Wireless Array
Installing the Wireless Array 37
About IEEE 802.11ac 
802.11ac is a continuation of the IEEE 802.11 standard. It multiplies the maximum 
data rate—up to ten times the 802.11n maximum will ultimately be available. 
Along with increased data rates, it offers simultaneous transmission to multiple 
clients. 
802.11ac will be rolled out in two phases. Wave 1 products available in 2012-2013 
support 80MHz channels and up to 3 data streams for a maximum data rate of 1.3 
Gbps. Wave 2 and future products will add 160MHz channels and up to 8 
streams, for a maximum data rate of 6.93Gbps. 
Xirrus currently supports up to three streams (in units with 3x3 radios) and 80 
MHz channels. Xirrus models that offer 802.11ac support this technology on all 
IAPs, not just on one. IAPs are individually configurable to different modes or 
groups of modes (such as 802.11a, 11b, 11g, and 11n). Xirrus optimizes 802.11ac 
performance further with ACExpress™. This innovation intelligently separates 
high-speed and lower-speed mobile devices on separate IAPs to maximize system 
performance. 
The major advantages of 802.11ac are: 
 Faster speeds than 802.11n over the same coverage area, operating at up 
to 1.3 Gbps in Wave 1 implementations. While the maximum distance 
that a Wi-Fi signal can reach is unchanged with 802.11ac, multiple 
antennas increase the data rate at every distance. 
 Operates only in the less congested 5 GHz spectrum, which offers 
“cleaner” air and supports much greater capacity than the 2.4 GHz 
spectrum still used by 802.11n.
 Supports simultaneous communications to multiple clients on a single 
channel with multi-user MIMO in future Wave 2 products. 
 Extends the techniques pioneered in 802.11n: more antennas, more spatial 
streams and wider channels to improve throughput.