Simultaneously Transmitting and Reflecting Reconfigurable Intelligent Surface Assisted NOMA Networks

Simultaneously transmitting/refracting and reflecting reconfigurable intelligent surface (STAR-RIS) has been introduced to achieve full coverage area. This paper investigate the performance of STAR-RIS assisted non-orthogonal multiple access (NOMA) networks over Rician fading channels, where incidence signals sent by base station are reflected transmitted nearby user distant user, respectively. To evaluate STAR-RIS-NOMA networks, we derive new approximate expressions outage probability ergodic rate for a pair users, in which imperfect successive interference cancellation (ipSIC) perfect SIC (pSIC) schemes taken into consideration. Based on asymptotic expressions, diversity orders with ipSIC/pSIC achieved carefully. The high signal-to-noise ratio slopes rates pSIC equal $one$ $zero$, In addition, system throughput is discussed delay-limited delay-tolerant modes. Simulation results provided verify accuracy theoretical analyses demonstrate that: 1) outperforms that orthogonal (OMA) conventional cooperative communication systems; 2) With increasing elements $K$ factor $\kappa $, capable attaining enhanced performance; 3) superior STAR-RIS-OMA.