Massive-Beam MIMO for LEO/VLEO VHTS

This paper presents a new concept of high-gain steerable massive-beam MIMO phased array. Massive-MIMO technology is well developed for terrestrial communications but has not yet been implemented for satellite communications primarily due to factors such as long transmission delay, short coherence time and high atmospheric losses, which makes it impossible to obtain the required instantaneous channel state information (iCSI). The proposed method uses massive number of overlapping beams in orthogonal beam space and simplified linear precoding using statistical CSI to achieve the massive MIMO performance. The massive orthogonal-beam-space array results in higher signal strength (SNR) for the pilot signals and much faster array processing. This concept is particularly suited for future low-orbit very-high-throughput satellite (VHTS) communications.