80+80 MHz channel bonding (discontiguous 80+80).160 MHz channel bandwidths (contiguous 80+80).Borrowed from the 802.11n specification:.Newly introduced by the 802.11ac specification:.Borrowed from the 802.11a/ 802.11g specifications:.The first three fields in the header are readable by legacy devices to allow coexistence Adds four new fields to the PPDU header identifying the frame as a very high throughput (VHT) frame as opposed to 802.11n's high throughput (HT) or earlier.Coexistence mechanisms for 20, 40, 80, and 160 MHz channels, 11ac and 11a/n devices.
MAC modifications (mostly to support above changes).Beamforming with standardized sounding and feedback for compatibility between vendors (non-standard in 802.11n made it hard for beamforming to work effectively between different vendor products).Some vendors offer a non-standard 1024-QAM mode, providing 25% higher data rate compared to 256-QAM.256- QAM, rate 3/4 and 5/6, added as optional modes (vs.Downlink MU-MIMO (one transmitting device, multiple receiving devices) included as an optional mode.Space-division multiple access (SDMA): streams not separated by frequency, but instead resolved spatially, analogous to 11n-style MIMO.Multiple STAs, each with one or more antennas, transmit or receive independent data streams simultaneously.
Downlink multi-user MIMO (MU-MIMO, allows up to four simultaneous downlink MU-MIMO clients). Support for up to eight spatial streams (vs. Optional 160 MHz and mandatory 80 MHz channel bandwidth for stations cf. New technologies introduced with 802.11ac include the following: 6.1 Commercial routers and access points. It meant Wave 2 products would have higher bandwidth and capacity than Wave 1 products. Subsequently in 2016, Wi-Fi Alliance introduced the Wave 2 certification, which includes additional features like MU-MIMO (down-link only), 160 MHz channel width support, support for more 5 GHz channels, and four spatial streams (with four antennas compared to three in Wave 1 and 802.11n, and eight in IEEE's 802.11ax specification). From mid-2013, the alliance started certifying Wave 1 802.11ac products shipped by manufacturers, based on the IEEE 802.11ac Draft 3.0 (the IEEE standard was not finalized until later that year). The Wi-Fi Alliance separated the introduction of ac wireless products into two phases ("waves"), named "Wave 1" and "Wave 2". This is accomplished by extending the air-interface concepts embraced by 802.11n: wider RF bandwidth (up to 160 MHz), more MIMO spatial streams (up to eight), downlink multi-user MIMO (up to four clients), and high-density modulation (up to 256-QAM). The specification has multi-station throughput of at least 1.1 gigabit per second (1.1 Gbit/s) and single-link throughput of at least 500 megabits per second (0.5 Gbit/s). The standard has been retroactively labelled as Wi-Fi 5 by Wi-Fi Alliance. IEEE 802.11ac-2013 or 802.11ac is a wireless networking standard in the IEEE 802.11 set of protocols (which is part of the Wi-Fi networking family), providing high-throughput wireless local area networks (WLANs) on the 5 GHz band. *: (Wi-Fi 0, 1, 2, 3, are unbranded common usage. Wireless networking standard in the 802.11 family Wi-Fi Generations
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