Optimization of AP Placement and Array Topology for Distributed MIMO Systems Under Near-Field Propagations

In this letter, we develop a near-field system model for a multi-user distributed multiple-input multiple-output (D-MIMO) system based on a non-uniform spherical wave (NUSW) channel model. The proposed model incorporates key physical characteristics, including the projected aperture of isotropic antenna elements and the radiation pattern of directional antenna elements, to accurately capture near-field effects. To maximize the average system capacity, we propose a meta-heuristic optimization algorithm that alternates between access point (AP) placement and array topology design, effectively reducing computational overhead while achieving near-optimal solutions. Simulation results demonstrate the effectiveness of the proposed approach.