DOA Estimation for Joint Sensing and Communication with Nonorthogonal Waveform

In this paper, a virtual sensing matrix-based direction-of-arrival (DOA) estimation method is proposed for the joint sensing and communication system. To maintain high communication rate, fully nonorthogonal communication waveforms are employed, which however, limit the virtual array derivation in the existing DOA estimation methods to achieve accurate estimation. To address this problem, we formulate a virtual sensing matrix from the estimated sensing channels, rather than directly constructing the virtual array from the received signals. As such, the reliance on the waveform orthogonality during virtual array derivation can be avoided. As a result, the DOAs of non-cooperative targets can be estimated by treating the virtual sensing matrix as the equivalent first-order observation matrix of an augmented virtual array and incorporating the subspace processing. Simulation results validate the effectiveness of the proposed method in both estimation accuracy and angular resolution.