Performance Analysis of RIS Aided IBFD STAR Wireless Networks

This paper considers a simultaneous transmission and receive (STAR) communication framework empowered by an in-band full-duplex (IBFD) radio and multiple reconfigurable intelligent surfaces (RISs). We present a mathematical framework for calculating the bit error probability (BEP) of the RIS-aided IBFD STAR communication system. In particular, we first derive the mean and variance of the signal-to-interference-plus-noise ratio followed by its moment generating function, which is used to obtain the BEP. We not only consider the effect of direct line-of-sight self-interference (SI) at the IBFD node but also take into consideration the reflected SI (RSI), which may arise due to misalignment of some of the RIS elements. Numerical results are presented for BEP and bit error rate (BER) of the STAR system with respect to the number of reflecting elements at the RISs, amount of RSI at the IBFD base station, and modulation orders of uplink and downlink transmission, that explicitly illustrate the feasibility and value of deploying RISs to aid future IBFD STAR communication systems.