ISAC-oriented access point placement in cell-free mMIMO systems

Abstract

In mobile communication networks for integrated sensing and communication, site planning of access points fundamentally determines both communication quality and sensing performance. This paper aims to tackle the AP placement problem under the setting of cell-free massive multiple-input multiple-output, which represents a promising direction for network architecture evolution. Seeking a balance between the sum-throughput of communication and the Cramér–Rao lower bound of target sensing, the access points are first pre-placed by solving a convex optimization and further adjusted with optimal angular geometry. The final step involves employing nearest neighbour projection to refine access point positions in the cell-free massive multiple-input multiple-output system, ensuring alignment with integrated sensing and communication requirements. The numerical results show that the proposed algorithm achieves 90% of the optimal communication sum-rate and 95% of the optimal target localization accuracy.