Two-Stage DoA Estimation for ISAC System Based on a MIMO OFDM Radar

In the next generation of communication networks, mobile networks and widely deployed based stations will achieve statisfactory integrated sensing and communication (ISAC) functions under the standard multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) architecture and waveform. In this paper, we focuse on an ISAC system based on a MIMO OFDM radar and propose a Two-Stage mutiple signal Classification (MUSIC) direction of arrival (DoA) estimation algorithm. In order to achieve a precise estimation while maintaining low computational cost, an estimate on the direction of the user is roughly obtained in the first stage, and then refined in the second stage. Compared with traditional DoA estimation algorithms including MUSIC and discrete fourier transform-compressed sensing, the root mean square error (RMSE) for multi-target DoA estimation can be reduced by two orders of mangnitude under the same computational cost.