The FCC has authority to regulate transmission under Sec. 301, 302a. Problem: it does not have explicit authority to regulate passive reception. This creates problems because the ability of a receiver to receive signal is what determines interference. A weak receiver requires greater protection.
Traditionally, manufacturers sought to improve reception for robustness purposes. However, there are now cases where it makes economic sense to build weak receivers. This forecloses more intense use of neighboring spectrum, because out of band emissions (OOBE) create interference with previously established services (such as broadcast television).
solution: Rather than regulate receiver standards, the FCC has authority to define harmful interference and must protect licensees from same. The FCC shall establish harmful interference standards based on the presumption that the receiver meets specific characteristics. Any interference that results from the use of substandard receivers is not "harmful." This works because, pursuant to the statute, it is the licensee that is entitled to interference protection under the terms of their license (Section 309(h)). A passive receiver is not entitled to interference protection. This is the same logic currently used to define the protected contours for broadcast stations. Only stations within the defined geographic contours are protected under the license. Receivers outside the protected contour are not entitled to protection, even if they actually receive the signal and where more accurate modeling predicts they will receive the signal. Rather, like market definition, the definition of harmful interference is subject to FCC definition, not definition based on previous use. Indeed, reliance on previous use is expressly prohibited under Section 304.
There. I can die happy if necessary.