A practical Power Allocation Scheme for Improving Throughput of NOMA systems in 5G networks under Perfect and Imperfect SIC

Non-orthogonal multiple access (NOMA) is one of the multiple access technologies that can improve system throughput in 5G networks. The power domain multiplexing scheme in NOMA is designed to multiplex users on the same radio resource with different power levels that can maximize system throughput in 5G networks. The power ratio scheme is used between the multiplexed users as a means of allocating additional power to the user with weak channel condition, and less power to the user with better channel condition. In this study, we propose a practical power allocation scheme in which the SIC is perfect and imperfect in the NOMA system. Moreover, we develop a theoretical framework detailing the utilization of SC and SIC in the NOMA system using BPSK. This scheme is useful to improve throughput in 5G networks in terms of parameter superposition coding, successive interference cancellation, and power ratio. An exhaustive analysis is provided to illustrate the concept behind NOMA also to suggest the exact value of the power ratio. A fair power allocation scheme is employed to address this power ratio issue using mathematical simplification. Our fixed power ratio allocation results show an improvement in system throughput when 50% of the channel power is allocated to the user with weak channel condition. The results demonstrate that the fair power allocation scheme increased the throughput by 14% compared to the fixed power allocation.