The European OBP system supporting ISDN and new emerging commercial services

The paper reports, in the frame of the “ESA On-Board Processing Demonstration Project” step 1 contract, on the transmission and communication aspects impacted by the evolution of the basic system concepts to cope with the growing requests for new communication satellite services. The new requirements that call for a reassessment in the transmission area are: use of 20/30 GHz band, which offers better flexibility in terms of available bandwidth; the service availability requirement is satisfied recurring to a suitable choice of coding technique and use of advanced on-board technologies; multiple high gain spot coverage with frequency reuse, with minimum satellite antenna size; the preferred solution respectively for up and down link coverages; small earth stations with solid state HPA; selectable bit rates/access schemes on uplink SCPC, single frequency TDMA (SF-TDMA) and multi-frequency TDMA (MF-TDMA) carriers depending on the user terminal cost/requirements. Investigations on the communication control area originate from the need of meeting the following new requirements: extension of the services to residential users; management of an increased population of user stations