Performance Analysis of Sub-carrier Assignment Algorithms for Three-Users in MC-NOMA System

Non-Orthogonal Multiple Access (NOMA) is widely recognized as a vital technology for next-generation wireless networks, primarily due to its significant advantages in Spectral Efficiency (SE) and ensuring user fairness. In this paper, various Sub-carrier Assignment Algorithms (SAA) are explored to understand their functioning, and their performance is evaluated in terms of SE, user fairness, and computational complexity, focusing on a scenario with three users sharing a single sub-channel. Previously, all these existing SAA performances were evaluated by employing two users within the sub-channel. The simulation results show that the Spectral Efficiency Maximization (SEM) algorithm gives superior performance in SE in the context of three users per sub-carrier. Conversely, the Worst-Case User First Sub-carrier Allocation (WCUFSA) algorithm is the top performer for fairness considerations. Regarding computational complexity, the Worst Sub-carrier First (WSF) algorithm proves more efficient than the existing SAA.