Interference analysis of broadband space and terrestrial fixed radio communications systems in the frequency range 12 to 30 GHz

This thesis presents research into the principles of spectrum sharing analysis methods developed for investigating implications of interference from Nongeostationary Fixed Satellite Service (NGSO FSS) systems into Geostationary Fixed Satellite Service (GSO FSS) systems and Fixed Service (FS) terrestrial radio systems operating or planned for operation in the 12 to 30 GHz frequency range. Spectrum sharing is an effective way of allowing new services to operate without cancelling the existing allocations in the same part of the spectrum. The use of spectrum sharing results in re-use of the available spectrum among different services and, therefore, increases the efficient use of the radio frequencies. However, it is necessary to carry out extensive feasibility studies into technical or operational compatibility between the services involved. Often, sharing constraints are placed on systems, such as the power of emissions and the transmitter and receiver antenna pointings to reduce the interference into negligible levels. Traditionally, radio spectrum allocated to GSO FSS has been shared with FS. In recent years, there has been a growing interest in the use of low Earth orbits and a number of NGSO FSS constellations has been designed to provide broadband data services. This has led to the allocation of certain bands used by the FS and GSO FSS systems to NGSO FSS. In line with the new allocations, NGSO FSS, GSO FSS and FS systems are required to co-exist in parts of the 12 to 30 GHz frequency range. The primary objectives of this research were to identify principal factors affecting the feasibility of spectrum sharing and to develop spectrum sharing analysis methodologies to examine the implications of these factors with a view to identifying sharing constraints that would give rise to an acceptable sharing environment