Reducing Inter-CPU Coordination in User-Centric Distributed Massive MIMO Networks

This letter proposes a method for reducing inter-central processing unit (CPU) coordination in user-centric (UC) distributed massive multiple-input multiple-output (D-mMIMO) networks, also called cell-free networks. A two-stage heuristic approach is proposed to reduce the number of inter-coordinated user equipment (UE) (UEs connected to multiple CPUs) in each CPU. Firstly, each UE connects to a master access point (AP) and a primary CPU; then, AP selection is executed. Secondly, each CPU performs a fine-tuning algorithm to drop the worst inter-coordinated UEs. Simulation results reveal that one can reduce inter-CPU coordination while yielding slight degradation in spectral efficiency and improving energy efficiency.