Interference cancellation for cell-edge users in massive MIMO-NOMA systems: a contemporary overview

Massive multiple-input multiple-output (MIMO) systems integrated with non-orthogonal multiple access (NOMA) hold promise for achieving high spectral efficiency but encounter challenges stemming from increased Multi-Access Interference (MAI), particularly notable for users located at cell edges. This paper presents a novel MIMO-NOMA framework designed to effectively mitigate MAI, specifically tailored to address the complexities faced by cell-edge users. Our proposed framework overcomes the limitations of conventional MIMO-NOMA systems by introducing a solution that minimizes the requisite power level escalation for ensuring reliable communication, a particularly crucial consideration as user populations expand. Comparative analysis reveals that our approach yields substantial improvements in spectral efficiency and system capacity when contrasted with traditional MIMO-NOMA configurations. Moreover, our framework facilitates the accommodation of a larger number of users within a single channel, thereby optimizing network resource utilization. To further enhance interference mitigation while upholding user Quality of Service, we introduce a novel user grouping strategy termed Triangle-NOMA, leveraging network interference analysis to efficiently group users, with a specific emphasis on alleviating interference for cell-edge users. The proposed framework integrates comprehensive analysis, precoding techniques, and an efficient detector to optimize user performance. Simulation results validate the efficacy of our approach, demonstrating significant system-wide enhancements.