Intersil Gives 11g a "Nitro" Speed Boost

By Ed Sutherland

April 24, 2003

The chip maker says this free software update will triple the speed of data flow on its PRISM GT and Duette-based 802.11g WLANS.

Imagine a Ferrari stuck behind a slow-moving mini-van and you can understand the quandary of high-speed 802.11g gear slowed to a crawl by wireless networks dominated by equipment based on the slower 802.11b standard. One Californian chipmaker wants to inject a little Nitro into your Wi-Fi connection.

Intersil , maker of the chips for companies such as Netgear and D-Link, has unveiled 'Nitro,' a free software fix enabling networks comprised mainly of 802.11g devices to triple the speed of data flow.

"With PRISM Nitro, our studies show up to a 3x improvement in performance for 802.11g clients operating in mixed-mode wireless networks," said Larry Ciaccia, vice president and general manager for Intersil's Wireless Networking Products Group.

In terms of data rates, Intersil says 11g users could see speeds climb to as much as 30Mbps in real world use.

The company says Nitro is the first turbo-mode for 11g based upon the standard's latest draft version -- 7.1 -- from the IEEE 802.11g Task Group. The software achieves its 3x improvement in throughput with "prioritization algorithms and enhanced protection mechanism," according to an Intersil statement.

The problem Nitro seeks to resolve is one that was known during the earliest stages of 802.11g's rollout: if 802.11b and 802.11g equipment are used side-by-side in a network, the effective speed of data transmission will drop.

Although 802.11g maintains backward compatibility with 11b, it comes at a price. While 11g and 11b operate in the same 2.4Ghz real estate, the two standards use differing modes when swapping data packets.

OFDM vs CCK

While 11g uses orthogonal frequency division multiplexing (OFDM), designed for faster standards, such as 802.11a, 11b employs slower complementary code keying (CCK), modulation. In order to maintain compatibility with 11b, the slower CCK must be accommodated by 11g. 802.11g includes a protection mechanism that stops 11b communication long enough for 11g packets to travel in a short burst. Unlike methods used by competitors, such as Atheros Communications, Intersil's Nitro burst handles several simultaneous data packets in the same channel.

By addressing the issue of mixed networks, Ciaccia said the software would allow the industry to "deliver on the high speed promise of 802.11g in real-world environments."

Nitro is aimed specifically at the company's multi-mode PRISM GT and PRISM Duette chipsets.

Intersil claims Nitro will work with "any draft 802.11g solution," but says other products on the market today do not "support even the minimum protection mechanisms required by the latest 802.11g draft standard."

Although targeted at the mixed network market, the company says Nitro "provides up to 50 percent greater throughput performance in homogenous 802.11g networks."

Because Nitro does not include the quality-of-service components needed for wireless multimedia, Intersil is advising the use of Nitro's "burst-mode" be limited to data transmission. But the company expects there to be an overall improvement in the efficiency of 11g networks.

"The .11g clients will now have sufficient bandwidth to stream video and take advantage of the higher total speed while .11b clients are present," according to Intersil.

Nitro will begin shipping this quarter.

802.11 Planet Conference Wondering what else is going to change about 802.11g this year? Join us at the 802.11 Planet Conference & Expo, June 25 - 27, 2003 at the World Trade Center Boston in Boston, MA. Intersil and others chip vendors will be on hand to discuss The State of 802.11g: Facts vs. FUD (that's Fear, Uncertainty, and Doubt).



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