Robust NOMA-Assisted OTFS-ISAC Network Design With 3-D Motion Prediction Topology

This article proposes a novel nonorthogonal multiple access (NOMA)-assisted orthogonal time–frequency space (OTFS)-integrated sensing and communication (ISAC) network, which uses unmanned aerial vehicles (UAVs) as air base stations to support multiple users. By employing ISAC, the UAV extracts position and velocity information from the user’s echo signals, and nonorthogonal power allocation is conducted to achieve a superior achievable rate. A 3-D motion prediction topology is used to guide the NOMA transmission for multiple users, and a robust power allocation solution is proposed under perfect and imperfect channel estimation for max–min fairness (MMF) and maximum sum-rate (SR) problems. Simulation results demonstrate the superiority of the proposed NOMA-assisted OTFS-ISAC system over other systems in terms of achievable rate under both perfect and imperfect channel conditions with the aid of 3-D motion prediction topology.