Performance of MIMO-NOMA-ISAC Based on Signal Alignment

This paper proposes a framework of multiple-input multiple-output based non-orthogonal multiple access for Integrated sensing and communications (ISAC), which incorporates signal alignment to enhance system performance. Sensing rate (SR) and communication rate (CR) are derived under three different precoding designs: sensing-centric design, communications-centric design, and Pareto optimal design. Moreover, the SR-CR regions achieved by ISAC and frequency-division sensing and communications (FDSAC) are studied. Numerical results reveal that ISAC outperforms FDSAC in terms of both SR and CR and can achieve a broader rate region, clearly showcasing its superiority over the conventional FDSAC.