STAR-RIS-aided Full Duplex Communications with FBL Transmission

Simultaneous refracting/transmitting and reflecting reconfigurable intelligent surface (STAR-RIS) has emerged as a potential technology for future-generation wireless networks to support extremely high data rates with a broader coverage area. In this work, with an aim to provide a novel analytical framework, we investigate the performance of a STAR-RIS assisted full duplex (FD) wireless communication system under finite block length (FBL) transmission. In particular, we first derive the probability density function and cumulative distribution function of the signal-to-interference-plus-noise ratio (SINR) for the uplink and downlink users. We then analyze the system performance by deriving closed form expressions for their block error rate (BLER) and goodput. Finally, we validate the accuracy of the derived analytical expressions using Monte-Carlo simulations and show that as the number of elements in the STAR-RIS is increased the system performance also improves. Furthermore, we graphically demonstrate the impact of imperfect channel state information and compare the performance of STAR-RIS in mode switching (MS) and energy splitting (ES) protocol.