System-level throughput of NOMA with SIC in cellular downlink under FTP traffic model

In this paper, we investigate and compare the system-level throughput of non-orthogonal multiple access (NOMA) with a successive interference canceller (SIC) and orthogonal multiple access (OMA) in the downlink using a realistic file transfer protocol (FTP) traffic model. In the FTP traffic model, a user is assigned a finite payload to transmit when it arrives, and it leaves the system after the payload transmission is completed. This model is more realistic than the full-buffer traffic model, which is assumed in previous NOMA investigations. Furthermore, we evaluate the system-level throughput with various user scheduling criteria. Under the realistic finite-payload traffic model, a very high throughput gain in the vicinity of the cell using NOMA can be translated to improve the cell-edge user experience. Through extensive computer simulations, we clarify the behavior of NOMA with a SIC in the realistic traffic model in conjunction with various user scheduling criteria. The simulation results suggest that NOMA with a SIC is a promising multiple access scheme for systems beyond 4G.