IEEE 802.11 (legacy mode)

Wireless networking standard From Wikipedia, the free encyclopedia

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.

More information Gen., IEEE standard ...
Wi-Fi and IEEE 802.11 generations
Gen.[1][2] IEEE
standard		 Adopt. Link rate
(Mbit/s)		 RF (GHz)
2.4 5 6
— 802.11 1997 1–2 Yes
802.11b 1999 1–11 Yes
802.11a 6–54 Yes
802.11g 2003 Yes
Wi-Fi 4 802.11n 2009 6.5–600 Yes Yes
Wi-Fi 5 802.11ac 2013 6.5–6,933 [a] Yes
Wi-Fi 6 802.11ax 2021 0.4–9,608 Yes Yes
Wi-Fi 6E Yes Yes Yes
Wi-Fi 7 802.11be 2024 0.4–23,059 Yes Yes Yes
Wi-Fi 8[3][4][5] 802.11bn TBA Yes Yes Yes
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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.[citation needed]

The original standard also defines carrier sense multiple 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.[6]

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]

Comparison

More information Frequency range, or type, PHY ...
802.11 network standards
Frequency
range,
or type		 PHY Protocol Release
date[7]		 Freq­uency band Channel width Stream
data rate[8]		 Max.
MIMO streams		 Modulation Approx. range
In­door Out­door
(GHz) (MHz) (Mbit/s)
1–7 GHz DSSS[9], FHSS[A] 802.11-1997 June 1997 2.4 22 1, 2 N/a DSSS, FHSS[A] 20 m (66 ft) 100 m (330 ft)
HR/DSSS[9] 802.11b September 1999 2.4 22 1, 2, 5.5, 11 N/a CCK, DSSS 35 m (115 ft) 140 m (460 ft)
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)		 N/a OFDM 35 m (115 ft) 120 m (390 ft)
802.11j November 2004 4.9, 5.0
[B][10]		 ? ?
802.11y November 2008 3.7[C] ? 5,000 m (16,000 ft)[C]
802.11p July 2010 5.9 200 m 1,000 m (3,300 ft)[11]
802.11bd December 2022 5.9, 60 500 m 1,000 m (3,300 ft)
ERP-OFDM[12] 802.11g June 2003 2.4 38 m (125 ft) 140 m (460 ft)
HT-OFDM[13] 802.11n
(Wi-Fi 4)		 October 2009 2.4, 5 20 Up to 288.8[D] 4 MIMO-OFDM
(64-QAM)		 70 m (230 ft) 250 m (820 ft)[14]
40 Up to 600[D]
VHT-OFDM[13] 802.11ac
(Wi-Fi 5)		 December 2013 5 20 Up to 693[D] 8 DL
MU-MIMO OFDM
(256-QAM)		 35 m (115 ft)[15] ?
40 Up to 1,600[D]
80 Up to 3,467[D]
160 Up to 6,933[D]
HE-OFDMA 802.11ax
(Wi-Fi 6,
Wi-Fi 6E)		 May 2021 2.4, 5, 6 20 Up to 1,147[E] 8 UL/DL
MU-MIMO OFDMA
(1024-QAM)		 30 m (98 ft) 120 m (390 ft)[F]
40 Up to 2,294[E]
80 Up to 5,500[E]
80+80 Up to 11,000[E]
EHT-OFDMA 802.11be
(Wi-Fi 7)		 Sep 2024 2.4, 5, 6 80 Up to 5,764[E] 8 UL/DL
MU-MIMO OFDMA
(4096-QAM)		 30 m (98 ft) 120 m (390 ft)[F]
160
(80+80)		 Up to 11,500[E]
240
(160+80)		 Up to 14,282[E]
320
(160+160)		 Up to 23,059[E]
UHR 802.11bn
(Wi-Fi 8)		 May 2028
(est.)		 2.4, 5, 6 320 Up to
23,059
8 Multi-link
MU-MIMO OFDM
(4096-QAM)		 ? ?
WUR[G] 802.11ba October 2021 2.4, 5 4, 20 0.0625, 0.25
(62.5 kbit/s, 250 kbit/s)		 N/a OOK (multi-carrier OOK) ? ?
mmWave
(WiGig)		 DMG[16] 802.11ad December 2012 60 2,160
(2.16 GHz)		 Up to 8,085[17]
(8 Gbit/s)		 N/a OFDM,[A] single carrier, low-power single carrier[A] 3.3 m (11 ft)[18] ?
802.11aj April 2018 60[H] 1,080[19] Up to 3,754
(3.75 Gbit/s)		 N/a single carrier, low-power single carrier[A] ? ?
CMMG 802.11aj April 2018 45[H] 540,
1,080		 Up to 15,015[20]
(15 Gbit/s)		 4[21] OFDM, single carrier ? ?
EDMG[22] 802.11ay July 2021 60 Up to 8,640
(8.64 GHz)		 Up to 303,336[23]
(303 Gbit/s)		 8 OFDM, single carrier 10 m (33 ft) 100 m (328 ft)
Sub 1 GHz (IoT) TVHT[24] 802.11af February 2014 0.054–
0.79		 6, 7, 8 Up to 568.9[25] 4 MIMO-OFDM ? ?
S1G[24] 802.11ah May 2017 0.7, 0.8,
0.9		 1–16 Up to 8.67[26]
(@2 MHz)		 4 ? ?
Light
(Li-Fi)		 LC
(VLC/OWC)		 802.11bb November 2023 800–1000 nm 20 Up to 9.6 Gbit/s N/a O-OFDM ? ?
IR[A]
(IrDA)		 802.11-1997 June 1997 850–900 nm ? 1, 2 N/a PPM[A] ? ?
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[D] DSSS, OFDM
802.11-2016 (802.11mc) December 2016 2.4, 5, 60 Up to 866.7 or 6,757[D] DSSS, OFDM
802.11-2020 (802.11md) December 2020 2.4, 5, 60 Up to 866.7 or 6,757[D] DSSS, OFDM
802.11-2024 (802.11me) September 2024 2.4, 5, 6, 60 Up to 9,608 or 303,336 DSSS, OFDM
  1. [A]
    This is obsolete, and support for this might be subject to removal in a future revision of the standard
  2. [B]
    For Japanese regulation.
  3. [C]
    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.
  4. [D]
    Based on short guard interval; standard guard interval is ~10% slower. Rates vary widely based on distance, obstructions, and interference.
  5. [E]
    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.
  6. [F]
    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.
  7. [G]
    Wake-up Radio (WUR) Operation.
  8. [H]
    For Chinese regulation.
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Notes

  1. [a]
    802.11ac only specifies operation in the 5 GHz band. Operation in the 2.4 GHz band is specified by 802.11n.

References

Further reading

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