Error Probability Analysis of Non-Orthogonal Multiple Access

In this paper, we analyze the error probability in a downlink non-orthogonal multiple access (NOMA) system for different modulation schemes. The power domain NOMA is a promising technology for the next generation wireless networks. Through successive interference cancellation (SIC) at the receiver and superposition coding (SC) at the transmitter, downlink NOMA allocates a channel (time, frequency, code, or space) to multiple users simultaneously and improves energy efficiency, spectral efficiency, and fairness. Since the error propagation of SIC is one of the challenges of the NOMA systems, the purpose of this paper is to obtain the error probability for NOMA users with different modulation schemes. In this paper, we obtain the symbol error probability expressions for a NOMA system with three users in different modulation schemes BPSK, QPSK. We also evaluate and validate all derivations through some numerical results, in addition, Monte Carlo simulation confirms the analytical expressions derived.