  In this paper, we investigate the potential of employing reconfigurable
intelligent surface (RIS) in integrated sensing and communication (ISAC)
systems. In particular, we consider an RIS-assisted ISAC system in which a
multi-antenna base station (BS) simultaneously performs multi-user multi-input
single-output (MU-MISO) communication and target detection. We aim to jointly
design the transmit beamforming and receive filter of the BS, and the
reflection coefficients of the RIS to maximize the sum-rate of the
communication users, while satisfying a worst-case radar output signal-to-noise
ratio (SNR), the transmit power constraint, and the unit modulus property of
the reflecting coefficients. An efficient iterative algorithm based on
fractional programming (FP), majorization-minimization (MM), and alternative
direction method of multipliers (ADMM) is developed to solve the complicated
non-convex problem. Simulation results verify the advantage of the proposed
RIS-assisted ISAC scheme and the effectiveness of the developed algorithm.
