When Full-Duplex Transmission Meets Intelligent Reflecting Surface:
Opportunities and Challenges
Abstract
Full-duplex (FD) transmission has already been regarded and developed as
a promising method to improve the utilization efficiency of the limited
spectrum resource, as transmitting and receiving are allowed to
simultaneously occur on the same frequency band. Nowadays, benefiting
from the recent development of intelligent reflecting surface (IRS),
some unique electromagnetic (EM) functionalities, like wavefront
shaping, focusing, anomalous reflection, absorption, frequency shifting,
and nonreciprocity can be realized by soft-controlled elements at the
IRS, showing the capability of reconfiguring the wireless propagation
environment with no hardware cost and nearly zero energy consumption. To
jointly exploit the virtues of both FD transmission and IRS, in this
article we first introduce several EM functionalities of IRS that are
profitable for FD transmission; then, some designs of FD-enabled IRS
systems are proposed and discussed, followed by numerical results to
demonstrate the obtained benefits. Finally, the challenges and open
problems of realizing FD-enabled IRS systems are outlined and elaborated
upon.