Interplay Between NOMA and Integrated Sensing and Communication
The interplay between non-orthogonal multiple access (NOMA) and integrated sensing and communication (ISAC) is explored. First, the basic principle and key challenges of ISAC is reviewed and the main motivations of employing NOMA in ISAC are discussed, namely from “multiple access of users” to “multiple access of functions”. Then, based on the characteristics of NOMA, several NOMA-ISAC frameworks are conceived from various perspectives, including connectivity enhancing, interference mitigating, and full resource sharing. Furthermore, the performance evaluation of NOMA in ISAC system is presented for both uplink and downlink scenarios, with considering resource allocation, performance metric selection, and capacity region characterization. Numerical case studies are provided for revealing the superiority of NOMA-ISAC over other baselines. Finally, several open research problems are discussed.