Future trends in digital On-Board Processors for telecommunication satellites

Since about 10 years, digitalization of signal processing in communication satellites has turned into reality. Digital On-Board Processors (OBP) are handling filtering, channel routing, beam forming, demodulation and decoding… They bring sensible benefits: enhanced performances, flexibility and reconfiguration capability. The digitalization is nevertheless limited to few channels in a payload due to the additional mass and power consumption of the Digital OBP. Digital OBP mainly call for two semiconductor technologies: the technology of analog to digital (ADC) and digital to analog (DAC) conversion and the technology of silicon-based digital integrated circuits (ASIC). The evolution of these two technologies are strongly linked with the Moore’s law. During the last four decades, Moore’s law has became a self-fulfilling prophecy for the semiconductor industry and forecasts the exponential evolution of transistor density (gate length), operation frequency, production cost and even computing power and memory capacity… It seems possible to assess a similar predictive law in a form of an observation and forecast for the performances of Digital OBP in space telecommunications. From the performances of past space digital processors and by considering what semiconductor technology they used, the predictive law enables to estimate the performances of a processor using a more advanced semiconductor technology. When applying the Moore’s law to the digital parts, it becomes possible to forecast the overall performances of digital OBP through time. Considering the full digitalization of communication payloads becomes a realistic goal for the end of the next decade (after 2015).