Joint Subcarrier and Power Allocation Scheme for Sum-Rate Maximization in OTFS-NOMA System

Orthogonal time frequency space (OTFS) modulation is one of the most promising techniques in the upcoming six-generation era. However, the multiple access and resource allocation strategies dedicated to the conventional communication system are no longer suitable to the dual-domain and multi-user OTFS system, owing to the complexity and diversity of interference between high-speed users and low-speed users when they are assigned in different domains. Considering the quality-of-service requirement of heterogeneous mobility users, we propose to jointly design subcarriers, power, and dual-domain resource block allocation for the non-orthogonal multiple access OTFS system to maximize the sum-rate. In order to solve the nonconvex optimization problem, we utilize an alternating optimization algorithm to iteratively address subcarriers assignment subproblem and power allocation subproblem. The simulation result verifies its superiority over the OFDM access scheme in terms of sum-rate and spectrum efficiency.