A Non-Orthogonal Multiple Access Assisted Integrated Sensing and Communication Network using Orthogonal Delay-Doppler Division Multiplexing

This work explores the integration of Non-Orthogonal Multiple Access (NOMA) and Orthogonal Delay-Doppler Division Multiplexing (ODDM) in an Integrated Sensing and Communication (ISAC) framework. The proposed system model leverages ODDM for high-mobility scenarios and NOMA for efficient resource utilization, thereby enabling enhanced communication and sensing trade-offs. To achieve a trade-off between communication and sensing performances, an optimization problem is formulated to maximize the weighted sum of sensing performance metric and communication throughput by jointly optimizing user grouping, power allocation, and beamforming, which, however, are coupled. To efficiently solve this problem, we decompose it into three subproblems, i.e., user grouping subproblem, power allocation subproblem, and beamforming subproblem, which are then solved in an iterative manner to improve system performances. Simulation results validate the efficacy of the framework under diverse mobility conditions, demonstrating improved sum-rate and sensing accuracy compared to Orthogonal Multiple Access (OMA) systems. This study provides insights into advanced ISAC architectures, critical for future 6G networks.