Interference Limits for AWS-4

I have filed a comment (PDF) on the FCC's proposed AWS-4 rulemaking.

I argued that receiver performance affects the allocation of spectrum and opportunities for the creation of new services; that receiver management does not necessarily mean imposing receiver standards; that the Commission should define interference limits, an explicit statement of the radio interference level that a licensee’s system needs to tolerate, for AWS-4 licenses; but that receiver performance standards are not needed in this allocation.

Four Concerns about Interference Limits

Dennis Roberson has flagged some concerns about the interference limit approach. (The approach is summarized in http://sdrv.ms/ReceiverLimits; to trace the evolution of the idea, see the root post Receiver protection limits, and subsequent posts listed there).

His questions have helped me understand the importance of characterizing interference limits as a way to define harmful interference more precisely, rather than as a description of the radio interference environment. I probably over-played the interference environment angle in some earlier accounts in an attempt to distinguish interference limits from receiver performance standards using the slogan, “It’s not about the device, it’s about the environment.” That’s still true – the environment is indeed more important than the device – but using interference limits doesn’t require the regulator to measure and monitor the RF environment.

Dennis’s concerns relate to:

1. The regulator’s ability to adequately define the current stable environment, much less a dynamic future state environment
2. A designer’s ability to figure out what environmental limits mean from a receiver design perspective
3. The ability to test a device to ensure that it really works in the specified environment and to convey these test results to the FCC to demonstrate the adequacy of the design
4. The regulator’s ability to field an economical approach to resolving issues when a receiver does not work and the manufacturer says the environment is the issue

Markets for adjusting interference rights

One of the problems I tried to solve with the proposal “Stamps and Stewards: A third way to regulate radio operation” was 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. There are other possibilities; this post explores using auction mechanisms.