Fluid Antenna-Aided ISAC Systems for Low-Altitude Economy Networks

In low-altitude economy (LAE) networks, integrated sensing and communication (ISAC) exhibits transformative potential yet is constrained by fixed-antenna architectures amid dynamic environments. Fluid antenna (FA) technology has accordingly been proposed as a mitigating solution. Nevertheless, the suboptimal synergy between FA and LAE platforms, alongside self-interference during signal transmission and echo reception, remain critical hurdles for ISAC's practical implementation in LAE contexts. To address these challenges, we propose a novel FA-aided ISAC system for LAE networks. Detailed models for the communication and sensing processes are introduced to support this system. Then, we formulate beamforming and antenna positioning strategies as a non-cooperative game, aiming to maximize the total communication and sensing rate for each ISAC BS. To tackle this complex problem, we decompose the game-theoretic problem into multiple sub-game optimization problems and analyze each separately. A mixed alternating iterative algorithm based on the sine cosine and particle swarm optimization (SCPSO) is developed to find the optimal solutions. Extensive simulations show the rapid convergence of the proposed mixed SCPSO-based algorithm. In addition, the FA-aided ISAC scheme for LAE outperforms conventional antenna positioning schemes. The results under different parameter settings further demonstrate that the FA-aided ISAC system for LAE significantly improves both communication and sensing performance through dynamic antenna reconfiguration.