How 802.11ac networking boosts the MacBook Air's Wi-Fi performance
One exciting aspect of the new MacBook Air release is the prospect of greater Wi-Fi speed and performance. That’s because Apple’s updated laptop sports built-in compatibility with the newest draft networking standard, 802.11ac, an upgrade of the current 802.11n. That draft standard (established by the Institute of Electrical and Electronics Engineers) is also built into Apple’s newly released AirPort Extreme Base Station and AirPort Time Capsule hard drive. The new MacBook Airs are among a handful of laptops with internal 802.11ac Wi-Fi adapters shipping to date.
New radio spectrum
Here’s what makes this new technology so fast: The 802.11ac standard uses the unlicensed 5GHz radio spectrum, which is considerably less crowded than the 2.4GHz spectrum, where devices ranging from cordless phones and baby monitors to microwave ovens can stomp all over your network. What’s more, the 5GHz spectrum provides many more available channels: 21 nonoverlapping channels in the United States versus only 11 in the 2.4GHz spectrum (and only 3 of those 11 channels don’t overlap).
The new AirPort Extreme.
The 802.11n standard uses channels with 20MHz of bandwidth on the 2.4GHz frequency band and channels with 40MHz of bandwidth on the 5GHz band. In contrast, the 802.11ac standard uses a channel with 80MHz of bandwidth.
Operating in the 5GHz spectrum isn’t the only factor that makes the new 802.11ac standard so attractive. Networks based on this standard also carry more data, thanks to its more robust encoding scheme. An 802.11n network using a 20MHz-wide channel can transmit data at 75 mbps over a single spatial stream, 150 mbps over two spatial streams, or 225 mbps using three spatial streams. An 802.11n network using a 40MHz-wide channel can double those numbers. But an 802.11ac network using an 80MHz-wide channel can deliver even higher throughput: 433 mbps over a single spatial stream, 867 mbps over two, and a staggering 1.3 gbps over three spatial streams.
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