Once widely implemented, especially in business networks, 802.11a supports data rates up to 54 Mbps. It utilizes the 5 GHz frequency band, which has significantly less congestion than other bands and less interference from other devices ensuring better signal integrity and fewer dropped connections. One disadvantage of 802.11a is that its effective overall range is slightly less than that of 802.11b and 802.11g. 802.11a signals are more readily absorbed by walls and other solid objects compared to 802.11b/g.
802.11b was released in 1999; the same year 802.11a was released. 802.11b access points, interface cards etc. were less expensive than 802.11a equipment which made it affordable for use in home and small business networks. 802.11b is better at penetrating solid objects such as walls compared to 802.11a but its maximum throughput is only 11 Mbps compared to 802.11a's 54 Mbps. For outdoor networks 802.11b is not as effective as 802.11a at penetrating trees and leaves as it operates in the 2.4 GHz frequency band. 2.4 GHz signals are absorbed by water found in trees and leaves limiting overall outdoor range.
Adopted in 2003 with the promise of higher data rates and reduced cost, 802.11g also operates in the 2.4 GHz frequency band. 802.11g supports a maximum throughput of 54 Mbps and is backward compatible with 802.11b devices/networks. 802.11g experiences the same interference issues as 802.11b as it operates in the crowded 2.4 GHz range. Examples of devices that operate in the 2.4 GHz band include microwave ovens, baby monitors, Bluetooth devices and cordless telephones not to mention a multitude of other 802.11b/g access points.
802.11n, released in 2009, was developed to improve network throughput by utilizing multiple antennas to increase data rates. This standard uses both 2.4 GHz and 5 GHz bands and provides high data throughput of up to 600 Mbps. Additionally 802.11n provides superior indoor and outdoor coverage, essentially doubling the range of its predecessors 802.11b/g.
802.11n uses Multiple-input Multiple-output (MIMO) technology which is a technique for sending and receiving more than one wireless signal on the same radio channel at the same time which increases overall throughput (up to 600 Mbps!)
The most recently released version of the 802.11 standard is 802.11ac. 802.11ac supports data rates of up to 1.3 Gbps! 802.11ac operates solely in the 5 GHz band, supports MIMO technology and can handle up to four spatial streams (Wave 1) along with wide 80 MHz (Wave 1) channels. 802.11ac also has the advantage of multi-user MIMO or MU-MIMO which is an advanced form of MIMO where an access point can send data to up to four client radios at the same time directing a separate spatial stream to each one compared to 802.11n access points that can only communicate to one client at a time. By implementing MU-MIMO overall Wi-Fi network efficiencies are realized even as more clients are added to the network.
Click on the image below to download our 802.11 standards chart