Effect of Imperfect SIC in Non-Orthogonal Multiple Access (NOMA) over Rayleigh Fading Channels

In the development of wireless communication, multiple access techniques are characteristic of different wireless system technologies. Non-Orthogonal Multiple Access (NOMA) is one of the strongest candidates for multiple access techniques in the fifth generation (5G) technology. NOMA can be used to accommodate massive connectivity and increase system throughput. Furthermore, NOMA can increase user capacity with non-orthogonal resource allocation. In NOMA, there is multiplexing in the power domain. This paper uses static power allocation with the Fix Power Allocation (FPA) approach on the transmitter. At the receiver, NOMA uses multiuser Successive Interference Cancellation (SIC) to cancel multiuser interference. In a practical scenario, errors during the SIC process can occur, resulting in imperfect SIC conditions. This paper discusses downlink NOMA performance with perfect and imperfect SIC conditions over the Rayleigh fading channel. The simulation results show that when the residual error value increases, there is a decrease in the achievable data rate, which means that the spectral efficiency decreases.