This is a concept where a cellphone can operate normally or in a private mode where it is not reporting to a local cell tower and therefore not tracked.
The constant RF transmitting does not occur. Only when a call is active does the cellphone transmit and then either using a unique Identifiers or as a normal cell call.
The private mode requires either a local Wi-Fi that is sending call codes, or a private or community cell tower that does so.
A semi-private mode would allow a phone to only be transmitting when no private codes are available and therefore no effort for the user.
This is a large project
Concepts maturing - resources lacking