Versatile two state model for Land Mobile Satellite Systems : parameter extraction and time series synthesis

(eng) A Land Mobile Satellite System (LMSS) is a satellite-based communication system that provides voice and data communications services as Internet, telephone, radio, TV, etc., to terrestrial mobile users. In a LMSS, the signal information travels from the satellite to the final moving terminal at the Earth. Furthermore, before arriving at the terminal, the signal propagates across the ionosphere and the troposphere causing impairments to the wave. Terrain, trees and buildings will cause the main distortions in the signal. All the impairments and distortions need to be characterized in order to understand the propagation phenomena affecting the channel, and to develop propagation models obtaining rules to relate these phenomena to the frequency, speed between the satellite and the mobile terminal, elevation angle or type of antenna. During the different stages of developing new systems and terminals, the channel characteristics need to be known, as they affect in the design of the different components of the system as the modem, the codec, etc. A wide range of experimental measurements have been performed on satellite mobile communication systems to obtain essential channel characteristics and to modelize the LMS channel. In this thesis, the Versatile Two-State statistical Land Mobile Satellite (LMS) channel model was taken as starting point. The model has been analyzed and improved. An automatic algorithm has been developed to extract the model parameters from experimental measurements. Finally a time series synthesizer has been implemented to reproduce the time-varying nature of the channel in order to help the system designer.