A Florida-based WiFi startup is developing chips to enable full-duplex WiFi repeaters, a step up from the half-duplex repeaters in use today.
WiDeFi Inc. of Satellite Beach, Fla., said Thursday it has raised $6.8 million in venture capital that it will use to further develop its repeater chips, which are due to enter production about April 2005, a WiDeFi executive said. WiDeFis funding was led by The Aurora Funds Inc. of Research Triangle Park, N.C., and Axiom Venture Partners of Hartford, Conn.
Depending on the signal strength, sources of interference and other variables, a WiFi access points range averages about 100 meters. WiFi repeaters, from companies such as Buffalo Technology Inc., Cisco Systems Inc.s Linksys division and D-Link Inc., are common and can extend the range of a wireless network still farther, using chips from Broadcom Corp. and Texas Instruments Inc.
But todays repeaters have a weakness: They work only in “half-duplex” mode, in which the radio listens for part of the time and broadcasts for part of the time on the same frequency, according to Brian Verenkoff, a marketing engineer for Buffalo Technology in Austin, Texas. Until recently, the repeaters, which serve as a Layer 2 bridge, couldnt maintain the WPA security protocol. If theres any interference, the repeater may simply drop the packet, Verenkoff said.
WiDeFis technology includes two radios on the same chip that can both listen to and transmit information. The technology works as a Layer 1 bridge, simply repeating what the chip hears on a slightly offset frequency to avoid interference, according to Ken Gainey, vice president of engineering at WiDeFi. Thats especially important for technologies such as voice over IP (VOIP), where random jitter can add latency to a voice conversation.
The two radios also mean that the chip will be standards-agnostic, Gainey said. “Our product doesnt care if its 802.11b or [802.11]g, or if theres some new standard for wireless LAN,” Gainey said.
WiDeFis technology also will be able to be used with WiMAX, the broadband wireless standard expected to roll out in chips from Intel Corp. and others late this year.
WiDeFis repeater does inject some delay into the signal, but that delay is constant, a critical element for quality-of-service broadcasts, Gainey said. WiDeFi hopes to ship its first sample chips in December to router manufacturers in the United States and Taiwan, he said.
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