Relay Selection for NOMA-Based Hybrid Satellite-Terrestrial Relay Networks.

In this paper, we study the impact of relay selection on the performance of hybrid state-terrestrial relay networks with a non-orthogonal multiple access (NOMA) scheme. By assuming that all nodes in the system are configured with one antenna and communicate under the NOMA scheme, we first derive the accurate outage probability (OP) of each user under the decode-and-forward (DF) strategy. Then, the asymptotic OP expressions of each user under the high signal-to-noise ratio (SNR) regime are also obtained. Finally, simulations are provided to validate the theoretical results as well as the superiority of NOMA scheme compared to time division multiple access (TDMA) scheme and demonstrate the effect of key parameters on the performance on NOMA user performance.