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

TL;DR

This paper demonstrates how a reconfigurable intelligent surface (RIS) can significantly improve self-interference cancellation in full-duplex radios, achieving over 100 dB suppression in a practical testbed.

Contribution

It introduces a novel RIS-assisted analog SI cancellation method for full-duplex radios, validated with a 256-element prototype and real-world measurements.

Findings

Achieved 103 dB total SI suppression without digital cancellation.

RIS-assisted cancellation added 59 dB to initial 44 dB antenna isolation.

Proves feasibility of RIS-enhanced full-duplex communication systems.

Abstract

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. SI suppression is a crucial requirement for FD communication as the SI severely limits the performance of a 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 an RIS to form a suitable cancellation signal in the analog domain. Building upon a 256-element RIS prototype, we present results of RIS-assisted SI cancellation from a practical testbed. Given an initial analog isolation of 44 dB provided by the antenna design, we are able to cancel the leaked signal by an additional 59 dB in the narrowband case, resulting in an overall SI suppression of 103 dB without additional digital cancellation. The presented case study shows promising performance to build an FD communication system on this foundation.