DoD treats Spectrum as Territory

The U.S. Department of Defense released a spectrum strategy document on Thursday (press release, pdf). I’ll leave discerning what (if anything) is actually new in it to the Pentagon watchers.

I was struck by the implications of the language used: the DoD conceives of spectrum as a place. Given that military success often seems to be framed as controlling or denying territory, this is not an auspicious starting point for spectrum sharing – which is about wireless system coexistence in many intangible dimensions, rather than all-or-nothing control of territory.

Counting Spectrum in an Age of Sharing

Mike Marcus’s recent blog post Dueling Spectrum Charts - Part 2 is a nice reminder (not that anyone who reads his blog needs it) that spectrum isn’t just MHz. The current focus on “spectrum sharing” underlines the fact that one has to think of space and time as well as frequency. A more accurate (but also much more geeky) metric would divide MHz by percentage of population covered, and percentage of time allocated.

Using an auction to decide the number of 3.5 GHz spectrum access administrators

The FCC faces a choice of whether to authorize one database administrator or many to run the spectrum access system (SAS) that will manage small cell operation in the 3.5 GHz band. This resembles the choice between an exclusive-use licensing or unlicensed regime. The FCC could use an auction to let the market decide by using a simplified version of the 2008 Bykowsky, Olson and Sharkey proposal.

Spectrum sharing is not a partisan issue – NOT

After his keynote at Dyspan yesterday, PCAST member Mark Gorenberg and his podium guests (and spectrum report co-authors) Dennis Roberson and Michael Calabrese were asked about the political prospects for the PCAST spectrum sharing recommendations (pdf). I can’t remember exactly who said what, but the message was that spectrum sharing wasn’t a partisan issue. Not so.

Stamps and Stewards: A third way to regulate radio operation

Radio operation to date has largely been regulated in two ways. The dominant approach has been licensing station operators, whether they’re amateurs, TV broadcasters, or companies operating cellular systems. In the last twenty years or so, device licensing (aka unlicensed in the US, and license exemption in Europe) has also become widely used: if a device has been certified to meet regulatory requirements, anyone can operate a “station” using it without needing a license. [1] In these two approaches, the regulation controls either the system operator (for licensed), or the device manufacturer (for unlicensed).

I’m exploring another way, where the regulator accredits a limited number of “stampholders” who can each an issue an unlimited number of “stamps.” One can see these stampholders as the designated stewards of a "spectrum commons," and the stamps as the mechanism they use for controlling access to a common pool resource. A device may only be sold if it bears the requisite stamp or seal, in addition to any other statutory requirements such as Part 15 certification. Control is exercised at the point of sale through labeling or marks.

This notes builds on the previous posts Licensing radio receivers (Aug 2011) and Licensed Unlicensed (Sep 2011). I learned long ago that if I can think of something, someone’s already done it. However, I haven’t found good precedents yet, and I’m still looking for canonical examples or ringing metaphors. Stamps (in the sense of signet rings and seals) and Stewards is the best analogy I’ve found so far. [2]

Follow-up: In Markets for adjusting interference rights (May 2012) I explore another way of negotiating adjustments to boundaries (e.g. power levels) between unlicensed bands and their neighboring bands given of the collective action challenges faced by unlicensed operators.

The extent of FCC/NTIA frequency sharing

Take a guess: What percentage of US frequencies are controlled by the Federal government (represented by the NTIA), and what percentage is shared with non-Federal [1] users, who are under FCC jurisdiction? And what’s the remainder, devoted solely to non-Federal users?

My intuition, for what it's worth, was completely wrong. I thought the Fed/non-Fed split was roughly 50/50, with a bit (say 10%) being shared. As I pointed out in my recent post about partitioning Fed and non-Fed allocations, the amount of sharing should be easy enough to establish. It turns out that Peter Tenhula of Shared Spectrum Company has done a lot of work on this [2], and he pointed me to the FCC’s spectrum dashboard where one can download an XML snapshot of the allocation database (currently the API only covers the range 225-3700 MHz).

The answer? It depends on the frequency range and how one counts [3], but very roughly 10% is Federal, 40% shared, and 50% non-Federal (i.e. FCC) only.

Here's a picture (click it to enlarge); an Excel file with my analysis is here.

Update, 21 October 2011: Perhaps the flaw didn't lie with my intuition, but with my interpretation of the data. A senior FCC person has pointed out to me that many supposedly "shared" allocations are, to all intents and purposes, controlled by Federal agencies, and non-Federal (i.e. FCC-managed) services are present only on sufferance, if at all (e.g. 220-2290 MHz); or "sharing" only occurs both Federal and non-Federal entities used the same service (e.g. air traffic or maritime radar). So the question still stands, pending further digging: how much sharing (for various values of "sharing") is really going on?

Partition, not sharing: An alternative approach to the Fed/non-Fed spectrum divide

South Sudan. Serbia/Kosovo. India/Pakistan. Britney Spears and Kevin Federline. Sometimes a clean break is best for everyone, particularly when there are fundamental differences in mindset. Enforced coexistence is not, for many couples, the best way to live.

Sharing between Federal and non-Federal wireless users (aka Fed and non-Fed) is a favored way to realize the FCC’s dream of finding 500 MHz for commercial mobile broadband services; as reported in TheHill.com, “It is unclear where the 500 megahertz of spectrum will come from, but a large portion will likely come from government agencies that do not use the frequencies efficiently.”

Fed/non-Fed sharing can be made to work, and worthy efforts are being made. However, I doubt it’s worth the effort, given the insane difficulty of negotiating band re-allocations, let alone sharing agreements; questions over whether 500 MHz is, in fact, either needed or would make a dent on cellular companies’ problems; and fundamental concerns about jurisdiction (see my August 2011 post No Common Authority: Why spectrum sharing across the Fed/non-Fed boundary is a bad idea).

It would be a better use of time and effort to go in the opposite direction: make the partition between Federal and non-Federal as clean as possible, and let each group of figure out sharing among its own constituents.

Licensed Unlicensed: Having your Coase, and your Commons too

I lighted on the notion of issuing a handful of receiver licenses in allocations where transmitter licensees don’t control receivers (e.g. TV, GPS) to facilitate negotiations between operators in neighboring bands; details blogged here.

The same idea could be applied to unlicensed allocations, where the unbounded number of operators makes it essentially impossible for Coasian adjustments to be made: a neighbor that would like quieter unlicensed devices has nobody to make a deal with, nor do unlicensed users have an effective way to band together to make a deal if they’d like to increase their own transmit power. This approach also has the benefit, as in the receiver license case, of giving the regulator a tool for changing operating expectations over time, e.g. ratcheting down receiver protections or increasing receiver standards.

The catch-phrase “licensed unlicensed” is obviously a contradiction in terms; it’s shorthand for a regime where non-exclusive operating permissions are issued to a limited number of entities, while retaining the key characteristic that has made unlicensed successful: the ability of end users to choose for themselves what equipment to buy and deploy. These entities can use or sub-license these authorizations to build and/or sell devices to end-users.

Follow-up post

• Stamps and stampholders: a third way to regulate radio operation

Spectrum “sharing”: the convenient ambiguity of an English verb

I realized while writing Spectrum Sharing: Not really sharing, and not just spectrum that my confusion over the meaning of spectrum sharing derives from two meanings of the English verb "to share":

(1) to divide and distribute in shares, to apportion;

(2) to use, experience or occupy with others, to have in common.

For example, the first is sharing a bag of peanuts, and the second is sharing a kitchen or an MP3 file. Cellular operators and economists tend to use the word with the first meaning, and Open Spectrum advocates with the second.

But that raises the question: is the double meaning inherent in the concept, or is it just an accident of English vocabulary?

I asked some friends about the regulatory terminology in other languages; so far I have information about Arabic, Chinese and German. If you could shed light on regulatory terminology in other languages, for example French, Japanese or Spanish, please get in touch.