Resource Allocation of OTFS-NOMA-based mmW Communication for Heterogeneous Mobility Users

Millimeter wave (mmW) is a promising technology for the next generation of mobile communications. However, the transmission efficiency and communication reliability of heterogeneous mobility user networks are limited by the frequent mmW beam alignment and the severe Doppler shift in the time-varying channel, respectively. To address this challenge, a joint resource allocation in frequency domain, time domain and power domain is investigated for the mmW communication network based on non-orthogonal multiple access (NOMA) and orthogonal time-frequency space (OTFS) techniques. The average spectral efficiency of high-mobility user equipment (H-UE) is maximized by the joint optimization of UE scheduling, beamwidth and transmit power. In order to solve the non-convex mixed integer problem of rate maximization, we propose the multi-dimensional resource allocation scheme based on alternate optimization method (AO-MRA), which decouples the initial intractable problem into two solvable sub-problems. In particular, based on the majorization-minimization approach, the scheduling algorithm is proposed to find the best UE scheduling for the NOMA groupings of heterogeneous mobility UEs, and the joint beamwidth and transmit power (JBP) algorithm is further designed for the optimal transmission time and power of base station in the mmW communication network. The proposed AO-MRA scheme can obtain effective suboptimal solutions of the initial problem. Simulation results demonstrate that the AO-MRA scheme is superior to other benchmark schemes in maximizing transmission efficiency. Moreover, the AO-MRA scheme is more suitable for low-power and high-bandwidth situations, and has superior spectral efficiency in terms of delay and Doppler high-resolution.