-carrier OOK) | ? | ? |
| mmWave (WiGig) | DMG | 802.11ad | December 2012 | 60 | 2160 (2.16 GHz) | Up to 8085 (8 Gbit/s) | — | OFDM, single carrier, low-power single carrier | 3.3 m (11 ft) | ? |
| mmWave (WiGig) | DMG | 802.11aj | April 2018 | 60 | 1080 | Up to 3754 (3.75 Gbit/s) | — | single carrier, low-power single carrier | ? | ? |
| mmWave (WiGig) | CMMG | 802.11aj | April 2018 | 45 | 540, 1080 | Up to 15015 (15 Gbit/s) | 4 | OFDM, single carrier | ? | ? |
| mmWave (WiGig) | EDMG | 802.11ay | July 2021 | 60 | Up to 8640 (8.64 GHz) | Up to 303336 (303 Gbit/s) | 8 | OFDM, single carrier | 10 m (33 ft) | 100 m (328 ft) |
| Sub 1 GHz (IoT) | TVHT | 802.11af | February 2014 | 0.054– 0.79 | 6, 7, 8 | Up to 568.9 | 4 | MIMO-OFDM | ? | ? |
| Sub 1 GHz (IoT) | S1G | 802.11ah | May 2017 | 0.7, 0.8, 0.9 | 1–16 | Up to 8.67 (@2 MHz) | 4 | MIMO-OFDM | ? | ? |
| Light (Li-Fi) | LC (VLC/OWC) | 802.11bb | December 2023 (est.) | 800–1000 nm | 20 | Up to 9.6 Gbit/s | — | O-OFDM | ? | ? |
| Light (Li-Fi) | IR (IrDA) | 802.11-1997 | June 1997 | 850–900 nm | ? | 1, 2 | — | PPM | ? | ? |
| 802.11 Standard rollups |||||||||||
| | | 802.11-2007 (802.11ma) | March 2007 | 2.4, 5 | | Up to 54 | | DSSS, OFDM | | |
| | | 802.11-2012 (802.11mb) | March 2012 | 2.4, 5 | | Up to 150 | | DSSS, OFDM | | |
| | | 802.11-2016 (802.11mc) | December 2016 | 2.4, 5, 60 | | Up to 866.7 or 6757 | | DSSS, OFDM | | |
| | | 802.11-2020 (802.11md) | December 2020 | 2.4, 5, 60 | | Up to 866.7 or 6757 | | DSSS, OFDM | | |
| | | 802.11me | September 2024 (est.) | 2.4, 5, 6, 60 | | Up to 9608 or 303336 | | DSSS, OFDM | | |
| 1 2 3 4 5 6 7 This is obsolete, and support for this might be subject to removal in a future revision of the standard ↑ For Japanese regulation. 1 2 IEEE 802.11y-2008 extended operation of 802.11a to the licensed 3.7 GHz band. Increased power limits allow a range up to 5,000 m. As of 2009, it is only being licensed in the United States by the FCC. 1 2 3 4 5 6 7 8 9 Based on short guard interval; standard guard interval is ~10% slower. Rates vary widely based on distance, obstructions, and interference. 1 2 3 4 5 6 7 8 For single-user cases only, based on default guard interval which is 0.8 microseconds. Since multi-user via OFDMA has become available for 802.11ax, these may decrease. Also, these theoretical values depend on the link distance, whether the link is line-of-sight or not, interferences and the multi-path components in the environment. 1 2 The default guard interval is 0.8 microseconds. However, 802.11ax extended the maximum available guard interval to 3.2 microseconds, in order to support Outdoor communications, where the maximum possible propagation delay is larger compared to Indoor environments. ↑ Wake-up Radio (WUR) Operation. 1 2 For Chinese regulation. |||||||||||