M.Sc.

Abstract: Exponential growth of mobile communications, radio links and wireless networks has increased interest in many topics in radio propagation. Much effort is now devoted to refine radio propagation path-loss models for urban, suburban, and other environments together with substantiation by field data. The objective for the system designer is to provide sufficient clearance of the obstacle without appreciable transmission loss due to the obstacle. The degree of intersection between the obstacle and the first Fresnel zone gives a good measure of obstruction loss.

Abstract: Optical code division multiple access (OCDMA) is used recently as access method in optical fiber networks without the need for traffic management or system synchronization. It takes advantage of the sporadic use of channels by allowing many users to be simultaneously connected to the network. Among OCDMA systems, frequency-encoded optical code division multiple access (FE-OCDMA) deserves close attention because it solves many obstacles which appear in conventional OCDMA systems such as multiple access interference (MAI). In this work, an incoherent FE-OCDMA systems are modeled.

Abstract: In this thesis, the various aspects related to controlling induction motors are investigated. Different control strategies are explored. The direct torque control (DTC) strategy is studied in details and its relation to space vector modulation (SVM) is emphasized. A SVM-based DTC strategy is suggested and a controller design which is based on the strategy is presented. A Simulink model representing the controller is developed and verified through this of MATLAB work.