Apart from the magnitude of the data rate improvements - three or four times that of today's widely deployed 802.11n networks - 802.11ac provides a host of other benefits. Users can expect higher-quality radio links, and see higher data rates (compared to 802.11n) maintained consistently as the distance from the access point increases. There will be much less traffic and interference in the 5GHz band, which is the only frequency band 802.11ac uses, compared to the 2.4-GHz band used by a majority of Wi-Fi clients today. And beamforming and the improved signal quality will compensate somewhat for the lower range of 5GHz vs. 2.4GHz.
Finally, 802.11ac is much more power efficient than 802.11n, reducing battery demand for mobile devices. And the much faster data rates mean that users can send and receive a given amount of data much faster, reducing time "on the air" and, again, using less power.
You can expect a range of 802.11ac product demonstrations and announcements (for the consumer market) at the upcoming Consumer Electronics Show in Las Vegas, Jan. 8-13.
In early 2013, the Wi-Fi Alliance will launch its 802.11ac testing, designed to certify 802.11ac interoperability of different 802.11ac products and brands. The "Wi-Fi Certified" brand will help to make 802.11ac a mainstream technology in short order.
Enterprise access points will begin appearing by midyear. One example is Cisco's previously announced 802.11ac plug-in module for its Aironet 3600 high-end access point. Cisco, and its rivals, have been upgrading their access points and controllers, adding memory, CPU power and other changes to handle the higher data rates as well as the anticipated higher demands that mobile Wi-Fi clients put on backend services such as encryption and authentication.
Vendors say they expect enterprises to phase in Gigabit Wi-Fi by adding 802.11ac radios first to high-density areas - with lots of clients or demanding applications or both. At some point, enterprises may have to upgrade WLAN controllers, wireline Ethernet backhaul, or switches (or some combination), and RADIUS and other backend network services.
For this infrastructure market, the radios will support two, three or four data streams. Chipmaker Marvell announced Dec. 3 the first 4x4 802.11ac system-on-chip, a companion to its client-focused 2x2 product. It's targeted at enterprise WLANs, carrier Wi-Fi networks, and video distribution applications.