Joint AP Selection and Power Control Optimization for Uplink User-centric Cell-free Massive MIMO

Selecting access points (APs) and power control are crucial issues in resource allocation within cell-free massive multiple-input multiple-output (MIMO) networks. The aim of these challenges is to manage inter-user interference, lessen the fronthaul load, and ensure system performance is maintained as the number of users increases. Unlike previous works that address these issues separately, this paper introduces an integrated optimization approach for both AP selection and power control in a user-centric cell-free network, constrained by users’ minimum quality of service (QoS) to ensure system fairness. The problem at hand is a mixed-integer non-convex challenge, and we address it by utilizing fractional programming techniques for its transformation and solution. Simulations were carried out for environments, both indoors and outdoors, following 3GPP standards. The results indicate that the joint optimization approach greatly enhances the overall network sum spectral efficiency (SE) compared to solving these issues independently, emphasizing the proposed method’s effectiveness.