Gene

Transmitter

Algorithm

Coordinate descent

Biology

Social psychology

Robustness (evolution)

Cognitive radio

Resource allocation

Telecommunications

Biochemistry

Computer science

Mathematical optimization

Beamforming

Computer network

Genetics

Cellular radio

Psychology

Mathematics

Channel state information

Relaxation (psychology)

Geometry

Duplex (building)

Chemistry

Spectral efficiency

Transmitter power output

Channel (broadcasting)

Wireless

Base station

Convex optimization

Maximization

Optimization problem

Regular polygon

Telecommunications link

IEEE Transactions on Communications

In this article, we investigate the resource allocation design for intelligent reflecting surface (IRS)-assisted full-duplex (FD) cognitive radio systems. In particular, a secondary network employs an FD base station (BS) for serving multiple half-duplex downlink (DL) and uplink (UL) users simultaneously. An IRS is deployed to enhance the performance of the secondary network while helping to mitigate the interference caused to the primary users (PUs). The DL transmit beamforming vectors and the UL receive beamforming vectors at the FD BS, the transmit power of the UL users, and the phase shift matrix at the IRS are jointly optimized for maximization of the total spectral efficiency of the secondary system. The design task is formulated as a non-convex optimization problem taking into account the imperfect knowledge of the PUs' channel state information (CSI) and their maximum interference tolerance. Since the maximum interference tolerance constraint is intractable, we apply a safe approximation to transform it into a convex constraint. To efficiently handle the resulting approximated optimization problem, which is still non-convex, we develop an iterative block coordinate descent (BCD)-based algorithm. This algorithm exploits semidefinite relaxation, a penalty method, and successive convex approximation and is guaranteed to converge to a stationary point of the approximated optimization problem. Our simulation results do not only reveal that the proposed scheme yields a substantially higher system spectral efficiency for the secondary system than several baseline schemes, but also confirm its robustness against CSI uncertainty. Besides, our results illustrate the tremendous potential of IRS for managing the various types of interference arising in FD cognitive radio networks.

Resource Allocation for IRS-Assisted Full-Duplex Cognitive Radio Systems