Rate-Splitting Multiple Access for Cell-Free ISAC Massive MIMO systems

This paper investigates rate-splitting multiple access (RSMA) in a cell-free massive multi-input multi-output (MIMO) system with integrated sensing and communication (ISAC). In this sytem model, we consider the maximization of the minimum rate subject to radar sensing constraints and a maximum power budget. A successive convex approximation based scheme is developed to solve the non-convex problem by optimizing the precoding vectors for radar and communication, as well as the common rate variables. Numerical results show the superior performance of the proposed RSMA method over conventional cell-free massive MIMO schemes under different scenarios with varying numbers of APs, antennas, and users.