Outage Probability Analysis of Non-Orthogonal Multiple Access in Cloud Radio Access Networks

To improve system capacity and spectral efficiency, as well as support more connections in cloud radio access networks (C-RANs), the application of non-orthogonal multiple access (NOMA), a promising technique in the physical layer, is considered in this letter. The stochastic geometry is used to obtain the outage probability of NOMA-based downlink C-RAN, in which the remote radio heads are uniformly distributed and serve two paired users simultaneously. A closed-form approximation for the outage probability is derived, and Monte Carlo simulations are provided to validate the accuracy of the theoretical analysis. Compared with conventional multiple access techniques, both the obtained analytical and simulation results demonstrate that the proposed NOMA scheme can offer better spectral efficiency and user fairness in C-RANs.