RIS-Enabled Integrated Sensing and Communication With Clutter Suppression for LEO Satellite Systems

Low Earth orbit (LEO) satellite (SAT) communication has become an important part of the new generation mobile communication networks by virtue of its advantages of low cost and wide coverage. Making full use of the infrastructure and spectrum resources of LEO SAT networks to develop integrated sensing and communication (ISAC) technologies has also become a research area with broad prospects. However, ISAC in LEO SAT systems may suffer severe performance degradation due to inherent wide-beam limitations, particularly when sensing targets and communication users coexist in clutter environments. To address this challenge, we propose a new reconfigurable intelligent surface (RIS)-aided LEO SAT ISAC architecture, which enables effective ISAC tasks with clutter suppression. Specifically, we investigate the joint SAT-RIS beamforming to maximize the illumination power of the target while guaranteeing the communication signal-to-noise ratio and suppressing the clutter power. Furthermore, we develop a semidefinite relaxation based alternating optimization algorithm to solve the non-convex ISAC problem. Simulation results demonstrate that the proposed algorithm significantly enhances the performance of the LEO SAT ISAC system compared to RIS-free benchmark schemes, highlighting the critical role of RIS in resolving the SAT’s inherent wide-beam limitations.