802.11ac: The Fifth Generation of Wi-Fi Technical White Paper
Wireless LAN sites will see significant improvements in the number of clients supported by an access point (AP), a better experience for each client, and more available bandwidth for a higher number of parallel video streams. Even when the network is not fully loaded, users see a benefit: their file downloads and email sync happen at lowlag gigabit speeds. Also, device battery life is extended, since the device’s Wi-Fi interface can wake up, exchange data with its AP, then revert to dozing that much more quickly. 802.11ac achieves its raw speed increase by pushing on three different dimensions: ● More channel bonding, increased from the maximum of 40 MHz in 802.11n, and now up to 80 or even 160 MHz (for 117% or 333% speed-ups, respectively) ● Denser modulation, now using 256 quadrature amplitude modulation (QAM), up from 802.11n’s 64QAM (for a 33% speed burst at shorter, yet still usable, ranges) ● More multiple input, multiple output (MIMO). Whereas 802.11n stopped at four spatial streams, 802.11ac goes all the way to eight (for another 100% speed-up).