A research study submitted in partial fulfillment of the requirement for the degree of Master of Engineering, School of Engineering and Technology

Research Studies Project Report (M. Eng.) - Asian Institute of Technology, 1995

The recent emergence of several Low Earth Orbit Satellite Systems which aims to provide Personalized Communications Services by the end of the century necessitates a study on the possible interference that they might cause to each other due to the sharing of the same frequency spectrum. Since the relative position and pointing of these LEO satellites constantly change with time, the parameters affecting the interference also change accordingly. This research study presents a general model for the analysis of interference between LEO satellite systems considering its time-varying geometry and constellation aspects. The design of an optimum LEO satellite constellation is considered and analyzed based on some important parameters. The analysis of interference is based on the calculation of the Carrier-to-Interference ratio in the downlink path of the service link and the results showed that the characteristics of the systems constellation affect the level of interference as well as to the percentage of time interference occurs. Interference is more to a higher altitude orbit than those systems at much lower orbits and it became worst as the interfering constellation became bigger. For coordination purposes, some parameters should be varied as to minimize the interference between systems.