802.11ac

The previous IEEE Wi-Fi standard, which was designed to improve wireless services in the enterprise as well as support multiple streams of HD video in the home. Also known as "Wi-Fi 5," "Gigabit Wi-Fi" and "5G Wi-Fi," products became available in 2012 before the standard was approved in early 2014.

Operating only in the 5 GHz band, devices are backward compatible with 802.11n, which is expected to co-exist with 802.11ac until the 2020s. An 11ac access point employs beamforming, which uses feedback to aim the transmission at the receiving device. In addition, 11ac beamforming was standardized for vendor interoperability for the first time.

11ac Wave 2

The second generation Wave 2 supports multiuser MIMO (MU-MIMO) with a total of eight simultaneous streams and up to four per client. See beamforming, 2.5/5G Ethernet, 802.11n, 802.11ad, OFDM and QAM.

 802.11ac and 802.11n SPECIFICATIONS

                 11ac         11n
               (Wi-Fi 5)    (Wi-Fi 4)

 Band           5 GHz       2.4/5 GHz

 Modulation    256-QAM       64-QAM

 Max Antennas     8             4

 Channel MHz   20, 40,      20, 40
               80, 160

 11n
 (40 MHz channels)
 1 stream                   150 Mbps
 2 streams                  300 Mbps
 3 streams                  450 Mbps
 4 streams                  600 Mbps

 11ac Wave 1
 (80 MHz channels)
 1 stream     433 Mbps
 2 streams    867 Mbps
 3 streams    1.3 Gbps

 11ac Wave 2
 (160 MHz channels)
 1 stream     867 Mbps
 4 streams    3.39 Gbps
 8 streams    6.77 Gbps