OFDM-Based Multiband Sensing For ISAC: Resolution Limit, Algorithm Design, and Open Issues

In integrated sensing and communication (ISAC) systems, communication signals are supposed to provide high-resolution sensing services. Toward this goal, multiband sensing has recently emerged as a promising technology that jointly utilizes multiple noncontiguous communication bands to improve the sensing performance of ISAC systems. In this article, we first introduce the multiband signal model in the presence of phase-distortion factors, discussing the challenges and benefits of multiband sensing to reveal its intrinsic properties. Then, we investigate the resolution limit and discuss a specific sensing algorithm design of multiband sensing technology, which is designed to leverage multiband gains to achieve high-resolution sensing performance. Finally, a series of open research topics is discussed, which may bring new insights for future research on multiband sensing for ISAC.