Performance Analysis of User-Centric Clustering and Limited Cooperation in Cell Free Architecture

User-centric clustering is a valid solution to enhance the coverage and throughput for future mobile communication networks. However, the size of clusters, the location of nodes, and the number of cooperating nodes within the cluster can all have an impact on the data rate of the typical user. In this paper, the user-centric clustering with limited cooperation (LC) in downlink cell-free (CF) architecture is considered, and the effect of composite channels and intra-cluster cooperation on the data rate of the typical user is analyzed from a theoretical derivation level. Specifically, the user classification, the distributions of distances between the serving nodes, and the average data rates of each type of user are given, respectively. The approximate expressions of the Laplace transform (LT) of interfering power for different types of users are obtained with the Gauss-Hermitian integral approximation, and the long-term average data rate of the typical user is derived. Finally, Monte Carlo simulations are executed to verify the accuracy of the theory. The results show that shadowing fading should not be ignored for accurately evaluating user performance, and it is particularly important to reasonably select the radius of the cluster and the cooperation threshold that controls whether the access points cooperate or not.