  The massive multiple-input multiple-output (MIMO) transmission technology has
recently attracted much attention in the non-geostationary, e.g., low earth
orbit (LEO) satellite communication (SATCOM) systems since it can significantly
improve the energy efficiency (EE) and spectral efficiency. In this work, we
develop a hybrid analog/digital precoding technique in the massive MIMO LEO
SATCOM downlink, which reduces the onboard hardware complexity and power
consumption. In the proposed scheme, the analog precoder is implemented via a
more practical twin-resolution phase shifting (TRPS) network to make a
meticulous tradeoff between the power consumption and array gain. In addition,
we consider and study the impact of the distortion effect of the nonlinear
power amplifiers (NPAs) in the system design. By jointly considering all the
above factors, we propose an efficient algorithmic approach for the TRPS-based
hybrid precoding problem with NPAs. Numerical results show the EE gains
considering the nonlinear distortion and the performance superiority of the
proposed TRPS-based hybrid precoding scheme over the baselines.
