Adaptive Joint Beamforming and Fluid Antenna System Design for 6G ISAC
For mobile ISAC systems, this work provides a real-time, hardware-efficient solution to adapt antenna topology to dynamic environments, though it is an incremental application of existing RL methods to a specific problem.
The paper proposes a Soft Actor-Critic-based framework for joint optimization of fluid antenna positions and active beamforming in 6G ISAC systems, achieving 4 ms inference latency, 42% communication improvement over alternating optimization, and 57% antenna reduction versus SCA-SDR with comparable performance.
Fixed-Position Antennas (FPAs) are constrained by static physical topologies and struggle to adapt to rapidly varying wireless environments. By dynamically reconfiguring the antenna positions, Fluid Antenna Systems (FASs) introduce additional spatial Degrees of Freedom (DoF) for wireless optimization. This paper investigates the joint optimization of Fluid Antenna System (FAS) topology reconfiguration and active beamforming for mobile Integrated Sensing and Communication (ISAC) systems. To enable real-time decision making, an end-to-end optimization framework based on the Soft Actor-Critic (SAC) algorithm is proposed. Simulation results show that the proposed scheme achieves an online inference latency of only 4 ms. Compared to the widely used alternating optimization, it improves communication performance by 42%. Moreover, it achieves performance comparable to the SCA-SDR benchmark while requiring 57% fewer antennas, demonstrating superior hardware efficiency.