Design and performance analysis of reconfigurable intelligent surface and half-duplex amplify-and-forward relay hybrid network system

A Reconfigurable Intelligent Surface (RIS) can relay signals from the transmitter to the receiver. In this regard, RISs operate similarly to traditional relays. We design a Multiple-Input-Multiple-Output (MIMO) system with a hybrid network of RIS and Half-Duplex (HD) Amplify-and-Forward (AF) relay. We model the system's signal propagation and propose a new algorithm to get the system's Achievable Rate (AR) value. We complete simulations to evaluate the performance of the RIS and HD-AF relay hybrid network system compared to the system assisted by either the RIS or HD-AF relay. The simulations indicate that many factors can considerably influence the system performance. Selecting an optimal placement for the RIS and relay can result in the best performance for the RIS and HD-AF relay hybrid network system in situations where the direct link between the receiver and transmitter is absent.