Abstract:In this paper, we investigate the downlink power adaptation for the suborbital node in suborbital-ground communication systems under extremely high reliability and ultra-low latency communications requirements, which can be formulated as a power threshold-minimization problem. Specifically, the interference from satellites is modeled as an accumulation of stochastic point processes on different orbit planes, and hybrid beamforming (HBF) is considered. On the other hand, to ensure the Quality of Service (QoS) constraints, the finite blocklength regime is adopted. Numerical results show that the transmit power required by the suborbital node decreases as the elevation angle increases at the receiving station.