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IceFyre Moves Into Dual Mode

Like a cryogenic patient emerging from deep freeze, chip startup IceFyre Semiconductor Corp. is waking to a changed world.

IceFyre was founded in 2001, at a time when it looked like 802.11a (which is capable of transmitting 54 Mbit/s over 5GHz frequencies) would eventually displace the slower 802.11b (which boasts a meager 11 Mbit/s over 2.4GHz). In fact, company officials say they first pitched themselves as an alternative to Atheros Communications, the startup that produced the industry's first commercially available 802.11a chips.

Of course, WLAN chic has taken over since then, with 802.11b propagating madly and pre-standard 802.11g products (capable of 54 Mbit/s over 2.4GHz) already hitting retail shelves.

No problem, IceFyre's founders say. Their specialty all along has been orthogonal frequency-division multiplexing (OFDM), a transmission technique that's common to 802.11a and 802.11g – and that suits IceFyre well for a dual-mode, 802.11a/g kind of world.

"Really we've developed a new class of OFDM baseband and radio," says Mark Roberts, vice president of marketing. "We always knew we had a strong value proposition for 802.11g, but the standard was moving so slowly [back then], there didn't seem to be much point pursuing it."

IceFyre is sampling the ICE5350, an 802.11a chip that integrates the radio, baseband, and power amplifier (there's one main piece it leaves out – more about that later). But its hopes are pinned mainly on two product lines in the works: the SureFyre chip set for 802.11a, and the TwinFyre 802.11a/g set.

SureFyre backpedals on the original strategy by separating out the power amplifier (PA); the company gets more output power by using a gallium arsenide (GaAs) PA, which can't be integrated with the radio/baseband chip. The PA will sample in the second quarter of 2003, followed by the combined radio and baseband chip in the third quarter. TwinFyre, which also keeps the PA separate, is due to sample in the first quarter of 2004.

IceFyre's been lying low for the past year, to the point where Atheros officials admit they didn't know if the company was dead or alive. But now the startup has begun making noise again: It recently began sampling its 802.11a chips and picked up $19 million in January from investors including Covington Capital and Motorola Inc. (NYSE: MOT).

IceFyre was also set to give the first demonstrations of its 802.11a chips at the recent Wireless Systems Design Conference and Expo -- but U.S. customs wouldn't let the Kanata, Ontario firm bring the equipment across the border.

So what's IceFyre got that Atheros doesn't? IceFyre claims its parts consume little power and can transmit at longer range than most 802.11b devices. Both advances stem from the way IceFyre handles OFDM.

OFDM splits a transmission into 52 mini-signals, 48 of which carry data. Each signal is then sent at a relatively low speed, avoiding the distortion inherent to higher data rates. On the receiving end, the slow-speed signals are summed together, resulting in total data throughput of up to 54 Mbit/s.

The problem is that those 48 signals can coincidentally join up to create spikes in signal amplitude, exactly like ocean waves that overlap to create a bigger wave. WLAN circuitry has to be prepared for such a spike, so most companies design extra wiggle room into the power amplifier, which makes the device less efficient overall.

IceFyre uses a proprietary algorithm to split the original transmission into halves, each of equal amplitude, thus avoiding the problem altogether. The two halves, when summed, reproduce the original, variable-amplitude signal. It's basically a math trick, but with real-world benefits.

But Atheros claims that makes for a less elegant design on the hardware side. "The tradeoff is more electronics, because some parts of the transmitter have to be doubled up," says Craig Barratt, vice president of technology.

Then there's the fact that Atheros' products have improved since 2001. Its second-generation 802.11a parts can match the range of 802.11b, and the new products skimp on power consumption too. Barratt claims Atheros' chipset runs at less than 1W, just like IceFyre's parts.

One quirk of IceFyre's design is that the media access controller (MAC) isn't included. Most companies fold this function into the baseband chip, but IceFyre officials say many OEMs have their own MACs, meaning they have to make provisions to bypass an integrated MAC.

It's an unusual approach, but it could be prosperous if consumer electronics firms develop their own MACs. Both IceFyre and Atheros are expecting consumer electronics to be a substantial market for standalone 802.11a chips, allowing high-definition TVs to pipe signals around the home. One example of this approach came this week when Matsushita, owners of the Panasonic brand, announced an 802.11a chipset for video (see Panasonic Intros Video WLAN).

— Craig Matsumoto, Senior Editor, Light Reading
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