PROVISION OF MULTIMEDIA SERVICES OVER EUROPE BY MEANS OF GEOSTATIONARY SATELLITES WITH MULTISPOT COVERAGE USING SMALL TERMINALS

The possibility to provide multimedia services over a wide area using small mobile terminals represents a challenging task. This task is eve n more challenging especially if high frequency bands are used and hig h service availability is required, considering that the atmospheric c onditions are very severe and geographically variable within a wide ar ea. The use of high frequencies is necessary to provide wideband servi ces at high data rate for a large number of users and the link availab ility has to be comparable with that provided by other systems working at lower bands. In the frame of the Advanced Communications Technolog ies and Services program of the European Union a team of thirteen part ners is working since September 1995 on the design of a satellite sys tem named SECOMS (Satellite EHF Communications Multimedia Services) (L osquadro and Vatalaro, 1995; Losquadro, 1996). The system aims at prov iding multimedia services by means of GEO satellites utilising set-top or palm-top terminals working respectively at Ka-band (20/30 GHz) and at EHF-band (40/45 GHz). Within the SECOMS project the problems menti oned above have been studied in depth and the main system parameters h ave been finalised. This paper aims at a description of the main syste m characteristics of the SECOMS project and suggesting a design approa ch for satellite systems providing multimedia services to mobile users . The proposed approach consists in providing an adjustment (static or dynamic) of the satellite EIRP among the spot beams to get the same l ink availability within the coverage area using the same terminal, con sidering that the distribution of rain fade statistics depends on the location. To this aim several technical solutions can be adopted.