A joint radar-communication (JRC) system having both radar sensing and communications capabilities is developed to improve the spectrum utilization efficiency. The common transmit array of the joint system is divided into K fully-overlapping subarrays. The transmit antenna elements within each subarray coherently transmit a waveform, and the waveforms transmitted from each array are orthogonal to each other. When the communication receivers are in the radar sidelobe directions, the communication symbol is embedded in both the magnitude ratio and the phase rotation, and circular M-ary Quadrature Amplitude Modulation (QAM) is used. When the communication receivers are in the radar mainlobe direction, the communication symbol is embedded exclusively in the phase rotation between each waveform pair, and M-ary Phase Shift Keying (PSK) is used. Under the assumption of medium pulse repetition frequency (PRF), the data transmission rate of the proposed JRC system is in the range of Mbits/s.
