Movable Antenna-Enabled Multiuser Communication via Array Position Optimization Based on Hybrid Spherical-Planar Wave Model

Abstract

This letter investigates a movable antenna (MA)-enabled multiuser communication system, where the base station (BS) is equipped with multiple movable subarrays to realize group movement of antenna elements. To balance the modeling accuracy of the spherical-wave model (SWM) and the simplicity of the plane-wave model (PWM), the hybrid spherical-planar wave model (HSPWM) is adopted and tailored to the considered MA system, where spherical-wave propagation is characterized across different subarrays while planar-wave propagation is assumed within each subarray. A two-timescale optimization framework is further developed to reduce the overhead of subarray movements, in which the array position vector is optimized based on statistical channel state information (CSI), while the transmit beamforming is designed using instantaneous CSI. Simulation results show that the proposed design based on the HSPWM for the MA system achieves nearly the same performance as that based on the SWM when the modeling error of HSPWM with respect to SWM is lower than −20 dB.