The move to mobility is placing unprecedented demands on Wi-Fi technology to become more “wire-like” to support isochronous, latency-sensitive applications like streaming IP voice and video – not so easy in an increasingly noisy RF world.
With the well-publicized barrage of data traffic hitting networks from new wireless-only smartphones, iPads and other media-rich handhelds, companies must now contend with an explosion of concurrent users, myriad devices and data volumes that easily exceed the capacity of their networks.
So-called “superphones” routinely average more than 1 GB a month and as a category, superphones eat about 700-800 MB of data each month. By the end of 2011, it’s expected that the average U.S. consumption per smart device will be approximately 325 MB, up 112% from 2009. IP video is driving this consumption even higher.
Given the enormous installed-base of 802.11 silicon embedded in virtually every conceivable device, Wi-Fi is arguably the most expedient and cost-effective way to relieve strained networks while quickly and easily expanding them into new areas – keeping a tight focus on where traffic is heaviest.
But Wi-Fi has its own set of problems, most of which center around wildly fluctuating performance from an increasingly noisy spectrum and spotty signal coverage.
Conceived as a consumer technology of convenience for the home, Wi-Fi was never designed to function as a ubiquitous utility for a large number of simultaneous users moving their devices around while watching streaming multimedia. Conventional omni-directional antenna technology, used on nearly every Wi-Fi system on the market today, does next to nothing to adapt signals within this this dynamic and constantly changing RF environment. This is where the vast majority of Wi-Fi reliability, range and performance problems lie.
Enterprises must pay particular attention to new technologies that automate Wi-Fi spectrum management and provide a more adaptive approach to dealing with RF spectrum problems such as interference, obstacles, and changing client orientation.
Essential to faster and more reliable Wi-Fi performance is achieving a higher signal-to-noise plus interference (SINR) ratio. A higher SINR means better signal delivered to clients, faster data rates and more network capacity. But how do you deliver a stronger signal to clients while decreasing interference?
Advanced Wi-Fi implementations (so-called “dynamic beamforming”) use adaptive antenna arrays (a collection of high-gain, directional antennas that are controlled by software) to overcome these issues.
Instead of inefficiently sending and receiving signals in all directions at all times, adaptive antenna arrays constantly focus and direct Wi-Fi transmissions (like a lighthouse) only where they are needed and over the fastest, least noisy signal paths. This results in remarkable Wi-Fi improvements: up to 10dBi of signal gain and 17dB of additive gains resulting from interference rejection.
These systems have the unique ability to reject interference and other RF noise that cause packet loss. Packet loss severely degrades voice and video quality as clients are forced to retransmit data. This causes delays for everyone trying to access the Wi-Fi network. By mitigating interference (analogous to noise cancelling headphones), packet loss is minimized – so voice over IP calls stay crystal clear while streaming IP video remains flicker free.
Built-in client feedback mechanisms allow these systems to learn if the antennas chosen for a given client are achieving the highest data rate, best signal-to-noise ratio and lowest packet loss. And because these smart antenna arrays are software controlled, they can be automatically switched (on a per packet basis) to combat interference and obstacles - placing traffic on better signal paths with no human intervention.
Adding this technology to 802.11n now gives enterprises the muscle to deal with the influx of multimedia traffic hitting their networks from these new handheld devices while delivering much more reliable wireless access because the system adapts to environmental changes on the fly. Wow.
David Callisch is vice president of marketing at Ruckus Wireless. The Ruckus ZoneFlex includes a WLAN controller and access points (APs). It is the first centrally managed, multimedia 802.11g Wi-Fi solution that delivers industrial-strength features and functionality not available in any low-end consumer AP or high-end WLAN system. Ideal for hotels, schools, airports and small-to-medium businesses (SMBs) with little or no IT staff and a limited budget, the Ruckus ZoneFlex products are designed to handle the new requirements of business services such as voice over Wi-Fi, IP-based video and secure enterprise access.
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