"So far the theory. If you look at the Paging Channel (PCH) of cells in real-world networks, you see a significant (10-20%) amount of paging requests that conta

"So far the theory. If you look at the Paging Channel (PCH) of cells in real-world networks, you see a significant (10-20%) amount of paging requests that contain paging by IMSI. This seems strange on first sight, given the theory..."[1] So you can't spy on everyone, but you can spy on some subscribers whose phone is in that state. [1] https://laforge.gnumonks.org/blog/20100628-the_reason_for_paging_by_imsi/ https://laforge.gnumonks.org/blog/20100628-the_reason_for_pa...