An Efficient Joint Angle and Range Estimation Scheme for THz ISAC Systems with Single RF Chain

Integrated sensing and communications (ISAC) has attracted great attention in recent years. Thanks to the large available bandwidth and large antenna array, terahertz (THz) ISAC has the potential to achieve high range and angle resolution for wireless sensing. Considering the cost and complexity of implementing THz radio frequency (RF) chains, analog beamforming with a single RF chain is a more practical choice. However, due to the extremely narrow THz beamwidth, the time-division sweeping for angle estimation may lead to unacceptable overhead. Therefore, how to achieve efficient angle estimation under a single RF chain is a challenging problem. In this paper, we leverage the ThzPrism architecture to enhance the angle coverage, which can spread the beams at different subcarriers in different directions. We show that the angle and range estimations are coupled under the ThzPrism architecture. To this end, a joint angle and range estimation problem is formulated. By utilizing the sparse feature of target distribution, a multi-measurement vector (MMV) compressed sensing algorithm is proposed to resolve this problem. Moreover, to reduce the complexity of the algorithm, we leverage the beam-spreading feature of ThzPrism to partition the whole angle coverage area into many small subareas, which can effectively reduce the dimension of the original compressed sensing problem. The effectiveness of our proposed scheme is validated by simulation results, which show a better performance of both angle and range estimations than the existing scheme.