About Tom Evslin

Video Profile of Tom Evslin

Follow Tom Evslin on Twitter


Add to Technorati Favorites!
Powered by TypePad
Member since 01/2005


« Election Congratulations | Main | Maybe We Don’t Need So Much Credit »

The White Space Opportunity - Priceless

"Priceless" is not an overstatement of the value of the radio spectrum opened for free, unlicensed use by the Federal Communications Commission order on TV white spaces. Literally, this spectrum is priceless because no one has to buy a license to use it – just like the spectrum we all use for WiFi today. Figuratively, this spectrum is priceless because it's impossible to calculate the innovation which will result from making the spectrum available WITHOUT specifying either the technology to use it (other than non-interference with licensed use and power limitations) or the applications which can be built here. Voice? Data? Entertainment? Power management? Who knows? Stuff we never even though of; you can count on that.

Priceless or not, some numbers help with appreciating the size of the opportunity.

In the recent auction of comparable spectrum for LICENSED use, Verizon paid over $4.7 billion dollars for exclusive rights to 22Mhz nationwide. This is roughly four television channels – these channels are 6Mhz each. The total TV space consists of almost 50 channels – just under 300Mhz altogether. In rural areas where there are few-over-the-air TV stations, most of that will now be available for unlicensed use! The chart below from dailywireless.org shows some examples:

The 39 channels (234Mhz) available in Burlington, Vermont COULD provide mobile Internet access to everybody in and around the city at speeds better than 10Mbps (with the usual caveat that not everybody uses all of the service all the time) and that access could include all the talking and texting and picture sharing these people now do on their cell phones. It is highly likely that such services will be offered using this spectrum both by local entrepreneurs and national networks. Since the service providers don't have to pay for this spectrum and since they will be competing with each other, it is likely that the services will be very cheap not only compared to mobile data and voice today but also to the current price of cable and DSL access. See why I'm excited?

Even if the spectrum is free, radios aren't. Cellphones have radios in them, obviously; So do WiFi cards and WiFi transmitters and Bluetooth earbuds. Experience shows us that the price of radios serving huge markets in UNLICENSED spectrum quickly falls. Think how cheap WiFi and especially Bluetooth devices are; they operate in tiny relatively undesirable scraps of spectrum compared to the about-to-be-free white spaces. In an excellent comment filed with the FCC by a number of organizations including The Consumer Federation of America and Common Cause, the chart below shows how innovation has flourished since frequencies have been opened up for unlicensed use:

Note the flat line of devices being invented to use the licensed frequencies vs. the explosion of devices including WiFi, Bluetooth, and many other technologies we now take for granted in the unlicensed space.

The innovation leads not only to new devices but also very low prices and brand new services and products like WiFi hotspots and Bluetooth cars.

The need for over-the-air broadband and expanded cell service is greatest in rural areas where there also happens to be the greatest amount of unused former TV spectrum. But there is a significant amount of white space available in every market including major cities – note the 22 channels in LA. That's important because it means that devices and services designed for the white spaces will have a national market which includes urban areas.

If Horace Greeley were alive today, he'd say "Go unlicensed, young people, go unlicensed." The opportunity is priceless.


TrackBack URL for this entry:

Listed below are links to weblogs that reference The White Space Opportunity - Priceless:


Mickey Rose

In the FCC's view, use of this unlicensed spectrum plays into its aims to enable access to broadband services in unserved parts of the US, while also sparking new technology investment. The FCC originally adopted the white spaces proposal in November 2008.

Craig Plunkett

Another excellent analysis is by Brough Turner here:

Rick's comment is spot on about site acquisition, the fundamental issue in overbuilding incumbents.

Tom Evslin


Great and very impressive analysis. Once the regs are published (supposed to be a few weeks) so we know what power outputs are allowed where, how would you like to join me as a VTA volunteer to help with this spreadsheet?

I agree it's an important analysis.

Tom Evslin


No incremental cost calls to China are already available - Skype-to-Skype, or example, and video in the bargain. Grandson Jack in California and his grandparents in Ireland are online and onscreen together for the same incremental cost that Mary and I have for seeing and talking to Jack from Vermont - nada.

It's all because all of us have broadband and computers - much more expensive if we used our landline phones or cellphones for this.

But once enough good access bandwidth is available, this benefit - no incremental cost for communication - spreads almost everywhere. The cost of equipment still will lock some people out, however.


Can I please have my commodity voice and data service now? When a call to China is the same incremental cost as an email to China, the world will finally realize its potential for flatness.


Again, the question is authorized power level. Agree on the high level opportunity of having more
unlicensed spectrum. But let's look at the 100 mW power level, even in a rural situation, which
typically has more favorable RF propagation conditions. Just noodling the path loss, say we have
a cell site every 5 km, we're operating at ~600 mhz or so, then the path loss, free space, is 102 dB.
100 mw is 20 dbm, 18 dB sector antenna at the BS, so the receive level is 20-102+18 = -82 dbm at
the base station receiver (I recall there being a proposal for higher downstream levels, so as usual
the upstream path dominates link planning). Then for a 6 mhz channel size, the best the noise
floor can be is ~ -106 dbm, so the SNR at the receiver is 41 dB. Once you allow for typical
receiver noise figures (around 5 dB for this type of device), loss due to walls (if indoor: ~5 dB
in this band), some allowance for fading (10 db?), we're down around 26 dB SNR or less, which
starts to constrain the waveforms one can run inside the OFDM carrier. Lower delivered bit
rates at the cell edge. But think about that a bit - in a rural area, can you afford to go build
a tower or cell site every 5 km (3 miles)? Traditional cell sites consume a lot of capex to
build, then opex charges (rent, backhaul, power) also contribute mightily to the problems in
a spreadsheet business model. I keep coming back to the conclusion that if rural wireless
really made financial sense, someone would be doing it at scale in another available band
(2.4, 5.8, or 3.65 in certain areas). So I don't believe that this is a spectrum cost problem
at all, and in any event the power levels proposed so far will not make 700 a revolutionary
enabler. 700 helps in a belt and suspenders way, I think - use it to setup a low bit rate
canopy overlay over a 5.8 design, indoor, self installed transceivers. Note, I'm talking to
scale, not a couple starving WISPs here and there - what would it take, cost wise, to build out
a fixed wireless system that covered 100% of Vermont (all households)? That is the test -
building a large system is a non trivial investment, even when compared to the financial
test of acquiring licensed spectrum at latest auction price levels (mhz*pop). So we have
free spectrum now, but the cost of building infrastructure is the real 600 lb gorilla sitting
in the room with us. Would be interesting to see a spreadsheet model developed by
the VT Telecomm Authority. At the very least, it would help all of understand whether
& how much in the way of subsidies would be called for.

Not trying to prove man can't fly with these thoughts, just trying
to noodle what a state-wide WISP might look like, and if it could
make money. Good ole capitalism at work.

Post a comment

If you have a TypeKey or TypePad account, please Sign In.

Now on Kindle!

hackoff.com: An historic murder mystery set in the Internet bubble and rubble

CEO Tom Evslin's insider account of the Internet bubble and its aftermath. "This novel is a surveillance video of the seeds of the current economic collapse."

The Interpreter's Tale

Hacker Dom Montain is in Barcelona in Evslin's Kindle-edition long short story. Why? and why are the pickpockets stealing mobile phones?

Need A Kindle?

Kindle: Amazon's Wireless Reading Device

Not quite as good as a real book IMHO but a lot lighter than a trip worth of books. Also better than a cell phone for mobile web access - and that's free!

Recent Reads - Click title to order from Amazon


  • adlinks
  • adsense