Movable Antenna-Enabled RIS-Aided Integrated Sensing and Communication

Abstract

In this paper, we investigate a movable antenna (MA)-aided integrated sensing and communication (ISAC) system, where a reconfigurable intelligent surface (RIS) is employed to enhance wireless communication and sensing performance in dead zones. Specifically, this paper aims to maximize the minimum beampattern gain at the RIS by jointly optimizing the covariance matrix at the base station (BS), the reflecting coefficients at the RIS and the positions of the MAs, subject to the power budgets at the BS and the communication requirements at the users. To tackle this non-convex optimization problem, we propose an alternating optimization (AO) algorithm and employ semidefinite relaxation (SDR), sequential rank-one constraint relaxation (SRCR) and successive convex approximation (SCA) techniques. Numerical results indicate that the MA-enabled RIS-aided ISAC system outperforms conventional RIS-aided fixed position antenna (FPA) systems. In addition, the variation in channel characteristics reveals the trade-offs inherent in optimizing antenna positions in the RIS-aided ISAC system.