Full-Duplex meets Reconfigurable Surfaces: RIS-assisted SIC for Full-Duplex Radios

Reconfigurable intelligent surfaces (RIS) are a key enabler of various new applications in 6G smart radio environments. By utilizing an RIS prototype system, this paper aims to enhance self-interference (SI) cancellation for in-band full-duplex(FD) communication systems. In FD communication, SI of a node severely limits the performance of the node by shadowing the received signal from a distant node with its own transmit signal. To this end, we propose to assist SI cancellation by exploiting a RIS to form a suitable cancellation signal, thus canceling the leaked SI in the analog domain. Building upon a 64 element RIS prototype we present results of RIS-assisted SI cancellation from a real testbed. Given a suitable amount of initial analog isolation, we are able to cancel the leaked signal by as much as -85 dB. The presented case study shows promising performance to build an FD communication system on this foundation.