Joint Beamforming and Segmenting Parameter Optimization for Segmented RIS-Assisted Cell-Free Network

Integrating Reconfigurable Intelligent Surfaces (RIS) into Cell-Free networks is a key direction for the future evolution of mobile networks, offering substantial potential for energyefficient communication architectures. This paper proposes an innovative segmented RIS-assisted Cell-Free network model and studies the weighted sum rate (WSR) maximization problem with complex segmentation pairing. Owing to the nonconvexity of the problem, we decouple the active beamforming, passive beamforming, and segmentation matrix into three subproblems using an alternation optimization framework. Specifically, fractional programming, successive convex approximation, and the swap-matching-based algorithm are adopted to solve the variables in an iterative way, respectively. The simulation results illustrate that the proposed strategy approaches 97.37 % of the WSR performance of the unsegmented RIS-assisted Cell-Free network with lower beamforming complexity through segmentation optimization.