Abstract
This thesis examines a new market for satellite communication serving small fixed-station business systems. This market requires transmission between a large number of smaller and cheaper earth terminals. The traffic requirements for satellite business services in Europe by the year 2000 have been reviewed. An advanced regenerative on-board processing business satellite with 13 spot-beams for the European coverage was then proposed to meet the expected traffic growth. This satellite system is designed to meet the needs of the user rather than, as traditionally, the user fitting in with the satellite. SCPC/FDMA and R-TDMA (reservation-TDMA) multiple access schemes were found to be most suitable for the proposed system serving many small users whose traffic was mixed voice, data and video. The architecture of the satellite payload has been studied and two main functional blocks, transmultiplexer and baseband switch were identified. The use of the transmultiplexer is to transform the EDM channels into TDM and the baseband switch is to provide full connectivity between all the stations so that the revolutionary idea of having a "switchboard in the sky" can be realised. The development work for the baseband switch is reported in detail in this thesis together with a comparison of different architectures for the baseband switch. A proof-of-concept model for the baseband switch was designed, built and tested. From the test results, the feasibility of implementing the baseband switch using the chosen architecture was proved. Another main area studied in this thesis was device technology. The present and future capability of bipolar, CMOS and GaAs technology has been investigated concentrating mainly on digital devices and semi-custom technology. Since the satellite is operating in an hostile environment, it has been necessary to study the effects of radiation on semiconductor devices. The outcome of these studies indicate that it is very promising to launch such advanced satellite payloads in the late 1990's.