Spectrum hogs: Fit to be slaughtered?

George Ou: The war between the University of Texas and its students over scarce 2.4 GHz airwaves has gotten so ugly that the University banned 802.11 b/g device usage in the dorms. What's the solution?

COMMENTARY -- Remember the DSL-Cable wars? Pacbell had their hilarious "Web-hog" TV advertising campaign that depicted neighbors feuding over shared cable bandwidth and spray-painting insults on each other's homes. Well, that was then and this is now.

Today, the war is between the University of Texas and its students over the scarce 2.4 GHz airwaves. The dispute could be a harbinger of things to come for businesses and residences. In fact, the fight has gotten so ugly that the University has taken the draconian position of banning 802.11 b/g 2.4 GHz device usage in the dorms to prevent spectrum hogging.

It wasn't long ago that even the wireless chipset giants Broadcom and Atheros were pointing the finger at each other over their respective jacked up "Turbo" or "Afterburner" 802.11g mutations -- products that essentially hogged all three of 11g's 2.4 GHz channels to squeeze out a little more performance. Since then, they have cleaned up their bad neighbor behavior; their products will back down on multiple frequency usage if another device is within range trying to use one of the same channels. Fortunately, we have the 802.11n standard being hammered out by the IEEE to deliver much higher speeds without wasting multiple channels.

At the heart of the problem is the scarcity of channels in the 2.4 GHz unregulated range. When looking at the configuration console for an 802.11b or g-based Wi-Fi access point, one might be fooled into thinking that all 11 displayed channels are available. In reality, however, (barring a technical cheat that permits the usage of four channels), only three of those channels (1,6,11) are ones that, out of the box, don't interfere with each other.

If things weren't bad enough, Bluetooth radios and certain cordless phones also play in the 2.4 GHz range. Why not ban the use of 2.4 GHz cordless phones instead? (There are still 900 MHz phones for sale.) As the ZDNet news story mentions, 802.11a is still permitted, but most of these college students would have to fork out twice the money to go 802.11a or, worse, do a full retrofit of all their existing devices.

In the U.S., 802.11a has so far been granted eight non-overlapping channels by the FCC (In some countries, it's been granted 24 channels.) Ultimately, 802.11a is where a wireless society will have to go. But banning 802.11 b/g today is not the right thing to do, nor is it clear that the University has the authority to do so.

What the University should do is allocate two channels for student usage and two channels for campus infrastructure. The students, in turn, should negotiate power levels and channels alternating among their neighbors so that everyone is not blasting the spectrum at the same time. Better yet, the MIS students -- with the help of their professors -- could take this as the perfect learning opportunity to design and manage a highly saturated but harmonious 802.11 b/g environment.

The problem of spectrum collision will worsen with the proliferation of Wi-Fi. Only cooperation with your neighbors in business locations, at school, and at home will address the problem. The alternative -- fighting with your neighbors -- will result not only in poor or unworkable performance, but will do wonders for destroying your reputation.


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