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UWB Wireless Access Could Be Here Soon
fluppy88 writes: "802.11b doesn't have anything on UWB. With a potential of 1000M bits/sec it blows the pants out of 802.11b and doesn't eat up the tightly controlled spectrum. This article on CNN gives an interesting introduction to UWB, another candidate in the future of wireless." It was mentioned here a while ago, but much more mired in controversy about whose idea it was. Now there are several companies which seem anxious to get products based on UWB to market -- if it's approved.
I've seen news about a 802.11(a) that was supposed to do something like 100Mb/sec speed!
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:)
<a href = "http://www.80211-planet.com/news/article/0,4000,
802.11a 54-100Mb/sec</a>
(the hell with the alphabet's order i guess?
Now my question is, are these "standards" going to be backward compatible like ethernet on a switch or are we going to see technologie switch every 3 months?
It doesn't cost a fortune to use/implement, it might blow the pants off of 802.11b.
Hooking up some 70 dollar wireless ethernet cards makes 802 pretty damn cool, even if it is only an 11mbit (compared to 1000) connection.
Here is the correct link:
(damnit, i have to type more text than HTML tag to get past the lameness filter Argh!!)
802.11a 54-100Mb/sec
I wonder what that means? The FCC is going to kill this quick if it messes with GPS, which is IMO, more important.
All of the subjectivity in (how one defines unacceptable) will probably cause everyone to take a few more years before they start doing anything with this.
-- Dan
For one thing, because UWB pulses don't actually use a traditional radio signal, called a carrier, UWB transmissions don't take up any of the radio spectrum. Spectrum is limited, and demand for it is growing fast. That's one reason for the FCC interest: UWB would allow a whole new class, and volume, of voice and data communications that, in effect, wouldn't take up any more "space" in the crowded radio spectrum.
But there is concern that UWB transmissions, especially for UWB devices that will operate below about 2 GHz, will interfere with other broadcasts. These include the Global Positioning System (GPS), public safety nets, air traffic, marine navigation and communications, AM and FM radio, and television broadcasts, to name just a few.
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.
(BTW pulse transmissions do take up spectrum, even if they don't have a carrier...)
You're using her as bait, Master!
Another technical and practical article at Intel - Ultra-Wideband Technology for Short- or Medium-Range Wireless Communications
...and IF it is approved outside the US as well!
This is not unimportant. Prices drop and rapid adoption increases when a standard is worldwide (like 802.11b on 2.4 GHz).
The 5 GHz equivalent of 802.11b (.a) will be approved at the world radio freqeuency conference in 2003 (light speed for governments) - and I was already told by the British govt Radio Agency
that the UK frequency will differ slightly from the US frequency. And that the 5 GHz standard wil be approved for commercial use (unlike the current 2.4 GHz standard).
That's just for one country, the UK. Imagine when all others (Japan, Europe, etc) also get in on the act. Result: nothing moves.
So, nice as all these new 'standards' are, I am afraid they will slow down wireless adoption.
---
BDOS ERR ON A:>
Honestly this reads like an advertisement for an also-ran technology. The difference being that in the computer space under consideration this technology doesn't even run. It's predicted that it could be great, but so was bluetooth. And neither one is here for any practical use. See that word 'potential'. That's all this is. A potential technology for use by us with personal computers and the desire for wireless bandwidth. 802.11b (and a) are real technologies. And 802.11b is here today working at speeds far above what most users need (the highest speed DSL or Cable Modem lines can't saturate this link). Tomorrow's 802.11a is 5x the speed and not significantly more complex. Do you really want your wireless data transmissions being interfered with by the 'noise' coming off a Pentium chip?
Some choice cuts:
The low power limits the range, but there are features of pulse transmission and some tuning techniques that can, in effect, extend or maintain the range.
But there is concern that UWB transmissions, especially for UWB devices that will operate below about 2 GHz, will interfere with other broadcasts. These include the Global Positioning System (GPS), public safety nets, air traffic, marine navigation and communications, AM and FM radio, and television broadcasts, to name just a few.
"There are substantial disagreements [among the interested parties], especially over what are the adequate margins for protecting these bands against interference," says Julius Knapp, deputy chief of the FCC's Office of Equipment and Technology. "FCC Chairman [Michael] Powell has said to Congress that we'll address the issue before the end of this year."
Looks like trouble!
There is no free lunch. Any RF communications system, no matter what buzz-words it has, uses RF spectrum. UWB is a broadband noise source. Depending on siting, power levels, and the number of devices deployed, this could cause severe interference to other users of the RF spectrum. Your car may not emit much pollution, but when 5 million of your neighbors drive cars, we have a problem. Due to inadequate FCC regulations, there is already a high level of RF noise in many places.
Mea navis aericumbens anguillis abundat
The article doesn't seem to say, but since the system is digital AND operating in the same part of the spectrum currently dominated by electrical noise, wouldn't they have a problem with occasional incorrect bits? Especially as distance increased and the signal strength got closer to background levels.
Anyone know what kind of fault tolerance is built into this thing? How do they deal with the interference that's already there?
From the article:
For one thing, because UWB pulses don't actually use a traditional radio signal, called a carrier, UWB transmissions don't take up any of the radio spectrum.
Third, because UWB operates in the electronic "noise" area of the spectrum, it requires little power.
So, it's just like a regular spread spectrum technology. Yay, let's everyone use this! We'll just add loads of background noise to wherevere we use this technology. "We're not using any radio spectrum" is pure bollocks. Of course they are using it, just for an extremely wide range of frequencies, so it seems like background noise. Fine as long as you only have one or two transmitters. How do you think it would work with existing system when there are many more users?
I just find it strange that CNN buys the hype.
I know this is not the most practical question, but I have been wondering for a while whether it would is possible to do a Search for ExtraTerristrial Intelligence (or a sky survey for whatever reason) for ultrawide band signals. I've heard that it is very difficult to detect UWB if you don't know exactly what you're looking for, but perhaps someone who knows a lot about ultrawideband could comment on its general detectability.
For the typical HOME user, 802.11b should be more than enough speed. MAX I've even gotten to the internet is about 5 meg and that was an odd circumstance, and for local file serving, heck my hard drive cant even write/read that fast What i'd be most interested in seeing is a greatly improved RANGE, so I could walk down to the beach with my laptop, sit in the sun and have internet access.. maybe even have a beach cam for all those great views at the beach... of the sunset of course.
Don't Tread on Me
This weeks issue of network world has an article on UWB as well. You can read it online atc us .html
http://www.nwfusion.com/news/2001/0827specialfo
Jeff Knox
Much the same claims were made for spread-spectrum technologies such as CDMA, where it was believed that the same frequencies could be used for multiple simultaneous transmissions. The results for customers of vendors who believed the hype has been pretty awful - Sprint PCS for instance, a CDMA user, has a well-deserved reputation for having capacity problems in most areas, even in the poorly populated rural areas where CDMA is supposed to be such a godsend.
It's possible that UWB has no affect on other systems using the same frequencies, but unless it's proven in widespread use, this is going to be hard to believe. At the very least, interference (CDMA's albatross) is likely to be a factor, reducing the effectiveness of each transmission.
Given the same article is claiming that UWB can't be used for frequencies below 2GHz for fear of interfering with existing transmissions, I suspect that no serious scientist trusts all of the claims of UWB supporters.
And the thing I find most annoying: UWB may actually be useful, just as the world is better for spread spectrum technologies, and FM, and all the other technologies that were hyped to the sky and back when they were introduced as "increasing capacity". But as its supporters are making claims that appear to be ridiculous, and as this comes on the back of similarly ludicrous exaggerations from other radio technology camps, I wonder how much its own supporters are harming its further adoption.
You are not alone. This is not normal. None of this is normal.
"These systems can use 50 to 70 milliwatts of power," says Adrian Jennings, technologist with Time Domain in Huntsville, Ala., one of the pioneer vendors in UWB. "That is one ten-thousandth the power of a cell phone."
50 to 70 milliwatts is one ten-thousandth the power of a cell phone? That would place an average cell phone at somewhere around 600W.
Strange, I don't remember seeing huge heatsinks and 12" fans on any cell phones lately.
Tarsnap: Online backups for the truly paranoid
Has any SETI research taken into account that the little green men might be using UWB? Maybe all of cosmic radiation is just broadcasts of age-old alien episodes of Lucy and the X-Files and so on.
Finally, UWB promises to be highly secure. It's very difficult to filter a pulse signal out of the flood of background electronic noise, and vendors such as Time Domain are encrypting the zeros and ones being transmitted by the pulses.
Okay, here's my question then. If it is so difficult to distinguish the pulse signal from ambient noise, how would one device be able to hear the other device? The whole security problem with 802.11 was the fact that the card could be put into a packet dumping mode that allowed users to view the raw packets, which would then allow them to brute force crack the encryption within meer hours. No other special equipment is needed. So as long as the cards allow promiscuous mode, filtering out the signal from ambient noise is not a problem. All you really need to concentrate on is breaking the encryption scheme. Hopefully they come up with a better method than 802.11 has.
This UWB term I've never heard of, but I worked at a company that was developing 802.11a goods. This sounds like the same, as the article touts ~40-55mb/ps (I don't know what this 1000MB/ps shit is).
:)
I wasn't one of the engineers working on it (I was actually a high school co-op who worked on higher-level code in the same dept), so some of my facts may be off. 802.11a (or at least the variant we were working on) used a modulation scheme called OFDM. OFDM was "invented" in the 1960s if I remember, but the technology is finally catching up with the math to allow for mass production and the data precision required in the algorithm.
OFDM would fit with the articles blurb about it being in the "noise" area. Basically, a baseband signal is multiplexed into multiple low-power subcarriers, which are aligned in such a way that the intersymbol/intercarrier interference (ISI/ICI) is minimized. Basically, this means orthangonally (at 90 deg angles), so that the peak distabution of one carrier occurs at the zero points of the carriers on either side of it. So it's a particulary advanced form of FDM. All that low power shit comes from this fact, and that the nature of noise is amplitude-related, not frequency related. Plus, data interleaving and error detection coding (described below) goes on during baseband processing I think. I forget the symbol length and all that in detail crap, but there is QAM coding and FFTs/IFFTs going on in the process. (I remember 64-QAM being a popular initial choice.) Error correction/detection might be left open in the specs (i.e. it could be this or that), but the one I was familiar using was reed-soloman (a convolutional encoding method used with CDroms) and/or turbocoding (a very advanced convolutional encoding method which gets pretty close to the limit imposed by the Shannon theorem).
OFDM has been defined as packing the data as close as physics will allow, and it whoops 802.11b in both range and bandwidth. I think it will be both in the 2GHz and the 5.4GHz bands.
Sounds exciting. The race is on.
I have seen a good intro paper on OFDM before, but I lost the URL, here is a more indepth one on it: http://www.eng.jcu.edu.au/eric/thesis/Thesis.htm
Sorry about the spelling, I'm not using a spell checker.
First of all, I'd like to say that I'm not a radio engineer. However it seems to me that with any device intended for communications there are just two options:
The conclusion from this is that one cannot have an endless number of channels. And wherever there's a limit, it will be reached, since spectrum is expensive and people will like more channels for less. So I don't think we have a panacea here.
Imagine the guerilla networks with these babies! hehe ... With everybody having these high speed links to eachother, maybe someday we won't need the internet backbones anymore! heck, maybe someday we won't even need the internet! this is the ultimate decentralized network, baby!! :P
-- The Linux Wizard
(p.s. I can't post from my account! WHY????)
Damn, 1000M bits/sec?
All I need now is a hard drive that will do that.
Now, Timothy actually checks to see if this story has been here before, and lo and behold, it has been! And he gives that link and explains why this version of the story should still be posted.
Next thing you know, there's going to be timely and relevent stories here. You know, like "Stuff that matters".
Remember, for anti-censorware information, you want to go here and not here, right jellicle?
UWB is a clever form of spread spectrum technology. Spread spectrum (SS) is defined as any radio communications system in which the occupied bandwidth is much wider than the baseband (information rate) signal. The most common forms of SS include FM broadcast radio, where 200kHz is used to transmit about 50kHz of signal, and CDMA - cellular phone spread spectrum invented by Qualcomm. Spread spectrum was actually invented by the actress Heddy Lamar for use during World War II and was used for secure communications between Roosevelt and Churchill.
Spread spectrum has a parameter called "spreading gain" which is the ratio (expressed in DB) of the occupied bandwidth to the baseband signal. UWB is a form of spread spectrum with an extremely high spreading gain - it occupies a whole lot of spectrum (contrary to some claims) to transmit a relatively small amount of information. However, because the signal is spread over a very wide frequency range, very little signal is required on any given frequency (or technically, in any given narrowband channel). Thus the signal appears to ordinary receivers as an increase in background noise, and under most circumstances will not do so in a noticeable way.
Traditional spread spectrum uses one of two modulation techniques to mix the information signal with a spreading signal: direct sequence (DSS) and frequency hopping (FH).
Direct sequence uses a bandwidth constrained random noise generator (typically a pseudo-random digital bit stream) and multiplies the baseband signal by this. It is also band limited, either/or by filters or the spectral characteristics of the pseudo-random noise. DSS is used in CDMA cellular phones.
Frequency hopping involves moving the carrier frequency frequenly, typically in a pseudo-random manner. In fact, usually the frequency changes a number of times for each bit transmitted.
Both techniques allow reception of the transmitted information by synchronous detection - the spreading signal is duplicated in the receiver, and used to recover the baseband signal. In the case of DSS, you generate a precisely timed replica of the transmitter's pseudo-random sequence, and multiply it by the input from the antenna (or in the intermediate frequency stages - dependinng on receiver design). Low pass filtering (integration) of the output yields the original signal.
Spread spectrum systems have some or all of the following characteristics:
To get back to UWB, it uses very narrow pulses as its spreading signal. The Fourier spectrum of a very narrow pulse shows a very flat distribution of energy over a very wide bandwidth. In this sense, UWB is spread spectrum. Likewise, it recovers the signal in a similar manner as other spread spectrum signals - it uses a regenerated narrow band pulse to synchronously sample (a form of multiplication) the radio spectrum, thus recovering the original pulse (minus pulse spreading caused by reflections and frequency dispersion).
AFAIK one could duplicate the behavior of a UWB system by using an extremely wide band direct sequence system. It would provide the precise ranging, see-through wall radar characteristics. It would have the low detectability. It would have the low interference to narrower-band signals. However, the UWB system appears to be much easier and inexpensive to build.
The only good weather is bad weather.
There seems to be a lot of confusion about how this works. I actually don't have a clue either, but based on the little bit in the article I can speculate. Perhaps a real physicist can correct me:
A pulse in "frequency space" (thinking back to Fourier transforms) is actually composed of an infinite number of frequencies. In other words, to produce a square wave (a pulse) you have to add together a ton of sine waves at different frequencies. The more sine waves you add together, the better your approximation of the pulse. Going the other way, a pulse can be decomposed into sine waves in an analogous fashion.
So, an EM pulse would actually have some effect right accross the radio spectrum (hence the name "Ultra-Wide"), but could properly be said to not use any particular portion of the spectrum.
Is this at all correct? If so, then wouldn't a bunch of these devices pretty much screw up all other forms of radio?
It is tempting, if the only tool you have is a hammer, to treat everything as if it were a nail. - Abraham Maslow
The FCC has decided to regulate this by limiting unlicensed impulse devices to 2GHz and up, and mandating very low power levels. (The ground-penetrating radar devices need to work below 2GHz, so the FCC required them to have a "pointing downward" interlock switch.) So this is going to be a short-range technology.
Interference works both ways. The FCC is only concerned about unlicensed UWB devices interfering with other uses. It's the UWB manufacturer's problem to deal with interference on the receiver side. This is hard, given that these things suck up a huge chunk of spectrum. The receiver is a spread-spectrum device, with processing gain, but ignoring powerful signals anywhere within the band may be a problem.
The LLNL impulse radar systems were of very limited use for this reason. The one real product from that research is Bindicator's level indicator used in grain silos and similar tanks. The LLNL technology seems to work best inside RF-shielded spaces.
So far, all successful applications of this technology are low-bandwidth. Getting high bandwidth in a noisy RF environment is hard. I suspect this is going to be one of those "up to" technologies; sometimes, in some places, you get really good bandwidth. But most of the time you don't.
Wireless technologies such as 802.11b and short-range Bluetooth radios eventually could be replaced by UWB products that would have a throughput capacity 1,000 times greater than 802.11b (11M bit/sec).
Who's paying who not to give publicity to the (low) throughput of Bluetooth? I understand that people who have bought into it have adopted this marketing strategy of pushing it's features and not it's speed, but does the media have to buy into this strategy. I've seen hundreds of articles mention Bluetooth, and I've only ever seen one mention it's speed. (That was on the register, so it hardly counts as mainstream.) This especially bothers me since as far as I can tell there's nothing that Bluetooth can do that couldn't be implemented with fancy software (except for that whole low power thing...), and from what I've heard (I've never been able to get a Bluetooth device close enough to any 802.11 equipment to find out for myself) Bluetooth and 802.11 don't play nicely with each other.
UWB systems produce RF emissions across a vast bandwidth, exceeding 1 GHz in some cases. Many devices don't have a conventional carrier frequency, but are characterized by a "maximum in the power spectrum envelope." Within any given conventional frequency band, the receivable power from a single UWB device is so low that it is far below the noise threshold of the conventional devices that operate in that band. The emissions are not receivable even by sensitive measurement equipment unless the UWB device is within few meters. For these types of wideband emissions, the potential for interference is determined entirely by the nuances of the "victim" receiver implementation. Conventional spectrum management techniques rely on the existence of an interference threshold -- a power level which may be measured independently of a particular receiver implementation. This threshold does not exist in the same sense for UWB devices; a separate value and measurement technique would have to be defined for every receiver implementation in the entire emission rage of the UWB device itself. The UWB industry claims (and has some evidence to support) that such an exhaustive list of values is not necessary given the low power level of the devices.
The important questions is how potential victim receivers will cope with an aggregate of many UWB emitters operating at the same time. If this technology is widely adopted, will there be an aggregate noise effect that is significant? Much work has already been done to cope with the noise properties of microwave ovens, which are centered at 2.45 GHz. See this report , p. 48 of the pdf. The large hump near 2.45 GHz is due to emissions from microwave ovens, and is measurable anywhere there is a sizable population (town > 20,000 people) in the U.S. Microwave ovens are very different than UWB devices -- they emit several orders of magnitude more power, and are bandwidth limited, but there are many technologies that operate within this band despite their emissions (802.11b is one of them). These technologies were designed specifically to operate in the noise environment generated by microwave ovens, and the band itself is designated to be a kind of "free for all" frequency range known as an ISM (Industrial, Scientific and Medical) band. Existing receivers in the bands where UWB devices produce emissions were not designed in such a manner.
Nevertheless, the potential increase in communication capacity offered by UWB devices demands that it be scrutinized for interoperability with these existing receivers, and given a chance to fulfill its promise.
Yes, it can be both
No it can't.
There is only so much spectrum. The faster you change the signal, the broader the chunk of spectrum you use.
You can use it for a shorter time, and end up with the same time-bandwidth product.
You can control signal intensity more finely to encode more bits, until the ambient noise (or weaker interfering signals) would confuse the decoder.
You can direct your signal so that most of the energy goes toward the receiver rather than spreading out uniformly (though this gets harder as the bandwidth gets wider).
You can restrict its polarization to one of a complimentary pair, leaving the complimentary polarization's half of the spectrum free (or using it for a second or a return signal).
... A radar (with its very directional antenna) will show only a wedge of light in the direction of your transmitter. (Which is how the authorities will find you to shut you down - if they get there before the neighbors with the torches and pitchforks.)
But that's IT.
If two transmitters are hitting a receiver with energy in the same chunk of spectrum they interfere. Spread the actual bits around so they're transmitted redundantly in different parts of the spectrum (not just hop the carrier to put a burst of bits in one chunk and move on) and you might be able to pull them out of some interference. But then you've used up several times as much spectrum in the first place - as have the interfering signals from other users of the same scheme.
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 [uwb.org] has more information.
This scheme doesn't "not use spectrum". It uses the ENTIRE spectrum - up to the limit of the transmitting equipment. The shorter the pulse (so you can space them more closely and send more bits) the higher the limit. When it talks it steps on EVERYTHING - one pulse, one "POP" in a radio, one fleck of snow on a TV screen, one bright spot on a radar. The has to be above the noise floor itself to be heard - and the "noise floor" includes all those other signals it's interfering with.
If your data rate is low you can keep the signal weak - at the receiver. The pulses spread out their energy over an enromous chunk of bandwidth, so your reciever can measure the energy over the whole specrtum and recover the desired data from the other signals-assuming there is only ONE transmitter using this scheme, of course.
But electromagnetic signals fall off with inverse-square. Near the transmitter you're not just "raising the noise floor". You're generating a continuous lightning bolt.
Want to send data a hundred miles? Imagine you were doing this with VISIBLE light. You're modulating an arc light at your transmitter, bright enough that the output of a solar cell a hundred miles away has more signal from your arc light than from all the other light sources (including any other arc lights) combined. Now imagine somebody on your block trying to read morse-code flashes from a distant colored lightbulb, using his own solar cell and a color filter.
Run a protocol so the radio versions of your "arc lights" take turns and you can run a network. (Think of running "Ethernet" in the real aether.) But that's ALL you'll be able to run. Goodbye TV, goodbye AM and FM radio, goodbye aircraft band, police band, CB,
Meanwhile, just as the time-limited signal of time-domain modulation schemes selectively "punch a hole" in the time distribution of the signals of the frequency-domain modulation services, the frequency-domain modulation signals selectively punch holes in time-domain modulation signals. The "hole" is in the form of pattern sensitivity - selective interference with those bit patterns that correspond to the energy distribution of the frequency-domain signal. Your pulse strength has to be great enough to "shout down" this interfering signal, or those bit patterns just don't go through uncorrupted.
Time-domain and frequency-domain signals don't play well together. And the time-domain kids got to the playground first. Do you want ANOTHER war with broadcast media? Remember, if they lose it's their death, so they'll fight REAL HARD.
You can avoid the war by shaping your pulses so the energy stays in a limited band (at the cost of limiting your data rate correspondingly). But within that band you can only use time-domain schemes. You've "divided the playground". And the smaller the hunk of playground you got, the lower your data rate. Shaping your pulses stretched them out - and you have to move them farther apart to tell them apart at the receiver. How much playground do you think you can get for your gang's exclusive use?
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.
Each one of those "arc lights" raises the noise floor - by a bunch. More noise means you can't measure the signal from the desired "arc light" as accurately - which means you get less bits-per-second from it.
The total number of bits-per-second available to ALL transmitters at any given receiving antenna is a constant described by Nyquist: 2 * bandwidth in cycles-per-second * base-2 log of the signal-to-noise ratio.
But the distribution in space of the "raised noise floor" is a face-down morning-glory flower. Like those surfaces where they roll a ball bearing to demonstrate orbits, but upside-down.
Imagine a rubber sheet: You grabbed it at your transmitter and stretched it WAY up - until the sheet at the distant receiver was raised enough that the receiver could detect you yanking. And your neighbor's TV antennas are up on the peak with you. (And so is your network antenna...)
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.
You sacrifice a part of your bandwidth to send a pre-defined, typically repetitive, synchronization signal, to keep the receiver synchronized with the transmitter. Think of the start/stop bits on a serial line, the framing bits in T1, T3, or SONET, or the vertical and horizontal sync bars in a TV signal.
The more bandwidth you sacrifice, the faster your receiver's clock syncs up when reception starts. If you're transmitting bursts you can put most of the sync at the start of the burst to get things locked quickly (and identify the signal and its start), then use just enough to keep the receiver locked for the rest of the burst.
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
The article mentions "potentially lower costs" but doesn't give any target prices or rationale for why the costs would be lower.
The next gen 802.11 (the .a spec) will run at over 50Mb/sec, at prices
not that much higher than the original 802.11b services. Who's going to
pay for a mere 2x improvement in an untested technology unless the costs
are very significantly lower?
Either way, the capacity is limited, and either way, as you allocate resources to one way of transmitting data, you create interference for the other way. In small numbers, UWB interference will be largely unnoticeable, but if it caches on as widely as its proponents claim it will, it may drown out traditional frequency based allocations. You get a situation roughly analogous to the interference problems between Bluetooth and 802.11.
I think UWB is basically an attempt to circumvent current frequency-based allocation schemes, and to replace our cheap, non-proprietary frequency-based infrastructure with a proprietary, patented, and more costly sequence-based scheme. Once millions of these devices are deployed and we are starting to see interference, manufacturers will whine and complain that they can't be banned anymore because the economic cost is too high.
In short, let's not fall into that trap. We already have spread spectrum technologies that are more sophisticated: they limited transmissions not only by sequence but also to a given, allocated frequency band. That works fine. We don't need UWB, and adopting UWB now would probably lead to bigger problems down the road.
I've worked off and on in UWB research since 1991- in fact I used to work with Doug Cummings, one of the people mentioned in the Article (at the University of Texas Applied Research Laboratories). I've been hearing UWB hype for ten years now- but really, there is no magic to it, and it has some very real limitations.
UWB as a communication method depends on the time position of signals, which can be severely affected by the motion of the transmitter or reciever, especially if it is accelerating or decellerating. Traditional modulation techniques can and will be affected by UWB, though in many cases, it may just raise the noise floor.
The biggest problem with UWB right now is that it is a political football. The established users of the spectrum want to protect their "territory" from all threats, real and imagined. From what I've seen the reasoning is very much "It's different, so it must be BAD." In truth, UWB is another form of modulation. Just like FM has advantages (and disadvantages) in comparison to AM, so will we view UWB in the years to come.
Some day it will be used- it won't revolutionize communications, but it may give us a little more efficient use of spectrum- Like Turbo codes and the like, they give us an incremental increase in what we can do. Claude Shannon's "Limit" still holds and puts bounds on what we can do.