Wi-Fi Takes On Bluetooth

Ozmo hopes to replace Bluetooth with the Wi-Fi that computers already have

PHOTO: Anna Demain

Why does a laptop need both Wi-Fi and Bluetooth? A Bluetooth chip creates a personal area network, allowing peripherals like keyboards, mice, and headsets to communicate wirelessly with a laptop or mobile phone. But why can't that network be a subset of the Wi-Fi local area network? Why can't Wi-Fi manage all our wireless communications?

Two big problems have prevented convergence, but they've both been solved by Ozmo Devices, a Palo Alto, Calif., start-up--and at a data rate that's much faster than Bluetooth's.

First, while a computer's Wiâ''Fi can communicate with other Wi-Fi devices, it cannot do so at the same time it's talking with a router. So for a Wiâ''Fi–enabled keyboard to interact with a laptop computer without taking it off-line, the keyboard would need to contact the router, which would then route the data back to the laptop. But this is so inefficient that users would notice delays in keystrokes showing up onscreen.

Ozmo has written a software patch that allows a laptop's Wiâ''Fi to communicate in tiny time slices, using some to talk with local peripheral devices and the rest to maintain its connection to the router. Company cofounder Roel Peeters says the strategy of letting the laptop talk directly to a peripheral keeps latency to about 10 milliseconds, the same as Bluetooth's.

Second, Wi-Fi is notorious for the way it sucks up power--typically cutting a laptop's battery time in half, making Wiâ''Fi unsuitable for a small-battery-powered headset or keyboard. Ozmo's chip set not only draws far less power than off-the-shelf chips but also outperforms Bluetooth, because it goes to sleep when not actively engaged in sending or receiving data. Based on inâ''house testing, Peeters estimates the power consumption to be one-third to one-fourth that of Bluetooth's. The tradeoff is the peripheral's data rate--9 megabits per second versus Wi-Fi's standard 54 Mb/s. Still, that's three times as fast as Bluetooth's top speed.

Intel had already been working to add personal area networking to Wi-Fi when Ozmo's chip set came along. Intel's ambitious research initiative, dubbed Cliffside, is expected to allow much higher data rates so that a computer could send a high-definition movie directly to a television screen, for example. Cliffside is far from commercial release, but in the meantime, Intel has adopted Ozmo's technology for the lower end of the data-rate continuum. New Centrino-based laptops will come with Ozmo's software patch.

Any reports of the impending death of Bluetooth may be exaggerated, however, or at least greatly premature. The first Wi-Fi peripherals with Ozmo's chip set won't ship until 2009. Meanwhile, Bluetooth is shipped in half the world's cellphones, one-third of its laptops, and, in 2007 alone, 7 million cars. The Bluetooth Special Interest Group, a trade association, claims the technology is embedded in more than a billion devices today.

Belkin International, in Compton, Calif., will be one of the first to come out with Wiâ''Fi–enabled keyboards, mice, and headsets. But the company expects to sell them only with new PCs, according to senior technologist Brian Van Harlingen. It can take years to displace an existing technology, no matter how technically superior the new one might be.

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