Hybrid beamforming for ISAC based on mmWave cell-free MIMO

Aiming at the scarcity of communication spectrum resources and the advantages of cell-free MIMO in resource utilization, a millimeter-wave cell-free MIMO-ISAC system is proposed. In this system, while the base station provides services for users, the multi-antenna user equipment can actively detect multiple targets. The research goal is to design analog and digital beamformers to optimize the weighted sum of communication and radar beamforming errors. Two kinds of power constraints are considered in the study, and the improved orthogonal matching pursuit algorithm and the Riemann conjugate gradient algorithm are used for optimization. Through the simulation analysis of the communication spectrum efficiency and the radar beam pattern, the results show that the hybrid beam scheme can achieve a compromise performance in terms of spectrum utilization and beam pointing, and this scheme has potential application prospects for improving system performance.