Monday, August 1, 2011

The Next Step for Wi-Fi: Low-latency, Gigabit 802.11ac

The next big step for Wi-Fi is to make the leap to gigabit capacity with 802.11ac. As part of its Wi-Fi Day celebrations (08/02/11), Qualcomm Atheros hosted a press event in Silicon Valley to discuss how this future Wi-Fi will develop. The next rev of Wi-Fi technology, expected later this year, promises this performance boost along with new multi-user, multi-simultaneous stream capabilities.

The Wi-Fi standards have moved all the way through the alphabet from 802.11a, 802.11b, g, n, etc., and now use a double letter designation.

"802.11ac is the next big deal" said Bill McFarland, VP of Technology for Qualcomm Atheros, because it upgrades both the PHY and MAC layers for a greater than a 2x boost in rate-at-range of HD video streaming and will see widespread deployment in consumer electronics fairly quickly as it displaces 802.11n silicon.

Some key attributes of 802.11ac:

  • Unlike 802.11n, 802.11ac is exclusive to 5 GHz spectrum because this band offers more non-overlapping channels and has fewer interferers.

  • 802.11ac client silicon will support a fall-back to 802.11n when 802.11ac is not available. 802.11ac base stations will support concurrent 802.11n and 802.11ac clients.

  • 802.11ac gets its performance boost by using wider channels

  • The latency of 802.11ac is improved over 802.11n

  • Beamforming was promised in 802.11n but not really implemented in practice unless the same vendor's silicon was in both the client and access point. This problem has been fixed in 802.11ac with the industry agreeing to one beamforming methodology.

  • 802.11ac will offer better support for more significantly more clients on wireless networks.

  • Performance-to-power has been improved. Faster downloads means the radios can return to low-power standby modes faster.

  • The range of 802.11ac and 802.11n are similar.

McFarland also provided an update on the 60 GHz .11ad standard, which leverages even wider channels for in-room connectivity at up to 7 Gbps. The 60 GHz Wi-Fi would offer a true network connection, differing from other high-speed cabling option, such as Thunderbolt or USB 3.0 which are not IP-based. McFarland believes 802.11ac and 802.11ad will be complementary. In May, Qualcomm Atheros introduced the industry's first tri-band Wi-Fi chipset that integrates the multi-gigabit performance of in-room 60 GHz band with seamless handoff to 2.4 GHz and 5 GHz band Wi-Fi. The chipset was developed in partnership with Wilocity, a developer of 60 GHz multi-gigabit wireless chipsets.

McFarland expects chips for 802.11ac to begin sampling later this year. Chips for 60 GHz 802.11ad may sample a bit earlier, but he expects these will have a longer product design cycle, so 802.11ac products will probably appear on the market first and have a faster adoption curve.


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