Cognitive Radio Assisted Non-Orthogonal Multiple Access: Outage Performance

In this paper, the performance of overlay cognitive radio (CR) in secondary networks as utilizing non-orthogonal multiple access (NOMA) is examined. We consider transmission quality from the relay to the far NOMA users who expect to multiple access to core network. In this system model, weak users who have weak signal and weak channel condition are focused on. Our proposal analysis contributes to improve the outage performance of far NOMA end-users. We first identify signal to noise ratio (SNR) to discover separated signal for each user, and exact expressions of outage probability is examined in assumption that receiver can delete the interference with successive interference elimination completely. Then, we determine outage and throughput performance based on the noise ratio signal (SNR) achiveved. Theoretical and simulation results prove that the both proposed models can attain the outstanding performance enhancement in secondary network for far NOMA users.