Sparsity-aware adaptive beamforming design for IEEE 802.11ad-based joint communication-radar

The IEEE 802.11ad millimeter-wave WiFi waveform can be simultaneously used for high range/velocity resolution radar and Gbps data rate communication in vehicular applications. The angular field of view (FoV) for radar sensing, however, is limited by the employed directional analog beam. In this paper, a sparsity-aware beamforming design is proposed that permits a trade-off between communication rate and radar detection/estimation performance in the angular domain. The proposed design uses random transmit antenna subsets to form a coherent beam towards a communication receiver while simultaneously perturbing the sidelobes of the resulting beam pattern. Sidelobe perturbation results in random grading lobes, which we exploit for compressed radar sensing. The system performance trade-off involved in the adaptive beamforming design is evaluated using a novel joint communication-radar rate metric. Numerical results demonstrate subset size optimization enables the detection of short-range radar targets with high probability and angular resolution in a wide FoV at the expense of a slight hit in the communication data rate.