Frankenstein at the FCC

A full-text search for “Frankenstein” on ECFS (the repository for official records in the FCC's docketed proceedings from 1992 to the present) on 22 Feb 2020 returned 91 results. I was surprised the number was that small.

Satellite Constellation Spectrum as a Common Pool Resource

The radio allocations of satellite constellations in non-geostationary orbit (NGSO) are an FCC-managed commons. In an earlier post, I explored how the bands allocated to NGSO constellations could be managed by assigning private rights by auction. I envisaged a set-up where operators could pay for priority protection, creating an interference protection ranking. In this post, I explore the possibility of treating NGSO allocations as a common pool resource.

Auctioning non-exclusive mmwave licenses

Petri Mähönen, Ljiljana Simić and I recently filed comments in the Spectrum Frontiers proceeding, FCC Docket No. 14-177 (filing page, pdf, docket on ECFS). We argued that the operating and propagation characteristics of mm-wave systems mean that non-exclusive licensing – meaning in this case, a limited number of large-area licenses assigned by auction – is an appropriate middle path between exclusive large-area licensing (which may lead to under-utilization) and unlicensed (which may not provide sufficient interference protection).

Resulting field strength rules: New reasons for an old idea

Current transmit power limits don’t provide sufficient constraints on interference, particularly when applied to modern systems (such as in the millimeter-wave bands) that deliver signal levels that change dramatically and rapidly from moment to moment, and place to place. I believe that limits on resulting field strength, rather than transmitted power, will be necessary in new allocations, particularly in the millimeter-wave bands.

Satellite constellation license auctions

Broadband satellite constellations in non-geostationary orbits (NGSO) will share frequency bands. They will interfere with each other from time to time. How should such conflicts be resolved? FCC rules encourage constellations to coordinate their operations, treating the shared NGSO bands as something like an FCC-supervised commons. However, spectrum regulators have increasingly used auctions to assign radio operating rights (cf. cellular licenses), and largely left it to the market to solve coordination problems. Could spectrum auctions be used for NGSO operation?

Principles for interference assessment and receiver protection in FCC rulemakings

A key consideration in spectrum policy, particularly the allocation of new services, is the protection of existing services against harmful interference. However, regulators take an ad hoc approach to defining harmful interference. We would be better served if everyone knew, up-front, the principles a regulator was going to use when making decisions about a new allocation.

Julie Knapp’s comment at a recent FCC TAC meeting have inspired me to sketch out some principles/guidelines/framework for the FCC when looking at protecting services during rulemakings. Julie pointed out that the TAC Spectrum and Receivers Working Group now has an opportunity to synthesize and make actionable our work of the last few years.

(Update: The FCC TAC adopted "Basic Principles for Assessing Compatibility of New Spectrum Allocations" [pdf] at its meeting on December 9, 2015. I participated in drafting this document, and I'm delighted that it aligns well with the principles I outlined here.)

Six weeks of spectrum auction tweets

I created an animated GIF to show how twitter traffic about spectrum auctions changed over the first six weeks of the AWS-3 auction, i.e. November 15 to December 27.

Adjudication versus Enforcement

Mike Marcus (web site) has suggested that enforcement problems can be divided into two categories:

#1. Cases where behavior explicitly violates existing rules, e.g. use of the wrong frequency, or equipment that doesn't comply with rules.

#2. Unanticipated interactions between systems that either lead to service degradation but do not self-evidently violate any rules, or raise complex legal issues of whether there is a violation.

Mike suggests that the second category includes "cellular booster" interference to cellular systems, police radar detector "fuzzbuster" interference to VSATs, the Nextel/public safety intermod problem in 800 MHz, and impairment of 700 MHz cellular due to FM transmitter harmonics (discussed on Mike’s blog).

The fact that the spectrum community informally refers to both categories as enforcement problems while the second is actually a question of adjudication highlights a problem caused by the FCC’s rudimentary judicial function: while it has more than 250 people in the Enforcement Bureau (2014 Budget), it only has one (!) administrative law judge.

It seems to me that (1) being clear about the enforcement/adjudication distinction and (2) actually having an adjudication function separate from both rule making (the legislative function) and enforcement (the executive function) would not only help us think more clearly about spectrum problems but would also lead to quicker resolution, to everyone's benefit.

Discussion

As an administrative agency (caveat: IANAL) the FCC combines the three branches of government under one roof: legislative, judicial and executive. It makes rules (legislative), decides whether they have been broken (judicial), and takes action to detect alleged violations, and punish them if violations are found (executive).

Mike’s Category #1 (explicit violations of existing rules) is enforcement, defined by the OED as “the act of compelling observance of or compliance with a law, rule, or obligation”: it presupposes that adjudication has already taken place. The examples in Category #2 (unanticipated interactions) are actually questions of adjudication, i.e. “A formal judgment on a disputed matter” per the OED: they're difficult precisely because it's not clear whether there's been a violation, or by whom.

The FCC is very loosey-goosey on this distinction, as has been pointed out over the years; see e.g. Ellen Goodman’s 2004 Telecosm paper, Phil Weiser’s 2009 FCC Reform paper and our recent Hamilton Project paper.

Distinguishing clearly between these two categories could also address a blind spot about the need for enforcement in the Dynamic Spectrum Access (DSA) community. If enforcement is addressed at all by advocates of Spectrum Access Systems (SAS), it’s usually waved away with assurances that the rules in the database will solve all problems. (Jerry Park’s presentation at the January 2014 FCC 3.5 GHz SAS workshop is an exception, but even he focuses on attacks on the database, rather on how to decide disputes.)

Mike's distinction made me realize that the DSA/SAS community probably equates enforcement with Category #1. It's then plausible to believe that a system that prevents explicit rules violations solves, or more accurately obviates, "enforcement problems." However, the arcane interactions between radio systems in the wild and the difficulty in assigning responsibility for them make it important to highlight the Category #2 problems: these unintended issues are not only more likely to cause problems – and cause them unexpectedly – that failures in rule sets, but by their nature they will require judgment (in both a legal sense, and in the sense of requiring assessment of hard-to-compute complexities) to resolve.

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.

Harm claim thresholds could help sharing in the 3.5 GHz band

I have filed comments on the FCC's proposed new rules for the 3550-3650 MHz band (proceeding 12-354).

TV/cellular guard bands - second thoughts

In a recent post ("The FCC's TV/cellular guard bands don't compute") I wondered whether the guard bands between TV and cellular service that the FCC proposed in its Incentive Auction NPRM (pdf) had been designed to make room for more unlicensed in the TV bands. Having spoken to some experts, I’ve concluded that I was probably wrong about that: my new best guess is that they’re a benefit for the cellular industry.

The FCC's TV/cellular guard bands don't compute

The FCC incentive auction NPRM [1] proposes 6 MHz guard bands between cellular and TV services (actually 6-11 MHz, depending on how the auction works out). The number is arbitrary, and could well have been chosen on political grounds to make room for more unlicensed in the TV bands.

The impact on interference from cellular systems into TV receivers is much the same whether the guard band is 1 or 20 MHz: most receivers will be unaffected, and for the small but significant number that suffer harm (0.5-5%?), only receiver filters will really help. The real question is: who's responsible for buying and installing those filters - the consumer or the cellular companies?

TV whitespace vs. cellular power limit anomalies

In the previous post, I considered interference between cellular base stations and TV receivers. What about interference between cellular handsets and TV? Considering this case highlights striking contradictions between the low power allowed for TV whitespace devices and the high power the FCC proposes for cellular operation: 20 dBm for whitespace personal devices but 37 dBm for cellphones, in both cases with a 6MHz guard band.

Post-auction cellular interference into TVs?

How many TV receivers will be affected by interference from cellular services as a result of the FCC’s "incentive auction" plan?  The FCC’s proposal doesn’t venture an answer; I don't think it even asks the question. Ofcom’s technical analysis in the UK’s rearrangement of the TV bands to accommodate more cellular service suggests that the number will be small, but not negligible. Ofcom therefore decided to require cellular operators to install filters on TV sets where there is a problem; the FCC has not raised this possibility.

In summary, the UK modeling suggests that TV reception will be affected in about 5% of  homes if there's a 11 MHz guard band between TV and cellular channels; the FCC's proposed guard band will be 6 - 11 MHz, depending on auction outcomes. By far the most effective way to mitigate this interference is by installing a TV receiver filter in affected homes.

Transmitter versus receiver specifications: measuring loudness versus determining understanding

In arguing that regulators should attend to receivers as well as transmitters, I’ve may have mistakenly left the impression that they’re symmetrical, e.g. that one is a reflection of the other. For example, in “Four Concerns about Interference Limits” I observed that a communication system can be engineered to operate successfully either by improving receivers, or by delivering more transmitted power.

However, this framing is potentially misleading. It could be taken to mean that transmission and reception are two sides of a coin, that they are similar in kind, but that one is the reflection or complement of the other. They’re actually more like the outside (transmission) and inside (reception) of a black box - a black box like the human head, say.

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?

Who gets the apple? Part II: A salty problem

Here's another analogy; one that includes a nod to dispute resolution. For those who know and/or love Coasian economics, it's our old friend the pollution example, though tweaked to be radio interference in light disguise. It's also, incidentally, based on a true story I heard from someone who works for a large county's water district.

Imagine a city along a river, and a downstream farming community. Urban development results in more salt being added to the river; increased salinity can reduce crop yield. Salty water is therefore analogous to radio interference between transmitters (cities) and receivers (farms).

The harm to crops is a shared responsibility, though. For example, the city can reduce the amount of downstream salt by building a water treatment plant, and the farmers can accomodate more salty water by changing crops - spinach will be fine on water that's too salty for celery.

Let's imagine that a Federal Crops Commission (call it the FCC2) is responsible for managing this problem. It might instruct the city and farms to "coordinate" to find a solution to the problem, with a guideline that water may not be "too salty". As in the apple example, this is difficult to do without defining what counts as too salty, and who bears the responsibility for salinity.

If the FCC2 limits the salt the city can dump in the river like the FCC controls radio emissions, it would specify a ceiling of, say, 5 tons of salt per day - with a rider that the resulting water can't be "too salty". This is not very helpful to the farmers, however, since they care about the resulting salinity; seasonal variations in water volume or the salinity entering the city limits from upstream affect the resulting salinty. It doesn't help the city either, since it can't be sure how much water treatment capacity to build; 4 tons/day of salt might still turn out to be too much if the farmers downstream choose salt-intolerant crops and/or the river level is too low.

Matters are compounded when the city and the farming community fail to reach agreement, and go to the FCC2 to resolve a conflict. (They have nowhere else to go, since the courts defer to the FCC2 as an expert agency to decide what "too salty" means in a particular case.)

Neither side can predict what the outcome of the FCC2's deliberations will be, since it doesn't always decide the merits of individual cases in isolation. It has many proceedings before it at any given time; for example, the FCC2 might be pushing the farmers to get organic certification, and negotiating with the city about the rezoning of agricultural land for urban development. The solution the FCC2 negotiates between the city and the farmers might encompass all these other matters, not only making the result of the salinity dispute unpredictable, but failing to establish a precedent that others might use later.

A better approach would be for the FCC2 to regulate the resulting salinity in water leaving the city (to, say, 5 ppm), remove any mention of "too salty" from its regulations, and provide a way for contending parties to get a specific case resolved efficiently. It might give the farmers the right to stop the city water plant releasing water into the river if the salinity exceeds 5 ppm (leading to a negotiated solution, where the city might pay the farmers' coop $300,000 to raise the limit up to 10 ppm in dry months), or if there are too farmers to negotiate with individually it might choose a liability regime (leading to a court-imposed payment of say $30/acre if salinity exceeds 5 ppm and some farmers sue the city).

Social network visualizations - an online symposium

My work on the evolution of FCC lobbying coalitions has been accepted in the JoSS (Journal of Social Structure) Visualization Symposium 2010 (link to my entry). Jim Moody of Duke has done a wonderful job collecting a dozen visualizations of social networks. Each is worth exploring; in particular, see the thoughtful comments that the JoSS staff provided to each entry in order to stimulate debate.

Improving FCC filing metadata

On 10 May 2010 I filed a comment on two FCC proceedings (10-43 and 10-44, if you must know) concerning ways to improve the way it does business. I argued that transparency and rule-making efficiency could be improved by improving the metadata on documents submitted to the Electronic Comments Filing System (ECFS).

I recommended that the FCC:

• Associate a unique identifier with each filer
• Require that the names of all petitioners are provided when submitting ECFS metadata
• Improve RSS feed and search functionality
• Require the posting of digital audio recordings of ex parte meetings
• Provide a machine interface for both ECFS search and submission