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These folks didn't seem to have too much trouble trying to get the signal through walls ;)

http://www.uwb.org/RadarVision2i/rv2iperf.htm
That is a pretty primitive picture, some of the stuff in labs is quite a bit more advanced.

BTW, is anyone noticing font corruption on that page in Firefox?

UWB radar. Ultra-Wideband Radar. Uses ultra short pulses. Go here: http://www.uwb.org/

..But I came out of the article wanting to know more about UWB

For internet access, WiFi outstrips DSL, Cable, and even Corporate T1s. I'm more concerned about getting honest Broadband (100 Megabits/sec or more) to the home. Cordless internet is fast enough for now.

--Mike--

I find the discussion about '.mobile' somewhat boring, just because I have yet to see a really compelling mobile phone/online experience.

All announced next-gen phone chips are coming with WiFi integrated. What happens when your WiFi access point allows cellular users to roam? Then you can do cool things like walk into work and have your work phone routed to your cell phone. Similarly, you can walk into your house and your home phone rings on your cell phone (or verse-visa). Videoconferencing, picture taking, movie taking, music video, DVD movies (that are blasted to your TV via UWB)...

Its all coming soon. Of course, a new TLD isn't really needed but it will fit in there somewhere.

Bah, who needs a new bluetooth when Ultra Wideband can do it better anyway?

Or is that what they are going to call it?

Here are a few more articles on the subject that IMHO are a bit more substantive:

From BusinessWeek

From M Commerce Times

Some Information on its Problems:

A brief primer from the Ultra Wideband Working Group

And a very in depth look at the history of UWB

-john

Here's a FAQ from the Ultra Wideband Working Group.

It's not clear that it will be allowed to be deployed widely, since it may in fact interfere with the spectrum allocated for other uses. As the U.S. Governmetn's Ultrawideband (UWB) Signal Characterization Project says:

Many claims have been made that UWB communication transmitters can effectively share spectrum with existing users. Some of these claims have not been independently verified.

We'll have to wait and see...

Through Google I found the UWBWG, and there's lots of detailed papers at Aetherwire. Interesting reading.

Why should you have to pour the millions of dollars in maintainance of a VLA sized unit to talk to a sat that costs a fraction of a percent of the ground station?

Because the ground station is reusable?

Regardless, if you can narrow your signal to a specific enough frequency, you could pick it up with an accurate amature ham set.

All this talk about more transmission power being better...drives me nuts. If people can limit their transmissions to extremely specific frequency ranges (or use timed broad-spectrum pulses)

Where do they get these guys? First he says that it doesn't use any spectrum...then he says that anything below 2 GHz will interfere with existing Nav and Comm systems. Gotta be one or the other. Can't be both.

Yes, it can be both

UWB works by sending single-cycle pulses. The information is carried by when the pulse is transmitted with respect to a reference.

Since there is no carrier, it doesn't affect a specific part of the spectrum. However, since there is no carrier, it affects all parts of the spectrum by adding to the noise floor. That is what the big problem with this technology is and why the FCC is looking so closely at it. The UWB Consortium has more information.

Personally I don't see a problem with raising the noise floor for this technology because, as I understand it, it raises the floor uniformly and, if I understand this correctly, the actual number of devices transmitting doesn't play into this.

I've been interested in this for a while. Time Domain (warning, flash-heavy site) is a company which has been playing with this for a long long time. I was rather skeptical of this when I first heard of it but my opinions on it are changing. Hell even EDN had an article on it.

The only thing I don't quite grok is how they can get two devices to have such rock-solid stable time references (we're talking sub-picosecond jitter) without secondary clock transmitters and keep them that way. If anyone out there can help shed some light on it I'd love to hear from you.

erhaps I don't fully understand this invention, but to me it sure looks like snake oil.

You don't understand the technology.

Check out the Ultra WideBand Working Group, time domain (mentioned in the article) and dozens of other sites. The pulses are what makes this thing work and the spectral splattering is exactly intended. They're trying to get FCC approval since it doesn't cause (enough) harmful interference to take down communications with existing equipment.

It's way cool stuff. Check the UWB link provided; they want to use this for positioning, through-wall "radar" and communications. It has very serious potential. If I can find the EDN issue which gave an in-depth study of this I'll post back.

I've been keeping my eye on Ultra WideBand for a while now; it has very surprising uses in positioning, communication and measurement. There's even a working group which tries to keep tabs on the entire area.

Years ago I heard about time-domain. I don't work for them but when I first heard of them I thought it was vaporware. I'm kind of sorry I didn't take them seriously the first time around.

At 5GHz, walls attentuate the signal even more than at 2.4GHz, the 802.11b standard, so it remains to be seen how close you will get to the 54MBs signalling rate. With the MAC protocol overhead, even in the best enviroment, you'll loose between 30-50%. This is not just a wireless feature, 100 MBs Ethernet also gets a MAC penalty, just not as much as wireless.

What will really impress the geek in all of us is a new wireless products utilizing Ultra Wide Band (UWB) techniques. A UWB radio tranmits its signal using gaussian monocycles instead of sine waves. With ultra-low power emmisions and over 2GHz of spectrum, conventional narrow-band systems are not disturbed and UWB signals appear as white noise making UWB very hard to detect. Highspeed bandwith, precise precision and location, and RADAR capabilities are being demonstrated today. A leader in the field is Time Domain. The FCC is expected to rule on legalizing UWB this fall.

'Impulse radio' is a lot more than just an "interesting wireless link," it is a technology that will revolutionize our use of the radio spectrum. Rather than transmitting information as modulations in an analogue radio wave's frequency or amplitude (FM or AM), Time Modulated Ultra Wideband transmits information in RF pulses (called monocylces), positioned with an accuracy of trillionths of a second. It operates with just miliwatts of power, yet signals can be received for over a mile.

I first read about TimeDomain several years ago. The technology sounded pretty much ready to go, but they were being stymied by the vast regulatory bueracracy that is the FCC (selling radio spectrum is a cash cow, and if you were the FCC, would you eagerly antiquate a profitable revenue stream?). TimeDomain was also duking it out with an Alphabet Soup Government agency (one of the national laboratories?) over who had patent rights, those issues have recently been resolved.

There have been some comments about bandwidth congestion - ultrawideband technology will virtually eliminate all such concerns. Sending out around a milliwatt of power, spread over several GHz of bandwidth, makes it difficult to tell the difference between signal and background noise.

TimeDomain's homepage - http://www.time-domain.com/
The Ultra Wideband Working Group site - http://www.uwb.org/
NY Times Article (1998) - http://www.n ytimes.com/library/tech/98/12/biztech/articles/21t ime.html
Time Domain's Coverage in national media - http://www.time-domain.com/news/newss ect.html

Battery life with some grunt is important for some applications, such as for a public neural LAN. (an R&D project I am currently working on.)
High-bandwidth often requires high speed CPU grunt to make routing decisions and other network monitoring tasks. Especially with the promise of UltraWideBand technology becoming available in the future, I look forward to the day of being able to power an external node purely by a low cost low power solar panel.
A transceiver which is barely indistinguishable from noise, transmits data at 5Mbps and can run on a pen light battery for a couple of years.
Wack a couple of these together with a Transmeta CPU, solar panel (enough to power two 50uW 5Mbps transmitters) to create a node on a publically accessable neural network and 'Voila'!
A self-configuring, self-healing, low-cost, high-bandwidth, high-density network.
I'm interested in doing it! If anyone else is, please let me know.
Check it out at www.uwb.org.
C.Burgess - email: colvinb@eclectic.com.au

Ultrawideband is a form of spread spectrum. The major difference between it and traditional forms of spread spectrum is that it is spread over a band which is wide relative to the center frequency (>25% of center frequency)

For example, Qualcomm's CDMA is spread over 1.25MHz around a center frequency in the 800MHz band while a typical UWB system covers over 1GHz starting at around 500MHz.

Conventional spread spectrum systems use frequency hopping or direct sequence to spread the signal. UWB uses a simple and often forgotten form of spread spectrum called time hopping where short pulses are transmitted at pseudo-random intervals. The reason this modulation is used is simply because FH and DS cannot be practically implemented over such a wide bandwidth.

It's not new. It has been used in jamming resistant radars for at least two decades. What's new is an implementation on a single chip which is potentially cheaper than even conventional carrier-based RF technology at large quantities.

The primary advantage of ultrawideband is its insensitivity to fading. Narrowband transmissions can experience significant attenuation of the signal due to signals travelling through different reflection paths canceling out each other. A wideband signal is virtually immune to this and therefore requires about 20db less power usually taken as a safety margin against fading.

Ultrawideband systems can communicate over significant distances using a lower power spectral density than the electromagnetic noise generated by a typical computer.

The primary limitation to using ultrawideband systems is the wording of part 15 of FCC rules - apparently while your computer is allowed to pollute the spectrum for no good reason it is not allowed to transmit the same power INTENTIONALLY.

The FCC has issued a NOI (Notice Of Inquiry) seeking comments on possible change to these rules. Opposing comments come from the usual suspects: mostly users of the restricted bands such as government agencies.

Links:

Ultrawideband working group
Aetherwire - makers of an ultrawideband gizmo called the locator which is both exciting and very frightening.