IEEE 802.11ac in detail

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802.11ac

 The first thing to get out of the way is – like past Wi-Fi standards – 802.11ac is backwards compatible with 802.11b, g and n. This means you can buy an 802.11ac-equipped device and it will work just fine with your existing router. Similarly you can upgrade to an 802.11ac router and it will work happily with all your existing devices. That said you will need both an 802.11ac router and an 802.11ac device to enjoy the standard’s biggest benefits. And those begin with…

802.11ac Speed

 With any new wireless technology speed is always the headline-grabbing feature but, as with every wireless standard to date, the figures tossed around can be highly misleading.


 1.3 gigabits per second (Gbps) is the speed most commonly cited as the 802.11ac standard. This translates to 166 megabytes per second (MBps) or 1331 megabits per second (Mbps). It is vastly quicker than the 450Mbit per second (0.45Gbps) headline speeds quoted on the highest performing 802.11n routers.

So wireless ac is roughly 3x as fast as wireless n? No.

These figures are ‘theoretical maximums’ that are never close to being realised in real world scenarios. In our experience wireless n performance tends to top off around 50-150Mbit and our reviews of draft 802.11ac routers have typically found performance to be closer to 250-300Mbit. So 2.5x faster when close to your router is a good rule of thumb (though far more at distance, which we’ll come to shortly).

Happily this gain is likely to increase as 802.11ac devices advance. Wireless 802.11n supports a maximum of four antennas at roughly 100Mbit each, where 802.11ac can support up to eight antennas at over 400Mbit each.

Smaller devices like smartphones tend to fit only a single antenna, but it gets even bigger in tablets (typically two to four antennas) and laptops and televisions (four to eight). In addition no 802.11ac router released so far has packed more than six antennas.

A final point: beware routers claiming speeds of 1,750 Gigabits. It is a marketing ploy where the manufacturer has added the 1.3Gbit theoretical maximum speed of 802.11ac to the 450Mbit theoretical maximum speed of 802.11n. Sneaky.



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