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LinCom boards bandwagon for dual-mode 802.11

Posted: 11 Jan 2002 ?? ?Print Version ?Bookmark and Share

Keywords:lincom? lincom wireless? wireless chip? rfic? ieee 802.11a?

LinCom Wireless Inc. is the latest in a growing list of wireless chip vendors vying to deliver IEEE 802.11a and 802.11b combo solutions later this year. "We will be one of the first companies" to supply such a chip, promised Vince Hu, cofounder and president of the Los Angeles-based fabless semiconductor company.

LinCom is developing a chipset, called ComboLink, that includes both the 802.11a and .11b modems, MAC software and a dual-band, direct-conversion RFIC.

Practically every startup with 802.11a plans is now promising to provide some kind of dual-mode chipset, said Navin Sabharwal, vice president of residential and networking technologies at Allied Business Intelligence Inc. But none will actually ship such a combo product until the third or fourth quarter, he added.

Those already developing dual solutions include Envara Inc.; Resonext Communications Inc.; a partnership of Spirea AB and Embedded Wireless Devices Inc.; and Systemonic. That latter startup, which originated at Dresden University in Germany, recently acquired products and IP developed by Raytheon Co.'s RF networking group.

"Wireless chip vendors are feeling heat not only from system OEMs but also from Microsoft Corp.," said Sabharwal. OEMs are demanding a seamless solution that allows a transition from today's widely accepted 802.11b standard to 802.11a. And Microsoft, which already supports 802.11b natively in its XP OS, has said that to get Windows certification, any 802.11a device must be backward-compatible with 802.11b.

Still, 802.11a and 11b dual-mode product development is said to involve some heady engineering feats to achieve reasonable yields at a palatable premium over 802.11a-only solutions. The MAC portion must be based on an architecture flexible and powerful enough to handle switching of multiple protocols, said Sabharwal. Even harder is the integration of the two radios handling the 2.5GHz band for 802.11b and the 5GHz band for 802.11a, he said, and "there are not a lot of examples out there yet" based on a unified, dual-band architecture using a minimum number of components.

Instead of putting two separate radios together, LinCom is developing a dual-band direct-conversion RF IC. Although the company declined to detail the architecture, Hu said much of the risk involved in developing 802.11a and .11b standards-based wireless technologies "is already behind us." We think we have a leg up on others, as both of our 802.11a and 11b modems are already working."

The company is planning to offer its ComboLink chipsetincluding the dual-band RFIC, baseband chip and MAC softwarefor about $35. That's close to the price of an 802.11a-only product, Hu said.

What about 802.11g?

It is unclear whether the .11a-and-.11b combo will prove a popular solution. It's possible that a dual-mode chipset pairing the 802.11a and upcoming 802.11g standards will end up dominating the market. The 802.11g spec has been developed to offer the same data rate as 802.11a yet maintain backward compatibility with .11b, without two radios.

Following many months of contentious lobbying and voting, the IEEE in November finally passed a proposal for 802.11g that will boost data rates in the 2.4GHz spectrum from the 11Mbps now possible with 802.11b to a maximum rate of 54Mbps.

The proposal calls for two modulation/access schemes: complementary code keying, used in 802.11b, and the newly permitted OFDM, used in the 5GHz 802.11a standard.

LinCom Wireless' focus for the time being is on the 802.11a and .11b combination. However, Craig Lewis, director of sales and marketing, claimed that the same solution, designed for network interface card applications, will be able to support 802.11g's mandatory modea wireless solution based on OFDM operating in the 2.4GHz band.

"I think that 802.11g can go either way," said analyst Sabharwal. "It could get so widespread that it becomes a de facto 802.11b standard. Or the market may find 802.11g too confusing, so that it goes straight to 802.11a" and skips .11g entirely.

So far, the only company with a combined 802.11g and .11a solution on the road map is Intersil Corp., which together with Texas Instruments Inc. is a major proponent of 802.11g. Intersil could be a dark horse if the market embraces 802.11g, Sabharwal observed.

Junko Yoshida

EE Times





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