Intelligent Hybrid Nonorthogonal Multiple Access Relaying for Vehicular Networks in 6G

Abstract

In this article, we propose an intelligent hybrid nonorthogonal multiple access (NOMA) relaying system for the next generation of millimeter-wave (mmWave) band end-edge-cloud vehicular networks, which mainly comprises the cloud high-throughput satellite (HTS), edge base station (BS), and end vehicle nodes (VNs). Specifically, by taking account of the movement of the end VNs in the edge BS, we investigate three typical scenarios due to the mobility of the end VNs during the downlink transmission, including quasistatic, intracell, and intercell scenarios, and formulate the optimal power allocation problem of the intelligent hybrid NOMA system for the throughput maximization and outage probability (OP) minimization. Concretely, we first present an iteration power allocation (IPA) algorithm to derive the optimal set of power coefficients for the NOMA transmission in the quasistatic scenario, and also design a power reallocation method based on the expectation–maximization (PREM) algorithm for the intracell and intercell scenarios. Simulation results validate that our proposed algorithms can approach to the exhaustive search method and outperform the existing optimal NOMA schemes. Further, we exploit the effects of the number of the moved end VNs, which can offer some useful guidelines for the design of the next-generation vehicular network.