Tuesday, August 02, 2011

Why Wi-Fi as we know it is in trouble

Today, 8/02/11, is the perfect time to contemplate the future of 802.11 networks

By Bill McFarland, VP of technology for Qualcomm Atheros,

Aug. 2, 2011, isn't just the day that the U.S. risks defaulting on its debt. It is also 802.11 day (8/02/11), a day when the wireless industry should ponder its future because today's Wi-Fi networks are about to be hit by a perfect storm of problems.
Until recently, users relied on Wi-Fi networks simply to access Web pages and email -- fairly non-demanding traffic that doesn't consume a ton of bandwidth. But users have gone from "connecting" to "consuming," as they download music from iTunes, stream movies from Netflix and Hulu and enter into multiplayer games on their Xboxes and PlayStations.

Devices have changed, as well, offering "control" capabilities. In homes, everything from thermostats to home healthcare equipment to light bulbs (yes, light bulbs) will connect to the Internet via Wi-Fi networks. In businesses, of course, all sorts of office gear connects to the Web for diagnostics and to deliver value-added services.
Eventually, many of these "control" activities will be automatic, with devices communicating amongst themselves and adhering to preset policies. For instance, during periods of peak energy consumption, utilities will avoid brown-outs by turning off air conditioners of willing customers. Office copiers will sense that toner is low and order more. Sprinkler systems will connect to weather service information so lawns won't be watered during rain storms.
Most of these "control" activities will happen automatically with little or no human intervention. Devices will function as "users," performing an array of simple tasks - that is if the gateway networks are up to the task. 

Pushing Wi-Fi forward

For Wi-Fi to handle all of this, standards must evolve. Here are four problems that must be overcome:
* 2.4 GHz is crowded and prone to interference issues.
* Current Wi-Fi networks are unable to keep up with rising volumes of rich media traffic.
* 2.4 GHz networks have insufficient throughput for supporting new types of media, such as high-definition video.
* Current Wi-Fi networks can't offer high data rates to multiple devices simultaneously.
A few of these problems are obvious today. Cordless phones, garage door openers, baby monitors and microwave ovens all interfere with Wi-Fi traffic in the 2.4 GHz band. Moreover, adjacent access points can interfere with one another. And if you've ever logged into an overcrowded public Wi-Fi network, those super slow connections are a sneak peak of what all networks look like as more and more wireless devices compete for bandwidth.
Other problems are just over the horizon. Most of us aren't trying to stream high-definition video - yet. Of course, five years ago, few of us were even streaming audio. Most of us also aren't connecting more than laptops, tablets and, occasionally, smartphones to Wi-Fi. As chip prices continue to drop and Wi-Fi capabilities get built into more devices, 802.11n networks will grind to a halt.
Fortunately, a new standard is in the works that will address these problems. 802.11ac operates in the clean 5 GHz spectrum where there aren't any non-802.11 devices generating interference, and where there is a large amount of spectrum for devices to spread out.
THE FUTURE: Toward a Gigabit Wi-Fi Nirvana: 802.11ac and 802.11ad
The 5 GHz band provides "wider" channels, offering 80 MHz and 160 MHz channel bandwidths, an improvement over the 40 MHz maximum of 802.11n. In fact, in the 2.4GHz band, most 802.11n networks are restricted to only 20 MHz wide channels. Using the 5 GHz spectrum, 802.11ac will be able to deliver 1Gbps throughput, more than six times that of typical 802.11n devices.
Another big advantage in 802.11ac is multi-user MIMO. Traditionally, an access point can only communicate with one device at a time. It appears to be communicating with multiple devices simultaneously by jumping among different devices and dividing the time -- and throughput.

Multi-user MIMO enables an access point to communicate simultaneously with multiple devices, delivering higher overall throughput and a steadier stream of traffic to each device. To use an analogy from wired networking, traditional Wi-Fi behaves like an old-fashioned Ethernet hub, while multi-user MIMO is like a non-blocking switch. 802.11ac provides simultaneous connections for up to four devices without having to divide up time among users.
Of course, as networks get saturated, this may not seem like enough. However, many devices -- say thermostats or sprinkler systems -- will come online infrequently, and most will access networks when other devices aren't active. Moreover, the fact that the 5 GHz band is uncluttered means that homes and offices can have multiple 802.11ac access points without worrying about interference and having to bring in engineers to set channels and frequencies. [See: "Tips for navigating the evolving wireless LAN landscape"]

Importing concepts from other networks

New forms of 802.11 have other advantages as well. Concepts from Personal Area Networks for direct device-to-device connections will catch on, so that when you want to view home movies from your camcorder on your HDTV, you simply connect the two, rather than routing traffic through an access point.
Another possibility -- and one that wireless providers should seriously consider -- is designing 802.11ac access points so they can also serve as extensions to 3G and 4G cellular networks. Most smartphones these days have multi-mode capabilities, so service providers could incentivize the use of Wi-Fi, offering discounts for calls or data routed over Wi-Fi. Consumers would also benefit from stronger signals inside their homes or offices, where cellular signals tend to degrade. The key to this vision is creating a seamless user experience as the device roams between traditional cellular and 802.11ac-based off-load networks while carrying data streams and potentially even voice calls. Achieving this will require deep expertise in both 802.11ac and cellular devices.
Today, we're on the brink of the era of the "Internet of Everything." Houston, Los Angeles, Minneapolis and San Francisco have all rolled out smart parking meter stations, which can wirelessly approve credit card payments. Eventually, you should be able to download an app that will direct you to available parking spots.
Wireless sensor networks, many of which rely on Wi-Fi to connect to the Internet, are monitoring everything from soil conditions in vineyards to corrosion in pipelines. And more devices will be coming online soon, including everything from refrigerators to pacemakers.
IMS Research reported that in August 2010 more than 5 billion devices connected to the Internet. Putting that in perspective, there were only 500 million connected devices in 2007. Industry estimates see 1 trillion devices coming online by 2013 or 2015.
According to Metcalfe's Law, the value of a network is proportional to the square of the number of connected users. As more users (or devices) come online, the network's value increases dramatically.
With 1 trillion-plus devices coming online soon, it's imperative that the 802.11ac standard gets ratified, and devices are launched as soon as possible. 802.11n was slowed by vendor in-fighting. It's critical to avoid such foot-dragging this time, since we are entering an era where Internet-connected devices will be responsible for everything from flood control in dams to airport runway safety.
As more devices come online, public networks will become mission-critical for the whole country. It's imperative, then, that the wireless gateway between devices and the Internet is robust enough to handle that mission-critical role.

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