Najett NEJI
Mon, 12/12/2011 -
14:00 to 15:30
Amphi Janet - Supélec
Étude de la Compatibilité Radioélectrique du Futur Système de Communication Aéronautique en Bande L"


Membres du Jury
M. Eric ALLAIX Direction Générale de l’Aviation Civile  Chef de pôle (examinateur)
M. Alain AZOULAY SUPÉLEC  Professeur (directeur de thèse)
M. Pierre DEGAUQUE Université de Lille 1 Professeur (rapporteur)
M. Raul DE LACERDA SUPÉLEC Enseignant-chercheur (encadrant)
M. Marc HELIER Université Pierre et Marie Curie Professeur (rapporteur)
M. Thierry LETERTRE SUPÉLEC Enseignant-chercheur (invité)
Mme Françoise PALADIAN Université Blaise Pascal Professeur (examinatrice) 
M. Lionel PICHON Laboratoire LGEP CNRS-SUPÉLEC Directeur de recherche (examinateur)
M. Olivier OUTTIER Direction Générale de l’Aviation Civile  Ingénieur (invité)
M. Adroaldo RAIZER Université Fédérale de Santa Catarina Professeur (invité)
In the beginning of the 21th century, the aeronautical authorities expressed their need to develop a new system for aeronautical radiocommunications, because the air-traffic is increasing and that current communication systems between pilots and air-controllers are reaching their capacity limits. The L-band Digital Aeronautical Communication System (L-DACS) is the part of the future system that will be operating in a part of the aeronautical L-band (960-1164 MHz), already occupied by a large number of radio-frequency legacy systems. Consequently, it is essential to consider its radio-frequency compatibility (RFC) for the development of the future L-DACS system. 
This thesis aims at identifying the principal issues related to RFC and studying its critical situations. Such topics are fundamental in aeronautics, as any communication or radionavigation dysfunction may endanger flight and passengers security. Some obtained results will be used for the L-DACS standardization and its specifications finalization.  
We first analyze the state-of-the-art in both aeronautical communications and RFC, focalizing on updated specifications of both preselected L-DACS candidate systems. We then propose a deterministic algorithm to compute the interference level in order to study the RFC in the frequency domain under identified critical scenarios. Since the frequency-domain analysis seems to be insufficient in several cases, we develop a different methodology, called the time-frequency approach, to analyze the RFC for such situations. We apply this new approach to analyze the effect of an L-DACS interferer on a Distance Measuring Equipment (DME) receiver, using an aeronautical RFC test-bed that we implemented at SUPELEC. 
This work has been performed in collaboration with the French Civil Aviation Authorities (DGAC), which are an important actor in aeronautical communication regulations and aeronautical spectrum management in France. The thesis contributes to DGAC studies at national as well as international levels. 
For further work, we suggest to generalize the proposed time-frequency approach to analyze the RFC between any two radio-frequency systems, taking into account additional parameters related to system dynamics and their technology properties.