Joint PA and FDA beamforming for radar-communications systems

Integrated wireless communications and radar detections have so far mainly relied on phased-array (PA) antennas with only considering the beampatterns in angle domain. In this paper, by taking advantage of frequency diverse array (FDA), which can generate beampatterns in angle, range and time domains, we propose a novel finite orthogonal random FDA, whose beampatterns feature periodical pulses in time or range domain. By applying this technology into radar and communications (RadComm) systems, a compact dual-functional structure of joint PA and FDA is designed. With the proposed novel structure, the common information, such as channel status information and direction-of-arrival can be easily shared for both PA communications and FDA radar. Based on the built joint PA and FDA channel models, different beamformer designs are proposed by jointly optimizing the signal-to-interference- noises of the communications and radar. In addition, we robustify the proposed method by considering the case of channel estimation imprecision. Numerical simulations demonstrate the performances of both communications and the radar with the proposed approaches are over than that of the conventional PA RadComm systems.