On the Performance Analysis of RSMA Based Transmission in STAR-RIS-Aided ISAC Systems

In this paper, we consider rate splitting multiple access (RSMA) based simultaneous refracting/transmitting and reflecting (STAR)-reconfigurable intelligent surface (RIS) aided downlink wireless network for the data transmission from an access point (AP) to two Internet-of-Things devices (IoDs) over Nakagami fading channel. AP executes the integrated sensing and communication (ISAC) principle to eliminate the issue of undesired interference between a communication system and a target. RIS association with RSMA is used in the system to enhance the quality of signal at a higher sum rate. To evaluate the performance of the proposed system, we analyze the outage probability and ergodic sum rate. Simulation results show the impact of the diversity order of Nakagami parameter, and configurable elements of RIS on the system performance along with the sensing performance of AP. Almost 10% rate enhancement is achieved through RSMA compared with non-orthogonal multiple access (NOMA) technique at 10 dBm transmit power.