FUNCTIONAL AREAS FOR ADVANCED MOBILE SATELLITE SYSTEMS

In the third generation of mobile systems several satellite systems, e ach tailored to specific user requirements are expected to be integrat ed with the terrestrial cellular network. This article deals with the extension to satellite systems of the a dvanced networking concepts wh ich are emerging in the third-generation framework. In particular, it focuses on the basic functional areas for mobile satellite systems, na mely, the cell and the location area. It is worth stressing that prope r definitions of the satellite cell and satellite location area concep ts, as well as an appropriate design of the satellite cell and satelli te location area layouts, are essential, since the mobility procedures (cell reselection, paging, localization, handover) make systematic re ference to theseconcepts. The topics exposed in this article are appli cable to any satellite system regardless of orbit type, from geostatio nary (GEO) to low Earth orbits (LEO): the satellite spot-beam arrangem ent, access technique, and on-board switching capabilities (ranging fr om transparent payloads with reduced switching capabilities to satelli te systems provided with on-board processing capabilities and intersat ellite link).