As we discussed in last week’s blog, we are barely out of the gate with 802.11n and already two emerging standards are likely to shake up the wireless world: 802.11ac and 802.11ad. 802.11ac is in many ways a “lessons learned” from 802.11n, addressing issues like power consumption while still offering even higher data rates. 802.11ad will expand data rates even further and take advantage of a new spectrum and new technologies, which will enable entirely new use cases for 802.11. As users become more dependent on Wi-Fi, these two protocols will build on the success of 802.11 wireless at home and in the office. In today’s blog, we’ll define both 11ac and 11ad and look at use cases for each of these standards.
802.11ac and how it compares to 802.11n:
802.11ac leverages many of the same key technologies as 802.11n, including channel bonding and MIMO (multiple input, multiple output), it just does it a bit smarter. Let’s take channel bonding, for example. Channel bonding is a very efficient method that essentially doubles the data rate, regardless of other technologies in use. But it does have some practical limitations, and many companies are not taking advantage of what should be an easy data rate enhancement. Why? Although 802.11n is designed for both the 2.4 and 5GHz bands, many users are deploying 11n in only the 2.4GHz band, mainly for backward compatibility with existing b/g clients. Given the limited bandwidth and tight channel allocation in the 2.4GHz band, there’s not much flexibility to make channel bonding work, and when configured incorrectly, it can cause serious interoperability issues with existing b/g deployments, whether the user’s or their neighbor’s.
In order to combat these issues, 11ac is specifically designed for the 5GHz band. The 5GHz band offers more channels with wider channel spacing, and is far less sensitive to interference. Additional protocol enhancements are also being specified to make channel bonding less likely to cause interoperability issues. This includes the ability of devices to assess whether adjacent channels are clear and available for channel bonding, and for devices to reserve wider bandwidths in advance of data transmissions, thus allowing channel bonding to increase from 40MHz in 11n to 80, and even 160MHz under certain conditions in 11ac.
Even though data rates are increasing significantly with 11ac, to as high as 6.93Gbps under certain specialized conditions, power consumption will decrease for equivalent data rates, making 11ac much friendlier for mobile devices. 802.11n is pushing the power limits, especially for mobile/portable devices, to the point where most portable devices cannot come close to taking full advantage of 11n capabilities. Through the use of more efficient data encoding mechanisms, 11ac allows devices to use fewer multiple transmissions paths while still achieving higher data rates, and it’s the additional RF transmission chains that really eat up power. In 11ac you’ll see a 3x improvement in data rate over 11n for the same number of MIMO bit streams.
While 802.11ac is not scheduled for IEEE ratification until December 2013, companies like Apple and Netgear are already making announcements regarding 11ac support, and consumer products are expected on the market as early as the end of 2012.
802.11ad, a product of the Wireless Gigabit Alliance
Like 802.11ac, 802.11ad improves upon the wireless capabilities introduced in 802.11n. 802.11ad uses spectrum in the unlicensed 60GHz band, where far more overall bandwidth is available than in either the 2.4 or 5GHz bands currently utilized in 802.11. The Wireless Gigabit Alliance (WiGig) initiated the specification development to take advantage of this spectrum, but their work has been rolled into the IEEE 802.11ad draft specification.
Ideally, 802.11ad will allow devices to communicate over four, 2.16GHz-wide channels, delivering data rates of up to 7 Gigabits per second, even for mobile devices with limited power, a significant improvement over both 11n and 11ac.
802.11ad will provide native 802.11a/b/g/n/ac support, enabling devices to seamlessly switch between 2.4, 5, and 60 GHz bands. One of the biggest advancements, though, comes from the single carrier for lower power consumption, which enables advanced power management and longer device battery life.
What 802.11ac and 802.11ad mean for you:
From the consumer perspective, 802.11ac will provide the ability to fully support a ‘multi-media home’ through its single-link and multi-station enhancements, allowing for simultaneous streaming of HD video to multiple devices throughout the home, rapid synchronization and backup of large data files, wireless display, and 3G and 4G offloading, to name a few. Essentially, with 11ac, you’ll be able to wirelessly network your TV, DVR, smart phone, and sound system for complete on-demand access through an AP or other Internet-connected device.
On the other hand, 802.11ad is really all about the “Wireless Office.” With its built-in support for traditional wired connections, like PCI-e, USB and HDMI, coupled with multi-Gbps data rates and a range of at least 10 meters, 802.11ad is likely to finally deliver on the promise of true cordless computing ala the promises of Bluetooth, as well as support a native Wi-Fi network for wireless Internet access.
Both of these standards could mean huge advancements in the way consumers and businesses access and utilize wireless networks and devices. Increased speed, and increasingly interconnected devices, will continue to drive the explosive growth of 802.11.
However, the realities of 802.11ac and 802.11ad have yet to be seen. 802.11n, though highly successful, is still not reaching its full potential, years after the final specification was ratified. Practical limits are testing theoretical specifications, and although 11ac and 11ad are addressing these practical limitations in 11n, they are likely to introduce new and yet to be seen practical limitations of their own. Though certainly worth carefully watching, it’s highly unlikely that an enterprise upgrade to 11ac or 11ad is right around the corner.
If you’d like more information on 802.11ac/ad, watch our free OnDemand webcast here.