Handover and Radio Link Performance Analysis on Standalone Non-Orthogonal Multiple Access (NOMA) Environment

Non-Orthogonal Multiple Access (NOMA) has emerged as a promising alternative and complementary approach to conventional Orthogonal Multiple Access (OMA) techniques. This potential arises from NOMA’s utilization of mechanisms such as Successive Interference Cancellation (SIC) and Superposition Coding (SC), which effectively manage interference and contribute to significantly enhanced channel capacity and spectral efficiency. In a standalone NOMA setting that features a cellular deployment model consisting of 19 Base Stations (BS), each employing single-cell NOMA configurations with an optimal occupancy of 10 users per cell, the Handover (HO) performance was assessed through the application of the A3 event. This event is triggered when the User Rate and Signal-to-Interference plus Noise Ratio (SINR) of the target cell surpass that of the current serving cell. The results demonstrated that the most frequent location for Handover(HO) occurrences was at the outer edge of the BS with 81.8% of HO decisions made outside of 69.4% of radial distance from the center of BS, primarily due to experiencing significant interference. The simulation also demonstrated the 6:1 ratio between successful HO and Handover Failure(HOF), while showing 20:1 Radio Link Failure Rate $(R_{RLF})$ indicating a direct correlation between these two parameters. Both events were observed to transpire within similar locations in the cellular model. Moreover, the user mobility exhibited a positive correlation between $R_{RLF}$ due to frequent fluctuations in SINR.