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Battle between Bluetooth and WiFi; postponed

Both Bluetooth and Wifi (802.11b) use the same frequency spectrum, and there are fears of destructive interference. And the IEEE is trying to avoid the battle - but is it really working towards peace?

The problem facing the IEEE is a fundamental one. The Bluetooth SIG wants to keep its current spec stable, so that customers are able to buy with a certainty that things won't go out of date. By contrast, the 802.11 wireless LAN groups are stuck with an obsolete design with obsolete security, and wants to update both as quickly as possible.

Propaganda is the main weapon, not technology, in this battle.

The 802 committee and the IEEE would appear to have found a sympathetic listener in Glenn Fleishman, who wrote an excellent dissertation for O'Reilly explaining the origins of all the various wireless standards, and explaining the internal politics of task group G of the 802 committee, and the need to get a faster WLAN standard.

Fleishman's take was that "Bluetooth would be a woodpecker in the 802.11b tree, reducing throughput on both systems" which isn't a bad summary, according to those who have actually deployed both Bluetooth and WiFi in the same area. According to pioneering Bluetooth access point installer Red-M, there is a reduction of bandwidth in both if they're on top of each other.

"Fortunately," continued Fleishman, "the IEEE's Personal Area Network (PAN) working group, 802.15, had prioritized work on co-existence between Bluetooth and 802.11b, as well as future 802 wireless specs. The 802.15.2 task group recently approved a proposal that allows adaptive hopping, in which Bluetooth transceivers can avoid heavily trafficked frequencies, benefiting both systems."

Which sounds brilliant; but it requires Bluetooth SIG to abandon its hardline goal of keeping version 1.1 stable - and rush out a new version. It almost certainly isn't going to happen.

According to Cconvergence the SIG rejected the IEEE's approach: "Our position is that version 1.1 of the specification is stable and robust and the focus is now on bringing products to market that use that version. There is no version 2.0 [under development] at this time."

Nick Hunn, managing director of TDK Grey Cell, was more forthright, says Cconvergence, and described this plan as one of several "bully-boy schemes coming out of the 802.11b industry to say that wireless LAN should always win over Bluetooth."

It's probably premature to predict any immediate resolution of the dispute. The 802 committee has yet to finalise the 11g (54 megabits at 2.4 GHz) standard, and it is almost certainly going to a second ballot this week. That uncertainty means that any other negotiations pending will stay on hold until people know where the 802 people are going.