M.Sc. Tezi Görüntüleme | |||||||||||||||||||||
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| Summary: The increasing demand for higher data rate wireless mobile communications services has accelerated the need to develop more innovative communications infrastructures. Terrestrial ground-based systems and satellite systems are the systems which is used for providing mobile communications services. An innovative way of overcoming the shortcomings of both terrestrial ground-based systems and satellite systems, is to provide cellular communications via “High Altitude Platform Station (HAPs)”. So there are many researchs in this area.In this thesis, propagation modeling and performance analysis on the HAPs are obtained. Elevation angle is the dominant parameter on the model. All possible propagation environments are divided into four groups: suburban (SU), urban (U), dense urban (DU) and urban high rise (UHR) area. These groups are modeled using well-known statistical models with a dependence on elevation angle. The main parameters are the elevation angle, Rayleigh and Ricean factors, and percentage of time a given fade depth is exceeded. To observe the effects of the parameters on the model, the correlation coefficients between model parameters and the fade depth are calculated. At the same time, probability distribution of elevation angle and fading depths are calculated, expressed as a distribution function with a dependence on elevation angle. In a conclusion, obtained models are combined with free space path loss, and full formulations of total path loss for the four possible HAPs propagation environments at 2-6 GHz frequency band are given. Then, channel performance analysis is made for all possible propagation environments.
Key Words: Wireless Communications, Broadband Wireless Access, Mobile Communications, High Altitude Platform Station, HAPs, Propagation Modelling, Path Loss, Channel Performance. | |||||||||||||||||||||