Cisco Wi-Fi

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).
The design constraints and economics that kept 802.11n products at one, two, or three spatial streams haven’t changed much for 802.11ac, so we can expect the same kind of product availability, with first-wave 802.11ac products built around 80 MHz and delivering up to 433 Mbps (low end), 867 Mbps (midtier), or 1300 Mbps (high end) at the physical layer. Second-generation products promise still more channel bonding and spatial streams, with plausible product configurations operating at up to 3.47 Gbps.
Second-generation products should also come with a new technology, multiuser MIMO (MU-MIMO). Whereas 802.11n is like an Ethernet hub that can only transfer a single frame at a time to all its ports, MU-MIMO allows an AP to send multiple frames to multiple clients at the same time over the same frequency spectrum. That’s right: with multiple antennas and smarts, an AP can behave like a wireless switch. There are technical constraints, and so MU-MIMO is particularly well suited to bring-your-own-device (BYOD) situations where the devices such as smartphones and tablets might only have a single antenna.
802.11ac-enabled products are the culmination of efforts at the IEEE and Wi-Fi Alliance pipelines. IEEE 802.11ac delivered an approved Draft 2.0 amendment in January 2012 and a refined Draft 3.0 in May 2012, with final ratification planned for the end of 2013. In parallel, the Wi-Fi Alliance is expected to take an early IEEE draft, most likely Draft 3.0, and use that as the baseline for an interoperability certification of first-wave products in early 2013. Later, and more in line with the ratification date of 802.11ac (that is, after December 2013), the Wi-Fi Alliance is expected to refresh its 802.11ac certification to include testing of the more advanced 802.11ac features. This second-wave certification should include features such as channel bonding up to 160 MHz, four spatial streams, and MU-MIMO. Overall, this arrangement closely follows how 802.11n was rolled out.