transportation systems form a part of the critical infrastructures in
that provides the essential services that strengthen the society and serve as
the backbone of a nation’s economy, security, and health. Hence, Railway
signaling, which involves the communication between trains and the control
stations is critical. However, the Intentional Electro Magnetic Interferences
(IEMIs) generated by low power electromagnetic jammers operated in railway
environments pose a fierce threat.
systems are especially vulnerable since the system is distributed across a
large area, which is essentially unguarded. The scenario of a person with malicious intention who illuminates or
injects electromagnetic energy (which can be of any frequency envelope, from dc
to gigahertz and narrow-band signals to ultra wide band transients) into a
system with the goal to interfere or destroy it is today a possible situation. Indeed, many
types of radio jammers are for sale on the market. Jammers can be used to upset
or disrupt the radio communications of railway operators. So, the prevention, forecast
and detection of jamming is vital. The researches and studies conducted in this
area revolve around mechanisms to detect a jamming signal than preventing its
occurrences or protecting the signal of interest from jammers.
This work involves the development of
mechanisms to protect the radio signal from intentional jamming signals in
railway environments. A detection method derived from existing EMC tests using
a template to define different zones of functioning is developed. Although this
work is initiated by a railway issue, GSM and GSM-R are derived from a common
communication protocol and existing jamming devices can, for some equipment,
cover the contiguous frequency bands of both systems. The monitoring systems
that automatically trigger cellular phone communications in case of detection
of abnormal situations like malicious or unauthorized intrusion can be the next
level of application.
This rest of this work is organized
in the following way: Chapter 2 presents the literature survey of this work.
Some important characteristics of the radio communication and of the jammer
which are relevant for the study are presented in Chapter 3. Chapter 4
describes the laboratory test bench developed to generate a representative
radio communication as well as jamming signals. Chapter 5 describes the general
principle of a supervised detection method and focuses on a particular
implementation we made on the test bench and the results are analyzed. Chapter
6 presents the laboratory realization of a prototype sensor based on such a method
and presents results.