Uplink Signaling and Receive Beamforming for Dual-Function Radar Communications

Current techniques for dual-function radar-communications (DFRC) have been focused on downlink communication and information embedding into the emission of the radar system. In this paper, we consider the problem of half-duplex uplink communications in dual-function multiple-input multiple-output (MIMO) radar communication systems. The DFRC system consists of a dual-function platform which functions as a MIMO radar during transmit mode and simultaneously receives and processes signals reflected from targets and uplink communication signals transmitted by a communication user. We propose a method for uplink signaling via forming a number of uplink beams carrying the same number of data symbols. Moreover, we employ non-adaptive and adaptive beamforming techniques at the radar receiver to separate the received communication signal from the target return even if they arrive from the same spatial angle. Cross-interference between the received communication and the reflected radar signals is mitigated using adaptive beamforming. We assess the effectiveness of the proposed uplink communication technique by numerical results.