Vulnerability Analysis of the Wireless Infrastructure to Intentional Electromagnetic Interference

Contemporary society is greatly dependent upon a set of critical infrastructures (CIs) providing security and quality of life. Electronic systems control the safety-critical functioning of most CIs, and these electronic systems are susceptible to electromagnetic interference (EMI). A threat to the infrastructures is that adversaries, such as terrorists, could disrupt the functioning by using electromagnetic (EM) sources. This is defined as intentional electromagnetic interference (IEMI). The European Commission released a research call to protect the CIs against EM attacks, and the project STRUCTURES—lead by an European consortium—addressed this call and got funded. The work presented in this thesis was conducted within STRUCTURES. The research goal of this thesis is to study the vulnerability of the wireless communication infrastructure to IEMI. Wireless communication is today being used all over the world and the dependence of society upon wireless networks is growing. Communication is essential for the safe and effective functioning of the emergency services and herewith for the safety of the civilians. A detailed insight into the vulnerability of wireless systems should result into the identification of proper protection strategies and countermeasures to increase the robustness of the CI. The development of new innovative protection techniques is not part of this work. The vulnerability analysis of the wireless communication infrastructure in this thesis starts with a threat analysis of an IEMI attack. It is necessary to not only look at technical attributes such as susceptibility levels, but also take the likelihood of an IEMI event into account. It is concluded that IEMI is a serious threat for wireless communication due to the high vulnerability of the wireless link and the wireless receivers, and the high likelihood of an IEMI attack. The susceptibility of wireless communication systems is analyzed next. Three different interference mechanisms are recognized—physical damage of the receiver, saturation of the receiver, and jamming—that could result into a denial-of-service (DoS) of the system. Generic experimental methods are presented that can be used to experimentally test the susceptibility levels of wireless receivers, and a terrestrial trunked radio (TETRA) base station is investigated. The base stations are not equipped with RF limiters, rendering them vulnerable to physical damage of the receiver. It is concluded that the inter-v Summary ference mechanisms are fundamentally different and protection strategies need to be addressed separately. Therefore a robust communication system should be designed by experts from various disciplines such as EMC experts, radio engineers, antenna engineers, …