  A non-orthogonal multiple access (NOMA) empowered integrated sensing and
communication (ISAC) framework is investigated. A dual-functional base station
serves multiple communication users employing NOMA, while the superimposed NOMA
communication signal is simultaneously exploited for target sensing. A
beamforming design problem is formulated to maximize the weighted sum of the
communication throughput and the effective sensing power. To solve this
problem, an efficient double-layer penalty-based algorithm is proposed by
invoking successive convex approximation. Numerical results show that the
proposed NOMA-ISAC outperforms the conventional ISAC in the underloaded regime
experiencing highly correlated channels and in the overloaded regime.
