Performance Evaluation between the RIS and Full/Half-Duplex Relay

Reconfigurable Intelligent Surface (RIS), is a technology that uses a meta-surface to reflect signals to the user. the use of RIS as a passive full-duplex relay to support wireless communications is a powerful means of providing a potential 6G technology with the unique qualities of low cost, low energy consumption, good reliability and high capacity. Active fullduplex relaying is a similar technology that has evolved from the half-duplex relaying known today and is also a potential 6G technology. both RIS and full/half-duplex relaying act as nodes between source and destination, how can we pick between the two to improve system performance? In this study, we examine the performance of these two technologies from the operator’s perspective. To provide a deterministic calculation for the comparison, we derive closed expressions for the reach rates of RIS and active relaying and propose an evaluation model to make the comparison fair. The results of the study show that RIS and different relaying methods, especially RIS and full-duplex relaying, two newly developed techniques, are candidates for 6G and have significant advantages in overcoming the deterioration of NLOS routing.