Exploiting antenna diversity to enhance hybrid cooperative non-orthogonal multiple access

Cooperative non-orthogonal multiple access (C-NOMA) is a novel multiple access technology that is considered as a promising solution for 5G and beyond. The technique has been proposed as a combination between NOMA and cooperative communications, such as device-to-device (D2D) communications. In this letter, we will address some limitations of the state-of-the-art C-NOMA model and promote an enhancement to the contemporary version. The improvement is based on an exhaustive exploitation of the antennas mounted at the users devices. Based on this, we revisit the rate analysis and the performance optimization of C-NOMA systems. Simulation results reveal the robustness of the proposed scheme in the presence of high self-interference (SI) and insightful comparisons with other previously proposed schemes in the literature are provided.