What is 802.11ac Wi-Fi, and how much faster than 802.11n is it?
IEEE 802.11ac is a wireless networking standard in the 802.11 family (which is marketed under the brand name Wi-Fi), developed in the IEEE Standards Association process, providing high-throughput wireless local area networks (WLANs) on the 5 GHz band. The standard was developed from 2008 (PAR approved 2008-09-26) through 2013 and published in December 2013 (ANSI approved 2013-12-11).
The specification has multi-station throughput of at least 1 gigabit per second and single-link throughput of at least 500 megabits per second (500 Mbit/s). 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).
How fast is 802.11ac?
In theory, on the 5GHz band and using beamforming, 802.11ac should have the same or better range than 802.11n (without beamforming). The 5GHz band, thanks to less penetration power, doesn’t have quite the same range as 2.4GHz (802.11b/g). But that’s the trade-off we have to make: There simply isn’t enough spectral bandwidth in the massively overused 2.4GHz band to allow for 802.11ac’s gigabit-level speeds. As long as your router is well-positioned, or you have multiple routers, it shouldn’t matter much. The more important factors will be the transmission power and antenna quality of your devices.
And finally, the question everyone wants to know: Just how fast is Wi-Fi 802.11ac? As always, there are two answers: the theoretical max speed that can be achieved in the lab, and the practical maximum speed you’ll most likely receive at home in the real world, surrounded by lots of signal-attenuating obstacles.
The theoretical max speed of 802.11ac is eight 160MHz 256-QAM channels, each of which are capable of 866.7Mbps, for a total of 6,933Mbps, or just shy of 7Gbps. That’s a transfer rate of 900 megabytes per second — more than you can squeeze down a SATA 3 link. In the real world, thanks to channel contention, you probably won’t get more than two or three 160MHz channels, so the max speed comes down to somewhere between 1.7Gbps and 2.5Gbps. Compare this with 802.11n’s max theoretical speed, which is 600Mbps.
For outdoor PtP best performance will be 2x2 MiMo speed of max 866Mbps radio speed and real max throughput 500Mbps.
The 5GHz spectrum in the UK from 5150MHz (5.15GHz) to 5850MHz (5.85GHz). 3 different bands (Band A, B and C). Each band has its own maximum allowed effective radiated power output and specific rules as to where it can be used and 5.8Ghz required a Light License.
This info is contained in the table below
|Band||Low||High||Indoor/Outdoor||Max Power Level||License Requirements|
|B||5470MHz||5725MHz||Indoor/Outdoor||1000mW (1W)||License Free|
|C||5725MHz||5850MHz||Outdoor (FWA)||4000mW (4W)||Licensed|