October 2005

Hearing Multiple Signals

MIMO, the new wireless technology, promises faster and more powerful Wi-Fi. But just how well does it work?

By Michael Fitzgerald

Anyone who uses wireless anything -- a Wi-Fi network at a hotel, cellular phones, BlackBerries -- knows some of the problems with the technology: Wireless networks transmit data much more slowly than most wired ones, they don't always work, and they have a maddening tendency to disconnect without warning. There's a constant worry of being out of range or having a bad connection.

Still, each new generation of wireless gadgets gets better, generally cheaper, and seemingly more popular. Now an emerging wireless networking technology called MIMO promises real breakthroughs in speed, accessibility, and reliability. That has implications for today's corporate networks, home Wi-Fi networks, and cellular networks.

MIMO stands for "multiple input, multiple output." Wi-Fi routers based on the technology use a series of radios in conjunction with several "smart" antennas to send and receive signals simultaneously. Handling multiple signals makes possible much stronger, more reliable, and faster transmissions -- in theory.

Consumers will see MIMO in a new class of wireless networking products categorized as "pre-n," after the nomenclature of the Institute of Electrical and Electronics Engineers' 802.11 wireless Ethernet standards committee. The IEEE wireless standards with the broadest impact have been, in the order in which they reached market, 802.11b, 802.11a, and 802.11g.

There is not yet an 802.11n, but the consumer market for pre-n products is already flourishing. One of the leading manufacturers, Airgo Networks, a Palo Alto, CA, startup, has already sold more than four million MIMO chipsets, which appear in wireless networking routers and adaptors from LinkSys, Belkin, and other vendors.

Indeed, while MIMO has not yet become a Wi-Fi standard, routers and PC cards based on it are easy to find, both online and in stores. Samsung has even put MIMO on the motherboards of two of its notebook computer models selling in Asia and Europe (most U.S. electronics companies are expected to wait until the IEEE approves its standard before integrating MIMO into their systems). Meanwhile, Orthogon Systems, a British startup, has begun offering networking equipment aimed at long-range networks that uses a method similar to MIMO.

To see how well MIMO actually works, I bought a Belkin router that uses the Airgo chipset. The router is equipped with three radios and three antennas, which are intended to increase its range, reliability, and speed. In fact, Belkin claims an 800 percent improvement in coverage area over the best of current Wi-Fi routers and a 600 percent improvement in speed.

I had not previously set up a wireless router. And since my technical skills mostly involve breaking things in ways their makers had not imagined, I expected a challenge. I popped the installation CD into my notebook's drive and followed the instructions. When it came time, I plugged in the router, which boasted four Ethernet ports to connect to PCs, one port for the modem, and a plug for a power cord on one end and three nubby antennas sticking out of the other. Windows XP Home Edition, which I use, protested that I was installing an unknown device that could destabilize my system. Nevertheless, I pressed on.

To get Internet access, I ran a cable from my DSL modem to the router, which sits in my basement office, and then another cable from the router to my notebook computer. That worked fine. But when I installed the MIMO notebook card and pulled the cable, I lost my connection. It took a bit of poking around in the software that comes with the system to realize I needed to tell it to activate. (Okay, so the truth is, I was on the phone interviewing someone for this story and complained about the lost connection. He asked me whether the radio was on. One right-click of the mouse later, it was.)