Joint Resource Allocation for User-Centric Cell-Free Integrated Sensing and Communication Systems

The cell-free massive multiple-input multiple-out (MIMO) is an appealing architecture for supporting integrated sensing and communication (ISAC), since its macro diversity can resist the large-scale fading and enhance the detection probability. This letter focuses on user-centric cell-free massive MIMO ISAC system, which is jointly designed with the vector orthogonal frequency division multiplexing integrated signal. We set the sum-rate of the proposed ISAC system as the unified metric, and investigate a joint user scheduling and power allocation scheme. We effectively relax the non-convex resource allocation issue as a linear fractional program. Subsequently, we introduce a low-complexity branch and bound algorithm based on piecewise concave overestimating functions, which can efficiently maximize the sum-rate. Simulation results demonstrate that our proposed system provides superior sum-rate performance than the centralized and classical cell-free counterparts.