On the Performance of Uplink NOMA Short-Packet Communication System

In this paper, we investigate a two-user uplink non-orthogonal multiple access (NOMA) short-packet communication system in flat Rayleigh fading channels, which includes a base station, a central user and a cell-edge user. To derive the average block error rate of the system model, unlike the works in the literature where the product term ($\mathbb {E}[\epsilon _{c}\epsilon _{ee}]$) is omitted or set a lower bound, we propose a novel method based on probability density function that works well in the uplink NOMA system. We theoretically derive the asymptotic expression of the product term in uplink NOMA system by using double Riemann integral approximation. It is validated that simulation results are consistent with our theoretical analysis, which demonstrate that our closed-form of average block error rate can accurately measure the performance of short-packet communications in wireless systems.