Joint channel estimation and beam selection NOMA system for satellite-based Internet of Things

Multibeam low earth orbit (LEO) millimeter wave (mmWave) band high throughput satellite (HTS) is regarded as a key component in the upcoming satellite-based Internet of Things (S-IoT). The multibeam LEO HTS with non-orthogonal multiple access (NOMA) can support global coverage and low latency broadband access over a wide geographical area in a cost-efficient manner. However, the performance is constrained by the channel state information and subsequent beam selection in multibeam LEO HTS. We design a joint channel estimation and beam selection NOMA system for S-IoT in this paper, including the pseudo random ergodic (PRE)-throughput maximum (TM) scheme for massive multiple access, and the asynchronous CSI-assisted (AIA)-TM scheme for high throughput services. Moreover, we propose the PRE-fairness guaranteed (FG) and AIA-FG schemes for achieving better fairness with slightly loss of throughput. Simulation results show that the PRE-TM and AIA-TM schemes can adaptively reduce the required channel measurements, while approaching the optimal system throughput performance of the exhaust searching (ES) scheme with a much lower computational complexity.