WiFi and its Amendments

It is obvious that wireless devices and Access point (AP) are able to communicate with each other if they operate on same band. Band means range of frequency used by particular wireless device. Wi-Fi uses two bands for the communication, 2.4-GHz and 5-GHz. Frequency range used for wireless communication in 2.4-GHz band lies between 2.400-GHz and 2.835-GHz. Frequency range for 5-GHz band lies between 5.150-GHz to 5.825-GHz. The 5 GHz band is further divided into 4 distinct bands-
5.150 – 5.250 GHz
5.250 – 5.350 GHz
5.470 – 5.725 GHz
5.725 – 5.825 GHz

Amendments Frequency band  Max data rate  Notes 
802.11-1997  2.4-GHz  2 Mbps  Original 802.11 standard introduced in 1997. 
802.11b  2.4-GHz  11 Mbps  Introduced in 1999. 
802.11a  5-GHz  54Mbps  Introduced in 1999. 
802.11g  2.4-GHz  54 Mbps  Introduced in 2003. 
802.11n  both 2.4-GHz and 5-GHz  300 Mbps  Introduced in 2009, HT (high throughput), also called Wi-Fi 4
802.11ac  5-GHz  1 Gbps  Introduced in 2013, VHT (very high throughput), also called Wi-Fi 5
802.11ax  both 2.4-GHz and 5-GHz  9.6 Gbps Introduced in 2019, also called WiFi-6 

IEEE 802.11b :
It is first standard developed for wireless network (IEEE 802.11) in 1997. It has maximum coverage network of about 45 meters and operate on 2.4GHz frequency band. It provides a maximum theoretical speed of 11 Mbps. Components of devices implementing this standard are cheaper. This standard was very famous among customers because of inexpensive devices and installation.

IEEE 802.11a :
The letter ‘a’ in this standard makes you think why this standard comes after 802.11b. Actually 802.11a comes along with 802.11b but it uses a new complex technology called OFDM (orthogonal frequency division multiplexing) for signal generation. Implementation of this standard was expensive so it was used only in businesses at that time. It operates on 5Ghz frequency band and has a maximum theoretical speed of 54 Mbps.



IEEE 802.11g :
This standard uses same technology i.e, OFDM as 802.11a. It operates on 2.4GHz frequency band and provides a maximum theoretical speed of 54 Mbps. 802.11g devices are compatible with 802.11b devices but with speed of 11 Mbps. This standard provides an improvement over 802.11b standard. Now customers can enjoy a better speed and coverage at some minor upgrades.

IEEE 802.11n (Wi-Fi 4) :
It uses a technology called MIMO (multiple input multiple output) where multiple transmitters/receivers can operate simultaneously at both transmitting and receiving end.This multiple use of transmitters/receivers provide a significantly higher bandwidth and power. It operates on both 2.4GHz and 5GHz frequency band and called dual band Wi-Fi. It provides a maximum theoretical speed of 300 Mbps (450 Mbps if using three antennas).

IEEE 802.11ac (Wi-Fi 5) :
Advancement in this standard id MU-MIMO (Multi-user MIMO). MIMO directs multiple signals to a single client but with MU-MIMO multiple signals can be directed simultaneously to multiple devices. It also uses a technology called Beaming in which antennae uses a radio signals that can be directed to a single specific device. It provide speed ranging from 433 Mbps to 1 Gbps and operates only on 5GHz frequency band.

IEEE 802.11ax (Wi-Fi 6) :
It also uses MU-MIMO technology but with some improvements. It offers increase in multi-user from 4×4 to 8×8. It also offers a traffic congestion avoidance system making it efficient and reliable at public places. It provides a maximum speed of 9.6 Gbps and operates on both 2.4GHz and 5GHz frequency band (means dual band Wi-Fi).

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