Comparative Study of Reconfigurable Intelligent Surfaces Against Relay Systems: Amplify-And-Forward and Decode-And-Forward Approaches

The concept of reconfigurable intelligent surfaces (RISs) has emerged as a promising paradigm for manipulating the channel propagation environment to satisfy the targeted key performance indicators for future wireless communication systems. This paper investigates the performance of RISs in wireless communication systems compared to traditional relay-assisted systems with some specific scenarios. We employ detailed simulations to analyze the impact of RIS elements on system performance. Our findings demonstrate that increasing the number of RIS elements leads to significant improvements in key performance metrics, particularly for the bit error rate (BER) and the path-loss (PL) impact on the system. However, the study also reveals a critical circumstance that RIS-aided system performance can change dramatically when positioned at a specific location. This research also compares and shows performance divergences between RIS, amplify-and-forward (AF) and decode-and-forward (DF) relays at different positions for all systems.