Rate Splitting for Uplink CR-NOMA Systems based on Intelligent Reflecting Surface

In this work, we propose a rate splitting (RS) scheme for intelligent reflective surface (IRS) assisted cognitive radio (CR) inspired non-orthogonal multiple access (NOMA) system, where the primary user's (PU's) quality of service (QoS) requirements must be guaranteed. We apply the IRS to assist the PU's transmission and attain an improved intolerable interference threshold, which in turn improves the secondary user's (SU's) outage performance. Regarding the RS scheme, we derive the target rate allocation, optimal transmit power allocation and successive interference cancellation (SIC) decoding order for SU. In addition, closed-form expression of the outage probability is derived for the SU. The simulation results show the enhanced outage performance achieved by the proposed scheme over the existing schemes.