Fluid Antenna Enhance Multi-user Communication via Antenna Configuration and User Selection

Fluid antenna (FA) technology is a promising solution for enhancing wireless communication performance by dynamically adjusting antenna positions within a predefined region to improve channel conditions. In this paper, we investigate a multi-user communication system empowered by FAs. Specifically, we jointly optimize the transmit beamforming vector, antenna positions, and user selection to maximize the sum rate of all users. To solve the resulting non-convex optimization problem with intricately coupled variables, a low complexity algorithm named joint semi-orthogonal user and position selection (FA-JSUPS) is proposed. It iteratively selects the user and its corresponding antenna position that yield the highest channel orthogonality, based on the simple yet sub-optimal zero-forcing strategy. Simulation results validate the effectiveness of the proposed algorithm compared to other benchmark schemes.