The optimum number of users using sequential Power Allocation on PD-NOMA

Abstract

Power allocation in the power domain non-orthogonal Multiple Access (PD-NOMA) influences Successive Interference Cancellation (SIC)'s ability to decode received signals. A significant power allocation value will make it easier for the SIC process to decode the received signal. However, the total power allocation for all users is a maximum of the transmit power from BS. Therefore, an algorithm is needed that divides the power allocation for each user so that PD-NOMA can work optimally. This paper proposes power allocation for PD-NOMA in the downlink direction using a sequential power allocation (SePA) algorithm. The proposed SePA algorithm considers the number of users, user distance, and SIC. We also compared SePA performance to Orthogonal Multiple Access (OMA) on the same bandwidth, the number of users, and user distance. The simulation results show the sum rate and the optimum number of users in PD-NOMA for each SePA. Each SePA constant has an optimal number of users when compared to OMA. The optimum number of users for SePA [0.9] on the 8th user, SePA [0.8] on the 12th user, and SePA [0.7] on the 16th user.