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.

Is harmful radio interference decreasing?

Spectrum analysts (including me) often proclaim that harmful interference is a growing problem, or at the very least a growing risk. That sounds plausible, given the growing profusion of radios, packed more and more densely together. But what if the opposite is true?

Q&A: Risk-assessment, harm claim thresholds and adjudication

In my testimony before the Senate Commerce Committee on Wednesday July 29, 2015 I recommended three spectrum management reforms. A summary and links to the written testimony and video are in an earlier blog post. This post offers some Q&A.

The three reforms were: (1) moving away from worst case interference analysis and using risk-informed methods that consider not only the consequences but also the likelihood of harmful interference; (2) providing more clarity about operators’ interference rights and obligations by specifying harm claim thresholds; and (3) giving any spectrum user the option of taking action directly against any other, either in front of an FCC judge or in a federal Court of Spectrum Claims.

Senate Testimony: Risk-assessment, harm claim thresholds and adjudication

I testified today before the Senate Commerce Committee hearing on “Wireless Broadband and the Future of Spectrum Policy.” My written testimony is here; this is the summary I presented during the hearing. I’ve posted some Q&A in a subsequent post. My remarks are recorded in the archived webcast, starting at 58:02; see also a question from Chairman Thune and my reply starting at 2:05:43.

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.)

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).

Harm claim thresholds for satellite earth stations

I'm reasonably confident at this point about deriving harm claim thresholds for cellular neighbors and TV receivers (see e.g. the TPRC 2012 paper http://ssrn.com/abstract=2018080). Here's a first cut (a few months old, but I'm behind on blogging...) at thresholds for satellite earth stations.

Testimony: Harm Claim Thresholds

I was privileged to testify yesterday at the House Committee on Energy and Commerce’s sub-committee on Communications and Technology hearing on the topic “The Role of Receivers in a Spectrum Scarce World.”

My testimony (pdf; my oral testimony at time code 0:17:23 in the YouTube video on the hearing web page; the members' questions start at 0:27:00; some press here and here) tried to make four points:

1. We need to improve the ability of radio systems in one frequency band to tolerate reasonable signals in adjacent bands. 
2. Receiving system operators must bear some of the responsibility, but need to know what those responsibilities are.
3. Regulators can bring receiving systems into the mix by setting harm claim thresholds (aka interference limits or receiver protection limits), i.e. the interference levels that a service needs to tolerate without being able to bring a harmful interference claim.
4. Congress can play a role by keeping up the pressure, allowing the FCC to move ahead, and funding FCC technical investigations.