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

Multibeam low earth orbit(LEO) millimeter wave(mm Wave) band high throughput satellite(HTS) is regarded as a key component in the upcoming satellite-based Internet of Things(S-Io T). 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-Io T 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 PREfairness 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.