Cluster based resource management using H-NOMA in heterogeneous networks beyond 5G

High throughput, secure transmission, and minimum interference are required in beyond-fifth-generation (B5G) networks. For this purpose, a mix of hybrid non-orthogonal multiple access (H-NOMA) and mobile user clustering (MUC) in a heterogeneous network (HetNet) can be explored. In this paper, we propose sum-secrecy throughput (SST) maximization problem based on a novel MUC-assisted downlink (DL) H-NOMA strategy in the presence of an eavesdropper in HetNet. We compare the performance of the proposed strategy for HetNet and a high-powered base station-only (HPS-only) network. We also compare the performance of the proposed strategy with the existing orthogonal multiple access only (OMA-only) and non-orthogonal multiple access only (NOMA-only) strategies. We have used an ������-optimal outer approximation algorithm (OAA) to solve the formulated problem based on the proposed strategy. We have evaluated the performance of the proposed strategy by considering key performance indicators (KPIs), i.e., the mobile user (MU)'s admission in the cluster, MU's association with the HPS or low-powered base station (LPS), power allocation (PA) to MUs, quality of service (QoS), fairness in association with HPS or LPS, and SST. Extensive simulation results considering KPIs reveal that the proposed strategy performs better (1) in HetNet, (2) for HetNet compared to the HPS-only network, and (3) compared to the existing OMA-only and NOMA-only strategies in HetNet. Additionally, the proposed system model is compared with Amin et al. (2021) and Fu et al. (2022) in terms of SST and the simulation results reveal that the proposed system model's performance is superior compared to Amin et al. (2021) and Fu et al. (2022) regarding SST.