  This paper exploits the potential of reconfigurable intelligent surface (RIS)
to improve radar sensing in a non-orthogonal multiple access (NOMA) empowered
integrated sensing and communication (NOMA-ISAC) network. The objective is to
maximize the minimum radar beampattern gain by jointly optimizing the active
beamforming, power allocation coefficients and passive beamforming. To tackle
the formulated non-convex problem, we propose an efficient joint optimization
algorithm by invoking alternating optimization, successive convex approximation
(SCA) and sequential rank-one constraint relaxation (SRCR) algorithm. Numerical
results show that the proposed RIS assisted NOMA-ISAC system, with the aid of
proposed scheme, outperforms the RIS assisted ISAC system without NOMA.
