First Public White-Space Network Is Alive 97
An anonymous reader writes "The first public white space network officially launched on Wednesday in Claudville, Virginia. It uses sensing technology from Spectrum Bridge with software and Web cams supplied by Microsoft and PCs from by Dell. The project was funded the TDF Foundation. White space networks use unlicensed television spectrum and have been called 'WiFi on steroids.' They offer more bandwidth, over larger areas, than does WiFi. IT companies duked it out with broadcasters for years to get white spaces approved by the FCC. They finally got the FCC's nod in November, 2008."
Good thing (Score:1)
Re: (Score:2)
It should have.
The frequency range is far more suited to cell service than the current ranges, it has better building penetration and greater range.
Cell is what the people want. The ridiculous prices we pay for cell service is in part due to the shortage of bandwidth. (And before you jump on the obscene profits bandwagon, go read a few 10Ks of cell companies. Its not all that rosy in profit land).
Public WIFI will simply once again prove the Tragedy of the Commons, as if we haven't learned that enough times
Re: (Score:3, Insightful)
Anything will prove "The tragedy of the commons" as it doesn't really need proof at this point. However, expanding the commons is like that. The alternative is a shrinking commons, or actually having enough accountability and imputability that it's not really "the commons" anymore, but some form of public property under private ownership or management. I for one welcome expanding commons.
As for cell bandwidth, the process is so political, it's not really surprising they refuse or fight less for frequenci
Re: (Score:2)
Anything will prove "The tragedy of the commons" as it doesn't really need proof at this point. However, expanding the commons is like that. The alternative is a shrinking commons, or actually having enough accountability and imputability that it's not really "the commons" anymore, but some form of public property under private ownership or management. I for one welcome expanding commons.
Or, the commons can be managed, as commons are all over the world, and all throughout the US, even though it seems it's the Americans who seem all too quick to forget this fact when the topic of the "tragedy of the commons" arises.
They can be managed by the government. It works with parks, and beaches, and waterways, skies, roads...
So, with this spectrum, just have the government provide a set of rules that favors wide adoption of individual citizens, while keeping a few people from ruining it for everyone
Re: (Score:2)
Exactly. Remember old style Ethernet? It was another example of commons; there was a single bus, and only one computer could be transmitting on it at a time. And yet, somehow, it worked well when lots of computers were all trying to use it at once (well, within the limits of the total available bandwidth). How did it work? By using the same (very primitive) algorithm for allocating space on all of the clients.
There's no reason why this same model couldn't be used for public airspace; anyone can use
Re: (Score:2)
There is unfortunately an absolutely fundamental reason why this is different from ethernet.
Ethernet collision detection works only if you can detect the other side transmiting at the same time as you.
Even neglecting the 'as the same time as you' part - if the interfering transmitter is beyond the range that you can decode the data from it, you can't tell it from the background noise, and you can't avoid transmitting over it.
As an easy to understand and not too misleading analogy.
Consider a sports stadium.
I
Re: (Score:2)
Re:Good thing (Score:4, Insightful)
A foot long? Oh come on!!!
We are talking about "700-megahertz" band, covering TV channels 52 to 69 (698 to 806 MHz).
The upper end of this is only marginally longer wavelength than the 850MHz band used for 850-GSM cellular today.
This bandwidth could easily be merged into the cellular spectrum with virtually no change in antenna length required, or at best a marginal increase in length that would easily fit in the modern smart phone package format.
A quarter wave antenna for 850MHz is 3.3 inches.
for 800MHz a length of 3.50 inches is optimal.
for 700MHz 4.01 inches, etc.
The iPhone is 4.25 inches tall. Similar phones have similar sizes, all of which would accommodate a quarter wave for these frequencies.
Re: (Score:1)
Re: (Score:2)
4.01 inches is a fairly long antenna and to large to fit in lots of phones
You realize that antennas don't have to be straight, right? Helical coil is perhaps the most common shape for an antenna....
Re: (Score:2)
>>>We are talking about "700-megahertz" band, covering TV channels 52 to 69
No we're talking about channels 2 to 51. These devices are unlikely to use VHF, so let's confine that to 14 to 51 which still requires a 9-inch antenna at the lower end... so the grandparent poster was exaggerating but mostly correct when he said "phone users don't want foot-long antennas"
Re: (Score:1)
I think you're contradicting your earlier post that 700 MHz would be "far more suitable for cell service than the current ranges", icebike. Penetration and propagation losses, as well as more detailed channel characteristics such as fading rate, fade depth, and delay spread, will be very similar at 700 MHz and 850 MHz simply because, as you pointed out above, the relative change in wavelength is small.
There may be something to talk about when comparing 700 MHz to 2 GHz because that's a factor of 3 differe
Re: (Score:1)
Re: (Score:2)
They would not have used it.
AT&T decided that good working 850mhz around here needs to be replaced with the useless 1.2gig crap. I went from 5 bars in the house to 1 in a couple of spots because of their retarded decision. They dont care about better coverage, they care about better profits.. 1.2 gig gives more profit as it carries more services they can overcharge for.
Whitespace would not have had the profit margins they wanted.
Re: (Score:2)
Actually ATT is going in the opposite direction.
They are moving their 3G service down to 850 where ever they have the licenses to do so.
Re:Good thing (Score:5, Interesting)
It would be interesting to see whether the use of this spectrum white space "commons" will be effective.
Re: (Score:2)
I hear you and understand your point, but I offer this bit of history to remind
you how corrupt, evil, and fraudulent the Telcos can be.
http://www.tispa.org/node/14 [tispa.org]
$200 Billion USD of tax payer money went poof.
We were promised 25 Mbps to all homes in major metros.
What we got was high latency DSL that was slower than a cable modem.
Over a dozen nations with a LOT less money have better broadband than the US.
It is not a issue of money, their hands are DEEP in the public coffers after
their lobbyists greased the
Re: (Score:2)
"If you repeat a lie often enough, people will believe it." - I forget the name of the guy but he was correct. The $200 billion didn't go poof. It was used to upgrade noisy analog lines to clean digital & enable 56k in areas that used to have only 19-24k (remember 56k was a big deal in the 1990s). And yes it was used to provide high-speed DSL which I think is a fine service. I pay a mere $15 a month.
Finally: There was NO requirement in the 1996 Congressional bill for fiber-to-the-curb. I've r
Re: (Score:1, Offtopic)
Somebody please post the "stud dogs" troll!
Laziest first post ever.
Re: (Score:1, Offtopic)
Using Television Spectrum (Score:1)
What channel is Hulu on? v.v
Re: (Score:3, Interesting)
In other news, the residents of Claudville VA are no longer able to watch distant stations in Roanoke due to these internet devices broadcasting over the channels.
The FCC Chairman's comment - "You're not supposed to see out of market stations anyway." One of the local viewers replied, "Now I only get 5 stations from Salem NC, where I used to get 10 from both Salem and Roanoke. They took away my channels."
Re: (Score:2)
Re: (Score:1)
Re: (Score:2)
Re: (Score:2)
I tried connecting, and apparently I got lots of traffic, but all I got was a blank screen.
I haven't even tried connecting, and I won't be doing so any time soon. I'm not going to buy any equipment for these networks until the big industry players resolve their format war. One camp is trying to standardize on tabs, and the other is pushing for spaces.
Is this statement misleading? (Score:3, Interesting)
Someone correct me if I'm mistaken, but doesn't lower frequency (30mhz to 300mhz) mean less bandwidth? I could see bonding several channels at once to achieve a higher bandwidth, but doesn't this mostly offer greater range?
Re:Is this statement misleading? (Score:5, Informative)
As far as the range? You can make a microwave signal go light years and a HAM signal go a few feet (although, there will be some distortion for transmitting a signal over a distance shorter than the wavelength). The range is more of a function of signal power.
Re: (Score:2)
Citation or clarification needed.
This is only true if the receiving antenna is basically wrapped around the transmitting antenna. From a practical perspective it doesn't happen, you'd just connect the wires directly and avoid the time domain issues you are referring to.
Re: (Score:2)
I noticed huge deadspots in the room where there was almost no radio signal and other spots where it was distorted evilly.
This is called "nearfield" distortion. Generally speaking, receivers need to be at least one wavelength away to work reliably. Also, Tx antennae need to be at least one wavelength off the ground, or it changes the impedance of the whole array.
You can read about this on t
Re:Is this statement misleading? (Score:5, Informative)
Of course higher carrier frequencies don't have a higher bandwidth, because bandwidth is a property of the whole system, including the data signal and modulation method. You can make the bandwidth as big or small as your system's constraints allow (e.g. one constraint might be to keep most of your transmitted power inside the allocated bandwidth).
If your data signal is modulated in the exact same manner regardless of the carrier, varying the frequency of the carrier will not affect the transmitted signal's bandwidth. The carrier frequency imposes the upper limit on the data signal's frequency, and thus a higher carrier frequency will theoretically allow for a high data rate.
Practically, however, the data signal is almost always much smaller than the carrier signal, and the transmitted frequency is subject to many other important factors such as noise, signal propagation through the environment, etc... In the case of 2.4GHz vs. 800MHz carrier frequencies, there is no practical gain in potential data rate.
This is all based on my limited understanding of communication theory. Please correct me and/or provide further details if possible!
Re: (Score:1)
But here's why most people associate higher frequencies with higher bandwidths: typically RF devices scale as percentages.
You're dipole that covers 10% bandwidth at 2.4Ghz is going to cover up to 200MHz of spectrum. You're dipole at 300MHz is only going to cover 30MHz. You can shove more data through 200MHz than you can 30MHz. Now, of course, you have to get that amount allocated, but the lower frequencies are packed, so the FCC typically gives out bigger chunks as you go higher in f
Re: (Score:2)
Rather than guessing you could just google "width of TV channel".
The answer is 6 megahertz. That's how much room these TV Band Devices (TVBD) will have for communicating over the internet. That's approximately 40 Mbit/s using 16VSB with a theoretical max of 96 Mbit/s if you strip all error correction.
Re: (Score:1)
Rather than guessing you could just google "width of TV channel".
The answer is 6 megahertz. That's how much room these TV Band Devices (TVBD) will have for communicating over the internet. That's approximately 40 Mbit/s using 16VSB with a theoretical max of 96 Mbit/s if you strip all error correction.
16VSB would be 4 bits/symbol @ 6Msymbols/sec = 24Mbit without error correction (25.85 if you stay with ATSC's symbol rate of 6.46Msymbols/s). The wikipedia article on 16VSB is correct about bits/symbol then fails to get the math right about being "twice the data capacity of 8VSB" which is 3 bits/symbol.
Re:Is this statement misleading? (Score:4, Insightful)
You're horribly wrong.
Distance has everything to do with frequency. You aren't going to have shortwave/ham radio skipping around the world with a 2.4GHz transmitter no matter how much power you put into it. Similarly, there's a reason WiFi is popular at 2.4Ghz but the higher 5Ghz band used with the now-forgotten 802.11a standard has been vastly less utilized.
Frequency determines how well a signal will disperse around obstacles, and therefore, whether it will work AT ALL if you don't have 100% line-of-sight between transmitter and receiver.
Re: (Score:1)
Re: (Score:2)
Not entirely... Higher frequencies will disperse less, so they can be broadcast in a much more narrow cone (see: high-gain antenna), so that a much stronger signal will arrive at the (much smaller) destination. Compare flashlight versus, eg., a laser, to see the difference.
OTOH, like on earth, lower frequencies will disperse around an obstacle, rather than being stopped entirely, so if there's any solid objects in the vacuum, the same princip
Re: (Score:2)
OT, you just made me snicker at Microsoft. On the Xbox 360 they backed HD-DVD and 802.11a. Fail, fail.
Re: (Score:2)
I'm horribly wrong out of context, but perfectly correct if you think about it.
"They perform EME (earth-moon-earth) using microwave radios with regularity." (see below)
Frequencies have a lot to do with obstacles and path-loss, line of site, moving through water (or other mediums), but not distance.
Re: (Score:2)
Sure they do. Note that NASA, as you said, uses the highest frequencies they practically can. Distance has a lot to do with it.
Re: (Score:3, Informative)
Uh, no. Range is not a function of signal power. It more is a function of the overall signal/noise ratio and the sensitivity of the receiver. This includes noise introduced in the transmitter, natural/other noise, and noise introduced in the receiver. An antenna system with gain can both concentrate and attenuate signals, depending on the directivity and where its pointed.
BTW, I got over 1400 miles out of a little 0.3 watt ham signal, but thats no where near as impressive as Earth still being able to r
Re: (Score:2)
Uh, no. Range is not a function of signal power.
Range is a measurement of how far you can go before path loss (note: many people think path loss is inverse square, this is only true in free space, there are a few situations where it is better and a load where it is much worse) reduces the signal to a level where the SNR is too bad to receive it. Crank up the transmit power and you increase the recieved signal power and hence improve the SNR at any given distance.
An antenna system with gain can both concentr
Re: (Score:1)
Uh, no. Range is not a function of signal power. It more is a function of the overall signal/noise ratio and the sensitivity of the receiver. This includes noise introduced in the transmitter, natural/other noise, and noise introduced in the receiver. An antenna system with gain can both concentrate and attenuate signals, depending on the directivity and where its pointed.
BTW, I got over 1400 miles out of a little 0.3 watt ham signal, but thats no where near as impressive as Earth still being able to receive signals from Voyager 1 and 2 nearly 10 billion miles away. That's impressive.
-Michael
This post is horribly misleading. If range wasn't a function of signal power, why on earth don't we have handsets which operate with microwatt transmit power instead of (typically) something on the order of a tenth of a watt?
Range is certainly a function of transmit power. If you have line of sight between the transmitter and receiver, every factor of 4 increase in transmit power (6 dB) doubles your range. It should be pointed out that often times we don't have line of sight for cellular, even when the
Re:Is this statement misleading? (Score:4, Informative)
You can make a microwave signal go light years and a HAM signal go a few feet
Just for clarification, ham radio operators operate in the microwave region as well. They perform EME (earth-moon-earth) using microwave radios with regularity.
Some info here: http://www.dxzone.com/catalog/Operating_Modes/EME/ [dxzone.com]
Re: (Score:2)
Re: (Score:1)
Re: (Score:2)
>>>Analog TV did nothing to try and reduce space occupied...nothing but waste.
This statement couldn't be more wrong. Why do you think analog television is interlaced rather than progressive scan? Answer: The engineers made that decision to save space and reduce the channel size from 12 to 6 megahertz. Why do you think they overlaid the color image with a nominal resolution of only 160x486? Again, to save space. Analog did "nothing" to reduce space is not an accurate representation of the work
Re: (Score:1)
Re: (Score:2)
>>>Each TV channel occupies 10mHz...space 640mBPS
Also your numbers are wrong. 10 millihertz? 640 millibits/s? I'm going to assume you mean 10 Megahertz which is still not correct. Each channel spacing is 6 or 8 MHz, and the maximum theoretical bandwidth on these channels is 96 and 128 Megabits/s respectively, although a more realistic speed with 16VSB or COFDM plus error correction is only 40-60 Mbps - nowhere near 640.
As a broadcast engineer... (Score:5, Interesting)
Re: (Score:2)
What's scary to me is how important broadcast TV is to so many. Internet access is far more useful than TV, not to mention, you can watch TV on it. As far as I'm concerned it makes more sense to use every bit of spectrum currently allocated for television to provide ubiquitous wireless internet access.
Re: (Score:1)
Re: (Score:2)
If they can figure out a way to implement something like the Emergency Alert System [Wikipedia] on the internet, you might be able to convince me
I would suspect that it should be possible to railroad connections using packet inspection and mangling and railroad people off to a page, video stream, audio stream, Autocad document, or whatever. It would be a fairly brutal thing to do, but it would be functionally equivalent to BEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEP and a blue screen on your TV. Of course, the repercussions are significantly more severe. On the other hand, the EAS already doesn't help me if I am one of the many who have given up on broadca
Re: (Score:2)
I'm not buying it. Wireless internet is already using ten times as much bandwidth as broadcast television, and it still can't provide the same level of service.
Also, speaking frankly, my local television sucks which is why I watch distant signals from Baltimore and Richmond (about 60 miles in opposite directions). If the TV Band/whitespace Devices block my access to these cities due to transmitting directly over the stations, then I'm going to track down the gadgets and politely ask the owner to turn them
Re: (Score:2)
It seems to work well .. but wait I suddenly have a splitting headache, be right back ...
It's Obvious Where This is Heading (Score:5, Interesting)
Webcams? (Score:2, Interesting)
Re:Webcams? (Score:4, Informative)
The school system is using them for "distance learning". They aren't really relevant to the story.
Re:Webcams? (Score:4, Funny)
I'm confused... what do they need webcams for in this project?
Live porn. Hey, you have to fill that broadcast schedule with something.
100mW!? (Score:1)
I can't see them getting too much range out of that, not to mention that lower freqs = bigger antennas.
But more BW is always nice.
Re: (Score:2)
Those frequencies are largely unaffected by foliage and the walls of buildings, unlike the microwave frequencies used by WiFi. They also propagate over the horizon somewhat.
Re: (Score:2)
Re: (Score:1)
The part I don't understand is, why are they spinning it as "long range" & "a wifi killer" then?
Re: (Score:2)
The average wifi card in your laptop has a 30mW transmitter, seems rather pathetically low power to me.
100mW in VHF with the proper antenna has much better range than a wifi card at the same power with a proper antenna. For comparison, police walkie-talkies have transmit powers between 1W and 5W usually, and they can cover huge areas.
wif fi, that was invented by... (Score:3)
enjoy :-)
Why Claudville? (Score:4, Interesting)
Why Claudville? According to the Wikipedia page, there are around 20,000 people in the entire county. And according to the FCC DTV maps, they can only expect to receive two (!) TV stations, both from the Winston-Salem, North Carolina area. See here: (enter Claudville, VA) http://www.fcc.gov/mb/engineering/maps/ [fcc.gov]
That is perhaps why they are testing it there. Its not hard to avoid active TV channels if there are only two.. and they are on adjacent RF channels (31 and 32).
-molo
Re: (Score:3, Insightful)
You didn't read the "maps" correctly. They are expected to get two STRONG signals, and 6 weak ones. The weak ones are on UHF 19, 29, 51, 33 and 14.
If the "white space" devices in that area are as capable of reading the maps as you are, those people WILL only get two stations instead of the 8 they might, especially those people who have invested money in good outside antennas so they CAN get the other weak signals.
But
Re: (Score:1, Insightful)
Re: (Score:2)
Because outdoor antennas are necessarily high gain?
Re: (Score:2)
In my experiance outdoor antennas are usually a lot larger with a lot more elements than set top ones and presumablly this means they are higher gain.
Re: (Score:2)
>>>If they have an outside antenna, it's going to be highly directional.
(1) No. My CM 4228 is directional but not "highly" directional, since it still gets signals from the rear and side. (2) Directionality doesn't matter if the TV Band/whitespace Device User is standing between me and whatever station I'm trying to watch.
"Well honey I wanted to watch the Yankees game on channel 19, but unfortunately our neighbor is using his iPod on the same channel."
Re: (Score:3, Funny)
I'm not from Virginia, you insensitive Claud!
Re: (Score:2)
Because Claudville sounds like Baudville. *shrugs*
Wifi on STEROIDS!?!! (Score:3, Funny)
I don't think that word means what you think it... (Score:5, Funny)
I think you mean "live". If it's "alive" we have some real problems ahead of us.
Security? (Score:2)
Re: (Score:1)
No blacks, no Irish, no dogs.
Possibly stupid questions (Score:1, Interesting)
Re: (Score:2)
(1) No it's licensed to TV broadcast.
(2) TV Band/whitespace Device users are expected to turn-off their gadgets if they interfere with licensed stations (WABC, WCBS, WFOX, et cetera). However if they refuse there's no real punishment.
(3) Yes TV Band Devices are expected to be used by average people, so expect iPods and other gadgets to soon be transmitting over channels 2 through 51.
(4) Range is probably 1-2 miles same as today's cellphones but with enough power to drown-out television reception of stat
Whitespace (Score:1)