The role of satellites in personal communication services

This paper aims at providing a complete analysis of the issues relevant to satellite systems in the perspective of the third generation of mobile systems. The analysis considers, on the one hand, the possible satellite system evolutionary paths and, on the other hand, the satellite system requirements related to technological issues. As regards the satellite evolutionary paths, the paper provides a view of the satellite systems already in operation or currently being developed and outlines the guidelines followed by future satellite systems (in that respect, particular emphasis is given to small satellites). The analysis is performed by also taking into account the potential market and the regulatory issues. As regards the satellite system requirements related to technological issues, some key features such as integration with the terrestrial cellular networks, satellite system capacity, handover, synchronization, are discussed in the light of the technological innovations which are being proposed for the third generation of mobile systems. The above-mentioned issues are dealt with by referring both to time division multiple access (TDMA) and to code division multiple access (CDMA), i.e., the third-generation candidate access techniques