Interference and Link Budget Analysis in Integrated Satellite and Terrestrial Mobile System

There is an increasing interest to combine satellite and terrestrial components to form a single telecom network, this is called integrated satellite and terrestrial mobile system. In such systems, the ground component is controlled by the satellite resource and network management system. Further, the ground component uses the same portions of MSS (Mobile Satellite Service) frequency bands. However, frequency reuse between satellite and terrestrial components will inevitably generate co-channel interferences between satellite and terrestrial networks. It is one of the important factors that not only affect the user experience, but may even affect the normal operation of the network. This paper presents a model of an integrated mobile network consists of a multi-beam satellite, terrestrial base stations and dual satellite/terrestrial terminals. The types of interferences in the integrated system were analyzed, and some serious scenarios of interferences were simulated. The influence of several parameters such as the number of terrestrial station, the azimuth angle of the terrestrial station relative to the satellite beam center and the maximum transmitting power of the terrestrial station is then presented. The results have shown that the interferences due to terrestrial base station on satellite uplink are nonnegligible and can have a serious impact on the overall system performance.