A battery operated device that can be built out of cheap parts can cause denial of service for thousands of people by knocking out a large LTE base station.
The main problems that make such an attack even possible are in LTE’s architecture. LTE specifications do not require some extra verification that can prevent the attacks. The research paper posted on the National Telecommunication and Information Administration page from U.S. Department of Commerce’s website describes the following three attacks that are effective against LTE networks: Synchronization Signal Jamming, Primary Synchronization Signal Jamming, and Physical Uplink Control Channel Jamming.
According to Reed and his research assistant Marc Lichtman although it is hard to defend against such attacks LTE operators could start building a protection system against bogus synchronization signals to make one of three described attacks ineffective. The critical document describing how any LTE network can be taken down is located at the following URL: http://www.ntia.doc.gov/files/ntia/va_tech_response.pdf.
Although every cell phone grid in the world is vulnerable to the LTE attacks described in the above mentioned document we would still be able to use the existing 2G and 3G grids in case of a terrorist attack that uses these techniques.