Abstract
Representing the next generation wireless network, non-orthogonal multiple access (NOMA) has become crucial multiple accessing techniques in recent times. In this article, the core issue of NOMA system, allocating power to multiple users has been addressed. In NOMA, the increment in the power of one user increases the interference of other users because all the users utilize the same frequency band but distinguish by their power level. To cancel the signals of other users at reception, users must perform successive interference cancellation (SIC) by handling other users' signals as noise and finally decode its own signal. Incompetent power allocation could upturn the interference greatly, which decreases the data rate and user fairness, the result is degradation of the system capacity and unfair user data rate. Simulation results showed that power allocation of each user has a great impact on other users' data rate and total system capacity. In this article computational approach has been used to propose an optimum power allocation scheme for multiuser NOMA that valuable for optimizing the power and user fairness along with ergodic sum capacity of the system. We further compute the fairness index, the data rate of individual users and the entire system. Numerical finding and simulation results show that the suggested approach will be essential in power allocation.