| Abstract: | The word ‘telematics’ was used for the first time in France in 1978 by Simon Nora and Alain Minc; it is a contraction of the French words ‘tétécommunications’ and ‘informatique’, and defines a marriage between computers and data transmission networks. This paper describes the five systems which will be implemented to provide telematic services via satellite in Europe during the next few years: EUTELSAT, TELECOM 1, UNISAT, DFS and ITALSAT. The main characteristics of the ‘special service’ transponders are presented, showing that, in Europe, (a) 2 to 5 transponders per satellite will be devoted to the special (telematic) services; (b) 4 satellites out of the 5 use the 12.5–12.75 GHz down-link band for this purpose (only ITALSAT uses the 20 GHz down-link for the same purpose), and (c) e.i.r.p.s at 12 GHz are in the range 40–49 dBW. The ground and space segments corresponding to this new service are presented. The main peculiarity of the ground segment is the exclusive use of ‘small’ earth-stations equipped with fixed antennas and SCPC or 25–60 Mb/s TDMA multiple access equipment. Telematic services include videoconference at 2048 kb/s, voice services, computer-to-computer transfer of data, data distribution, remote printing, electronic mail, high-speed facsimile, offshore voice and data services, digital network overflow, transatlantic digital business etc… Customer bit rates start from 2.4, 4.8, 9.6 and 32 kb/s (for TELECOM 1) up to 2048 kb/s by 64 kb/s steps. Bit error rates are maintained below 10?6 (standard) or 10?10 (higher grade) during 99 per cent of the year using FEC. The five networks for telematics via satellite in Europe are independent. A large efficiency improvement of the different services should be obtained through a future interconnection of the various networks via intersatellite links. |
