Joint Resource Allocation and Reflecting Precoding Design for RIS-Assisted ISAC Systems

Abstract

Sensing begins to rise as a fundamental functionality in integrated sensing and communication (ISAC), especially for sensing-aided communication enhancement (SACE), where base stations (BSs) are promising to perform ubiquitous sensing for communication enhancement. Resource allocation between sensing and communication is a crucial issue in SACE. Therefore, this letter investigates a RIS-assisted SACE (R-SACE) mechanism that jointly designs the time resource allocation between sensing and communication at the BS and the reflecting precoding at the RIS. The performance-guaranteed sensing result obtained at the BS serves as the basis for the proposed R-SACE mechanism, which aims to maximize the average achievable capacity of the RIS-assisted communication link and suppress caused interference. The closed-form expressions of sensing performance metrics are derived. Alternating algorithm (AO) is used to iteratively solve a proved convex optimization subproblem and a transformed quadratic constraint quadratic programming (QCQP) subproblem. Simulation results show priorities of the proposed R-SACE mechanism in enhancing communication capacity while suppressing interference with assists of sensing and RIS.