re AT&t re: ATT suggests heavy data users overloading cell sites, must stop or pay?

[Dave Farber <dave () farber net>]

Begin forwarded message:

> From: Brett Glass <brett () lariat net>
> Date: December 12, 2009 6:18:22 PM EST
> To: dave () farber net, ip <ip () v2 listbox com>
> Subject: Re: [IP] approveAT&t re: ATT suggests heavy data users   
> overloading cell sites, must stop or pay?

> Dave:
>
> As a wireless provider myself -- though a fixed rather than a mobile  
> one -- I can thoroughly appreciate the bind that the cell phone  
> companies are in. Given the limited power and penetration of the  
> best available cell phones -- not to mention reflections and  
> intermodulation interference -- they're likely to get, at best, a  
> spectral efficiency of 2 Shannons. (The Shannon, named after Claude  
> Shannon, is a measure of spectral efficiency equal to 1 bit per  
> second per Hz. Because the time units cancel, it is a unit of  
> information -- appropriate for a unit that's named after the father  
> of information theory.) And that's if you're close to the cell site.  
> In many cases, you're down to half a Shannon or less.
>
> This means that, over a cell site's 5 MHz channel, the best a  
> cellular provider could ever do is pump out 10 Mbps -- and that if  
> the channel is being used for only one customer and the transmission  
> is continuous, which is never the case. In real life, the site will  
> be able to do occasional bursts of 3 Mbps. 3G, 4G, LTE, HSPA -- the  
> technology doesn't matter. Nothing can violate the laws of physics  
> and information theory.
>
> Now, a high quality audio stream takes up 128 Kbps -- an eight of a  
> megabit -- while a good video stream runs to 384 Kbps or more. And a  
> download will grab as much as it can -- up to the entire channel.  
> (P2P, of course, does its best to monopolize any network.) Is it any  
> wonder that cell sites are being exhausted?
>
> Fixed wireless providers like myself have similar issues. Because  
> the auction rules -- dictated by the largest and richest companies  
> -- preclude any small business from obtaining exclusively licensed  
> spectrum, we are stuck in a few narrow, congested  "junk bands" in  
> which signal to noise ratios are much lower than they are for cell  
> phones. We typically use 20 or 10 MHz channels -- bigger than the  
> cell phone channels -- , but often only get a quarter to a tenth of  
> a Shannon out of them, even with fixed high gain antennas, due to  
> constant noise from consumer devices. So, streaming is an issue for  
> us as well.
>
> Note that all of these constraints are the result of government  
> policy in combination with the laws of physics. If I had even a  
> small clear channel, I could provide much, much higher data rates  
> than the cell phone companies could. But in my area, a narrow 5 MHz  
> slice of the 700 MHz band went for more than 3 million dollars --  
> bid up by the cellular providers far beyond any price where one  
> could make a reasonable return on the investment.
>
> Unfortunately, this will happen so long as the foreclosure value of  
> spectrum exceeds its utility value. And the auction rules are so  
> slanted against small providers and new entrants (the requirement to  
> pay the full amount immediately, instead of paying month to month or  
> paying a percentage of revenues as one builds out, is an  
> insurmountable barrier to small operators and to innovators) that we  
> despair of ever obtaining the smallest sliver. So, don't blame the  
> providers. Especially WISPs. We're doing the best we can with what  
> we have, and it's not our fault that we cannot do more.
>
> --Brett Glass



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