Two papers in a short period of time describe how to implement easy IMSI Catchers in 4G, using OpenLTE, srsLTE or gr-LTE:

– “Easy 4G/LTE IMSI Catchers for Non-Programmers“, Stig F. Mjølsnes and Ruxandra F. Olimid (Norwegian University of Science and Technology, Trondheim)

– “Practical Attacks Against Privacy and Availability in 4G/LTE Mobile Communication Systems“, Altaf Shaik, Ravishankar Borgaonkar, N. Asokan, Valtteri Niemi and Jean-Pierre Seifert

Although these 4G stations aren’t functional, also can be use to downgrade our mobile to a 2G or 3G fake station using “TAU Reject” code “LTE services not allowed”.