My post Receiver Protection Limits may have left the impression that reception protection limits are similar to the dreaded and ill-fated interference temperature notion introduced in 2002 by the FCC’s Spectrum Policy Task Force.
Receiver protections are part of the "Three Ps" approach (Probabilistic reception Protections and transmission Permissions - see e.g. the earlier post How I Learned to Stop Worrying and Love Interference, or the full paper on SSRN). While both the Three P and Interference Temperatur approaches share a desire to “shift the current method for assessing interference which is based on transmitter operations, to an approach that is based on the actual radiofrequency (RF) environment,” to quote from the first paragraph of the Interference Temperature NOI and NPRM (ET Docket No. 03-237), the Three Ps approach differs from Interference Temperature in four important ways:
1. The Three Ps focus on solving out-of-band, cross-channel interference, whereas Interference Temperature is concerned with in-band, co-channel operation
2. The Three Ps are used to define new operating rights, whereas Interference Temperature tried to open up opportunities for additional operations in frequencies allocated to existing licensees
3. The Three Ps do not grant second party rights, whereas Interference Temperature permits second party operation.
4. Three Ps rights are probabilistic, whereas Interference Temperature definitions are deterministic.