A Cluster-Based NOMA Framework for Integrated Sensing and Communications

This paper proposes a cluster-based Non-orthogonal multiple access framework for integrated sensing and communications (ISAC). Based on the proposed model, we investigate three typical ISAC precoding designs: sensing-centric design, communications-centric design, and Pareto optimal design. Under each scenario, the sensing rate (SR), communications rate (CR), and their asymptotic expressions in high signal-to-noise ratio (SNR) regime are derived. High-SNR slopes are also obtained to gain better insights. Finally, the SR-CR rate regions achieved by ISAC and the conventional frequency-division sensing and communications (FDSAC) are studied. Numerical results reveal that ISAC outperforms FDSAC in terms of both SR and CR, and is able to achieve a more extensive rate region.