Multi-Domain NOMA for ISAC: Utilizing the DOF in the Delay-Doppler Domain

The integration of sensing and communication (ISAC) model is regarded as a key enabling technology for B5G and 6G, and has gained growing attention from both academia and industry. This letter proposes a Multi-domain NOMA (MD-NOMA)-based ISAC scheme. The proposed ISAC scheme enables parallelly and non-orthogonally transfer data streams in the TF (Time-Frequency) and DD (Delay-Doppler) domains while sensing potential reflectors. The additional DoF provided by the DD domain is utilized effectively. An iteration-based receiver is proposed to mitigate non-orthogonal interference. The proposed MD-NOMA-based ISAC framework’s efficiency, achievable rate, and complexity are given in this letter. Simulation results show that the proposed MD-NOMA-based ISAC is effective and has significant advantages in efficiency. The proposed MD-NOMA-based ISAC scheme provides a new paradigm for NOMA and ISAC waveform design and is promising for 6G applications.