Semesterwork

Summer semester 2007 - 2 students

Leaky Feeder Transmission


The Intelligent Transportation Systems (ITS) program is a broad research program initiated by the American Departement of Transportation in 2004. It focuses on intelligent vehicles, intelligent infrastructure and the creation of an intelligent transportation system through integration with and between these two components. ITS encompass a broad range of wireless and wireline communications-based information and electronics technologies. When integrated into the transportation system's infrastructure, and in vehicles themselves, these technologies relieve congestion, improve safety and enhance productivity.
In this project we will focus on railway aspects of the ITS and more precisely on the train-to-ground communication in tunnels. A usual way to build a communication link between a train and the ground infrastructure consists in installing antennas on the trackside. Yet in tunnels this is not possible due to the little space available between the wagon and the tunnel wall (structure gage). As an alternative to antennas, the leaky feeder is a slotted radio-frequency cable where each slot is acting as a radiating element. One can thus consider a leaky cable as a distributed antenna system that can be used in tunnels to provide a radio link between the train and the ground. The system is already in use at 900MHz for internal communication between railway operational staff (GSM-R system). But performance at higher frequency (5GHz) has to be assessed.
Indeed we would like to know if such a cable fixed on the tunnel walls could operate as a WLAN antenna to transmit data to passengers in the moving train. The Wireless Communication Group has developped a model that should now be confronted to the measurements.
In this project you will measure the channel impulse response of a leaky feeder in tunnel conditions, compare your results with the model and draw a conclusion for the validity of the model. Eventually you will improve the initial model with the outcome of your measurements. Both practical skills and theoretical knowledge are of advantage for this project.
relays

Type Semester work (2 students)
Subject area RF measurements, field and propagation theory
Type of work 50% theory, 50% measurements
Supervisor Dr. Stefan Berger, Dr. Etienne Auger, Dr. Gabriel Meyer
Professor Prof. Dr. Armin Wittneben