May 23, 2024

IEEE 802.11 WiFi STANDARDS

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IEEE 802.11wifi standards

IEEE 802.11 Standards is a part of IEEE 802 which is popularly known as WiFi used in Network connectivity. Many 802.11 wifi standards were introduced depending on the need.

IEEE 802.11 wifi standard

  1. IEEE 802.11standard was the original version released in 1997. ​
  2. It has two variations both having the same speed but it uses different RF spread spectrums.​
  3. IEEE 802.11 Standard uses either frequency-hopping spread spectrum (FHSS) or direct-sequence spread spectrum (DSSS) transmission scheme for transmitting the data.
  4. It provides a 1 Mbps or 2 Mbps data rate in the 2.4 GHz band with three non-overlapping channels.​

IEEE 802.11b​ WiFi standard

  1. 802.11b was released in July 1999.​
  2. It supports 2.4GHz radio frequency with a maximum data rate of 11Mbps at 20MHz bandwidth with Three non-overlapping channels.​
  3. It uses a High-rate direct-sequence spread spectrum (HR-DSSS) Transmission scheme with the QPSK modulation technique.​
  4. 802.11b uses CCK (Complementary Code Keying) for encoding the data for communications.​
  5. Uses single user single input single output antennas(SU-SISO)​.
  6. Distance Cover: 38m(indoor) & 140 (out).​

IEEE 802.11a WiFi standard

  1. 802.11 a was introduced in 1999.​
  2. It supports 5GHz radio frequency with a maximum theoretical data rate of 54 Mbps in 20MHz bandwidth with 12 non-overlapping channels.​
  3. The data rate decreases automatically from the maximum of 54Mbps to minimum of 6 Mbps(54/48/36/24/12/9/6 Mbps) to a maintain the connectivity when a client is moving away from the Access point
  4. With an increase in the distance or attenuation, the data rates also decrease.
  5. It uses the orthogonal frequency-division multiplexing (OFDM) transmission technique with 52 sub-carrier channels having maximum modulation of 64QAM.​
  6. Uses single user single input single output antennas(SU-SISO)​
  7. Distance Cover: 35m (Indoor) & 120 m (outdoor)​
  8. This standard was made to avoid interference with other devices which uses a 2.4GHz radio frequency.​

IEEE 802.11g WiFi standard

  1. 802.11g was introduced in 2003.​
  2. It supports 2.4GHz radio frequency with maximum data rates of 54Mbps in 20MHz bandwidth with 3 non-overlapping channels.​
  3. It uses the orthogonal frequency-division multiplexing (OFDM) transmission technique with 52 sub-carrier channels having maximum modulation of 64QAM.​
  4. Uses single user single input single output antennas(SU-SISO)​
  5. It is also backward compatible with 802.11b using DSSS and CCK.​
  6. Distance Cover: 38m(indoor) & 140 (out).​

IEEE 802.11n WiFi standard

  1. 802.11n was published in 2009.​
  2. It has made a big change in wireless networks.​
  3. It supports both 2.4GHz and 5GHz radio Frequencies with the max data rate of 600Mbps in 40MHz of 4×4 spatial streams.​
  4. The main purpose of this standard is to improve network throughput from 54Mbps to 72.2Mbps in a 1×1 spatial stream of 20MHz bandwidth.​
  5. Uses single user multiple input multiple output antennas (SU-MIMO)​
  6. Distance Cover: 38m(indoor) & 140 (out)​
  7. Backward capability with 802.11 a/b/g.​

Features Included in IEEE 802.11n​ standard :

Single user multiple input, multiple output antennas(SU-MIMO)​

 2. Frame aggregation A-MPDU & A-MSDU​

 3. Channel bonding (40MHz channels)​

 4. Block Acknowledgments (BLOCK ACK)​

 5. Short Guard Interval (short GI)​

 6. 802.11n interoperability (HT mode)​

 7. RIFS (Reduced inter-framespacing)​

 8. HT power management​

IEEE 802.11ac WiFi standard

  1. 802.11 ac was released in two waves.​
  2. 802.11ac wave1 was released in Jan 2014 and wave2 was released in June 2016.​
  3. WiFi 5 is a standard for Very High Throughput (Very High Throughput) applications​
  4. It supports 5GHz radio frequency with 24 non-overlapping having maximum data rates of 6.9Gbps in 160MHz bandwidth at 8×8 spatial streams.​
  5. It was the first WiFi standard developed that could theoretically achieve gigabit speeds as opposed to megabit speeds.​

Features Included in IEEE 802.11ac​ standard :

  1. Wider WiFi Channels ​
  2. Channel Bonding (can combine 8 of these to obtain a 160 MHz channel for a single client)​
  3. Downlink MU-MIMO – Multiple-Input Multiple-Output ​
  4. Maximum Spatial Streams(8×8)​
  5. Explicit beam forming​
  6. More Data Transfer with 256-QAM ​
  7. 400-ns (nanosecond) short guard interval.

The following table indicates two waves of IEEE 802.11ac overview :

IEEE 802.11ac key featuresWave 1Wave 2
Wifi channel bandwidth20/40/80MHz20/40/80/160MHz
MIMOSU-MIMOMU-MIMO
Spatial streams48
Beam forming explicit Beam forming onlyexplicit Beam forming only
QAM256 QAM256 QAM
Frequency Bands5GHz5GHz
Difference of wave1 and wave 2 in 802.11ac

Difference between IEEE 802.11n and IEEE 802.11ac​ standards

IEEE 802.11n​IEEE 802.11ac
802.11n supports 2.4 GHz and 5 GHz radio frequency bands with 20 and 40 MHz bandwidth802.11ac supports 5 GHz radio frequency with 20, 40, 80, 80+80 and 160 MHz bandwidth ​
It supports BPSK, QPSK, 16-QAM, and 64-QAM​It supports BPSK, QPSK, 16-QAM, 64-QAM and 256-QAM​
Supports SU-MIMO​It supports MU-MIMO​
It supports many versions of beamforming​Supports only explicit beam forming (null data packet)​
It supports up to four spatial streams​AP supports up to eight spatial streams and client supIEEE 802.11 Wi-fi STANDARDSports up to four spatial streams​
Supports single-user transmission only​It supports single-user and multi-user transmission​
It includes significant MAC enhancements like A-MSDU and A-MPDU​It supports similar MAC enhancements with high data rates Like A-MPDU and A-MSDU.​
Max Theoretical speed of 600Mbps​Max Theoretical speed of 6.9Gbps​

IEEE 802.11ax WiFi standard

  1. 802.11ax Wi-Fi standard is also known as Wi-Fi 6.​
  2. It uses 2.4GHz 5Ghz and 6GHz radio frequencies with maximum data rates of 9.6Gbps at 160MHz bandwidth with 8×8 spatial streams.​
  3. It supports OFDMA with 1024QAM  maximum frequency modulation.​
  4. Bandwidth: 20MHZ,40MHZ,80MHZ,160MHZ.​

Features of IEEE 802.11ax Features​ :

  • Introduced OFDMA(Orthogonal frequency division multiple access)​
  • BSS coloring​
  • Supports Down-link and up-link in OFDMA​
  • Downlink and uplink multi-user MIMO​
  • Transmit beamforming​
  • Higher-order modulation​
  • OFDMA with 1024 QAM​
  • Long Symbol Time and Guard Intervals​
  • Target wake time (TWT) power-saving mechanism​
  • Dual NAV timers​
  • Backward capability up to 802.11ac​

Wi-fi Standards802.11​a802.11​b802.11​g802.11​n802.11​ac802.11​ax
Year of Published​19991999200320092014(wave1)
2016​(wave2)
2018​
Supported Radios​5GHz​2.4GHz​2.4GHz​5GHz​​5GHz​​2.4GHz/5GHz​​
Max Data rates​11Mbps​54Mbps​54Mbps​600Mbps1.73Gbps(wave1)
6.9Gbps(wave2)
9.6Gbps
Bandwidth​20MHz20MHz20MHz20/40MHz20/40/80MHz20/40/80/160MHz​
Transmission scheme​DSSS-CCK​OFDMOFDMOFDMOFDMOFDMA
Modulation technique​QPSK64QAM64QAM64QAM256QAM1024QAM
Sub carrier spacing​312.5KHz312.5KHz312.5KHz312.5KHz312.5KHz78.125KHz
Number of streams​111Up to 4Up to 8Up to 8
Radios​SISO​SISO​SISO​SU-MIMO​MU-MIMO​MU-MIMO​
Symbol duration​3.2μsec3.2μsec3.2μsec3.2μsec3.2μsec12.8μsec​
Guard Interval​0.8μsec0.8μsec0.8μsec0.4μsec
0.8μ sec
0.4μsec
0.8μ sec
0.4μ sec
0.8μ sec
Wifi Standards

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