Non-Linear Devices + Non-Stationary Channel = SATCOM System, So What Signals Should We Use?

To unlock the full potential of global high-data-rate connectivity, climate monitoring and resilient disaster recovery, we must deliver revolutionary advances in satellite communication (SATCOM) systems. Achieving this requires understanding of the unique challenges posed by non-terrestrial networks, including the trade-offs between signal design and hardware performance. Historically, modulation schemes like PSK and APSK have dominated satellite systems due to their robustness and compatibility with non-linear power amplifiers. However, as demand for higher data-rates grows, QAM-based signals offer throughput gains — although they introduce greater sensitivity to Doppler shifts and amplifier non-linearities. SATCOM solutions should be flexible and intelligent enough to transmit and receive any signal type, adapting dynamically to mission requirements, environmental conditions and system constraints. For this we need PA characterisation for multiple signal standards.