A crucial engineering fact I’m not hearing from municipal TV white space proponents

Here it is: At 600 MHz, interference travels farther than it does at higher frequencies, all else equal.

The corollary to this, which you hear much more often from white space proponents, is that coverage extends farther at 600 MHz (better penetration of walls, etc.). The nice thing about that, they say, is fewer cells would be needed to provide, say, free Wi-Fi to a city. Fewer cells, however, mean more users are going to be sharing one access point. Each user will experience lower data rates as cell density decreases in a given area. Increase density, and they’ll interfere with each other more than they would on higher Wi-Fi frequencies.

This crucial engineering fact is why TV white space won’t provide for “Super Wi-Fi” nor “Wi-Fi on steroids,” for municipal Wi-Fi. For longer-distance rural links, those more of a point-to-point nature, I can see TV white space as part of a practical solution in some cases.

3 Responses to “A crucial engineering fact I’m not hearing from municipal TV white space proponents”

  1. Steven,
    I believe you are exactly correct. TV White Spaces will be more useful and applicable for rural broadband for WISPs point to point, or point to multipoint, service due to the better propagation characteristics of 600 MHz for underserved rural areas where broadband is only available via satellite services today. In addition, less TV white space will be available in cities where multiple broadcasters are present making it even less likely to be useful. Cities and urban areas will require more dense microcells via LTE and Wi-Fi for capacity coupled with cellular 3G/4G macrocells for coverage. I don’t see the value in TV white spaces in urban areas, quite frankly.

    Andrew von Nagy

  2. Darrin Mylet says:

    For now, that is correct. When the FCC moves to real propagation vs. grade B contour, that will open up more in Urban. Over time, we will find more “un-used” Fed spectrum in urban which might go into database/sensing model. Due to power levels, it is going to be very small cells which will require lots of backhaul. I see NLOS backhaul to Femto / Wi-Fi as key use case for our commercial white space product along with Indoor expansion of broadband. A mix of technologies is required for the next gen of Muni BB. Good spectrum policy is helpful too. More “neutral” engineers needed at FCC or on the payroll….Cant believe how much they are spending on Economists and Consultants on the Incentive Auction, massive.

  3. Anthony Fiti says:

    This is why I’m a big fan of using the 1.3GHz spectrum identified in the recent PCAST report (90MHz) for large-scale WiFi, specifically in cities. Its the right mix of propagation and density for urban environments, it wont mess with existing 2.4/5GHz base stations, its a large enough spectrum to provide fast wifi (80MHz 802.11ac). Its not necessarily governments that would run it, rather larger carriers – Cox, Time Warner, AT&T have WiFi networks.

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