STAR-RIS Protocols for Throughput Maximization of Uplink NOMA

This paper integrates simultaneously transmitting and reflecting reconfigurable intelligent surface (STAR-RIS) into a single-input-single-output (SISO) uplink non-orthogonal multiple access (NOMA) and investigates two STAR-RIS protocols, time switching (TS) and energy splitting (ES). We provide the optimization algorithms for user power allocation and the transmitting and reflecting (T/R) coefficients of STAR-RIS to enhance the overall system throughput under the quality of service constraints. Simulation results show that the ES protocol outperforms the TS protocol different from the observations made in the uplink STAR-RIS channel estimation.