Performance Analysis for Rate Splitting Uplink NOMA Transmission in High Throughput Satellite Systems

This letter investigates the return link performance of a high throughput satellite system, where the feeder link uses free-space optical technology while the user link employs radio frequency transmission. Based on the statistical channel state information, we first propose a scheme for combining rate splitting uplink non-orthogonal multiple access with beamforming in the user link to improve the spectral efficiency. Then, by assuming that the user link undergoes the shadowed-Rician fading while the feeder link experiences Málaga turbulence fading with nonzero-boresight pointing error, we derive a closed-form average throughput expression of the system with the proposed scheme. Finally, simulation results are provided to demonstrate the correctness of our theoretical analysis and the superiority of our proposed scheme to some previous works.