Antenna Trajectory-Aware Sum-Rate Maximization for Fluid Antenna-Enhanced Wireless Networks

This paper investigates the non-negligible latency associated with repositioning fluid antennas (FA) and delves into the challenge of maximizing the antenna trajectory-aware sum-rate for FA-enhanced systems. Different with conventional transmission schemes that swiftly reposition antennas to their desired positions, we introduce an innovative protocol that jointly optimizes antenna movement and signal transmission during the repositioning phase. To reduce the computational complexity, we reformulate the problem into a more tractable weighted minimum mean square error (WMMSE) framework, which is particularly tailored for FAs. Subsequently, we employ the WMMSE algorithm and a majorization-minimization technique to refine the beamforming strategies and antenna positioning, respectively. Furthermore, we introduce a planar motion mode that confines each FA within a designated region, leading to a low-complexity, closed-form solution. Numerical results demonstrate that the antenna trajectory-aware FA-enhanced system surpasses traditional systems in performance.