I assume, as it is unstated, that this requires quite accurate information about the radio signals of the device - probably at a level only accessible at the ra

I assume, as it is unstated, that this requires quite accurate information about the radio signals of the device - probably at a level only accessible at the radio of the mast. It's possible that these irregularities are encoded in the raw bit stream from the base station (e.g. to the Radio Network Controller), but they'd be lost here... So to put this in place, you'd probably need to add some additional hardware/processing capacity into the RNC or the base station (though, that's not too far fetched, seeing as most existing base stations are now over-spec'ed on space and power).