On ISAC Performance with Full-Duplex FAS-assisted BS

This paper studies the integrated sensing and communication (ISAC) performance of a full-duplex network assisted by fluid antenna systems (FAS). The base station (BS) operates in full-duplex mode and employs planar FASs for both transmission and reception. It simultaneously communicates with a downlink user, an uplink user, and performs target sensing. Our objective is to maximize the overall communication rate while ensuring the sensing requirements. Due to the non-convex and intractable nature of the optimization problem, we first reformulate it using the fractional programming (FP) framework. Subsequently, we iteratively optimize the antenna positions of both transmit and receive FASs, the beamforming vectors, and the uplink transmit power. The antenna position optimization subproblems are converted into convex quadratically constrained quadratic programs (QCQPs) and solved via the successive convex approximation (SCA) method. Simulation results demonstrate that the FAS significantly outperforms traditional fixed-position antenna systems by achieving higher communication rates.