Downlink NSP-MMSE Hybrid Beamforming Design for Dual-Function Radar-Communication Systems

Dual-functional radar-communication (DFRC) technique has been viewed as a promising component in the emerging platforms. When synthesizing the desired transmit beampattern, the degrees of freedom of waveform design is limited, which introduces interference between radar and communication. Moreover, most existing works are radar-centric or setting an extra parameter to trade off between these two functions, thus degrading the communication performance. In this paper, we investigate joint hybrid beamforming (HBF) in DFRC system. We first eliminate the interference from radar signal to communication by null-space projection (NSP), and match the desired radar beampattern. Meanwhile, we use the singular value decomposition (SVD) of communication channel to maximize spectral efficiency. To Further improve communication performance, we propose an Minimum Mean Square Error (MMSE) algorithm for the receiver. Simulation results show that the feasibility of the proposed scheme, which achieves a favorable performance for radar and communication.