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Legal, but "irrelevant" - 802.11g gets FCC green light

Theoretically, the path to 50 megabit WiFi is open. The FCC has changed its rules on what American users can do with the modulation technologies in wireless - making 802.11g legal in the USA. But does this actually matter if it doesn't work?

The last legal barrier in America may have been relaxed; but Nick Hunn of TDK Grey Cell believes it is irrelevant; 802.11g is, he says, a useless technology which will probably never get off the ground.

Writing here on NewsWireless Net Hunn described 11g as "the standard we don't need."

Essentially, 11g provides 50 megabits per second - the same data throughput as 11a - at 11b WiFi frequencies - in theory. Hunn believes it simply won't work in the real world.

Hunn said: "In order to take off, wireless LAN needs to be seen as simple. Users don't want confusion or interoperability problems. Unfortunately one part of the standards body has forgotten this and is threatening to wreck user confidence with the 'interim' standard of 802.11g."

It may be that 802.11g was a good idea at the time, when the road to .11a silicon looked long and arduous, Hunn wrote. "However, infighting between its proponents has delayed .11g to the point that it is now irrelevant and deserves a mercy killing."

He doesn't believe 11g will work. "By the time it arrives there will also be over 100 million Bluetooth devices around, all using the same chunk of spectrum as 802.11g. They'll provide a level of interference which ensures that 802.11g will fail to offer its potential increase in speed – it will just keep on stepping down to 802.11b data rates. There will also be around 20 million 802.11b devices in service and the backward compatibility modes of 802.11g ensure that if they're detected 802.11g once again slows back to 802.11b rates."

And Hunn concludes: "In other words the only place where 802.11g products will attain their promised higher speeds will be inside a screened box."

Gartner has greeted the FCC's ruling with some enthusiasm. "There are two important components to the FCC's ruling," and actually thinks it will make more difference to Bluetooth, than to wireless LAN technologies.

One important component of the ruling, says Gartner, frees Bluetooth from the requirement to evenly hop all through the 2.4-gigahertz band. This relaxation allows Bluetooth to perform collision avoidance between other radio systems and itself, making it easier to design reliable wireless networks that support multiple protocols.

Analyst Martin Reynolds said: "Think of the wireless spectrum as a three-lane highway in which all drivers are required to change lanes every 10 seconds — not so bad when the roads are empty, but a probable disaster when traffic mounts. The ruling makes life easier for designers of devices supporting multiple protocols."

These rulings apply to the United States only. Nonetheless, they will likely spur commercial development of the technologies and be adopted by other countries, says Reynolds.

The other ruling relates to the 802.11a standard, which uses OFDM (orthogonal frequency division multiplexing). "This technology is now allowed in the 2.4-gigahertz band - under similar rules to the FHSS technology used in Bluetooth, and the direct sequence spread spectrum (DSSS) technology used in 802.11b, writes Reynolds in a news analysis piece this week." [*see footnote] "OFDM is a recent entrant to the modulation game, effectively bundling dozens of high-bandwidth transmitters into a single channel."

This bundling is made possible by the influence of Moore's Law on digital signal processors, which are now powerful and cheap enough to realize this technology, writes Reynolds. "Therefore, 802.11g — the high-bandwidth alternative to 802.11b — is now legal. We believe that 802.11g will be bracketed by 802.11a at the high end, and by 802.11b everywhere else. However, it is effectively 'free' when used in a dual-band radio, so it will likely appeal to market niches."

* The Gartner report can be found at " Gartner's news analysis pages. I'd give the specific URL, but cleverly, Gartner uses Javascript to point to it and opens it in a restricted window; but follow this link, and search for "wireless" and you'll find it.