Scale change and regulatory change

The current and forecast growth in the number of satellite systems is putting strain on how the FCC and other agencies regulate satellites. There’s a lot of talk of regulatory reform, and calls for comprehensive rather than incremental change.

That leads me to wonder: are there instructive precedents where a step change in the scale of an industry or activity forced a complete restructuring of regulation; or conversely, where change in regulation let to a change of scale?  Perhaps there are examples where one might take lessons for the reform of space governance.

Permissionless Innovation, the Precautionary Principle, and Gardening

Adam Thierer’s insights about “soft law” being the middle ground between permissionless innovation and the precautionary principle reminded me of Michael Pollan’s portrayal of gardening as mediating between the wilderness ethic and humans micromanaging nature.

Templates and narratives for change

At the end of a conversation with David Runciman about powerful women on the Talking Politics podcast (reposted on the LRB podcast; their chat starts around 18:00), Mary Beard had this to say:

The idea that women have a model for doing [changing the structures within which women can think of themselves as ambitious, as powerful, as clever, as articulate, and able to make that kind of difference in the world] -- and I don't mean a kind of role model, but I just mean a kind of cultural template for doing that -- until we can provide a narrative and a template, then I think we've got a problem.

This resonates with what I try (and fail) to do in policy innovation. It's not sufficient to have a new idea (= template). You also need to have a story (= narrative) that explains why anyone should care, and why it makes sense.

3D Wireless: Managing spectrum in three dimensions

It is time to manage spectrum in three dimensions, rather than on a slightly wrinkled 2D sheet.

Risk-informed interference assessment

I've spent the last year or so thinking about ways to complement worst-case interference assessment with a more comprehensive approach that considers many potential interference hazards, not just a possibly implausible nightmare scenario. I have concluded that quantitative risk analysis, used in many regulated industries, is a suitable tool.

Unlicensed’s success: physics, not regulation?

Unlicensed allocations have generated a massive, and to many surprising, amount of innovation and value (see the References below). The question is: Why?

Almost all of the value so far has come in the 2.4 GHz ISM band, mostly due to Wi-Fi but also to a lesser extent Bluetooth applications. There is never a single, simple answer to a Why question about a complicated nexus of technology, politics and user behavior, but my impression is that unlicensed partisans believe that it's due pretty much exclusively to the techno-economic characteristics enabled by the rights assignment regime: “openness” (Benkler), “managed commons” (Milgrom, Levin & Eilat), or “rule-based access” (Thanki).

I think it's at least plausible that Wi-Fi's undoubted success has been due to a fortuitous coincidence of band choice, physics and timing as much as to regulation: It turned out that the interference range was small enough that users didn’t really degrade each other’s performance; and the networking needs of their applications could be met by the bandwidth available around them. In other words: the capacity of the channel was larger than the number of people who interfered with each other, multiplied by the data they wanted to move.

The Emperor has Objections: Replies to feedback on our “Is Wi-Fi Congested?” paper

Our TPRC 2013 paper “The Emperor has no Problem: Is Wi-Fi Spectrum Really Congested?” (http://ssrn.com/abstract=2241609) has generated quite a bit of interest. Here are responses to some pointed questions and comments we've received.

From spectrum efficiency metrics to parameter spaces

In my post FCC white paper shows that “spectrum efficiency” is meaningless I argued that spectrum efficiency metrics are not very helpful.

They won’t go away, though, because engineers and economists instinctively characterize systems numerically. Both tribes strive to separate a problem into smaller independent parts, each described quantitatively; metrics are just a symptom.  The goal is to convert a complex mess into a problem amenable to objective analysis, yielding an incontrovertible answer. No more messy politics! 

Since politicians always look for cover behind engineers and economists, simplistic metrics will always be with us – not least in radio regulation.  Given that reality, I’m going to dig into spectrum metrics a little more. I conclude that it could be more productive to define a series of axes in a parameter space than a single metric.

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.

Spectrum utilization and a Buddhist perspective on space

The “Spectrum as Space” metaphor implies that spectrum is a neutral container that can be filled with radio signals, leading to naïve notions of utilization such as empty and full spectrum bands. “Spectrum” is imagined a collection of axes which mark out an abstract space, such as frequency, geography, and time (e.g. Robert Matheson’s “electrospace” concept, cf. Matheson & Morris 2011, The Technical Basis for Spectrum Rights: Policies to Enhance Market Efficiency).

However, that’s not the only way to look at it. Non-spatial models such “Wireless as Trademark” work just as well (see my 2008 paper De-Situating Spectrum: Rethinking Radio Policy Using Non-Spatial Metaphors): by analogy, a trademark stands for both a part of the wireless resource (customarily, frequency band x geographic region x time slot), and signals. The wireless resource is all possible radio operations. In such an approach, one is much less likely to ignore the importance of receivers in this approach than spectrum-as-space, where only transmitters can “fill the space” with signals. Any radio operation includes the use of a receiver, and that receiver-transmitter pair influences what transmissions are possible by third parties.

Curiously, I found a relevant perspective on this problem in a book on ethics – Stephen Batchelor’s Living with the Devil. He writes:

One tends to think of space in terms of physical extension and location. A body “occupies” or “fills” a space. For there to be “no more space” means that nothing more can be fitted into a room or a vehicle or a document. Outer space is that virtually infinite expanse speckled with galaxies and stars separated by inconceivable distances. “Inner space” suggests a formless expanse of mind in which thoughts, mental images, memories, and fantasies rise and pass away. Space seems to be the relatively permanent place where temporal events happen.  

Buddhist philosophers see space differently. They define it as the “absence of resistance.” The space in a room is under stood as the absence of anything that would prevent one moving around in it. To cross from one side of the room to the other is possible because nothing gets in your way. Rather than being the place where things happen, space is the absence of what prevents things from happening. The space in the room is nothing in itself; it is just the absence of chairs or tables, glass walls or hidden tripwires that would obstruct movement within it. In encountering no such resistance, we are able to move about freely. [In the footnotes, Batchelor ascribes this approach to the Geluk school of Tibetan Buddhism.] 

The customary view that Batchelor outlines is “space as a set of dimensions” that informs the Spectrum as Space metaphor. One can transpose his summary to spectrum as “the relatively permanent place where [radio operations] happen.” The “Buddhist” view, on the other hand, would see spectrum as the absence of factors that would obstruct radio operations. Existing radio operations, including receivers, would provide resistance to new operations, even in quite distant frequency bands. And there is an interaction between the agent that wants to move about and the nature of obstructions: neither a mouse nor a monkey would have no trouble scurrying around in a restaurant, while a person would be obstructed by all the tables and chairs. Likewise, one has to first define the new operation one has in mind before deciding that spectrum is “occupied”; calculating utilization is not a straightforward matter of marking spectrum as “empty” or “full.”

FCC white paper shows that “spectrum efficiency” is meaningless

The FCC Technical Advisory Council’s (TAC) draft white paper on spectrum efficiency metrics (25 September 2011) is an excellent piece of work. It is authoritative, instructive, and demonstrates decisively that spectrum [1] efficiency metrics are a meaningless concept.

While they don’t say this in so many words, members of the Sharing Working Group perhaps intended this conclusion to be drawn; “spectrum efficiency” is a DC catchphrase that is hard to avoid, and it would probably be unwise to refute it overtly…

The following elements of the paper imply that the “spectrum efficiency” concept is useless:

1. There is no metric that can be applied across the myriad of different wireless services.
2. The metrics are incomplete, even within a service.
3. While the paper suggests metrics for specific services, the taxonomy of services is arbitrary.

Consequently

• There is no way to compare the “efficiency” of one radio service (aka one “spectrum use”) to another, denying politicians the pseudo-scientific rationale they dream of for converting a frequency band allocation from one use to another.

• Even within a given service type, there is no defensible way to rate one deployment’s performance over another; even if one scored much lower using the relevant efficiency metric, its defenders could invoke any of the long list of “additional efficiency considerations” to deny that the comparison was valid.

The paper also misses an opportunity: It hints at the importance of cost effectiveness rather than mere efficiency, but doesn’t address this broader context.

Follow-up posts:

• From spectrum efficiency metrics to parameter spaces (December 2011)
•  Three meanings of “spectrum efficiency” (October 2012)

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

TV white space databases: A bad idea for developing countries

Now that TV white space rulemakings are in the can in the US and UK, proponents will be pitching the technology to any government that’ll listen, e.g. at the Internet Governance Forum meeting to be held in Nairobi on 27-30 September.

It’s understandable: the more widespread white space database rules, the larger device volumes will be, and thus the lower the equipment cost, leading to wider adoption – a positive feedback loop. However, white space database technology is unnecessary in many countries, particularly developing ones.

Yet it verges on dodgy ethics for companies to hype this technology to countries that don’t need it, particularly since there’s a better solution: dedicating part of the TV frequencies that are freed as a result of the transition to digital TV (the “Digital Dividend”) to unlicensed operation, without the white space bells and whistles.

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.

Licensing radio receivers as a way to facilitate negotiation about interference

It’s a curious fact that, while receivers are just as much responsible for breakdowns in radio operations as transmitters [a], regulation is aimed pretty much exclusively at transmitters [b].

Since one can’t ignore the receivers in practice, arguments over interference almost invariably turn to receiver standards. Even if receiver standards were a good idea (and I don’t think they are - see my post Receiver protection limits: a better way to manage interference than receiver standards), the ability to adjust receiver performance by fiat or negotiation is limited when receivers are operated independently of transmitters.

I suspect that receiver licenses may be necessary to reach the optimum outcome in at least some cases. This post is going to take that idea out for a first test drive.

Regulators evidently have managed without receiver licenses (beyond their use as a way to fund traditional broadcasting) so far. Why introduce them now? I’ll give my usual answer: the dramatically increased demand for wireless is squeezing radio operators of widely varying kinds together to an unprecedented extent, and we no longer have the luxury of the wide gaps that allowed regulators to ignore receiver performance, and ways of managing it.

Follow-up post

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

“Quiet” doesn’t mean “unused”: The Downside of Under-defined Radio Rights

The FCC has promised to find and reallocate 500 MHz of radio frequencies to satisfy the burgeoning demand for high bandwidth mobile services such as video on cell phones. The idea, the hope, is that there are lots of unused bands to be repurposed. “Unused” is a tricky notion, though. I’ll take it to mean “radio quiet”: a radio energy detector doesn’t observe much if anything at certain frequencies, and the assumption is that a new service could transmit here.

Of course, nothing is as simple as that. Let’s assume that the services that actually operate in these quiet bands – and there are always incumbents, since every frequency has one if not many nominal users – can be found a new home, and that they’ll relocate. The harder problem is that a quiet band may not in fact be usable because of the equipment in neighboring bands. The LightSquared/GPS argument is a conveniently current example. The proposal to allow LightSquared to deploy lots of ground-based transmitters in a band where to date only satellite transmissions were allowed has caused shock and outrage among GPS users who claim that their receivers cannot distinguish between the LightSquared signal in the adjacent band and the satellite location signals in the GPS channel.

Since the FCC’s rules and precedents provide almost unlimited protection against "harmful interference" (a notoriously vague term) caused by new services, an incumbent is pretty much assured that it will be held harmless against any change. The situation is exacerbated because FCC licenses only specify transmission parameters and say nothing about the radio interference environment that receivers should be able to cope with. Radio receivers are thus designed and built as if their radio environment will never change; if a band has been quiet, none of the receivers in the adjacent frequencies can cope with more intensive use, since building in that protection costs money. (For complementary perspectives on this problem, and suggested remedies, see two short papers presented at a recent conference in Washington, DC: Kwerel and Williams, De Vries and Sieh.)

Thus, just because a band is quiet doesn’t mean that it’s unoccupied; it’s probably effectively occupied by the protection afforded to the cheap receivers next door that haven’t been required to, and therefore don’t, tolerate any substantial operation in the quiet channel. It’s as if the incumbent were a householder whose property used to be passed by track along which only ox wagons passed. She didn’t have to take any precaution against her dogs being run over by a wagon, such as building a fence, and this unlimited protection still holds even when the track is turned into an arterial road, holding passing vehicles completely responsible if a dog is run over.

Money could, but might not, solve the problem. Let’s say Tom Transmitter wants to deploy a new service
in the formerly quiet band, and that this would cost the incumbent neighbor, Rae Receiver, $300 million, either in lost revenue from diminished service and/or because of precautions such as new receiver filters that are needed to reject Tom’s adjacent band signals. If the benefit to Tom is big enough, if for example he could generate $500 million in profit, Tom could compensate Rae and still come out ahead. But how is the $200 million of potential gain ($500 million - $300 million) to be divided? This depends on Rae’s rights. If she has the right to prevent any operation by Tom (i.e. she can take out an injunction against him), she can demand essentially all his profits as a condition of operationlet’s say $499 million of his $500 million, whereas if she’s entitled to damages, she can only demand $300 million for actual losses. These are very different outcomes. Under an injunction, Tom’s incremental net profit is $1 million ($500 million - $499 million) and Rae’s is $199 million ($499 million - $300 million), whereas under damages, Tom’s net profit is $200 million and Rae’s is zero.

However, since the FCC doesn’t specify whether licenses are protected by damages or injunctions, Tom and Rae can’t begin to deal, since the legal basis of the negotiation is unclear. Tom will hope that he can get the whole $200 million incremental gain, and Rae will hope for it, too – a huge difference in expectations that will almost inevitably prevent the parties from coming to an agreement.

(There are further obstacles to reaching a settlement that I won’t go into here, such as uncertainty over what action by Tom actually constitutes damage to Rae due to ambiguity in the way FCC rules are currently formulated, and the freeloader/hold-out problems with negotiations involving many parties.)

What's to be done?

1. Any inventory of “unused” radio capacity should not only itemize radio quiet bands, but also the nature of the service and receivers next door, so that the cost of relocating, protecting or degrading the incumbent service can be estimated.

2. Any new licenses that are issued should specify whether they’re protected by injunctions or damages; this will facilitate negotiation.

3. Any new license should specify the receiver protection parameters the operator can rely on, and by implication what will not be protected.

4. Regulators should start retrofitting existing licenses to this new approach by specifying the remedy (#2) and laying out a timeline over which receiver protections (#3) will be dialed down from the current open-ended “no harmful interference” condition to more realistic and objective received energy levels.

The two page position paper I referenced above gives a quick introduction to these measures; for all the gory details, see the 15 page long version on SSRN.

Law without Categories?

A recent New Scientist story about the descent of birds from dinosaurs (James O'Donoghue, Living dinosaurs: How birds took over the world, Section 2, Was archaeopteryx really a bird?, 08 December 2010; subscription required) contained this passage:

The real question is, where do you draw the line between dinosaurs and birds? Ask different palaeontologists and you will get subtly different answers. That is because the distinction is basically arbitrary, says Xing Xu of the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing, China, who discovered many of the Chinese fossils [of feathered dinosaurs].

This is a common theme in biology: the boundaries between species are arbitrary. And yet we continue to think in terms of species, since categorization is such a strong human reflex.

Jurisprudence and regulation in particular is built on categorization, defining categories that determine the response to a particular situation. At the heart of current network neutrality argument is the question of whether  a company falls in "Title II" in which case a whole raft of  telecommunication regulation regarding common carriage applies, or "Title I" in which case they are much more lightly regulated.

However, as the analogy to biology illustrates, most interesting categories have fuzzy boundaries, making for a delightful amount of work for lawyers and lobbyists, but not necessarily helpful outcomes.

Taxonomies are backward-looking; they attempt to fossilize a reality but are constantly open to revision. (This necessity for revision undermines the certainty which category-based rules purport to offer since categories are less robust than they appear, necessitating the case-by-case interpretation which proponents of rules contend is the weakness of the alternative approach, principles-based regulation.) They evidently work well enough, though; they're pervasive. A paper by David Bach & Jonathan Sallet about VOIP regulation (The challenges of classification: Emerging VOIP regulation in Europe and the United States, First Monday, Volume 10, Number 7, 4 July 2005) explains the situation very well:

From a practical point of view, classification stands out because classifying different services is what regulators principally do. In an ideal world, one could just draw up rules for VOIP that address the aforementioned critical issues, keeping in mind the technology’s novelty and the substantial differences that exist between conventional circuit–switched telephony and innovative packet–switched VOIP. In the real world, however, a first step in the regulation of new technologies is usually to try to fit them into existing service categories, in part because those are the tools that regulators work with and in part because classification can provide shortcuts through complex regulatory problems. Alternatively, regulators may be inclined to ask whether VOIP service is "like" or "substitutable" for current services — an approach that may obscure technological achievement. Either way, much is at stake in these decisions.

Fitting VOIP into existing regulatory categories is not simply an administrative or technical act. Since categories are associated with distinct sets of rights and responsibilities that have distributional and market strategic implications, a large number of stakeholders have mobilized to affect the outcome. . . .

Unpacking the political economic dynamics of evolving VOIP regulation highlights a second, more analytic reason to focus on classification. The debate over how to classify VOIP represents the leading edge of the question whether regulatory classification is useful in a world of converging technologies. . . .

In the eyes of most regulators and industry observers, correctly categorizing VOIP provides a shortcut through regulatory uncertainty. Yet precisely this is the problem with classification. As policymakers almost reflexively ask how a new technology fits into existing categories, the underlying political and social objectives of regulation can get lost.

A behavioral alternative comes to mind: the regulations that should apply do not derive from the category into which an action falls, but from its consequences; in Bach & Sallet's terms, one needs to look to the political and social outcomes, not the inputs.

How I Learned to Stop Worrying and Love Interference

(With apologies to Stanley Kubrick.)

Radio policy is fixated on reducing or preventing harmful interference. Interference is seen as A Bad Thing, a sign of failure. This is a glass-half-empty view. While it is certainly a warning sign when a service that used to work suddenly fails, rules that try to prevent interference at all costs lead to over-conservative allocations that under-estimate the amount of coexistence that is possible between radio systems.

The primary goal should not be to minimize interference, but to maximize concurrent operation of multiple radio systems.

Minimizing interference and maximizing coexistence (i.e. concurrent operation) are two ends of the same rope. Imagine metering vehicles at a freeway on-ramp: if you allow just one vehicle at a time onto a section of freeway, people won’t have to worry about looking out for other drivers, but very few cars would be able to move around at one time. Conversely, allowing everybody to enter at will during rush hour will lead to gridlock. Fixating on the prevention of interference is like preventing all possible traffic problems by only allowing a few cars onto the freeway during rush hour.

Interference is nature’s way of saying that you’re not being wasteful. When there is no interference, even though there is a lot of demand, it’s time to start worrying. Rather than minimizing interference with the second-order requirement of maximizing concurrent operation, regulation should strive to maximize coexistence while providing ways for operators to allocate the burden of minimizing interference when it is harmful.

I am developing a proposal that outlines a way of doing this. Here are some of the salient points that are emerging as I draft my ISART paper:

The first principle is delegation. The political process is designed to respond carefully and deliberatively to change, and is necessarily slower than markets and technologies. Therefore, regulators should define radio operating rights in such a way that management of coexistence (or equivalently, interference) is delegated to operators. Disputes about interference are unavoidable and, in fact, a sign of productively pushing the envelope. Resolving them shouldn’t be the regulator’s function, though; parties should be given the means to resolve disputes among themselves by a clear allocation of operating rights. This works today for conflicts between operators running similar systems; most conflicts between cellular operators, say, are resolved bilaterally. It’s much harder when dissimilar operations come into conflict (see e.g. my report (PDF) on the Silicon Flatirons September 2009 summit on defining inter-channel operating rules); to solve that, we need better rights definitions.

The second principle is to think holistically in terms of transmission, reception and propagation; this is a shift away from today’s rules which simply define transmitter parameters. I think of this as the “Three P's”: probabilistic permissions and protections.

Since the radio propagation environment changes constantly, regulators and operators have to accept that operating parameters will be probabilistic; there is no certainty. The determinism of today’s rules that specify absolute transmit power is illusory; coexistence and interference only occur once the signal has propagated away from the transmitter, and most propagation mechanisms vary with time. Even though US radio regulators seem resistant to statistical approaches, some of the oldest radio rules are built on probability: the “protection contours” around television stations are defined in terms of (say) a signal level sufficiently strong to provide such a good picture at least 50% of the time, at the best 50% of receiving locations. [1]

Transmission permissions of licensee A should be defined in such a way that licensee B who wants to operate concurrently (e.g. on nearby frequencies, or close physical proximity) can determine the environment in which its receivers will have to operate. There are various ways to do this, e.g. the Australian “space-centric” approach [2] and Ofcom’s Spectrum Usage Rights [3]. These approaches implicitly or explicitly define the field strength resulting from A’s operation at all locations where receivers might be found, giving operator B the information it needs to design its system.

Receiver protections are declared explicitly during rule making, but defined indirectly in the assigned rights. When a new allocation is made, the regulator explicitly declares the field strength ceilings at receivers that it intends to result from transmissions. In aggregate, these amount to indirectly defined receiver protections. Operators of receivers are given some assurance that no future transmission permissions should exceed these limits. (Such an approach could have prevented the AWS-3 argument.) However, receivers are not directly protected, as might be the case if they are given a guaranteed “interference temperature”, nor is there a need to regulate receiver standards.

While this approach has been outlines in terms of licensed operation, it also applies to unlicensed. Individual devices are given permissions to transmit that are designed by regulator to achieve the desired aggregate permissions that would otherwise be imposed on a licensee. Comparisons of results in the field with these aggregate permissions will be used as a tripwire for changing the device rules. If it turns out that the transmission permissions are more conservative than required to achieve the needed receiver protections, they can be relaxed. Conversely, if the aggregate transmitted energy exceeds the probabilistic limits, e.g. because more devices are shipped than expected or they’re used more intensively, device permissions can be restricted going forward. This is an incentive for collective action by manufacturers to implement “politeness protocols” without regulator having to specify them.

Notes

[1] O’Connor, Robert A (1968) Understanding Television’s Grade A and Grade B Service Contours, IEEE Transactions on Broadcasting, Vol. 47, No. 3, September 2001, p. 309, http://dx.doi.org/10.1109/11.969381

[2] Whittaker, Michael (2002) Shortcut to harmonization with Australian spectrum licensing, IEEE Communications Magazine, Vol. 40, No. 1. (Jan 2002), pp. 148-155, http://dx.doi.org/10.1109/35.978062

[3] Ofcom (2007) Spectrum Usage Rights: A statement on controlling interference using Spectrum Usage Rights, 14 December 2007, http://www.ofcom.org.uk/consult/condocs/surfurtherinfo/statement/statement.pdf