Ergodic Rate Analysis and Optimization of Full-Duplex STAR-RIS Communication Systems

Recently, the concept of simultaneously transmitting and reflecting based reconfigurable intelligent surface (STAR-RIS) has attracted research interest due to its capability of serving both half-spaces unlike conventional reflecting-only RIS. In this paper, we perform ergodic rate (ER) analysis for full-duplex based STAR-RIS communication and then maximize the same subject to quality-of-service constraints of the users. We first present closed-form expressions of ER for both uplink and downlink users over generalized Nakagami - m fading channels. Further, to minimize the effects inter-user interference and residual self-interference, particle swarm optimization algorithm is employed in jointly optimizing the transmission amplitude, element partitioning and user transmit powers. Extensive Monte-Carlo simulations are carried out over different system param-eters to verify accuracy of the results and useful inferences are obtained.