Robustness of a TETRA base station receiver against intentional EMI

Terrestrial trunked radio (TETRA) is a digital radio standard that was developed to meet the needs of professional mobile radio systems. TETRA is vulnerable to intentional electromagnetic interference (EMI) because of the wireless link. The EMI can easily be front door coupled to the base station via the antenna and cause a denial-of-service of the communication. In this paper, the robustness of TETRA against front door coupled intentional EMI is investigated. Three different interfering mechanisms are discussed: damage of the receiver, saturation of the receiver, and masking the communication signal. The interference mechanisms are fundamentally different and needs to be addressed separately. We present two experimental methods to test the robustness of a base station receiver against different interference mechanisms. Results show that the analyzed TETRA base station is very robust against out-of-channel interference with moderate power levels. Intentional EMI is expected to be in-channel because an adversary will exploit the vulnerable frequencies, and this can disrupt TETRA communications.