Integrated Sensing and Backscatter Communication with Movable Antennas: State-of-the-Art Survey and A Novel Inverse Scattering Framework

In this paper, we put forward a state-of-the-art survey and a novel inverse scattering framework for integrated sensing and backscatter communication with movable antennas. Specifically, the proposed system employs inverse scattering-based sensing techniques for accurate tag localization and identification, combined with spatial modulation (SM) and quadrature spatial modulation (QSM) methods to facilitate reliable backscatter communication. We first establish an electromagnetic system model incorporating structural and antenna modes of the tags as well as clutter scatterers in the environment. By dynamically adjusting the load impedances of the tags, these structural and antenna mode components can be effectively separated. The structural and antenna mode components processed by the compressed sensing (CS) algorithms and the inverse scattering methods can respectively achieve high-precision localization of clutter scatterers and tags, as well as accurate identification of tags. In addition, channel state information (CSI) derived from antenna mode analysis during the localization and identification processes is utilized to seamlessly integrate SM and QSM techniques into the backscatter communication framework. The proposed integrated scheme achieves more robust and efficient transmission performance compared to conventional vertical bell laboratories layered space-time (V-BLAST) and single-input multiple-output (SIMO) schemes. To validate the feasibility and effectiveness of the proposed approach, we implement a proof-of-principle illustrative system comprising one transmit and one receive array, each configured as a $3\times 3$ uniform linear array (ULA). By evaluating the sensing capacity metric, we demonstrate that system performance can be further improved through the integration of movable antenna (MA) techniques. Simulation results confirm that the proposed system achieves high-quality localization and identification of both single and multiple tags in cluttered environments, while simultaneously ensuring reliable backscatter communication.