Downlink Resource Allocation in Multiuser Cell-Free MIMO Networks With User-Centric Clustering

In this paper, we optimize user scheduling, power allocation and beamforming in distributed multiple-input multiple-output (MIMO) networks implementing user-centric clustering. We study both the coherent non-coherent transmission modes, formulating a weighted sum rate maximization problem for each; finding optimal solution to these problems is known be NP-hard. use tools from fractional programming, block coordinate descent, compressive sensing construct an algorithm that optimizes weights scheduling converges smooth non-decreasing pattern. Channel state information (CSI) being crucial optimization, highlight importance of employing low-overhead pilot assignment policy problems. regard, variant hierarchical agglomerative clustering, which provides suboptimal, but feasible, scheme; our cell-free case, formulate area-based reuse factor. Our results show scheme large gains long-term network spectral efficiency compared benchmark schemes such as zero-forcing conjugate (with round-robin scheduling) respectively. Furthermore, superiority mode under ideal imperfect CSI area-based pilot-reuse factors consider.