Outage Performance of Millimeter-Wave Band NOMA Downlink System in Satellite-based IoT

In this paper, we investigate the outage probability (OP) of millimeter-wave (mmWave) band satellite-based internet of things (S-IoT) with non-orthogonal multiple access (NOMA) downlink system, where a terrestrial relay node amplify-and-forward (AF) the NOMA signal from a mmWave band high throughput satellite (HTS) to multiple destination nodes. We assume that the source-relay link undergos Shadowed-Rician fading and the relay-destination link undergos Rayleigh fading. Moreover, considering rain attenuation is the main factor at mmWave bands, we combine the multidimensional rain attenuation model with the statistical channel model to describe the mmWave channel. Then, analytical expressions of OP for the relay node with single and multiple antennas are derived, respectively. The effect of the power allocation coefficients in the S-IoT NOMA downlink system is also analysis. Finally, numerical and simulation results are provided to validate our analytical results, and compare the effect of rain attenuation on the system performance with conventional orthogonal multiple access (OMA) system.