TV White Space & The Future of Wireless Broadband

DeviceGuru writes "The unoccupied radio spectrum between broadcast TV channels may soon become a source of low-cost, ubiquitous broadband connectivity. Earlier this month, the U.S. Federal Communications Commission began Phase II testing of 'white space device' prototypes, to determine whether WSDs can operate without interfering with the other wireless devices commonly used in homes, offices, and public locations. A key advantage of white space wireless technology, compared to the combination of WiFI and WiMAX, is its TV-like ability to cover broad areas and penetrate walls and trees, using relatively low power levels."

Comments

Time Warner is going to just love this idea

[elrous0]

With companies like Time Warner, who are both broadband providers and important content producers for broadcast TV, is there any doubt where the broadcast TV companies are going to come down on this "interference" issue?

I can hear it now:

Broadcast TV: Senator, this new scheme causes huge interference with our broadcast signal
Senator: This wouldn't have anything to do with Time Warner giving you the broadcast rights to a bunch of their movies and TV shows for a song, would it?
Broadcast TV: Don't be silly. We can answer any other questions you may have at the campaign fundraiser we're holding for you tonight.
Senator: I think I'm beginning to appreciate your point of view.

-Eric

Whitespace?

[TimeTraveler1884]

I think this is a bad idea. If we start transmitting data in whitespace, words will become very difficult to distinguish from each other in any given sentence. For example "The quick red fox jumped over the brown lazy dog." by itself, is very readable. But once you transmit extra data in the whitespace it becomes: "The1quick0red1fox0jumped1over0the0brown1lazy0dog." - An invariable piece of shit. It's only a matter of time before the greedy providers decide they need more bandwidth and bleed over in to the primary data stream.

Now if we were to transmit in the margins or between the lines, that may just work!

Practical value?

[Firehed]

TV, unlike the internet, is a one-way medium. My TV may be able to pick up signals from a giant transmitter thirty miles away, and that's great. How would this work for internet connections? Something tells me that putting an antenna powerful enough to reach back to that tower inside my laptop isn't going to be too friendly with my battery life, let alone my non-shielded nuts.

Re:Practical value?

[TimeTraveler1884]

antenna powerful enough to reach back to that tower inside my laptop isn't going to be too friendly with my battery life, let alone my non-shielded nuts.

It's nothing to worry about. From the FCC site: "Between January 1, 2008, and March 31, 2009, all U.S. households will be able to request up to two coupons, worth $40 each, to be used toward the future purchase of eligible testicle and ovary shields. Eligible testicle and ovary shields are for the conversion of non-shielded testicles and ovaries, and therefore are not intended for anuses connected to a paid provider such as cable or satellite TV service."

Re:Practical value?

[jonesy16]

You got modded as funny but I think this is the most insightful comment on this page and I was thinking the exact same thing. That's great if we can use TV-like waves to blanket a large area with low power, reasonable bandwidth internet access. But how the hell is the upload signal going to work? My homeowner's associate even tries to prevent us from having TV antennas on our roofs (which is against the law for them to prohibit, but that's another story). But if the signal really is pretty low power, maybe a small return signal can be sent using only a modest sized/powered home antenna, who knows?

Why are we running out?

[cfulmer]

Isn't there just as much bandwidth between 3Ghz and 4Ghz as there is between 0Ghz and 1Ghz? Why do we carve out larger chunks at higher frequencies? It seems to me that the real answer is finer-grained transmitters and receivers.

Re:Why are we running out?

[link5280]

Higher frequencies get attenuated by walls, rain, trees, etc... more easily than the lower ones. Yes the higher frequencies have more available bandwidth but there are disadvantages. TFA mentions the pros of using the UHF and VHF spectrum.

Re:Why are we running out?

[frieko]

Nope. You're counting everything from 0 to 3.5gHz as your "3.5gHz band". That's a 3.5 gHz channel, not a 100mHz channel.

When you want to send a signal on a 100 mHz wide channel, you would first construct a signal that uses frequencies between 0 and 100 mhz. Then you can shift it up by 450 mHz and get a 100mHz channel centered at 500 mHz, or shift it up by 100 gHz to each frequency and get a 100 mhz channel centered at 100.05 gigahertz. But it's still the same bandwidth and capacity.

Re:Does "white space" last forever?

[Ephemeriis]

The problem with this idea is that it assumes that TV broadcasting will always be done the way it is today with unused space between the channels. If "white space" equipment gets deployed it is going to create a massive problem for any attempts to change use of the existing TV spectrum. Any future users of this spectrum are going to have to work around the applications now running in what used to be the "white space".

If I understand correctly, part of what this device does is detect television signals and avoid spectrum that is actually being used. That is part of what is being tested. The idea is that these devices would be allowed to transmit over fairly large chunks of the spectrum, but that they would automatically detect what is actually being used for television and only transmit in the gaps between channels. That is why there's so much concern about these devices causing interference - nobody is sure how well this detection/avoidance mechanism is going to work.

If it does actually work like it is supposed to it won't matter if the white space between channels moves or vanishes - the device will stop using that chunk of spectrum and move to another. The only real problem you'd have is if you completely saturated the spectrum with television, which could happen. But in that case the devices would simply be unable to find any white space and would not be able to transmit - it wouldn't actually interfere with the television broadcast.

That's how it's supposed to work, at least.

Re:Great, another choice for those who have lots

[Forseti]

Why would you need transmitters to provide whitespace? Whitespace is a range of frequencies where nobody transmits. Just because that whitespace is there even when there's a transmitter doesn't mean that it's provided by said transmitter! You do need a separate transmitter to provide this new service in those whitespaces, but that has nothing to do with the presence or absence of existing transmitters. Plus, at those frequencies, a transmitter could more easily provide service to rural areas, so it might indeed help people who have no other broadband options.

And no, you can't count on a wireless technology to help people living in a radio quiet zone. That's the kind of thing someone could (should) find out about and consider before buying property there. In any case, a quick search on the NRQZ seems to indicate that it is not, in fact, a deadzone. There are merely more requirements and restrictions for anyone wanting to place a transmitter there...