From Problem To Prodigy Product

Greg Raleigh has figured out how to turn lemons into lemonade. Dr. Raleigh, who is the CEO of Silicon Valley-based Airgo Networks figured out a way to turn radio reflections that cause interference and poor reception into a technology that does just the opposite by increasing the range of transmitters and receivers. The commercial result, so far, are wireless (WiFi) networking routers and adapters that increase both the speed and range of a home, office or public network without having to increase power.

(Click here to listen to an interview with Greg Raleigh, Airgo Networks CEO.)

Although there is a great deal of math and theory behind Raleigh's technology, there is nothing theoretical about the actual products. I have them in my home and can appreciate the advance when I use my laptop computer, especially if I'm in a remote area of my house or yard. Thanks to Airgo's technology, my wireless network is faster and extends considerably further than it did before.

The technology, called "MIMO" (multiple input multiple output), makes it possible to transmit data via standard wireless networks at rates up to 108 megabits per second over longer distances. That's twice the theoretical speed of today's 802.11g WiFi standard and more than 10 times faster than the 802.11b systems that are in widespread use. However the further you are from an access point, the lower the speed, so, regardless of the system you use, your actual performance will vary and will likely be lower, unless your PC or other device is in the same room as the access point.

MIMO-equipped routers and PC adapters are now available from major WiFi equipment manufactures including Belkin, Buffalo, SohoWare, NetGear and Linksys.

For the past several weeks, I have been using a Linksys WRT54GX Router with SRX. Before I installed the router, I was using a standard Linksys 801.11b system which worked fine with PCs and other wireless devices that were in nearby rooms but I had a hard time getting online from an upstairs bedroom or the backyard. Either I couldn't make a connection or, if I did, the data rate was noticeably sluggish. With the new device, I can now access the Internet on my laptop anywhere in the house, in the yard or even from my neighbor's house. At about $190, the router is considerably more expensive. Routers without MIMO technology start at under $65.

There are two parts to the MIMO solution — the router and the adapter that goes into the PC or other device. By itself, the router noticeably increases range and performance even if you have an older-style adapter in your laptop. But if you couple a MIMO router with a MIMO card, the range increases even more. I discovered this by installing a Linksys WPC54GX Wireless-G Notebook Adapter with SRX card in my laptop and taking a walk down the street. Four houses away, I could still access my home network.

Like the routers, MIMO adapters are also more expensive than standard 802.11 versions. Also, they are just starting to be built-in to notebook PCs. Raleigh expects MIMO products to be built into many wireless devices in the near future. Fortunately, MIMO is backwards compatible with other 802.11 products so that a MIMO router will work with any adapter and vice versa. All my older WiFi devices work fine with my MIMO router.
Raleigh says that the technology behind these products takes advantage of radio reflections that appear in the environment. "Something people thought for a 100 years was a bad thing was the most incredible opportunity to improve wireless that we had seen."

The problem that we've all come across while listening to a portable or car radio is called "multipath fading," radio reflections that occur in the environment that cause interference. That's why you sometimes lose a signal on your car radio for a moment, until you move your car. Raleigh, while he was doing graduate work at Stanford in the 90s, found that "if you use multiple input multiple output signals — more than one signal over the air at the same time on the same frequency channel — you could actually multiply your speed and increase your reliability and range at the same time."

According to Raleigh, every time you have a multiple reflection it's another opportunity to send a new signal. "If I have ten bounces or multipath reflections, I can send 10 times the signal and get ten times the speed."

MIMO routers have multiple antennas to use the reflections to increase coverage area and improve speed. Linksys claims that its MIMO routers, when paired with MIMO adapters, can "maintain "wireless connections up to 3 times farther than standard Wireless-G." The company advertises that "the farther away you are, the more advantage you get — the higher data rate and reflection-friendly technology can yield up to 8 times more throughput than Wireless-G in some situations."

From a practical standpoint in my home network, the main advantage is that it has eliminated dead spots. Before I installed the MIMO adapter, accessing my network from several rooms away was a bit of a hit-or-miss. Now I don't have to worry about it and the speed doesn't dramatically drop off as I move my laptop away from the router. The advantage will become more obvious if you're trying to move a video signal from a cable box or TiVO to a remote TV. MIMO makes using a WiFI network far more practical for video.

My advice: If you have a WiFi network that's working fine, than don't bother upgrading now. Prices will come down over time so you may as well wait. But if you're getting marginal coverage, you might want to consider upgrading to a MIMO router and if you need even better range or speed, consider also getting a MIMO adapter for your remote device.

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By Larry Magid