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

Recently, the concept of simultaneously transmitting and reflecting based reconfigurable intelligent surface (STARRIS) 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 MonteCarlo simulations are carried out over different system parameters to verify accuracy of the results and useful inferences are obtained.