*Wi‑Fi 0, 1, 2, and 3 are named by retroactive inference. They do not exist in the official nomenclature.[6][7][8]
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 802.11wireless networking standard released in 1997 and clarified in 1999. Most of the protocols described by this early version are rarely used today.
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.[9]
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.[citation needed]
^ abIEEE 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[update], it is only being licensed in the United States by the FCC.
^ abcdefghiBased on short guard interval; standard guard interval is ~10% slower. Rates vary widely based on distance, obstructions, and interference.
^ abcdefghFor 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.
^ abThe 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.
^802.11ac only specifies operation in the 5 GHz band. Operation in the 2.4 GHz band is specified by 802.11n.
^Wi-Fi 6E is the industry name that identifies Wi-Fi devices that operate in 6 GHz. Wi-Fi 6E offers the features and capabilities of Wi-Fi 6 extended into the 6 GHz band.
^The Wi-Fi Alliance began certifying Wi-Fi 7 devices in 2024, but as of December 2024 the IEEE standard 802.11be is yet to be ratified
^"What is Wi-Fi 8?". everythingrf.com. March 25, 2023. Retrieved January 21, 2024.
^Giordano, Lorenzo; Geraci, Giovanni; Carrascosa, Marc; Bellalta, Boris (November 21, 2023). "What Will Wi-Fi 8 Be? A Primer on IEEE 802.11bn Ultra High Reliability". arXiv:2303.10442.
^IEEE Standard for Information Technology- Telecommunications and Information Exchange Between Systems- Local and Metropolitan Area Networks- Specific Requirements Part Ii: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications. (n.d.). doi:10.1109/ieeestd.2003.94282
IEEE 802.11 Working Group (1997-11-18). IEEE Standard for Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications. doi:10.1109/IEEESTD.1997.85951. ISBN1-55937-935-9.{{cite book}}: CS1 maint: numeric names: authors list (link)
IEEE 802.11 Working Group (1999-07-15). IEEE Standard for Information Technology- Telecommunications and Information Exchange Between Systems- Local and Metropolitan Area Networks- Specific Requirements- Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications. doi:10.1109/IEEESTD.2003.95617. ISBN0-7381-1857-5.{{cite book}}: CS1 maint: numeric names: authors list (link)
