Weblogsinc today links to an ABI Research piece claiming UWB is about to be done-in by disputes over standards and 802.11n.
I haven't seen such basic scientific ignorance in a long, long time.
Let's start at the beginning, shall we? (Those are UWB pulses, from AT&T.)
The shorter the wave, the less distance it can go before it attenuates, or basically dies away. (It's just like waves coming to the beach...some don't make it onshore.)
At the same time, it takes less power to generate a very high-frequency wave than a low-frequency wave. That's why an AM radio tower is so large while mobile phone repeaters can be so small.
What you can do with a wave, in other words, depends on its frequency and power. DeWayne Hendricks could cover Tonga with broadband because he was using broad swathes of low frequencies at high power, and those frequencies are licensed to broadcasters in the U.S.
What does this have to do with the competitive nature of 802.11 vs. UWB? Everything.
The 802.11 bands are set at around 2.4 GHz and a set of swaths between 5.4-5.8 GHz. (And it's a continuous wave, as to the right, not the pulses of UWB.) On the other hand, UWB rides under the "noise floor" (think of it as background radio radiation) between 3-7 GHz. So you have relatively tight bands at low frequencies against a huge swath of frequency under minimal power (to keep under that floor).
UWB, in other words, is a very low range technology. The main uses today are for seeing bodies through walls and for getting very short distances. An 802.11 signal, on the other hand, can go all over your house quite easily.
The two can easily work together in an Always-On home. You could stick a server the size of a refrigerator magnet on the refrigerator, with a UWB radio that might read RFID tags on the food inside. The server (it could be a few chips, or a minimal hard drive) would maintain a database that could be transmitted, via an 802.11 link, to a main server in the living room, and then on to the wider Internet.
In other words, they're complementary, not competitive, due to the nature of the frequencies they use and how they work. You're not going to build an in-building LAN with UWB, and you're not going to get through metal walls with 802.11.
Why pretend otherwise? Because someone sees just one market and two products.
Dana Blankenhorn has been a business journalist for over 25 years and has covered the online world professionally since 1985. He founded the "Interactive Age Daily" for CMP Media, and has written for the Chicago Tribune, Advertising Age, and dozens of other publications over the years.
1. Jesse Kopelman on November 9, 2004 12:22 PM writes...
Your point is correct, but some of your technical arguments are not. Since all flavors of 802.11 use digital modulation techniques, it is not really continuous wave (CW is analog). Also, AM towers are big because AM antennae are big. The size of an antenna is proportional to the wavelength (and thus frequency). Lower frequency waves are bigger and need bigger antennae. Finally, the propagation characteristics of a wave are far more important than the power at which it is transmitted. The frequency factor is exponential, while transmit power is linear. Some frequencies also have special characteristics that extend their terrerstrial range (AM) or decrease it (60GHz) vs. what one would expect from free-space propagation.
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