Is ultra-fast Wi-Fi worth the gamble?

By Amy Storer, News Writer 22 Mar 2005 | SearchNetworking.com

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As an emerging technology promises to up the ante on wireless networking speed and range, industry experts warn large enterprises to hedge their bets when investing in it because of compatibility issues and a lack of products.

MIMO (multiple input, multiple output) technology is a method that includes two or more radios in a Wi-Fi device, allowing users to transmit two or more data streams on the same channel at the same time. The result: increased data throughput on the channel in proportion to the number of radios in the system.

MIMO technology was pioneered at Stanford University, and later by the founders of startup Airgo Networks Inc. The Palo Alto, Calif.-based company develops chip sets that take advantage of the extra throughput of MIMO, claiming achieve speeds of up to108 Mbps.

According to Airgo, the company's chip set supports 802.11a, b and g, as well as features of the 802.11i Wi-Fi security standard and upcoming 802.11e (quality of service) draft specification.

Dave Borison, Airgo's senior product director, said typical 802.11a, b and g products have only one radio in them to transmit and receive signals, and are designed only to accommodate limited "multipath" signals. Multipath is the phenomenon in which radio signals bounce off objects such as walls and furniture, so the radio receives an abundance of signals arriving at different times.

Said Borison, "MIMO products have created a paradigm shift in modern radio architecture where, rather than accommodating multipath up to certain limits, MIMO systems actually leverage the fact that signals bounce around a lot in business and home settings in order to achieve more reliable connections at greater distances."

Joseph Byrne, principal semiconductor analyst at Stamford, Conn.-based Gartner Inc., said MIMO will be the foundation of 802.11n, which is meant to boost WLAN performance, but the Institute of Electrical and Electronics Engineers isn't expected to officially approve it for at least a year.

Abner Germanow, an analyst at Framingham, Mass.-based International Data Corp., said enterprise-level MIMO gear is currently scarce, but he said it also depends on what you define as MIMO.

"There are a few products that are basically fancy antennas designed for enterprise use," Germanow said. "The consumer world has the Belkin, Linksys, Netgear and D-Link products, which would probably work for some small businesses as well."

For more information Learn why vendors are fighting over the definition of MIMO. Check out Chapter 1 of Wireless Networks for Dummies.

Germanow said compatibility is also an issue because MIMO vendors claim their gear is backward compatible with 802.11a, b and g access points so it can default back to a slower speed in case of a failure. But, Germanow said, today's pre-standard MIMO equipment will most likely not be compatible with the eventual 802.11n standard.

Germanow said network size should be the primary consideration for companies pondering the MIMO plunge. For a small business, investing a couple of hundred dollars in one or two routers to improve range and performance is not much of a risk at all.

On the other hand, because enterprise-level equipment is currently hard to find, Germanow suggested enterprises -- those companies with hundreds or thousands of access points -- wait for standardized 802.11n equipment and look for MIMO antennas to help with performance in areas with dense user populations.

Byrne said MIMO has a bright future because it provides higher wireless LAN bandwidth, both in terms of the throughput of individual links and the total number of links available. This, Byrne said, will enable WLAN to substitute for, rather than merely complement, wired LAN.

Byrne said even if MIMO maintains its complementary role in corporate Wi-Fi networks, increasing the total bandwidth and range of an individual access point gives companies the opportunity to deploy a smaller number of high-performance access points instead of a multitude of ordinary ones, reducing upfront deployment expenses and ongoing management costs.

Tags: Wireless Standards,  Wireless LAN Equipment,  Network ROI,  Networking Basics,  VIEW ALL TAGS

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